P11 nled by !ledges & Bell Ply. Ltd., Ma1ybo1ough, Viclolia Aviation Safety Digest
No. 18 June, 1959
Prepared in the Division of Air Safety Investigation Department of Civil Aviation
CONTENTS Page Head Protection is Important Engine Fire Leads to DC. 7 Crash t at Miami, Florida 4 l Oxygen Explosion 6 ~ -
6 r~ Touche ! .. & Fatal Piper Accident at Masterton, (. New Zealand 7
In-Flight Emergency 8
Stick lo Avgas .. 9
Propeller Safety 10
Do You Still Know! 15
Bristol ·vvayfarer Strikes Hill near Manchester, England . . . . 16 Two Accidents- One Cause 19 Head Protection is Important DC.3 Survives Mountain Strike in Crash helmets have proved their event of a crash because most of the Cloud, Arizona 20 life saving value for motor cyclists, aircraft structure and weight is Reluctant D ragon 23 racing motorists and military pilots. ahead of the pilot. In a crash this A fourth group they can help is structure absorbs a lot of the energy A Distorted Vision 23 agricultural pilots. of motion. On the other hand we know that the DH.82 has very little '"'hat's the Use ! . . 24 We have to face the fact that the overturn protection. We know too, nature of aerial agriculture opera that the shoulder harness attach Abandoned Take-off from New tions is such as to increase the risk ~ent is too low to give full effect Haven Airport, Connecticut 26 of a crash. We have had many ag iveness. ricultural accidents over the past Con-ect 'Veight ! 27 two or three years and it is inevit So there is a real risk - and we able that there will be more. T he have accidents analyses on file to The Inside Stor)' 28 agricultural pilot has to accept a prove it - that in a crash the pilot's greater than normal risk of a crash head can hit the ground or parts of Landing Accident, Boca Raton the aircraft like the windshield or Airport, Florida . . 30 and - if he is wise - take out in surance against it in the form of fuel tank. Learning About Fire 31 protective equipment. The only way to give him reason able protection against this danger Design Notes- Landing Gear Main Some aircraft like the DH.82 pro is by the wearing of a helmet. A Wheel Assembly . . 32 vide a built-in protection in the good helmet will protect him well.
1 The shell protects against pene there is always the chance of being a good Australian model will be on feet in the aircraft and the weather that he forgot about the presence wearing a protective helmet and his tration and abrasion, the suspension knocked out. If the aircraft burns, the market at a reasonable price. conditions at the time for this type of the obstructing power line ahead harness was tight on impact. Con and lining absorbs a good deal of the unconsciousness for half a minute of work can only be described as until it was too late. It is probable sidering the force of the impact and shock. or even less may mean the pilot's When you wear a crash helmet on your next agricultural job, in ideal, there being no wind, smooth that his attention was concentrated the deep score on his "hard hat" death, even though he be practically cool air and good visibility. The on the more immediate problems of his conclusions cannot be disputed. In planes which have good over unhurt by the crash itself. telligent people won't think you are turn protection, the pilot's head can a man from Mars. They will know nature and position of the obstruc the spray run but there were no un This pilot was a confi rmed "hard often be banged against the cabin that you are a pilot who has his tion was clearly established by the usual features of this run which hat" wearer prior to ' the accident roof or sides. Here, there is much Good imported crash helmets are head well screwed on - and who pilot before work commenced and might have engaged the pilot's at and, needless to say, he now has a less risk of fatal head injmy, but available now. We hope shortly that wants to keep it that way. he had devised a spraying pattern tention to a greater degree than any profound conviction of its value in which recognised its existence. It other run. In operating circum agricultural flying. would have been possible to fly be stances such as these there is usually neath the power line which the no means by which the pilot's con In contrast to this outlook we sciousness of the danger ahead can have on record a recent accident aircraft struck but this pilot nor Now Read On ••• be awakened and it is difficult to en in which an agricultura l pilot suc mally avoids such a practice since it visage any means by which this cumbed to severe hea d in juries considerably increases the risk of could be reliably or economically despite the fact that he owned a Late in the afternoon on l lth and realised that he was close to record shows him to be one of the flying into the crop. The tobacco achieved. Even in the most care " hard hat", had it with him on February, 1959, a DH.82 was en it, he applied full power and most experienced pilots engaged in being sprayed on this occasion was ful pilot the dangers of human falli the operating site, but for some gaged in spraying a tobacco crop pulled the aircraft up sharply. At the aerial agriculture section of the unknown rea son did not w ear it. in the Ovens Valley, Northern this point he could not see the wires industry. He had flown only three at least six feet high. In the split bility arc ever-present and an ac Victoria. Short ly after operations ceptance of this fact will go part of because of the background of dark hours in the preceding 24 hours, he second decision made when the We predict that in the not too were commenced the aircraft flew forest on a nearby mountainside. had 8-9 hours sleep during the pre the way towards preventing this dangerous proximity to the line was distant future the hard-headed into power lines, caught fire in the vious night and a further 3~-4 hours appreciated the pilot il'lstincti,·ely type of accident. air and immediately crashed out The aircraft made contact with sleep during the afternoon immedi obstinates will be outnumbered by of control into the open ground the wires across the starboard wings, ately preceding the accident. It is attempted to follow his normal and \'\le are not only concerned with the hard-hatted converts and we below. The aircraft burned out but nose and undercarriage. Only one quite apparent that physical fatigue previous practices. preventing accidents but also with strongly suggest that you, as an wire broke initially and the aircraft the pilot escaped with minor was not a contributory factor in this m m1m1smg m.i u1y. The pilot in agricultural pilot, leave the ranks injuries. carried the other two at least 60 accident. In his testimony, the pilot ha~ feet into the air where the aircraft made it patently clear that this ac ,·oh-ed in this accident attributes of the former right now so that you, On arrival over the crop to be turned over and dived vertically into There is no suggestion of any de- cident arose solely from the fact his survival to the fact that he was too, might survive. sprayed the pilot completed two cir the ground below. Fire broke out cuits in order to locate the obstruc in the aircraft as a result of electrical tions. He established the position of arcing even before it struck the two power lines, one crossing the ground. At the top of the "zoom" northern edge of the field and the after contact with the wires the -.:, · other running down the eastern edge pilot pulled the top straps of h is ' to a pump on the river. Taking into harness very tight and crossed his consideration other factors such as arms over his face. The ground the adjacent terrain and trees, the impact was heavy and the "hard pilot decided to carry out the spray hat" which the pilot was wearing ing runs north and south, but before struck some unknown projection in commencing in this direction, he the cockpit very heavily. He was completed two end runs parallel only momentarily stunned, however. with the line a t the northern end in and this condition quickly disappear order to ensure complete spray cov ed as he came into contact with erage. These end runs were carried " live" metal components of the air out without incident and the pilot craft and received severe electrical then flew to the southern end of shocks. The aircraft became en the field and carried out the first of veloped in flames but the pilot was the working spray runs towards the able to release his harness and es northern power line. This consisted cape. Although he was only wearing of three wires suspended some 30 a T-shirt and shorts the pilot es feet above ground level. At the end caped with scve1·e bruising and two of the first run he lifted the air cracked ribs; the sleeve of his T craft over the wires and then turned ~h i rt was scorched by electrical arc and descended over them for the mg. second run. During the third run which was again towards the power The pilot's flying experience line the pilot momentarily forgot amounled to some 4,400 hours, of about the obstruction but, when he which 3.700 hours have been gained suddenly remembered its existence on low level agricultural work. His
2 thal jusL about the time the flaps zone of No. 3 engine that the air of 23 degrees. It is obvious that the Fire Leads to DC7 Crash at Miami~ Flon'da reached full up position he felt a craft structure was not affected. rapid descent occurred during this Engine rhud and immediately noticed a Actually, only blistering of the paint Lurn of 113 degrees. (Summary based on the report of the Civil Aeronautics Board, U.S.A.) flash of light. H e turned to his was evident to the rear of No. 3 The captain was under consider right, looked out his window and nacelle, which substantiates the able stress during the emergency saw fire. He said the fire seemed small area and duration of the fire. At 0006 on 25th March, 1958, a DC.7C on Flight 971 crashed approximately three miles "":'est-north and despite his 20,000 hours of to him to disappear so he looked Unfortunately, the crew could not west of the Miami, Florida, International Airport. The accident occurred soon after take-off at night under Hight experience it is, probable that back to the engine instruments to be certain that the fire was under visual conditions. There were 24 persons aboard, comprising nineteen passeng.ers an~ ~flight crew ~f five . this situation brought out his former determine if they indicated an en complete control. R egardless of the difficulties in maintaining altitude Nine of the passengers were killed and the captain and first. officer were seriously m1ured. The aircraft, gine failure. At that time, he said, effectiveness of the fire control pro with an engine on fire in flight, was practically destroyed by impact and ground fire. and control during turns. T he air he recalls the captain saying, cedure, an immediate retmn to the craft was not heavily loaded and "Feather 3". H e also remembered airport was proper. there should have been little diffi THE FLIGHT mately li inches above the cylinder trailer stated, "Checking your posi the captain telling him to call the T he captain's order to the first culty in retmning to the airport with mounting flange on the thrust side. tion with the glasses, it seems to be tower and report that 971 was re The aircraft departed from Miami officer to advise the tower that they Lhree normal operating engines and The cylinder flange attaching cap leaving a very faint trail". The turning. H e said he picked up the terminal at 2356, taxied to Runway were returning to the airport pre the fourth, an inboard engine, screws were intact. The cylinder flight acknowledged these messages microphone but did not recall mak 27R where engine run-up was made, cludes any thought of landing al a feathered. I n fact, this aircraft, load wall contained evidence of scuffing and landed without incident. When ing any transmission. after which a normal take-off was place other than the airport. The ed as it was, and under the existing and ladder cracking was in evidence. the crew reported in to company The captain had been a captain accomplished. Shortly after take-off The No. 11 connecting rod had firsl officer was only able to start a tmospheric conditions, should have operations no mention was made of for Braniff for over 18 years. H is a climbing right turn was start~d. failed approximately six inches out his radio transmission ("Braniff been capable of climbing with one the smoking engine advisory from total fl ying time was over 20,000 During the tum the No. 3 engine board of its knuckle pin. All 971") before the accident occurred. propeller feathered at a rate of the tower. The captain reported the hours. According to company records malfunctioned and a fire developed knuckle pins, including No. 11, were about 470 f.p.m. T he rapid and aircraft ready for Flight 971. He 241 of this had been in DC. 7s and Well qualified witnesses estimaled in that area. The aircraft, still in free from indications of malopera premalure descent indicates that the previously had signed the flight log 11 7 .55 hours were acquired in the the highest altitude of the air a right turn, started to lose altitude tion at the master rod end. Cylinder captain displayed poor piloting tech which indicated no aircraft discrep 90 days prior to the accident. The craft during the flight to be approxi rapidly. While travelling in a north wall scuffing was also found on No. ancies. The ferry flight crew were nique by allowing his attention to northeasterly direction it struck the remaining 123 how·s were accumu mately 800 feet. This estimate is be diverted from his fligh t instru 2 cylinder of the No. 3 engine. passengers on Flight 971 of 25th lated during the previous nine consistent with the known perfor ground in an open marsh contain March and were fatally injured. ments by the engine fire, objects on ing scattered trees and underbrush. All major portions of the four months. · T he captain had approxi mance of the aircraft under the con the ground, and the emergency pro propelle~· assemblies were recovered. Tower personnel stated that the mately 200 hours of scheduled op ditions of power and configuration cedures being taken by other crew Most blades were shattered by con aircraft made a climbing right turn eration in DC. 7 equipment. He had employed until the moment of members. It INVESTIGATION tact with the ground. The No. 3 shortly after take-off. When it had also accumulated several Lhousand engine failure. is evident, there Visibil iLy in the airport area was hours in other four-engine Ly pe air fore, that the aircraft descended Ground impact marks revealed propeller was feathered. The pro reached an altitude of approxi reported as eight miles by the tower. peller dome settimgs and shim plate mately 900 feet a bright orange glov.• craft. rapidly from this altitude. T es ti Since the scene of the accident was that the aircraft struck the ground mony of the fl ight engineer and with approximately 25 degrees of impact marks on Nos. 1, 2 and 4 was observed on the right side of A review of company pilot checks approximately three m iles from the were examined and found to be the aircraft. The aircraft was fur of tl1e captain for a period of almost statements of passengers showed con airport, patches of ground fog at right bank while descending at an clusively that there was a sudden angle of approximately five degrees. positioned for a blade angle ?f a~ ther observed to enter a descent, 10 years disclosed that he had been the accident area would not have proximately 43 degrees, which is contacting the ground at 0006. Im given more than the minin1Um re descent and an abrupt change in interfered with the return of the The right wing tip made the first aircraft attitude. contact and the aircraft broke up 151 degrees above the low pitch mediately prior to impact, tower quired number of such checks. In flight. immediately thereafter when the in stop and indicative that consider personnel heard a call "Braniff 971". several instances it was necessary The captain took positive action I t is possible that, had the crew board right wing structure, the able power was being developed. No other messages were received for him .to be rechecked by company to break the climb attitude :md of the fen)' flight entered the tower Numbers 1, 2, 3 and 4 propeller from the flight following take-off. engines, and the fuselage struck the check pilots because of his initial established a shallow descent to report of ~moke trailing from No. 3 governors were also recovered. failure to receive passing grades. wards the airport. Nevertheless, the soft surface. The first and second officers both engine in the flight log, it would Some instrument flight checks re Board must conclude that he did not stated that pre-flight preparatiom have led to an inspection which All four engines, found approxi T he flight instrument panels were flected inabil ity to maintain altitude use proper Lechnique and allowed were routine and that no discrep would most likely have detected the mately 2,000 feet from the point of recovered from the wreckage. Im the aircraft to descend to the ancies were noted during the pre during turns; however, he did pass defective cylinder. I t is difficult to first impact, were removed from the pact forces had caused some exter rechecks and remained on fl)1in()' ground. His injuries blocked all nal damage to the panels and to take-off engine check. The first ! t> understand why this was not entered swamp and examined by the Power status. recollection of the flight despite his as it would h ave required an inspec plant Group. A piston and a cy certain of the instruments. All officer stated that the captain made sincere desire to testify regarding the take-off from the left seat. H e tion at Miami. Because of the fatal linder were found 1,350 feet and instruments were found to be oper ANALYSIS his actions during the emergency. further stated that take-off power 111 J Lu-ies to the crew of the ferry 1 550 feet, respectively, along the able. During the investigation of the T he first officer, also seriously in was applied and that he had adjust flight, the Board was unable to flight path. It was positively de accident the possibility was ad jured, was able to recall some of his The aircraft had been engaged ed the throttles to maintain a boost determine the reason for this in termined that these were the No. 11 vanced that the captain intended to own actions during the flight. The on a ferry flight and arrived from of 59f inches of manifold pressure. cident not being written up in the cylinder and piston of the No.. 3 Dallas at 1915 hours on 24th March, make an immediate off-airport land second officer, although injured, did aircraft log. engine. Investigation further ~is ing because of damage to the air not lose consciousness in the accident 45 minutes after official sunset. As The first officer said that the PROBABLE CAUSE closed that the other three engines frame by the fire. and vvas able to describe events of the flight approached for landing the take-off was extremely smooth and The Board determined that the were operating normally and de':'el airport tower controller asked the that the aircraft was off the ground The Hoard was aware that fire in the flight in more detail and better oping considerable power at im probable cause of this accident was fl ight "904 your No. 3 engine smok shortly after reaching V~. The fl ight is extremely serious and unless sequence. pact. the failure of the captain to main ing a little bit,'' to which the flight captain ordered the landmg gear quickly checked can affect the in Soon after passing the boundary tain altitude during an emergency Inspection of the No. 11 cylinder replied "Well I hope not". retracted, which the second officer tegrity of the structure. There is no of the airport on a heading of 270 return to the airport due to his of the No. 3 engine revealed that it accomplished. T he flaps were then doubt that a fire existed : however. degrees a right turn was started and undue preoccupation with an engine had failed from fatigue a.pproxi- Another message from the con- raised. The first officer further stated it was so confined within the No. 1 the ground impact was on a heading fire following take-off.
4 5 OXYGEN EXPLOSION Fatal Piper Accident at Masterton, NZ (Summary based on the re/1ortl of the Air Department, N ew Zealand)
A DC.4 at Darwin was being readied for the engines of the aircraft are operating. A Piper PA.1 SA engaged in top dressing operations at Wangaehu, Masterton, stalled and spun off fl ight. Refuelling and pre-flight inspections were a steep climbing turn at low altitude and burst into flames on impact. The aircraft was destroyed and in progress as an engineer positioned the oxy Ground power supplies, motorised ground the pilot died from injuries received in the crash. gen recharging tro lley adjacent to the mid servicing equipment and a ll likely ignition section of the fuselage preparatory i·o replenish sources shall be kept well clear (at least 50 THE FLIGHT INVESTIGATION wall of the hopper, which could re ing the aircraft's oxygen system . The trolley feet) of oxygen system recharging equipment sult in up to a 2 inch rearward T he accident occurred on 15th The unique film record re\·ealcd carried four oxygen bottles and was fitted with during recharging operations unless they are movement of the C. of G. If this February, 1958. At 0900 hours the accurately and conclusi,·ely the a control panel, mounted on steel brackets, flashproofed. had occurred Lhe C. of G., which farmers arrived on the strip with a sequence of events which culrninalecl comprising a manifold with four inlet points, was already 0.9 inch beyond the movie camera and asked Lhe pilot in the accident. an outlet with a control valve a nd a pressure Oxygen system recharging equipment shall be aft limit, a t take-off would have to make a dressing run parallel to gauge. inspected regularly for condition and before IL was clearly evident from the been at 26.9 inches aft, i.e., 2.9 use for freedom from foreign matter, parti the strip in order that a film might nose-up attitude of the aircraft dur inches beyond the afl limit. During The engineer connected the outlet to the air cularly grease and oil. be Laken. The take-ofT was normal ing the sowing run thal an inade the sowing run prior Lo the accident craft's recharging point and opened the control and Lhe aircraft was obsen·cd to quate rcsen·c of airspeed or power the nose of the aircraft was held valve. He then proceeded to open the valve on Lum on to a reciprocal heading and Recharging equipment shall be clearly plac \\'as a\·ail ablc to terminate the run well up and the discharge from the li ne up with the slrip. The sequence a bottle. As he opened this valve, there was an arded with instructions for its use. in a sleep climbing tmn. H aving hopper was light and of short clura of events from then until the air explosion accompa nied by flame. Although committed the aircraft to a situa Lion. With the attitude of the air suffering shock and burns to hi s right hand and Flexible hoses forming part of oxygen system craft struck Lhe ground was depicted tion which resulted in an incipient craft it is probable that the malerial on the film. arm, the engineer promptly closed the valve recharging equipment shall be maintained in spin the pilot took incorrect recovery came from the front of the hopper and the flame ceased. accordance with A .N.O. Section 108.2.16. The slope of the ground made it action and at no time during Lhe and that the mixture a t the rear of Subsequent inspection revealed that the necessary for the pilot to climb event was correct recovery action the hopper was not dislodged. T his Only flexible hoses shall be used for connect brackets carrying the control pane l had separ throughout the dressing run. The taken. From examination of the would accentuate any C. of G. aft ing oxygen recharging equipment to aircraft. tall of m ateria l from the aircraft film record it appeared li kely that condition. Moreover, there is a pos ated from the troll ey at the welded joints, the Aluminium alloy shall not be used for plumb was light and of short cl uralion and if instant and resolute correct re sibility that in a steep climbing turn hoses from the cylinders had pulled off the ing of high pressure oxygen systems recharg immediately il had ceased, the air co\'ery action had been taken at the mixture may fall to the rear of manifold connections, the outlet pipe had frac ing equipment. tured a t the manifold and the hose to the a ir craft star ted a climbing Lum to the the onset of the stall, the steep the hopper particularly if such a craft had punctured approximately four inches right which progressed until a nose nose-clown angle of impact, with Lurn is unbalanced. Brass plushing fittings shall not be used in consequent fatal results, could have from the va Ive. There were signs of severe up attitude of 55 degrees was reach The solution to the problem is oxygen recharging equipment unless they ed at an angle of bank of 50 degrees, been avoided. burning at the manifold inlet connection and have been tested for leakage due to porosity the avoidance of steep climbs or at the out let pipe as well as burning a nd the highest point of the turn being The pilot obviously knew the cor semi-stalled turns in a loaded air at two and one half times maximum working almosl immediately above the load blistering around the necks of the bottles. pressure of system . rect spin recovery action and yet, craft For as long as some pilots ing area. At the top of Lhe right when faced with this emergency, his The cause of the explosion has not been take these unnecessary risks there hand climbing Lurn at a h eight of immediate reaction was to apply determined but it probably occurred in one of High pressure recharging equipment (over will be some unnecessary accidents. belween 150 and 200 feet the air full opposite aileron and partial the fo llow ing ways. 500 p .s.i.) shall not be used for recharging craft flicked suddenly into a lefl. flap. At no time was opposite rudder The pilot held a commercial p ilot low pressure systems (under 500 p.s.i.) unless licence endorsed for Piper PA18A. (al Either the outl et pipe connection fractured it incorporates a pressure reducing valve. hand ·spin. The pilol immediately applied, nor was the control column or the hose to the a ircraft fa iled and applied fu 11 opposite aileron, one moved suffi ciently forward Lo un H e had flown a total of 867 hours the other damage was caused by the third Hap, held the stick partially stall the wings. T he action taken in of which 260 hours were on the Recharging equipment shall be fitted with an Piper PA l8A. He had been involved resultant reaction. Under j·hese circum oxygen purifier and filter to separate moisture back and the rudder in the central the application of opposite aileron stances the flame could have been caused position. After Lhree quarters of a would aggravate the autorotation in two p revious topdressing acci and coarse particles of any kind." dents, the fi rst in August, 1956, by ·rhe sponta neous ignition of some Lurn, when the nose was pointing by introducing a m easure of aileron when the aircraft failed to become combustible material at the point of the verlically downw~a rds, ailerons were drag. Any effecli,·e contribution to airborne and struck a concealed failure, when subjected to oxygen unde r TOUCHE! centralizetl and the stick moved hard wards recm·ery that might have re pressure. back, the conlrols remaining in this sulted from the application of flap post, and the second in D ecember, Returning from a fl ight, the pilot entered on position wiLh the rudder still central 1957, while attempting to take-off {h) Spontaneous combustion of some fine ly was more than offset by the delay the squawk sheet: "Something loose in the tail". until the aircraft s~ ruck Lhe ground, diagonall y across the strip in a high divided combustible materials in the lines i ntrn~iucecl in selecting al a time T he next morning when our pilot friend was having completed lt turns of a when every instant was of \·ital gusting wind, the a ircraft over or manifold w hen the oxygen was ad turned. handed the squawk sheet for initialling his fully developed spin. importance. mitted at a high pressure. acceptance of th!' work done, he found th!' fol lowing reassuring note: "Something loos!' in ta il The aircraft caught fire on im The mild stalling characteristics CAUSE Immediately after this incident the following tightened". pact and in spite of severe heat from of the PA 18A in the unladen con a concentralion of flame in the en dition is in marked contrast to the It was considered that the air restrictions and requirements in respect of the Brevity is fin e, but . . . use and maintenance of oxygen system re gine bay, two farmers and a loader extremely rapid development of craft stalled and spun into the charging equipment were issued - EXPLICITS ELICIT MORE EFFICIENT driver succeeded in extricating the Lhe spin observed in this aircraft. ground through the failure of Lhe FIX-IT. pilot from the wreckage. However, Investigation into the loading oper pilot lo maintain airspeed during a "Installed oxygen systems in aircraft shall (Courtesy of Flight Safety Foundation Inc.) he had been faLally injured at im ation disclosed the possibility of the steep clim bing turn at a low alti not be recharged during refuelling or while pact. c1ixture piling on the rear sloping tude.
6 ' 7 inches of manifold pressure and begin, "For the want of a lock 2200 r.p.m. on the three good en wire ... " gines, zero flaps. Airspeed increased In-Flight Emergency Removal of the No. 2 engine pro to 170 m.p.h. and flight was con tinued to Hilo. peller dome cap revealed the fly (Rej1roduced from "The lvlats Flyer") weight assembly lying loose with The rescue fleet that had been the retaining nut loc1> wire missing. Relying on his professional knowledge, the experience of Major Samuel Tyson (Aviation Safety Digest, set in motion at the onset of the Loosening of the flyweight assembly No. 13, March 1958) and with the help of what he called "the pilot upstairs", Major William P. Armstrong emergency wasn't needed. resulted in vibration of the oil trans and crew joined the ranks of Pacific "runaway propeller specialists" and turned in a Good Show by nurs fer tube with subsequent failure of ing a PACO Stratocruiser 700 miles to Hilo, Hawaii, alternately on two and three engines. There is an old adage that starts, the tube flange. T his resulted in "For the want of a nail a shoe was an aft movement of the oil transfer lost ... " and goes on and on until tube, allowing the inboard and out This Tokyo turn-around, which descent, with propeller oil replen The aircraft commander decided a kingdom has been lost. Investi had originated at Travis, had been ished during each attempt. to freeze the engine. Freezing pro board oil to mix. Lack of counter gation of this incident disclosed that, acting pressure in the dome allowed routine. (A slight overspeed on No. No luck. cedures were discussed with the en 2 had occurred on the last take-off, gineer and it was decided to reduce thanks to this crew's ability to suc the slipstream to move the blades but it came back immediately to The crew reversed course and the r.p.m. as m uch as possible by cessfully handle an inflight emer to low pitch ( 18°) resulting in an limits when toggled.) Major Arm headed for Hilo, the nearest suit intermittent freezing in order to re gency, a modern day paraphase overspeed and complete lack of con able landing field. strong, Commander of the 75th Air duce the possibility of losing the doesn't apply. If it had it would trol. Transport Squadron, arid Captain Major Armstrong contacted Hick prop when the engine froze. The Ted H. Mahoney, both aircraft am via HF, reported the emergency, engineer reported that he had been commanders, had taken turns at the and requested recording services to on a number of other flights where How did Major Armstrong feel after the C-97 settled te s•fety at Hilo? make a running commentary of the controls. They were on the last leg engines had to be frozen; in each "You get awfully tired in a hurry", he said. the long over-water run from emergency and actions being taken case this procedure was followed Hickam to Travis. They had been to overcome it. successfully. airborne three hours and twenty At 500 feet the plane was levelled minutes. Altitude was 9,000. Every off. Windmilling speed had dropped Because of the possibility of the No. 2 prop separating from the thing was serene. The seven-man to approximately 1800 r.p.m., but aircraft, No. 1 was feathered and crew, quietly and efficiently, worked drag was terrific. Due to the high at their respective duties. The mon power settings required on the three the prop turned to an "X" position Stick to A VGAS otony of the long flight was no good engines and the possibility of in an attempt to reduce the possi novelty to them. The gentle vibra No. 2 propeller coming off, jettison bility of damage should No. 2 In the highly competitive automobile fuel tha n the minimum specified for your a ircraft tions that coursed through the trans ing of cargo was decided upon. come off. business it is essential for the various distribu engine w ill q uickly lead to engine failure as port, the smooth, slightly undulating Hatches were opened and 9,000 At this time the No. 2 engine tors to keep the name of their product before the result of detonation. hum of tl1c four powerful engines pounds of general cargo were r.p.m. was 1800 and oil pressure 55 the public by intensive a dvertising. and the multitude of gauges on the thrown overboard. p.s.i. T he oil shutoff valve was clos This advertising materia l is prepared by some VAPOUR PRESSURE flight deck told them everything was Experimentation disclosed that an ed until the oil p ressure dropped to of the best exponents of the art and the per The vapour pressure of automobile fuel is normal. airspeed of 145 m.p.h. and a flap 5 p.s.i., then the oil shutoff valve suasive powers of such advertising may tend considerably higher than that of aviation fuel. setting of 35 degrees seemed to was opened. Dw·ing this seq uence Suddenly, and with no warning to influence even aviation people to whom it In consequence, there is a very real danger that work out best. This configuration the r.p.m. slowed to 1300. When whatsoever, number two propeller is not d irected. the use of automobile fuel in aircraft will lead ran away. Almost instantaneously provided the best balance of safe the r. p. 1~. started to rise the oil Now don't let all this advertisi ng tempt you to vapour locking of the fuel system under high it whirled up to 4,000 r.p.m. A control airspeed, drag and wind shutoff valve was again closed. Oil into trying automobile f uel in your aircraft. It a mbient temperature conditions a nd at altitude. rising, unforgettable, metallic scream milling r.p.m. No. 2 had slowed to pressure had risen to 40 p.s.i. and certainly won't give you any improvement over permeated the airplane. between 1600 and 1800 r.p.m. the shutoff valve was left in the the correct grade of aviation fuel-on the con· TETRA ETHYL LEAD Maybe they could make it. closed position until the pressure Captain Mahoney reacted immed dropped to 5 pounds again. This trary, its use~ can be positive ly dangerous in iately. He pulled the throttle back Replenishing of oil to No. 2 was some conditions. The lead content of automobile fuel (both time r.p.m. dropped to 900. The standard and premium g rades) is relative ly high on No. 2 and punched the red continued periodically to assure sequence was repeated with r.p.m. button with " 2" on it. lubrication. The flight was contin In brief, here are some points where auto and may exceed 2 mis. per gallon in some cases. dropping to 500, then, slowly and mobile fuel and aviation fuel differ significantly: As many light a ircraft engines are designed to ued under these conditions until it smoothly, to zero. No. 2 refused to feather. became apparent the aircraft would use a low lead fuel, the use of automobile fuel Power was pulled off all the not reach Hilo with the engine During the freezing sequence alti KNOCK RA TING may result in spa rk p lug fouling and could also engines, 55 per cent flaps were tude had slo..y ly dropped until the lead to a rapid deterioration of the condition windmilling since oi.l consumption Aviation fuels are graded in terms of their lowered, and the airspeed slowed to had increased to a point where all aircraft was flying at an estimated of the combustion chamber. 150 miles per hour. Holding air 65 to 75 feet over the waves. The knock rating and every precaution is taken to the oil available for replenishing ensure that the fuel supplied is true to grade. Remember, aviation fuel is produced against speed, a descent was started into would be consumed before the air entire crew was braced in ditching denser air near the surface in an position. On the other hand the knock ratings of motor exacting specifications and handled under a craft reached land. Indications from strict quality control system and the end result effort to further reduce the speed the cockpit were that No. 2 had As soon as No. 2 froze, No. 1 fuels are not normally disclosed and all claims of the uncontrollable propeller. ore purely qualitative. is a uniform, high quality p roduct which w ill suffered external damage. was unfeathered and a climb init produce the optimum performance from your Repeated attempts were made to No. 2 was smeared with oil (Oil iated to 1,000 feet. A cruise configu The use of a fue l w ith a knock rating lower engine. feather the propeller during the was coming out the breather.) ration was set up using 35 to 39 9 8 I service. \Vith this background it can blade resoh-e to give a thrust in the r.p.m. dictated by the constant be said that the possibility of major direction of Right, and a torque specd unit. The drag will then be strnctural failure in normal service force opposing and absorbing the ,·cry large, as shown by the pro can be discounted. The designer power delivered by the engine. In portions of the vector diagram in must therefore concern himself with (b) the blade is shown at a lower ( b ) . If the engine motoring power the provision of appropriate safe pitch than that appropriate to the is low (as in the case of a free I guards to ensure that malfunction normal flight condition of (a), so turbine engine) or, alternatively, in p ing of the propeller, engine or con that the angle of incidence of the the case of a reduction-gear failure rop e l l e r trol system cannot result in loads blade clement is now negative. The which leaves the propeller shaft free being applied: to the propeller which lift and drag forces on the element from its coupling to the engine, a ... are outside the accepted design now resolve to give a net drag in small negative angle of incidence limit, or result in excessive loads be the direction of flight, with a tor suffices to provide the windmilling ing transmitted to the engine or que force tending to turn the engine torque necessary to maintain the a ircraft. in its normal direction of rotation. governed r.p.m. scheduled by the ~s a r.e t y T he propeller is now absorbing constant-speed unit. T his case is Characteristics of Windmilling power from the airstream to assist illustrated in Fig. 1 ( c) , from which Propeller in rotating the engine, instead of it may be seen that the drag will lt has already been stated that absorbing the power from the en then be relatively small. If in such • the principal dangers arising from gi ne to produce thrust. a case, however, the propeller is no the malfunction of a variable-pitch The exact shape of the vector longer under the control of the • propeller are associated with wind diagram in a windmilling condition constant-speed unit, owing to some milling. T his is explained in Fig. 1, will depend upon the resistance of failure of that component or its which shows vector diagrams for a the failed engine to rotation. This drive, then in the absence of suit typical blade element (a ) in nor resistance is known as the motoring able safety features the blades will mal operation, and (b) , ( c) and power of the engine. If it is high reduce pitch under the action of the ( d ) in a winctmilling condition after as in the case of a large two-spool centrifugal and aerodynamic forces engine failure. In case (a) tl1e blade turboprop after a failure of the fuel imposed upon them, until this is shown to be operating at a small supply has occurred, and if the pro motion is arrested by the presence positive angle of incidence to the peller is still under the control of of a mechanical stop in the pitch resu ltant di rection of airstream upon the constant-speed unit, the blades change mechanism. it. The lift and drag forces on the will be driven to take up a large T his reduction in blade pitch a t negative angle of incidence in order first creates a higher negative angle to provide the windmilling torque of incidence than that shown in Fig. necessary to maintain the governed 1 ( c), thus causing the windmilling "'Q .,.r; propeller to extract surplus power Q"' from the incident airstream and to .,.,.,," FLIGHT accelerate itself to a much higher ~.... SPEED r.p.m. The system will eventually ~L ADE ,,_,. Fig. 7. Blade-vector dia LIFT THRUST 1c,">~v grams far a propeller in stabilize in the manner shown in JP>1r 12 13 which permits a continuous fi nc the overspecd governor, which sig One means by which protection is overspeed governor mounted on the feed line in the engine shaft. When l pitch signal (e.g., seizure of the nals the engagement of the mechan provided against loss of oil pressure propeller (in order that it may dir the engine th rottle lever is advanced "'ri ~ rnh-e in the maximum fine-pitch ical pitch lock. T he lock is engaged l Iii is the hydraulic lock, which ensures ectly sense propeller r.p.m., and not above the cruise position high pres :::> :::> delivery position ) is potentially the t sec. later. With the blades locked l a: that when pressure is lost the oil engine r.p.m. in the event of a fail sure oil is fed to the servo-piston ..;;( ...::c most dangerous type of failm e at this angle, 18 deg. finer than the present in the fine-pitch side of the m e in the transmission between the ,·ia this third oil line, thus bringing ...l which can occur. initial operating angle, the engine 0 FUEL GOV ERNOR INOPERATIVE pitch-changing piston is trapped, propeller a nd the engine) . When into operation the second governor "'..J cannot accelerate up to an r.p.m . -!- _ ./_ __ "z -lOOO The combination of such a fail thus arresting any further movement the propeller r.p.m. exceed the set spring and raising the governor .. 110 greater than 10 p er cent above in the fine-pitch direction. This lock ting of the overspeed governor, the datu111. This feature also provides a l'l ure with an unrelated contributory normal maximum, with an associ ..J.. -zooo failure of the automatic drag-limit has been in use on de H avilland governor valve releases the oil pres method of checking the functioning "' a ted drag of 5,900 lb. propellers exclusively for several sure holding the lock out of engage of the pitch lock, for by providing a: ing system may be claimed to be an "'..J 100 years, and has proved its worth on ment, thus allowing it to engage a manual override it is possible to ..J -l.000 extremely remote possibility, but is The design of the safety features "'~ described in this article has been a number of occasions. Due partly under the action of the peripheral select the lower overspced governor er MECHANICAL PITCH nevertheless considered here in 0. -4.000 to the difficulty of checking the springs. setting at a time when the propeller LOCK SI GNALLED order to illustrate that the mechan- founded on a comprehensive series bo' ,0 ical pitch lock still prevents the of a nalyses of the above type, cover functioning of a hydraulic mechan I t is clearly essential that the over r.p.m. exceeds this se tting, thus ism of this kind, however, the T yne causing the lock to be engaged. In occurrence of catastrophic drag or ing various combinations of single speed governor shall transmit its sig ~If THRUST r.p.m., although permitting a higher and double failures of the power propeller also incorporates a mech nal and engage the mechanical lock dication to the pilot of the correct anical pitch lock, which on engage functioning of the lock is then p ro order of drag than the very low plant a nd its control system. T he before the blades have moved to a values provided by the automatic inclusion of these features in the ment mechanically precludes any vided by the fall in r.p.m. of the BLADE ANGLE low pitch, and it is therefore desir drag-lirn.i ting system. In Fig. 5 the latest De H avilland propellers as further movement of the blades to able that the operating setting of Jocked-pitch propeller occurring 70 6-0 failure is assumed to occur at a true sures complete protection against wards fine pitch. the governor shall be only slightly when the engine power is reduced 1·0 2-0 30 4•0 by the use of the fuel-flow trim T IME (SECONDS) airspeed of 3 70 knots at sea level the particular dangers associated T his lock consists of two rings of above the normal r.p.m. in use at lever. The action of all these fea with the throttle in the flight-idle ratchet teeth mating in steps of ap the time. This condition is met on Fig. 5. Behaviour of a propeller following failures with those failures of high-speed tures is summarised in diagrammatic in c.s.u. ond drag-limiting system. position (e.g., at the end of a long, proximately 2! deg. of blade angle, the Tyne propeller by providing two fast descent) . After 1 sec. the propeller-driving engines affecting da tum settings on the overspeed form in Fig. 4. ! one attached lo the rotating p itch r.p.m. ha\·e risen to the setting of the propeller system. change cam and the other to the governor, the choice of setting being Fig. 5 shows the behaviour of the hub. The rotating ra tchet is free to coupled with the engine power lever propeller in terms of thrust, blade to ensure that the setting in use at ( This article written b )1 a DeH auilland Propellers Engineer, move axially on splines in the cam angle, and r.p.m. following the extracted from " Flight" 25th A pril, 1958) and is mechanically engaged by any given time is that which is primary failure of the control valve multiple springs, being h eld out of nearest to the normal operating in the constant-speed unit, with a engagement by the normal operating r.p.m. a t that time. contributory failure of the a utomatic pressure in the pitch-change mech T he change in datum from the drag-limiting system. Detailed stud anism. The lock is brought into en low to the high setting of the o\·cr ies of the effect of various single a nd gagement either directly by loss of speed governor is effected by bring double fail m e causes involving the oil pressure or th rough a signal in ing into operation a second gover engine and propeller have shown dicating the existence of a n over nor spring by means of a sen-o that a failure of the constant-speed speecl . This signal is derived from an piston connected to a separate oil unit control valve in a manner Do You Still Know I 1. The procedures to be applied when two-w ay communication with Air Traffic Control cannot be maintained. Fig. 4 (right). Schematic diagram illu strating TO FINE TO COAR Sf 2. That the word AIREP shall precede all position reports that will include operaticm ol mechanical pitch lack. PITCH PITCH in-flight weather data. (Below ) Part of the mechanical pitch lock assembly for the Tyne propeller, showing J_ That flight by public transport aircraft will not be approved at cruis ratchet teeth which are forced into engage ing levels below control area except on certain listed air routes. ment by multiple springs following loss of oil pressure or overspeeding. 4. That when commencing a change in level you should report leaving the original level. HYORO MEC HANICAL SIGNAL FROM ENGI NE TOAOUEMET ER COARSENS PITC H TO LIMI T 5. The dimensional units approved for use in Australia. DRAG AFTER ENGINE FAILURE MEOiANICAL PITCH LO CK 6. The various S.A.R. phases that are introduced if you fail to report ENGAGES IF :- your position. \ L (•)Oil PRESSURE IS LOST. OR ~---r-1@-r- (b) OVER SPEEO IS REGISTEREO FINE PITCH STOP POSITIVB.'I' 3 - LIM IT S MINIMUM PITCH OBTAINABLE IN FLICHT 15 THE INVESTIGATION pany check captain. He had flown aircraft. On his three previous Bristol Wayfarer Strikes Hill near Manchester, England this route several times previously flights with this captain he had The Crew at heights above 2,500 feet and on proved himself fully competent. (Summary based on th ~ report of the.. Ministry of Transport and The captain had flown over one occasion at 1,500 feet. Several times before he had flown Civil Aviation, United Kingdom ) 6,000 hours and 625 hours of this from Ronaldsway to Manchester had been on Bristol Wayfarers. H e The first officer had a total of via route Red Three but not via had proved competent in tests, re 1,740 hours of which 1,250 hours advisory route ADR159 and Wigan sponsible on duty, and was a com- were as second pilot in Wayfa rer beacon. On the morning of 27th February, 1958, a Bristol Type 170 a ircraft (Wayfarer) flying from Ronaldsway Airport, Isle of Man, to Ringway Airport, Manchester, crashed near the summit of Winter Hill, which is about nine miles off the intended track as shown an the map. The captain and the first officer were among the seven survivors of a total of 42 persons on board. The Court found that the accident was caused by the first officer tuning the radio compass to the incorrect beacon, and the neglect of the captain to check the radio compass was cited as a contributory cause. A synopsis of the Report on the Public Inquiry is presented here together with our comment on certain points contained in the report which we consider to be of particular significance. THE CIRCUMSTANCES which required the aircraft to report 0939 hours Preston cleared the air abeam of Blackpool. Forecast Weather Conditions craft as far as Wigan NDB at a height of 1,500 feet with instructions The route forecast for the flight The Flight to maintain "contact" or "visual was:- contact". At Wigan NDB a clear Cloudy with periods of rain. The aircraft .took off at 091 5 ance to Ringway was to be obtained Wind-300° / 25K. hours with the captain occupying from Manchester Control. I cloud-Stratus k -i base 600-1000 the left-hand seat. Other than a feet. Strato-Cumulus-amount not little cloud near the airfield the visi At 0942 hours Manchesler Con given, base 2-3000 feet. bility was good and improved as the trol requested the aircrafl lo con Visibility- 3-6 miles. 1-3 miles al flight progressed. When approaching firm the previous E.T.A. Wigan, Ronaldsway. abeam of the Morecambe Lightship which it did. At 0942! hours an Q .N.H. Ronaldsway-1024 mbs. the captain obtained a bearing from other aircraft in the vicinity, flying Ronaldsway which placed the air at 2,500 feet in cloud, advised the The forecast for Ringway Airporl craft slightly port of track. H e then crew not to forge t about the tele for E.T.A was: - handed over the controls to the vision mast. At 0944 hours Man Rain. first officer and went into the cabin chester Control asked, "Have you Cloud- Stratus 4/ 8ths base 800 feet. to talk to the passengers. checked Wigan yet please " The Strato-Cumulus 8/ 8ths base 1500 reply was "Negative". At 0944! feet. The first officer then did a gentle hours Control asked, "Are you in "S" turn to regain track and tried visual contact with the ground," The Flight Plan unsuccessfully to set up the Decca The reply lo this was also "Nega equipment. He then tuned in the ti ve". The flight plan was made out for radio compass, as he thought, to a flight from Ronaldsway to Ring the Wigan NDB. The captain re At 0944 ~ hours Manchester way along advisory air route ADR- turned to his seat after five minutes R adar, through Control, instructed 159, to Wigan NDB and then to in the cabin and noticed the radio the aircraft to "Turn right immed Ringway as directed by Manchester compass operating. The firsl officer iately onto a heading of two five Control. The cruising height select indicated to him that it was tuned zero. I have a faint paint on rada1· ed by the captain was 3,500 feet to Wigan beacon and the heading which indicates you are going over but just before departure the traffic shown by the magnetic compass ap towards the hills." The aircraft im situation dictated a choice of either peared to be consistenl with this. mediately acknowledged with "T wo a 15-minute delay or a change in '\t 0938 hours, one minute before five zero right Roger." The aircraft WHITEGATE +: the flight level to 1,500 feet. The E.T.A. at the reporting point abeam made no further transmission. latter was chosen and the time for of Blackpool, the first officer ad At 0945 hours while turning in the flight was estimated at 38 min vised Preston Control that the air dense cloud, the aircraft struck the utes. The first section of the flight craft was at that point and esti north-east slope of Winter Hill was to be under Preston Control mated Wigan at 0943 hours. At about 40 feet below the summit. 16 17 Condition of the Aircra ft stated that he was positi\'e that h e when abeam of Blackpool, the words had intended to tune to Wigan " Contact" or Visual contact" were I The Certificate of Airworthiness when he referred to the Aerad used. Although definitions of these was in order and the owners and Flight Guide to obtain the fre two expressions could not be found TWO Accidents operators had complied with all quency. When giving evidence he it was revealed that they had been regulations concerning the mainten could recall checking the identifi in use for many years and some de ance of the aircraft and its equip cation of the beacon after tuning gree of meaning h ad apparently -ONE CAUS~ ment. the compass, but had no recollection been conveyed by them. T he cap of the identification code group tain said he took them to mean which he heard. H e agreed that he flyi ng with visual reference to the As readers of this Digest will have observed, accidents for the most part Loa d a nd Trim must have, in fact, tuned the com ground and to have sufficient all follow a pattern a s to circumstance and cause. Occasionally, however, as in Several errors were made by the pass incorrectly and to make the around visibility to avoid collision. other fields of endeavour, an accident occurs which is outside the usual pattern error, had probably looked up Traffi c Clerk when calculating the and which is interesting for that reason a lone. The following is an account of .all-up-weight and the centre of \Vigan in the Aerad Flight Guide gravity before departure. These in then, due to some distraction, read two accidents which we believe are quite unusual, if not incredible, and are c luded an incorrect statement of the off the frequency and code group published more for that reason than any lesson to be learnt from them. '!ballast carried and the omission for Oldham. I t is perhaps significant from the calculations of one entire that Oldham appears four lines OUR COMMENT above Wigan and, of the ten bea row of passengers. In spite of this, During a dual trammg period in a DH.82 occupying the rear cockpit conducted a cai·eful cons listed on the relevant page, all By finding the incorrect tuning it was later proved that the load aircraft the student pilot taxied out, took-off check of controls having in mind the previous identification code groups begin of the radio compass as the cause of and trim had been within the per and: flew around the circuit making an approach day's experience. The take-off was commenced with the letter "M". In four cases the accident the Court has, beyond missible limits. and landing. T he aircraft touched down to the by the student pilot but, at 300 feet, the instructor the second letter is "Y". question, selected what was the initial or fundamental error in a right of the centre-line of the strip and then observed: the aircraft to be turning to the right. fatal sequence. It seems to us that commenced a swing to the right. The student He tried to correct this turn by applying left Decca Adjustment to QNH other circumstances combined with pilot did not straighten up and so the instructor rudder and in doing so he found his left rudder T he Decca equipment had been \\'hen an aircraft is about to this error to produce the fi nal result took over when the aircraft was getting close to pedal fully forward. He asked the student "Is unserviceable on this aircraft for cross the Q.N.H . Equidistant Line* and it would seem that the most the runway lights and applied power in an your left rudder fully out?" and the student :several weeks. On the morning of it is required by regulations to significant of these was the action attempt to take-off again. He lifted the aircraft answered in the allirmative intending to imply the flight the first officer noticed change the altimeter setting to the of continuing the fligh t in weather at a slow speed to avoid the lights and it then th at he was exerting some pressure on the left l:hat it had been repaired on the Q .N.H. currently stipulated for the which precluded the terms of the swung to the right. Even though the instructor rudder pedal. The instructor immediately took p revious day and he, therefore, tried area which it is about to enter. flight clearance being met. had full left rudder applied the aircraft con over, realising that they were experiencing a repe to set it up for flight but was un tinued to turn to the right, so he closed the tition of the trouble of the previous day, and a ble to do so before departure. This new setting should have been T he conditions of the clearance throttle and touched down again on an adjacent from that stage on Lhe student pilot did not again given lo the aircraft by Control when to Wigan N DB as the captain runway which was under construction. T he air touch the controls. it reported at the position abeam of understood them, included that he craft scraped both wing tips before corning to Blackpool. T his was not done, due should be able to navigate by visual rest. T he instructor attempted lo slop the right turn The Weather by applying left bank after confirming that use of to a misinterpretation of the regu reference to the ground and have After the accident the instructor noticed that In retrospect, the Court was of visibility sufficient to avoid collision. the rudder pedals was ineffective. The right turn lations by the Air T raffic Control the luggage locker door was open and thought the opinion that the forecast issued It seems indisputable that these con continued, however, and he decided to endeavour officer. T he captain, however, tha't this might have been the reason for the for the flight was accurate and ditions were not only reasonable to control the rate of turn with opposite bank should have requested this informa aircraft failing to respond to the rudder. When the should have given the captain ample but were a well-recognised require and the rate of descent with engine power, having tion but the evidence did not reveal repairs were finished he assisted the engineer to indication of the weather he would ment for a fl ight of this nature. ascertained that the right turn continued even why he had not done so. T he orig test the rudder controls from the rear cockpit. encounter. inal setting of 1024 mbs. was set with all power off. T his method helped to avoid for the entire flight whereas it Early on the following morning, the aircraft n umerous power lines which traverse the area should have been changed to 1021 was flown solo by a club member and then the but could not prevent eventual heavy contact with Tuning of the Radio Compass mbs. for the later section. In tl1is same student p ilot and instructor who had been in the ground on the right wing and nose; fortun Examination of the aircraft regard it was pointed out that KEY TO DO YOU volved in the minor accident of the previous day ately this occurred clear of residential a reas and wreckage showed the radio compass Winter Hill is 1,498 feet high and boarded the aircraft. T he student filled the con in light scrub approximately one m ile beyond the t o have been tuned to Oldham Bea the aircraft crashed 40 feet below STILL KNOW! trol column in the front cockpit and later when upwind end of the runway used for the take-off. the summit with the altimeter over -con at the time of impact. The 1. AIP /SAR/ 1-5 11:uning dial indicated 344 K cs., the reading by approximately 90 feet. The pilots were unable to provide the investigator with any reasonable •equipment was internally set to 344 2. AIP/RAC/1-9-4 IKcs. and the orientation of the loop Clearance to Wigan Beacon explanation for these a ccidents but in the course of his examination of the aerial was consistent with such a 3. AIP/ RAC/1-7-8 wreckage it was discovered that the rudder bar connecting the rear rudder setting. Oldham Beacon operates on In the terms of the clearance to pedals to those in the front cockpit was not installed. Further inquiries revealed a frequency of 344 K cs. with an Wigan Beacon given to the aircraft 4. AIP/RAC/1-4-1 jdentification code of M YL and that the connecting bar had been removed two days prior to the first accident Wigan operates on 316 K cs. with a • The QNH Equidistant Line separates areas 5. AIP/GEN/5-1 and that it was not subsequently replaced. It was also learned that no check code of MYK. When subsequently in which the standard altimeter setting used is the QNH prevailing at a specific was carried out either during repairs or in pre-flight preparations to see if informed of this the fi rst officer meteorological station within each area. 6. AIP/SAR/ 1-13 the rudder was operative from the front cockpit. 18 19 DC3 S"lurvives Mountain S"trike 1n Cloud, Arizona (Summary based on the report of the Civil Aeronautics Board, U.S.A.) A DC.3 aircraft struck a mountain ridge approximately 40 miles north of Phoenix, Arizona, and lost approximately 12 feet of the outer portion of its left wing. The aircraft, although substantially damaged, landed safely at Phoenix and the 26 occupants were not injured. THE FLIGHT control frequency and was given the and in the distance ahead there were appropriate approach instructions large cloud buildups. Because of this The aircraft was engaged on a and landing clearance. The aircraft weather condition it was decided scheduled service from Denver, landed at 1405 hours without further that an I.F.R. flight plan should be Colerado to Phoenix, Arizona, with incident. requested. Accordingly, the flight intermediate stops. Prior to depart called the company at Phoenix an.cl requested the latest weather. This ure from Prescott, Arizona, the pilot INVESTIGATION was given them. The crew then tried elected to change the flight from The separated portion of the left to call Phoenix approach control to I.F.R. to V.F.R. for the final stage wing was located at an approximate obtain an I.F.R. clearance and being of the flight to Phoenix. During the elevation of 4,600 feet on the west unsuccessful in reaching them again approach to Prescott, he had looked ridge of a mountain, the peak of called the company and said that it towards Phoenix and considered that which is 5,000 feet (see sketch) . was approaching Knob intersection The examination of the terrain at and wished an instrument clearance weather in that direction warranted the scene of the accident, and the from ARTC. This latter transmis a continuance of V.F.R. flight. wreckage itself, showed that the left sion was made at 1339 hours. At Departure from Prescott was made wing of the aircraft had struck a this time the flight changed its at 1321, hours. Following take small tree, some large rocks and course to a heading which would off the aircraft was climbed to a large cactus plant. Investigation re intercept Knob intersection. cruising altitude of 6,500 feet and vealed that the aircraft struck the The captain said the decision to proceeded to a point 35 miles from mountain in a nose-up attitude. Prescott where the latest Phoenix fly to Knob intersection and then seat belt. H e was positive that tlu· weather was requested at 1335 hours. A thorough examination of the ro Phoenix was made because the fligh t did not enter clouds from thl' The Phoenix weather report at 1330 entire aircraft showed that all dam Hight could be made over this route time of take-off until the descent hours was given as: 1,500 scattered, age was confined to the left " ·ing at a lower altitude, thereby saving prior to impact was made. 3,000 broken, 10,000 m·ercast, visi and aileron assembly. time. At 1344 hours the flight re ' '\T ritten statements were obtained bility 12 miles, wind west 18 to 30 ceived its clearance to fly from Knob from passengers on board the air knots; light rainshowers. The flight According to the testimony of intersection to the Phoenix omni and craft. Depositions were taken of acknowledged this message at 1339 the crew at the time of departure to maintain an a ltitude of 7,000 those from whom it was believed the hours and said that it was approach from Prescott there was an overcast feet. most pertinent information could b i.: ing the Knob intersection and re of 8,200 feet, scattered clouds at obtained. Their testimony was in q uested an Air Route Traffic Control 1,800 feet, and it had been raining The crew further testified that decided variance with the testimony clearance to Phoenix. Five minutes intermittently. The aircraft wa> immediately following receipt of this of the crew on several points. The later the flight was cleared fro:n climbed to a cruising altitude of clearance the climb to 7 ,000 feet was consensus was that following take Knob intersection to Phoenix omni 6,500 feet, and a course was taken begun. As climb power was applied ofT from Prescott the aircraft was and to maintain 7000. As there was toward Phoenix following the Black the aircraft began to settle. At first were placed in the full open posi applied. With the return of full flown near the base of the overcast no acknowledgement of the clear Canyon Highway, which lies cast this settling was not seriously con tion and the propellers at full low power to the right engine the air and for the first few minutes of ance, the radio operator called the of the Bradshaw mountains. The sidered; however, as it continued, p itch. By this time the aircraft craft regained airspeed and slowly fligh t was free of all clouds; that fli ght again. The flight answered and flight continued beneath the over additional power was applied. The was in a snow squall which returned to level flight and, al as the fligh t progressed southward said "Just hit a downdraught, de cast and free of all clouds until in fact that the aircraft was settling seriously impaired visibility. The though aileron control was seriously clouds were intermittently flown claring an emergency, changing to the vicinity of Rock Springs, Arizona became ]mown to the crew first by airspeed at that time indicated 90 restricted, the aircraft was cl imbecl through which completely obscured tower frequency". Following this (approximately 45 miles south of a drop in airspeed from 130 knots to knots and the mountain peak below to its assigned altitude and the flight vision; and that four or five minutes transmission the flight contacted Prescott) . There was only mild tur approximately 115 knots. The rate was hazily visible throu:;h the storm. to Phoenix was continued. The prior to impact the aircraft was fl y Phoenix approach control and re bulence throughout this portion of of-climb indicated a gradual rate of Despite all efforts to the contrary, crew saict that instrument weather ing in dense clouds. None felt or ceived the current Phoenix weather the fli ght. Nearing Rock Springs the descent; but, as the settling contin the settling continued until the left prevailed from the time of impact sensed any downdraught nor did and approach clearance. weather ahead appeared to be wors ued, a rate of descent of approxi wing of the aircraft struck the until the final descent at Phoenix. they hear application of power be ening. The captain said that the mately 1,000 feet per minute was ground. According to the captain, The captain described the air yond that which was used in cruise At 1400 hours the flight advised overcast was definitely lowering and observed. As it became increasingly immediately following impact the through which the aircraft descend configuration. Some passengers, the company that it was coming in the scattered clouds which had been noticeablr: that the added power wa> aircraft staggered, rolled to its left, ed 1,900 feet as a "soggy airmass". especially those who were accus and had lost a portion of its left beneath them appeared to be form not stopping the descent, even more and continued to settle. Power was He said the downdraught was not tomed to flying as airline passengers wing and aileron. After this message ing an almost solid cloud deck. power was added. Since this power immediately reduced on the right precipitous and caused little or no and two who fl ew their own aircraft, the flight again changed to approach The cloud layers were converging was also not effective the throttles engine and full right rudder was pressure of the body against the testified that the cloud deck beneath. 20 21 which the aircraft was flying ap The captain stated that he did cabin h eard any additional power peared to be lowering as the flight not at any time during the flight fly being applied. It is understandable progressed southward and that al through clouds prior to impact ex that if power was applied some of /Reluctant 2Jragon though they were not able to deter cept during the uncontrolled de the passengers might possibly have mine definitely the altitude of the Shortly after taking-off from Katherine, Northern Territory, the pilot of a DH.84 found that, although aircraft they believed that it was scent caused by the downdraught. heard it but paid no attention. How full power was applied, the aircraft would not climb above 100 feet and also that any attempt to increase flying lower than usual. They based The passengers aboard the air ever, the two passengers who are speed caused the aircraft to lose height. He landed the aircraft three miles from the aerodrome in the only this belief on the fact that when free craft, and the stewardess, testified pilots and whose ears arc scnsiti\'e available clear area but the aircraft overturned after running 160 feet. The pilot and two passengers from clouds they were able to that the aircraft intermittently flew co changing engine sounds were received minor injuries and the aircraft and a quantity of freight were substantially damaged. clearly ~ee and identify objects on through clouds and that for a few seated in the aircraft where they Lhe ground. Several passengers said The aircraft had flown from point attitude in the second paddock COMMENT they beli~~ved that just prior to im minutes before impact it was fly could hear these sounds and did Darwin to K atherine to pick up about 80 feet beyond the fence. This accident would have been pact the uircraft was flying in level mg in solid instrument weather. I t not. two passengers (the hirers) and a After 23 feet the tailwheel left the Oight. is recognised that the view which avoided h ad the pilot taken the In conclusion, the Board believes quantity of freight to be transported ground and after a further 140 feet care to load th e aircraft wiLh in the aircraft overturned. It was ap the passengers have from their win that the flight after departing Pres to an outstation. After refuelling, acceptable lim its. Action h as now ANALYSIS dows would differ greatly from the payload available was 605 lb. parent from the wheel marks that been taken by the operator to en cott attempted to fly beneath the braking had been applied almost the view which the crew has from plus the two passengers. The freight sure that a ll freight is properly The flight was eleven minutes overcast. The Board further be which was not weighed consisted from the point of touchdown until the cockpit. However, the testimony weighed and load charts drawn up. late departing Prescott because of en lieves that the overcast lowered mainly of glass louvres. The investi the undercarriage collapsed and the There was no need to learn this that the aircraft at times was flying route headwinds. Whether this in as the flight progressed towards gation revealed that 1,002 lb. of aircraft nosed over. lesson the hard way, as there is a in clouds was so clear that the freight was actually loaded, that is, any way affected the captain's de Phoenix and that intermittently the The cause of the accident was a wealth of information freely avail Board believes this condition existed. the all-up-weight was 397 lb. in cision to fly V.F.R. Lo Phoenix is aircraft flew through clouds ulti load condition which lowered the able on proper loading practices and excess of the maximum permissible. procedures. I t so happens in avia mately going on solid instruments not definitely known. The two air T he request for an AR TC clear Due to the careless manner in performance of the aircraft to the tion that the commonsense rules for way routes from Prescott Lo Phoenix, ance was made at 1339 hours. The several minutes before the crash. which the aircraft was loaded, it extent that the pilot deemed it the protection of life also protect was not possible to positively estab V-105 (Red 51) and V-105E, have clearance was given the flight at Also, meteorological conditions necessary to land immediately and the financial interests. The surpris lish the distribution of the load or this resulted in a landing on an ing thing is that this point is so minimum en route I .F.R. altitudes 1344 hours. One minute later the were not conducive to the presence the position of the centre of gravity. unsuitable area. frequently overlooked. out of Prescott of 10,000 and 9,000 station agent at Phoenix acknow of a sustained downdraught of the feet respectively. Since the elevation ledged a transmission from the Take-off was made on the scaled magnitude described by the captain. runway 5,000 feet in length, the of the Prescott airport is 5,042 feet flight in which the captain acknow The low-level winds were westerly wind conditions being light and an I.F.R. clearance using either of ledged the clearance and advised and therefore crossed the mountain variable, temperature 95 °F , and the A Vislorled ~ision these airways would necessitate a that he was declaring an emergency. ridge in a manner actually more weather fine. The tail came up after time-consuming climb. Considering I A student pilot on his first solo flight at Archerfield in a DH.82 touched The captain also said that at the running about 900 feet and the air also the possibility of additional de likely to produce updraughts rather clown on the main wheels and bounced some two or three feet into the air. tin1e the flight first encountered a craft became airborne after using lays as a result of I.F.R . flight it is than downdraugh ts. Added to this, Believing that he had bounced much higher than this he pushed the stick downdraught it was either at an 4,000 feet of runway. When the probable that these factors did con the Board belic\·es that a down forward and opened the throttle with the intention of landing again further altitude of 6,500 feet or was be pilot commenced to turn right at tribute to the captain's decision not down the strip. The aircraft struck the ground again and turned over on tween 6,500 and 7,000 feet. Since draught of this proportion, occur about 50 ft. the a irspeed started to to file an I.F.R. flight plan. its back. the elapsed time between the last ring in such a short time, would drop and he was obliged to continue In the original preparation for two messages was approximately have been apparent to the pas almost straight ahead. Level fligh t Al though this student had had a little difficulty in reaching the required this flight the captain decided, one minute the aircraft m ust have was maintained at about 100 feet standard during the dual training period, his instructor was at a loss to sengers. The Board believes there with full power but the airspeed explain such a poor performance even on fi rst solo. The training school after studying all the available descended approximately 1,900 feet fore that the aircraft was being weather data, that a cold front during that Lime. I t is not reason fl uctuated around 55-60 knots and was on the point of dismissing it as another case of first solo nerves when would be in the vicinity of Winslow able to believe that the crew, the flown at a dangerously low altitude the aircraft was in a nose high atti it was discovered that the student's goggles had correcting lenses a lthough en route to Prescott when the stewardess, or the passengers would over mountainous terrain. tude. It is appa 1~nt that the air his vision was normal. The effect of wearing these goggles was to cause flight arrived there. The fact that not have sensed a rapid descent of craf t had become airborne because a big change in depth p erception and, considering this handicap, it is he did not encounter the cold front this magnitude. The captain de of the increased lift associated with amazing that the student did so well in his earlier training. as expected, combined with the con scribed this unusual downdraught PROBABLE CAUSE ground effect, and once beyond this The goggles had been purchased as a disposals item and were RAF MK.X effect the aircraft was unable to tinuing rain at Prescott, should as being associated with a "soggy" The Board determined that the issue fitted with angular lenses, the front lenses containing a correction t1 ave forewarned the captain that a air mass and that such an air mass climb. and the side ones being normal. The student had noticed their effect on probable cause of this accident wa> tront might be encountered between would readily explain why no one After continuing m this manner his vision but was reluctant to blame the goggles for his training difficulties the attemp t by the pilot to Oy over Prescott and Phoenix. A check of felt the precipitous descent. The for three m iles the pilot considered fearing that this complaint would be regarded as a weak excuse. There is the sequence weather reports would captain stated that throughout the mountainous terrain by visual refer it was unsafe to continue the flight little doubt, however, that his misconception of the height to which the have confirmed this probability. A descent, power beyond that needed ence to the ground in weather con and decided to attempt a landing aircraft bounced in this landing was due to the effect of these unsuitable study of the available weather in tor cruising, was added three times ditions ,. •hich severely restricted in the only clearing available-a goggles. formation at Prescott should have and that the final application of forward visibility and necessitated cultivated area 320 feet wide divided Although more than one incident of this nature is not likely in a lifetime, further indicated to the crew that power was made by placing the into three paddocks 600 feet, 900 this occurrence points very strongly to the continuing need for an instructor's a descent to a dangerously low V.F.R. flight would be extremely throttles fully forward. Again, none feet, and 600 feet in length. The interest in his student's flying equipment to ensure that it is both adequate marginal. of the passengers in the aircraft altitude. aircraft touched down in the three and safe. 22 23 ...... from Sydney on the 244° diversion nor had the equipment been declared faulty by and at 0715 hours we were cleared to Sydney the communications staff. aeradio. R epeated calls were made to Sydney For the nexl week pilots who would normally aeradio endeavouring to notify them of our depar work 122.9 mes. after departure were briefed to ture but without success. At 0718 hours the tower use 122.1 mes, immediately any difficulty was ex was contacted again and we advised that we were perienced in working Sydney on 122.9 mes. Dur unable to contact aeradio. It was suggested by ing the same period, communications officers the tower to '"try again". We switched back to operating 122.9 mes. kept a special record of all aeradio and received them loud and clear. This signals received. During this period departure business of not being able to recei\·c Sydney calls from 215 aircraft were logged - in 202 aeradio has occurred to me and many others re instances the readability was recorded as "four peatedly when very close to the station. I suggest or five" and the difficulties in making· contact ex that investigation be made re the above to clarify perienced by the other 13 aircraft were traced to the position so that we will know if Sydney aeradio aircraft equipment faults. Concurrently, a sample can' t be bothered listening out on 122.9 mes. or survey of pilots' views was made but although if it is local conditions." this indicated there were occasional difficulties I mmediately on receipt of the report a check it was not conclusive. was made of the relevant tape recordings, all No fault could be found with the equipment frequencies, and the air traffic conLrol inter or aerial system. As the 122.9 mes. aerial was a l communications system, being recorded on the one the same location as the 122.1 mes. aerial and, as m ulti-channel tape. no difficulty was being experienced on 122.1 mes., On the playback: aerial siting was obviously not involved. (a) the initial call could be heard very faintly About two weeks after the completion of the but it was necessary to replay the recording survey it was noted that departure signals re six times before the details could be copied, ceived on 122.9 mes. were again weak and ( b ) the next two calls from the aircraft were distorted. It was thought that the strong signals similarly faint, on departure may have been blocking the RF stages of the receiver but a check indicated that ( c) air traffi c control were heard Lo ask aeradio the aircraft would normally have been a fair dis if the aircraft had been received, the com tance from the aerodrome. The receiver was munications officer replying that he thought again thoroughly checked and a faulty resistor he had heard an aircraft but he couldn't read was found in the audio limiter but no fault was the transmission, found in the RF section. The faulty resistor ( d) the aircraft then called aeradio again and would have adversely affected strong signals but contact was established. it was not a type of failure which wquld have I n checking the recorded transm1ss1on the resulted in intermittent operations. Therefore, it marked difTerence between the loud and clear is questionable if this resistor could have been signal received by the tower on 118.1 mes. and responsible for the previous poor reception. the weak signal received by aeradio on 122.9 What has been achieved? Nothing positive to mes. approximately a minute later, was readily date in relation to the difficulties reported. Cer apparent. I t was also noticeable that each of the tainly we ha\'C•n't received any more reports of recorded transmissions from the aircraft to aeradio poor communications concerning 122.9 mes. a t was stronger than the previous call. Sydney but that needn't mean very much for we Further checks of the recordings revealed that hadn't received any other reports of difficult com two other aircraft which had departed from munications prior to the submission of the incident Sydney 30 minutes earlier than the subject air report. craft exhibited a similar difference in the recorded signal strength of 118. l mes. and 122.9 mes. A OUR COMMENT fourth aircraft, after leaving 118.1 mes. inadvert The scope of the investigation makes it clear ently called on 122.1 mes. T his transmission was that the incident report was not pigeon-holed loud and clear. T he aircraft then called on 122.9 or given only cursory consideration. Every in mes. and was barely readable until it was some cident report or suggestion submitted through distance from Sydney. the incident system receives sim ilar treatment. At this stage it was clear that the incident If you have a problem, or if you consider report was not the result of the communications facilities or procedures can be improved, we officer not bothering to listen out. It appeared would appreciate your suggestions, and the that the 122.9 mes service was definitely inferior opportunity to review the situation with the a im to that of the other frequencies although no prev of achieving a higher standard of service and ious complaints from pilots had been received consequently a higher standard of safety. 25 were no indications of fluid leakage, least three facts. The first is that PROBABLE CAUSE Abandoned Take-off from New Haven Airport, engine roughness or below normal having been the captain of Convair performance. aircraft for more than two years The Board determined that the Connecticut and having acquired a total flying probable cause of this accident was The fire warning system on the time of 4,600 hours on this type, the improper technique of the cap lefl engine was checked for con tain resulting in the unintentional (Summary based on the report of the Civil A eronautics Board, U.S.A.) of which 1,322 were acquired as tinuity and was found to be intact captain, he should have known how retraction of the landing gear prior and capable of normal operation. to V 1 speed, which was made pos A Convair 240 abandoned its take-off at the New Haven Municipal Airport, Connecticut, on March 1, the landing gear retraction system All lests of the fire warning system functioned; also, he should have sible by a malfunclioning left gear 1958. The aircraft, with the landing gear retracted and the left engine nacelle and wing burning, skidded showed it to be capable of normal safety switch. A contributing factor to a stop on the runway. Considerable damage resulted and two of the five passengers received minor known that under normal operating operation. conditions, the landing gear selector was inadequale inspection by the injuries; the three crew members were uninjured. operator. During the functional testing of handle could not be raised to re the fire warning system in the cock tract lhe landing gear until the gear no longer carried the weight of the THE FLIGHT gear selector location. H e further tionecl near this witness, said that pit, the landi ng gear safety solenoid aircraft. said that following the observation he first saw smoke and fire when was observed to be continuously The aircraft was engaged on a of this fire warning, he looked back the aircraft passed the runway inter energised. The solenoid is normally The second fact is that the state scheduled passenger flight from at the left engine and saw fire in section, several hundred feet further de-energised when the landing gear ments of passengers and eyewitnesses, Boslon to New York with stops a t the vicinity of the outboard residual on. is extended and the weight of the which are substantiated by the ex New Haven and Bridgeport. The heat door. He immediately called aircraft is on the landing gear. The aminalion of the physical wreckage, flight to New Haven was uneventful this to the attention of the first The first impact marks on the function of the safety solenoid is to do not support the presence of fire and the a ircraft was prepared for officer, remarking, "we're on fi re, runway were made by the tail skid prevent inadvertent retraction of prior to ground impact. The third Correct Weight? th e second stage of the fligh t to put it back down" or words to that and the bottom skin of the fuse the landing gear when the aircraft and equally important fact is that Bridgeport. There is no air traffic effect, and then retracted the land lage immediately forward of it. is on the ground. The safety switch at the time of gear retraction more control tower at New Haven, and ing gear for a fast deceleration. The These marks started 1,380 feet from cover plate was removed and it was than ample runway remained to the aircraft moved onto the runway left firewall shut off valves were the beginning of the take-off roll found that the circlip on the switch brake to a successful stop and even The following report is offer and take-off was initiated from a then closed and the C02 fire ex and continued for a distance of shaft, which positions the switch had there been a fire in the left ed without comment e xcept taxi start without delay. This seg actuator arm, was missing. This tinguisher for this engine was dis 1,686 feet. Propeller slash marks engine no necessity existed for to say that a number of ment of the flight was being flown started about 120 feet beyond the missing clip allowed the actuator charged. Retracting the wing flaps scuttling the aircraft. similar reports are received by the first officer but the captain, and accomplishing the remaining initial impact marks and continued arm to move 7/16 of an inch from seated on the left, maintained dir engine shut down duties continued for a distance of 343 feet and 378 its normal position, permitting the The teslirnony of the captain is each year- ectional control during the initial until the aircraft came to rest. feet for the left and right propellers, switch contacts to remain closed. In inconsislenl with the clear and sub acceleration of the aircraft. Before respectively. Initial slash marks were this condition, the defective safety stantiated evidence on record in this "DHC.3, VH-- , was loaded the aircraft reached the intersection The fi rst officer testified that he switch energised the landing gear investigation. Under the circum spaced 2 feet 6 inches apart. T he in preparation for a charter of the runways, the landing gear observed the airspeed indicator at calculated ground speed of the air safety solenoid withdrawing the latch stances, the Board could not accept was retracted and the aircraft 85 knots, at which time everything craft at the time of ground impact, pin, thus allowing the gear selector the statement of the captain. The flight; the load consisted of skidded down the runway near its was normal and the aircraft was in based upon the propeller slash marks handle to be placed in the "UP" 13oard therefore concluded that fire tractor parts and as these centre and cam e to rest 1,050 feet a nose-up attitude ready to beco:ne position and the landing gear to and r.p.m. governor seltings, was did not occur until after the aircraft were too heavy to be weighed from the far end. The crew and airborne. H e further testified he saw approximately 93 knots, 7 knots be retract even though the weight of passengers left the aircraft through the left engine fire warning light low the V L speed of 100 knots. the aircraft was on the gear. Nor settled; that the captain, instead of on the company scales the the right emergency escape hatch and heard the warning bell after mally, lhe landing gear cannot be intentionally raising the gear as he weights provided by the chart and the partially opened front en the captain remarked that the en The left wing and the outboard raised while the landing gear strut stated, not knowing that the safety erer were accepted. The a ir trance. Fire around the left engine gine was on fire. At this time he side of the nacelle of No. 1 engine is compressed by the weight of the switch was malfunctioning, actually and the left outboard wing :uea had back pressure on the control were extemively damaged by fire. aircraft on the ground unless the craft was loaded and the caused considerable damage and was yoke and was preparing to increase latch pin, ·which protrudes through caused the gear to be raised u•1in• station engineer noticed that The left engine was removed in tenlionally. Poor piloting technique extinguished by the local fire depart the angle of attack of the aircraft a hole in the landing gear selector the tail strut was very low ment. in anticipation of V2 speed. He held tact from the aircraft and installed handle, is depressed manually, per was displayed by the captain in and the main wheel tyres back pressure on the control yoke on a test stand where it was operat mitting the handle to be raised. placing and keeping his hand on the ed a l 1,000, 2,200, and 2,800 r.p.m. were distorted. The load was until the captain informed him of Neither the captain nor the first landing gear selector handle and by INVESTIGATION the fire, at which time he retarded These three r.p.m. settings were sel officer was aware of this unsafe con removed and ta ken by truck · the throttles, p111ling them into the ected because they represented, in dition. his uncalled for action in applying to the Government weig hing The captain testified that just be reverse position. Immediately there order, an average slow engine speed, a n upward pressure on this lever fore reaching Vl speed he saw the after the aircraft settled to the an r.p.m. giving a manifold pressure in anticipation of the first officer's bridge where it was found to left engine fire warning light come ground. equal to the standard barometric ANALYSIS command to raise the gear. The be 799 lb. in excess of mani Serious accidents TIE-BOL have occurred due to breakage of landing g ea r w h e e I castings and forgings. Fracture usually is pre ceded by small fatigue cracks starting, and spreading rapidly until the weak ened wheel collapses when landing loads are applied.* Cracks are found WASHER wherever tie-bolt washers h a v e been improperly installed. Wash ers, carelessly placed with their sharp edge against the corner radius of the spotface, dig into the metal when nuts are tightened. This creates points of CORRECT INSTALLATION high stress concentration where fatigue is likely to begin. The danger is in tensified by the cracks being hidden under the washers until serious damage becomes evident. Main landing gear wheels of large air Rounded edges prevents craft have 18 tie-bolts, 36 washers and nuts, all of which are removed when tires are changed. The relatively large number of parts, and the washers being unsymmetrical, increases the possibility of errors being made in assembly.** Washers having both edges round ed to flt the spotface radius REDESIGNED WASHER eliminates th e possibility of a wrong install ation of washers being made. * Ref: Directorote of Flight Sofety Reseorch, USAF, Norton AFB, Calif. .... **Murphy's Low: "If on aircraft port con be installed incorrectly, someone will install it INCORRECT INSTALLATION that way."' ( By Courtesy Flight Safety Foundation, Inc.)