Coaching Corner… That doesn’t sound right…

It’s unlikely to be a full loss of power that surprises you, but more likely a partial loss of power, suggests Head of Coaching David Cockburn…

I’m sure we are all aware of the need to be ready for an engine failure at any time, especially immediately after take-off, even though the reliability of most modern engines can tempt us into a belief that it will never happen to us. After all, how many hours are flown in light aircraft and how many failures do we hear about?

Even if we think the likelihood of an engine failure is remote, we all went through practising forced landings and engine failures after take-off during our training, and hopefully we continue to practise them, even if it’s only on our two-yearly ‘flight with an instructor’. These practices were probably initiated by suddenly closing the throttle to simulate a catastrophic failure, after which we were able to concentrate on making a successful (we hoped) into-wind approach to a field. ‘Phew, got away with that’, we probably thought.

However, if we speak to pilots who have encountered a real problem with their engines in flight, we are likely to discover that it wasn’t such a sudden and complete failure. The AAIB has recently published a report tinyurl. com/partialpower into such an accident, which occurred last year. While the aircraft concerned was not a LAA type, the report’s conclusions are worth considering by all of us.

The climb immediately after take-off is the most critical phase for a pilot to be faced with an emergency, and that is why the PPL syllabus stresses the engine failure after take-off situation. However, as in the case of the fatal accident in the report, evidence suggests that when the engine has not completely failed, the pilot is likely to be tempted into a more dangerous situation than the one in which they originally found themselves. For that reason, LAA Coaches are encouraged to give members the opportunity to discuss, and hopefully practise, coping with a partial power failure in the initial climb after take-off during routine training flights.

The AAIB highlights the guidance booklet published by the Australian Transport Safety Board after a similar fatal accident a few years ago tinyurl.com/ ATSBpartialpower. I recommend it for study and consideration.

Like the ATSB, I would suggest that the risk of a power failure on, or just after, take-off can be reduced if we always operate our engines as the manufacturer recommends. During the start procedure, odd noises, or oil pressure readings, which are abnormal or slower to rise than usual, should give us pause for thought. We should also pay careful attention to its response during the pre-take-off power checks; an unfamiliar gauge reading, or unusual tone, at high rpm might be an early indication that all is not well. The same applies as we increase power to take off. Abandoning the take-off during the ground run should result in no more than a runway overrun and minor injury at worst, but if we do not notice any problems until we have left the ground, the risk of serious damage and injury is a lot greater, especially if there isn’t enough runway ahead to land and stop safely.

If we suffer a total power failure at a low height, we know to lower the nose to gain and maintain the glide approach speed, and then to land as close to into the wind as possible without turning through more than about 30° unless we are high enough to safely do so. If, however, there still seems to be enough power available to continue a climb, I have found as an instructor that most pilots will start to turn, probably in the hope that they can either complete a low circuit or at least land on the airfield in an abnormal direction. As has been seen in many fatal accidents, especially if the engine loses more power part way round the turn, the pilot may mishandle, stall and spin.

Downwind turn

Investigators tend to emphasise the increased stalling speed in a turn as a factor in loss of control accidents. However, that is not the only factor involved. A turn downwind produces an increase in ground speed and, as we learned when considering wind shear, the inertia of the aircraft in relation to the Earth tends to reduce its airspeed as its ground speed increases. However, the pilot is looking outside the cockpit, and at a low height the ground appears to be moving faster than before, which encourages the erroneous perception that airspeed is increasing, leading to an unconscious, and dangerous, rearward control column movement to reduce it.

Even if the pilot was able to maintain a safe airspeed during the turn, a reduction in power at that point will mean that the subsequent forced landing would be out of wind. Any contact with an obstacle would probably be at a higher ground speed than that of which the cabin structure is capable of protecting the occupants. We need to reduce the risk of that happening.

The more complicated an emergency procedure is, the more likely components of it are to be forgotten or mistaken. I suggest we stick to the EFATO drill we all know, but use whatever power is remaining to provide options to increase our safety. Even if we do not realise instantly that we have less power than we should, we should always be automatically adjusting our climb attitude in order to maintain our speed for our intended climb. The speed for maximum climb rate is usually very close to our gliding speed. So the first priority, whatever power we have available, is to gain and maintain that gliding speed.

If there is no power at all remaining we are committed to landing in the most suitable part of whatever area is in front of us. Any power which does remain can be used to reduce our rate of descent, and increase the size of the available area. If we have minimised drag by raising any flap there may be enough power available to maintain level flight at our gliding speed, or even permit a climb at a reduced rate. In any case, the priority must be to maintain that speed because any increase or decrease will reduce our performance, as will even a gentle turn.

However, we must remember that an imminent total failure is now likely. If there is any appreciable wind, we need to steel ourselves to avoid turning more than a few degrees, until we have enough height to turn all the way round into wind again if the engine completely fails at the worst possible moment. At least if we are not landing immediately we should have more time to carry out the other actions listed in our aircraft’s particular EFATO drill.

We can check for possible reasons for the problem and try to regain more power by switching fuel tanks and pumps, and checking mixture and magnetos. While carburettor icing is frequently cited by the AAIB as a probable cause of engine failure, and applying full heat is normally recommended as the initial action for a rough running engine, pilots may feel the reduction in available power when it is selected would place them in a more hazardous situation. Every situation will be different and I can’t advise – that is why the pilot is in command! We can also try to tell others that we have a problem and what we are doing about it.

If we cannot climb and are forced to land ahead, however much or little power remains, the possibility exists that the engine may provide a temporary increase in power again, messing up our landing and stopping distances. Once on a satisfactory glide-slope we should switch off the fuel and magnetos.

If we have been fortunate and still have enough power for a gentle climb, we need to consider whether, and at what point, we should make a turn back towards a more suitable landing area such as our departure airfield. The threat of a total failure will always be there; might a diversion to a long and wide runway with rescue facilities (if we can reach one) be a better idea? In any case, we should try to stay within gliding range of possible landing areas until we are safely at rest back on the ground. shall the involved. nine serious or life-threatening injuries. In no or

Recently, I have been emphasising Threat and Error Management (TEM), and it is essential in this area of flight. Operating our engine in accordance with the handbook can reduce the likelihood of failures, and careful pre-flight checks can help spot possible problems, but we must be ready to take the actions needed if the problems appear. I advocate making acceleration checks on the take-off run, but these are only useful if we are actually prepared to abandon the take-off if we do not achieve our check speed. Once airborne, we must be alert to make adjustments to our pitch attitude to maintain our climbing speed whatever happens, and to keep aiming more or less ahead until we have enough height to safely go elsewhere.

Accident reports indicate that the temptation to turn can be overwhelming. If we routinely brief ourselves and any crew members (perhaps not worry passengers) on what we intend to do if we experience problems during and just after each individual take-off then there is a chance we might overcome that temptation. Perhaps the briefing I suggested last month ought, more correctly, be: ‘If anything unusual happens during the take-off run, or if we haven’t reached (30) knots before we pass that tall tree (previously calculated stop point), I shall close the throttle and apply the brakes to stop. If we’re airborne and the engine isn’t giving enough power, I shall lower the nose, achieve (60) knots (approach speed) and land on what’s left of the strip or aim for a clear area ahead or slightly right (towards the wind). If I have enough power to avoid landing immediately I shall maintain speed and aim ahead towards a clear area. I shall not turn until I have achieved (600) feet (depends on the local hazards)’.

The AAIB report concludes: “During the period 2011-2021 the AAIB completed 16 field investigations in which the partial loss of power was involved. Arising from those 16 accidents, there were 15 fatalities and nine serious or life-threatening injuries. In two of these accidents there were no injuries, and both were as a result of flying the aircraft under control to a successful forced landing or ditching. There were five attempted turnbacks, all of which resulted in fatalities or injuries.” ■

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Jerry Parr