AIRCRAFT ACCIDENT Rleport ALLEGHENY AIRLINES, INC., CONVAIR 580, N5802 NEAR the BRADFORD REGIONAL AIRPORT DECEMBER 24,1968
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SA-410 FlLE NO. 1-0033 AIRCRAFT ACCIDENT RlEPORT ALLEGHENY AIRLINES, INC., CONVAIR 580, N5802 NEAR THE BRADFORD REGIONAL AIRPORT DECEMBER 24,1968 ADOPTED: JANUARY 28,1970 , i 1 ALtEGKENy AII&INES. INC., COW^ 580. N5802 NEAR THE BRAIIE'ORD REGIONAL AIRRPORT TABm OF CONTEWS . Pago Synopsis ....................... 1 Probable Cause .................... 1 I.. Investigation .................... 2 1.1 Xistory of the Flight ................. 2 1.2 Injuries to Persons ................. 4 1.3 Dmwe to Aircraft .................. 5 1.4 Other Damage ..................... 5 1.5 Crw Information ................... 5 1.6 Aircraft Information ................. 5 1.7 Meteorological Information .............. 5 1.8 Aids to Navigation .................. 6 1.9 Cmmunications .................... 7 1.10 Aerodrome and Ground Facilities ........... 7 1 .11 Flight Recorders ................... 8 (a) Flight Data Recordw .............. 8 (b) Cockpit Voics Recorder .............. 8 (c) Correlation of the two Recorders ........ 9 1.12 Wreckage ....................... 9 1.13 Fire ........................ 12 1.14 Survival ....................... 12 1.15 Tests and Researc'i .................. 13 1.16~ Other Information ................... 15 2. Analysis and Conclusions ............... 18 2.1 Andysis ....................... 18 2.2 Conclusions ...................... 27 FLpdings ' '-. (a) .................... 27 (b) Probable Cause ................. 26 3 . Recomemdations and Corrective Measures ........ 29 4 . Appendices A . Investigation and Hearing 1. Investigation 2 . Hearing 3 . Preliminary Reports B . Crew Information C . Aircraft Information D . Transcript of the Cockpit Voice Recorder Attachments I. ! SA-42.0 File No. 1-0033 NATIONAL TRAIJSWRJXTION SAFCM BOARD DEPARTkEFI OF TRAMSHIRTRT'ION AIRCRAFT ACCIDENT REFQRT Adopted: January 28, 1070 ALLEWXNY AIRLINES, INC., CONVAIR 580, N5802 rmTH E BWDFOW RFGIONAL AIRWRT BRADFORD, F'ENNSYLVANTA, DECEIGF8 24, 1968 SYNOPjIS On December 24, 1968, Allegheleliy Airlines Fli&t 736, a Convair 580, N5802, crashel. at approximately 2012 e.s.t., while executing an instru- ment approach to Runway 32 at the Br6dford Regional AirNrt, Bradford, Pennsylvania. There were 20 fatalities among the 47 persons on board the aircraft. The airc-aft made initial contact with trees approximately 2.5 nautical miles from the End of Runway 32 at an altitude of 2,081 feet m.s.1. (€6 feet above ground level). The aircraft thereaffer struck a tree at 33 feet zbove ground level and rolled to an inverted position before striking the ground. The weather observation in effect for Bradford Airpert at the time of tk accident shoved an estimated ceiling 2,000 feet br3ken and visi- bility of 1 mile in very light snow showers and blowing snou. An observation recorded 2 minutes after the accident showed in indefinite ceiling 800 feet obscuration and visibility 1 mile variable in light snow showers and blowing snow, with visibility variable Ietveen 1/2 and 1-1/2 miles. The Board determines that the probable cause of this accident was the coLtinuation of the descent from the ficsL approach fix through the Minimum Descent Altitude and into obstructing terrain at a time when both flight crewmembers were looking outside the aircraft in M attempt to esteblish visual reference to the ground. Contributing factors were the minimal visual references available at night on the approaches to the BraXord Regional. Airport; a small but critical navigational error during the later stages of the approach; and a rapid changr in visi- bility conditions that was not known to the crew. - 2- 1. IIiVESTIGATION 1.1 History of the Flight Allegheny Airlines Flight 736 (AL 736) of December 24, lye,, was a regularly scheduled p-ssenger flight originating in Detroit., MichigazL, and aestined for Wa;hington, D. C., with en route €top ct Erie, Wadford, and Iiarrisburg, Pennsylvania. aircraft atilized was a Convair 580, N5802. .1/ Flight 736 was approximately 50 minutes behind schedule leaving Detroit due primarily to delays cmsed by the loading of cargo and mil e.nd by the late arrival at &twit of N5802 on its previous flight. Fli@ 736 operated routinely thrcugh Bie, departing froa there xt approxi- mately 1.96 e.s.t., on si Instrunelt Fligst Rules (IFR) f1igh.c plan to Badford via airway Victor 12.6 Et an altitude of 'j,ooO feet. In compliance with instructiox from Pie Appoac3 Control, AL 736 reg rted passine a position 40 DME Files east of Erie at 1957. me flight was then instructed to descend to 4,oCO feet, clesred for an approach to Bradford, and directed to "report the VOR 4/ starting your approach." At the same time, AL 736 was informed that-the Bradford weather, based on the previous hourly obsenation, was "ceiling estimated two thousand one hundred broken, one mile, light snow showers, blowing snow, wind three hundred degrees, thirteen, gusting twenty-two, altineter is two nine seven seven.'' The flight repeated the altimeter setting, reported leaving 5,000 feet for 4,000 feet, and stated that "we'll check the VOR 0utbow.d." At 1.959:15, AL 736 repsea "level at four thousand," and again was requested to report when the approach to Bradford was ptarted. At xK)5:lO, Pie Approach Con5roltransnitted the following Bradford weather to AL 736: "Estimated two thousand broken, 1 mile, light snow, blowing snow, wind three ten, fifteen to twent.y five, altimeter two nine b.. seven seven." The flight acknowledged this message and, in responso to a request for their position, reported "four and one half (miles) from the VOR ." y Although the technically correct desipation for N5602 is Allison Prop Jet Convair 440, thjs type cf aircraf:: is most cornonly referred to as a Convsir 580, which is the terminology used throughout this report. 9 All times herein are eastern standard, based on the 24-hour clock. Distance Measuring Equipnent-an electronic means of measuring slant distance between the aircraft and a ground-based transmitter. Very High Frequency MiI Directional Radio Range. 7 . ,~ . .. .- . .- __ ___,..I ---- -.- - . -3- At 2006:25, AL 736 rewrted over the VOR outbowd at the beginning of the instrument approach procedure. 51 At that time, &-ie Approach Control instmcted. the flight to contaTt Wadford ?light Service Station (FSS) an3 to report back to Pie Approach Control when on the ground at Eradford. JU736 then called Bradford FSS and, at m6:35, received the following response: "Roger Allegheny seven thirty six. Understand over the VOR outbound, wind check three ten degrees, fifteen to twenty, altimeter two nine seven sever., you'll have the high intensity lights up on thirty two, you might just walk them down. Give us a call whenever y3u do. Fourteen and thirty- two is covered with hard pcked snow and rough ice, brshing poor by a Convair, sir." At EWS:47, AL 736 reported "procedure turn inbound" j rid was informed by Bradford PSS that the wind was from 290' at 15 kngts. This messaze was the last kr.own communication with AL 736. Tr.r accident dccurred at 2011: 51. The Bradford FSS specialist on duty recorded a special weather obser- vation at 2014 and immediately transnitted this report to AI, 736, bvt recei.vcd no acknowledgment. At approximtely 2019, Erie Approach Control attempted to contact AL 736 and, when unable to do so, callcd Bradford FSS in order to determine if the flight had landed. Bradford FSS advise3 Erie Approach Control that AL 736 was not on the grounA and thereafter both faci1it:es attempted, unsuccessfully, to establish radio contact with the flight. At approximately 2030, search end rescue procedures were initiated on the assumption that an 6ccident had occurred. Allegheny Airlines Flight 734 (AL 734), inbound from Jamestown, New York, arrived over the Bradford VOR at appruxinate~yX17 and was instructed to hold pending completion of the approach by AI, 736. Mter a period of delay of about 30 minutes, AL 734 eventually was anle to execute an approach to Bradford Airprt, during whicn thc crew sighted a fire on the ground approxi- mately 1-112 niles southeast of the Sra2ford 'JOR. This information was transnitted by AL 734 to Erie Approach Cmtrol at 2050, and thence relayed to Bradford FSS, which in turn advised t:;e parties involved in searching for the crash site. The wreckage was subsequently locate5 approximately 2-118 nautical miles southeast of the approac? end of Runway 32 snd 2,000 feet to the southwest of the extended centerline of that runway. The geographic coordinates of the crash site were: longitude 73"36'W., and latitude 41"45'56"N. The investidation did not disclsse any witnesses located on the ground -who had observed the ni?craft during the approach, up to and including impact. The approach chart utilized on tke approach for which Flight '736 was cleared is set forth in Attachment 1. i . .. -4- hbtcll of the survivors of AL 736 recalled that the stewardess had announced thlt the flight was approaching 3racllord Airport and that the pssengers should observe the "Seatbelt" ad "No Fnoking" signs. The survivor!. Generally described the 6escent 3s mcoth and normal, witil no forewarning of the impen ,in& impact. Most af tnem either were dozing or had their attention focuscd insite the cabix. Most of the passengers who were looking c-Aside the aircraft observed moderate to hcavy snow. One passen_rer, whc YZS seated zext to a window just aft of the trailing edge of the left winz, danced out the srindow and noticed a beam of light coming from mder the -2ing shinLr.e, down and f'omrd on the treetops. In add.ition, the an-dcty stz-nrdess, w!?o was seated in the rear, right aisle seat, observed the righi. 1ar.ciing lieht shinirg directly riownward toward the gr0ur.d. P.e passenger and the stewardess estimted that they first observed these lights about 4 to 7 seconds prior to impact.. Se-reral survivors stated that the first sign that anything was wrong was thr: SGUnd of tree branches scrarjing against the aircraft, while others descr7.bed the first contact as 6.