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Coping with emergencies
Forced landing procedures
Rev. 8 — page content was last changed 6 September 2010
Check the stopping distance required. The pilot should know the distance required to reach flight speed and then bring the aircraft to a halt. It may be necessary to abandon the take-off shortly after lift-off, due to power failure or just doubtful engine performance or other event — this is particularly important in short field or 'hot and high' take-offs. If take-off and landing distance (over a 50 foot screen) charts are available then the total distance needed to take off, abort at 50 foot, land and bring the aircraft to a halt is just the sum of the charted density altitude take-off and landing distances required. If the distance available is insufficient to take off, reach 50 feet, land and safely bring the aircraft to a halt at the departure, destination and en route airfields, then maybe the planned flight is really not a good idea.
Before taxiing ensure all extraneous objects in the aircraft are secured adequately so that they cannot foul the control lines or rudder pedals or become missiles in the event of an emergency landing. In addition you must ensure there is no possibility of anything becoming loose and wrapping around the tailplane, or passing through the propeller disc of a pusher-engined aircraft.
Always check the fuel tanks for water, don't change tanks just before take-off, and taxi out and take off on the fullest tank. Always do an engine run-up before take-off which, as well as the usual engine checks, is of sufficient duration to ensure fuel is flowing properly throughout the system.
Always plan to gain greatest altitude possible before reaching the airfield boundary, so take off into wind; don't do an intersection take-off; use all the distance available — runway behind you at the start of take-off is an asset stupidly thrown away. If the area outside the airfield boundary is rough, plan to climb out at Vx rather than Vy, and maintain full power until a good height and cruise speed is reached. The extra height gained with distance flown may be very handy if the engine fails.
Whether operating from a familiar or unfamiliar airfield, you must have some knowledge of the terrain surrounding the airfield and the position, slope and condition of likely forced landing sites plus associated hazards. If the airfield is unfamiliar then you must ascertain escape routes, potential forced landing sites and hazards during the initial overflight or by ground inspection.
After completing your take-off engine and cockpit checks, have a good look at the take-off path and rehearse your emergency procedure for any situation that may occur before you are established at a safe height.
When total or near-total power loss occurs after lift-off the cardinal rule is to 'fly the aeroplane!'; i.e. maintain control of the aircraft. This initially implies quickly getting the aircraft into the right glide attitude and waiting until the speed rebuilds to the appropriate glide speed, then fine trimming. (When changing from climb to glide attitude, the nose has to be pushed down through quite a few degrees, which might feel excessive — particularly if the aircraft was not trimmed to the climb speed.) In circumstances like this, some say the second and third edicts should also be 'fly the aeroplane!' and 'fly the aeroplane!'.
During the climb-out the aircraft is at a high aoa, producing very high induced drag — particularly so if climbing at Vx — and when the engine fails, speed decays very quickly, and even more so if the aircraft has a high parasitic drag. The pilot may take three to four seconds to react and move the control column forward, and the aircraft will then take a few seconds to rebuild a safe speed. During these periods the aircraft will be sinking, and if height and airspeed are insufficient the pilot is locked into an immediate and probably very heavy 'landing'. More turn-back information can be read in 'The turn back: possible or impossible — or just unwise?'; also read Mike Valentine's article 'The turn-back following engine failure'. wheelbarrowing is high.
You must also avoid tripping over the boundary fence while airborne, so just get it down (not nosewheel first) and use whatever reasonable means is available to decelerate. Long grass will help slow the aircraft but if necessary, groundloop it to avoid major or expensive obstructions, like a row of parked aircraft. The groundloop is induced by booting in full rudder (and brake) on the side to which you want to swing and will probably result in some wing tip, undercarriage and propeller damage, unless you impact something other than the ground. energy level) and the turn possibilities available at that height; i.e. can you safely turn through 30° or 45° perhaps even 60° using moderate bank angles and still make it to that much better looking site? Will the wind assist or hinder? It has to be a quick decision because at best you have just a few seconds available to plan the approach. If any doubt, go for 'into wind'.
Do not choose the site at marginal distance, even if it's perfect. Close by is better because the height in hand can be used for manoeuvring the aircraft into the best approach position. Because you have no power available you must always have an adequate height margin to allow for your misjudgements, adverse wind shifts, sinking air, vertical gusts and other unforeseen events — and you can dump excess height quickly by sideslipping. Remember that the rate of sink whilst sideslipping is high and the slip must be arrested before the flare.
Apart from being clearly within range the choice of landing site is affected by:
As height increases, the options increase for turning towards and reaching more suitable landing areas, making a short distress call and doing some quick trouble shooting.
Continue tracking down the approach path, whilst correcting for any crosswind component, and watching the position and apparent movement of the aiming point relative to the windscreen. Avoid premature use of flaps — although partial flap does help low-speed manoeuvrability and reduces stall speed at the expense of a steeper descent path. At each stage of the approach the aircraft should be re-trimmed to maintain the desired airspeed — and keep it balanced.
2. If the engine does not fail completely but is producing sufficient power to enable level flight at a safe speed, then it may be possible to return to the airfield. Make gentle turns, maintaining height if possible without the airspeed decaying, and choose a route that provides some potential landing sites in case the engine loses further power. It's a judgement call whether you should take advantage of a possible landing site along the way because the off-field landing is almost certainly going to damage the aircraft and possibly injure the occupants. But that must be weighed against the chance of further power loss before reaching the airfield, producing a much more hazardous situation; it is usually considered best to put the aircraft down at the first reasonable site. If there is insufficient power to maintain height then you must set up an off-field landing. Read the article 'Piper Worrier' in the January–February 2003 issue of Flight Safety Australia.
3. If the engine is producing intermittent power it is probably best to use that intermittent availability to get to a position where a glide approach can be made to a reasonable off-airfield site. Intermittent power negates the ability to conduct a controlled approach and could get you into a dangerous situation. So having achieved a position where you can start the final approach then shut down the engine by switching off fuel and ignition or, at least, fully close the throttle. Fully shutting the engine down early means the engine will be cold at touchdown, which reduces fire risk.
The diagram below illustrates an approach pattern allowing multiple choice of final approach and landing run. The wind is estimated to be in the north west quadrant. Path A is the planned approach and landing run from a base leg positioning location, paths B, C and D show alternate paths which either delay or bring forward the turn onto final to cater for height, wind or positioning differences. Paths E and F show the possibilities for a turn onto a landing path if it is required to do so before reaching the base leg positioning point.
Mike Valentine, the late RA-Aus Operations Manager, had a few very relevant comments:
The turnback part of the (Coping with Emergencies) series is particularly timely in view of the Skyfox accident last October and the Bantam accident three weeks ago, both of which involved engine failures and attempted turnbacks. It is an old problem and seems to be one that won't go away. In view of this, I hope you don't mind if I offer a comment on a particular point in post-engine-failure training.
My main background is in gliding (47 years), with about 30 years GA and 7 years ultralight instructing (Drifter, Gazelle, Skyfox) to add to the mixture. In gliding, we had a persistent problem with loss of control following a winch-launch cable-break and attempted turnback, a situation which is directly analagous to the problem which is plaguing us now. Most, if not all, such accidents were fatal. As Operations Director of the Gliding Federation of Australia, I had to try to address this problem and see if we could tame it. Rather than get involved here in a detailed analysis, I will just give you the bare bones of our efforts.
In researching accidents of this kind over a 30 year period (world-wide, not just Australia), a couple of common threads emerged. Firstly, in many cases there was never any need to turn back — there was ample strip ahead and all the pilot needed to do was to establish a safe speed, adjust the approach path with spoilers/airbrakes and land ahead. This is a crucial point and is often overlooked.
Secondly, and of equal importance, is the fact that, although a pilot may lower the nose after an engine failure, as briefed, the same pilot may not hold that attitude for a while and allow the speed to increase and stabilise. A glider in the full climb phase of a winch-launch is generally a fair bit steeper than an ultralight in the climb attitude, but the principle is no different (nor is the outcome, when the energy runs out).
We did the trials in representative types of training glider, from the 400 kg Kookaburra (33 knot stall, 20:1 L/D) to the 590 kg IS-28B2 (35 knot stall, 35:1 L/D) and the results were remarkably consistent. From a full climb attitude at 55 knots IAS, the cable release knob was pulled, simulating a wire-break. As one pilot immediately took recovery action, using strong nose-down stick movement, the other pilot started the stop-watch. From the time the 'wire-break' occurred at 55 knots to the time 55 knots once more appeared on the ASI was a consistent 6 seconds. This is the amount of time needed before a pilot can make any attempt to manoeuvre the glider. In the types of glider we are talking about, 55 knots is about 1.5 Vs and is regarded by the GFA training system as a 'safe speed near the ground'.
I have found that the above figures apply equally well to a Drifter.
However, with gliders we then went one stage further. We did it because we were dealing with aircraft which were fully approved for spinning. We tried simulating a winch-launch in free flight by diving to 80 or 90 knots and pulling up to an approximate winch-launch angle, then when the speed fell to 60 knots we lowered the nose and immediately applied aileron and rudder to commence a turn. The result was consistent spin departures, not necessarily immediately but certainly before reaching 180 degrees of turn.
All this means that lowering the nose after an engine failure is not the complete answer. If a pilot is not taught that the lowering of the nose should be followed by DOING NOTHING, just holding the new attitude and waiting for the speed to stabilise at the new figure before deciding what to do, he/she will not be protected from loss of control.
All this led to a change in training emphasis in the GFA training system.
(For an expansion of the foregoing read Mike Valentine's article 'The turn-back following engine failure'.)
When preparing this module I asked the late Tony Hayes — a very experienced, enthusiastic and highly respected AUF CFI — a few questions. The following was his response:
"I do not actually teach engine failures in the traditional sense of yank the power and "What are you going to do now?" type of thing. That is not teaching, it is checking correct response to something already taught. That is a bit of a non-event with my students as I expect the aircraft to be continually positioned so it has an escape route, if it is not so positioned then I work on the area via fundamentals of positioning rather than alarming and depressing demonstrations of why it is wrong!
So my actual 'emergency training' happens in separate areas that include circuit planning, speed management, theory and practical glide appreciation. The whole lot revolves around one single concept that I would very much like the AUF to adopt as standard (it is standard in the gliding world) and that is 'safe speed near the ground'!
In the theory area (which I do quite early as part of the fundamentals of control) I use the total drag curve rather than the more abstract polar curve. The interaction between parasite and induced drag is quite clear and the most energy efficient airspeed is clearly understood. To this is then superimposed the speed loss from an abrupt power failure and the average reaction time of a pilot at normal flying arousal levels. On a Thruster this is about 7 knots. 48 + 7 = 55 knots (which is also close to the aircraft's normal conditions approach speed). This is the 'safe speed near the ground' and I insist it is present at any time we are at or below normal circuit height.
This is effectively an insurance policy. The aircraft may now sustain a total power failure and will automatically start returning to maximum efficient airspeed by itself, while the pilot wakes up, and so conserves height. This also ensures that there can be no loss of control. The alternative is a probable climb on the low speed side of the drag curve with increasing sink rates and decreasing glide angles. More to the point is that diving the aircraft to get airspeed back will dump height alarmingly fast.
What I need to get across is a clear concept in the student's mind that the energy level in low-inertia, high-drag machines is equally as critical as positioning. A well positioned aircraft flown at the correct airspeed can recover. If flown too slowly at the point of failure, even though the angles and distance are right, the dive to recover airspeed will put the aircraft too low and may make recovery impossible! Those speed differences are not terribly alarming in themselves — just 5 or 6 knots is all it takes; which is probably one reason GA pilots get into trouble with ultralights.
Once in the undershoot situation from a botched recovery then the scene is set for an attempted 'stretch the glide' and the consequent classic stall/spin. That is also important. Actual sink rates are only really apparent near the ground and the pilot is instinctively going to start pulling back to ease sink, still with a substantial amount of turning to do, and flying too slowly in the first place.
The next major step after energy management is beginning to develop is a lot of passive instruction on circuit positioning via observation rather than being involved in actual circuit planning. I do a lot of control and direction refinement at a very early stage while flying the standard circuit pattern but not have the student even aware of what a circuit actually is. Once I come to circuit planning I can then quickly establish the reasons for distance/angle relationships for the type being used and the student is already well used to looking at them.
Once we arrive at the point that engine failures are normally 'taught' then instead of teaching them, per se, I teach 'glide appreciation'. This validates the circuit pattern positioning. It is fully briefed on a whiteboard and the student is then pre-warned in the air. There is NO surprise element at all! The student then (with a clear mind) soaks in all the clues and retains them. Rather than becoming a sweaty terrified mess with a clear impression there is hardly any time to do anything, I find my students really enjoy putting their skills to use and everything clicks into place.
Still not really finished yet though. When teaching circuit re-joins I instill the concept that while the prime interest is how to get down at a strange airfield (and we do take students to other local airfields 10 minutes flying away) they should deliberately do one extra orbit for the express purpose of looking at the 'way out' when they leave.
And that, in my book, is the real key to emergencies – total situational awareness and then controlling the situation! Fly defensively (without huge effort but as a consequence of sound training so you do it automatically). Last year one of my students on 3rd solo had a major engine failure on climb out — which was bloody tough luck but underlines that it can happen. He was correctly positioned, at the correct energy level, and recovered back onto the airfield from a cross wind landing — no problems and no further damage!
Knowing your aircraft, taking the time to consider conditions and study a strange airfield, having then a pre-prepared 'what if' game plan in advance will all result in pre-made decisions that only have to be refined if something does happen. This will control over 90% of engine failure drama.
The next module in this 'Coping with emergencies' guide deals with overcoming aircraft control failures.
Groundschool – Coping with emergencies
| Guide contents | Knowing the aircraft | Deceleration forces | Forced landing procedures |
| Overcoming aircraft control failures | Procedure when lost | Safety and emergency communication procedures |
| Aviation distress beacons | Understanding SAR services |
| Comfort and survival in a remote environment | ERSA emergency and survival procedures |
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