0 ' 0 ASD 134 SPRING 1987 0 LANDING Av1at1on Safety Digest is prepared by the Department of Transport and Communications and is published by the Australtan Government Publishing Service. It is distributed to Aus tralian licence holders (except student pilots). Contents registered aircraft owners and certain other Editorial persons and organisations having an operational interest in safety within the Aus· tra/1an civil aviation envlfonment. 4 Spring is in the air Flying has its ups and downs D1stnbutees who expenence delivery - especially in the Spring. problems or who wish to notify a change of address should contact: The Publications Distribution Officer (EPSD) Department of Transport and Communicat10ns 6 Afterthoughts? P 0. Box 1986, Carlton South. Vic. 3053, A safe flight is nicely finished off by a post-flight AUSTRALIA T'S SPRING at last. The birds are singing and it's time for us inspection. Telephone (03) 667 2733 to get back into the air after the winter lay-off. Most of us have just been through our leanest period of aviating for the year and we may be more than a little rusty. Our Covers familiarity with the aircraft and its systems, with procedures and Front. When the going gets tough ... the 7 The power of nature checks is at its lowest ebb. Our handling techniques - the vis­ Av1at1on Safety Digest is also available on tough get going. A major element in Thunderstorms deserve respect ual judgments and control inputs - are less automatic and may subscription from the Australian Government landing accidents is a late decision to go Publishing Service. There is a subscription - and a wide berth. need greater conscious effort. around. He who floats and flies away, form in this issue. lnqu;,ies and notifications It may be a wise precaution to have a dual ride wi th the CFI of change of address should be directed lo. lives to float another day? before we let ourselves loose on the world. Some study would Photograph by Brenton Hollitt be good value and so wou ld some 'air conditioning'. Mail Order Sales Pen tax SP 1OOO - Kodacolor Australian Government Publishing Service 8 Arrival - the best part of the journey? In the southern States. Spring weather can be changeable , with G.P.O. Box 84, Canberra, A.C.T 2601, Wha l does it take to make every landing a safe landing? frontal passages and gusty winds. The weather can turn fairly Back. In every walk of life. we have to fit AUSTRALIA quickly from sunny to heavy downpours. The rmal activity is in, to accommodate each other - there Telephone (062) 95 4411 . Telex AA62013 increasing and there can be significant mechanical turbulence. must be some give-and-take and there is Spring can ge a time of crosswinds. windshear and perhaps wet usually some unwritten code of behaviour. Subscriptions may also be lodged at runways. Aviation is no different. 'Do the right Commonwealth Government Bookshops m 13 How do I land thee? Let me count the thing' unto others and they will 'do the the capital cities. ways As we trundle the faithful craft ou t of the hangar, it is worth right thing' unto you. ['Do the right thing' reflecting on these conditions and our limitations and making There is more than one technique for landing an aircraft. unto the aeroplane also.] su re we are as prepared as the aircraft for the coming flights. My thanks to the N.S.W. State Pollution A major portion of this issue is devoted to the subject of the Control Comm1ss1on for permission to use approach and landing. Landing an aircraft safely, consistently material from their highly successful The views expressed in the Aviation Safety and well is the greatest challenge that we have to face. That is . campaign. Digest are those of the editor or the 14 Choosing the best approach individual contributor and are intended to not to say that all landings are poor. Attitude is the vital ingredient. stimulate discussion in the fields of aviation The vast majority of the thousands of Jandings carried out each safety and related areas. They do not year are safe and those that result in an accident or incident necessarily reflect the policy of the usually do not result in death or injury. Nevertheless. there are a Department. The articles are mtended to significant number of landing accidents and incidents (more serve as a basis for discussion and even argument in an effort to identify and resolve 15 A flare for landing than during all other phases of flight combined) and most of problem areas and potentially hazardous A new visual cue for initiating the flare. them are caused by you and me (the pilots of the ai rcraft) and situations. most of them are avoidable - if we pay attention to three aspects: decisions, Unless otherwise noted. articles in this publication are based on Australian • application, accidents, incidents or statistics. 18 The gentle touch • technique. Let the aircraft land itself. Reader comments and contributions are Some of you may have seen the new video, The Gentle Touch, welcome but the editor reserves the right to produced by the Department. It has been circulated to all flying publish onl'f those items which are assessed training organisations in Australia free of charge and may be as being constructive towards flight safety. shown and copied without restriction. I urge you to see it and 19 When everything turns to worms please let me know what you think of it. It is designed to pro· Reader contributions and correspondence mote discussion - as are the articles in this issue. Please talk shoufd be addressed to: Escape clauses - always check them. about them with your colleagues and only experiment when you have an instructor with you and when you have previously The Editor, briefed what you are going to try. Aviation Safety Digest Department of Transport and Communications Seat belt, belt, belt, belt, belt, belt, belt Editor: David Robson G.P.O. Box 367, 20 Editorial Assistant: Karen Hutchison Canberra, A. C. T. 2601 , AUSTRALIA I hear you knocking but you can't come in. Graphic Design: Lesley Gordon ©Commonwealth of Australia 1986 Photographs: P 4 Mike Cleaver ISSN 0045-1207 p 7. 8 BAS/ R85/979(7) Cat. No. 86 0310 3 DAVID ROBSON p 12, 13 Michael Jensen 22 Airflow Editor p 20 Steve Small Printed by Ambassador Press Ply Ltd The readers' column. 51 Good Street, Granville, N.S.W. 2142, Diagrams: Soussanith Nokham AUSTRALIA Aviation Safety Digest 134 There are four main types of turbulence - A wind gradient means that there is a graded mechanical, shear, thermal and wingtip vorti­ change, which is often sharp and pronounced ces. In our allowed airspace (below 500 feet (almost always an increase) in the wind vel­ agl), we can expect to find all of these types of ocity with height. The basic reason for this turbulence, at various times. situation is friction of the air with the earth's surface. A wind gradient is usually more severe 0 0 during stable conditions. Unstable conditions (usually caused by thermal activity) result in vertical air movement which mixes the air and evens-out the velocity at heights close to the Wingtip vortices are more likely to be found ground. The main times in which wind gradi­ near airrields, particularly joint-use GA/ UL ents can affect us are during a descent or turn fields. The vortex from an aircraft of equal within 100 feet of the ground (although it can wing-loading is quite noticeable; from a heavier be a problem even higher). aircraft it can be uncontrollable. Even a Cessna 150 produces vortices which may severely Turns in a wind gradient may also cause diffi­ affect ultralight aircraft. Since wingtip vortices culty because the wingtips are in air moving at flow rearward and downward from an aircraft, different speeds, so aileron response w ill be dif­ avoid flying below and behind anot her aircraft. ferent - and in an ultralight t he wind velocity A certain amount of t urbulence could mean a Take off shorter than a preceding aircraft and represents a significant proportion of cruise air­ slight bump in an airliner. However, the same land further down the runway than a preceding speed. If you are t urning downwind the lower Spring is in amount could have a quite severe effect on an air craft. Better still, wait for a couple of min­ wing will have more airspeed (hence more lift) ultralight, due to its very low size, mass and utes - and stay well clear of helicopters. so bank tends to decrease (or more control is needed): if you are turning into wind the situ­ the air wing-loading. The effect on GA aircraft also Shear turbulence often occurs at the meeting of ¥aries with wing-loading and would l>e some­ ation is the opposite and bank tends to increase cold and warm air masses. Air masses with dif­ - if the lower wing sta lls you are in serious where between the above two extremes. The ferent temperatures tend to move with differ­ danger is not so much the likelihood of struc­ t rouble, so either don't turn low down in strong ent velocities, due to their different origins or winds, or else fly faster near t he ground. tural damage from the thrashing of the air, but response to a pressure system. A cold or warm r ather the loss of control authority. Loss of con­ front , a sea breeze or simply an inversion will Thermals are rising parcels of air which arc trol at altitude could be recoverable or it could often present shear t urbulence.