Wednesday, 5 April 2017
LOSS OF POWER ON CLIMB OUT
Acknowledgements: GASCO Flight Safety Extra April 2017
Loss of power - full or partial - on climb out generates a “startle effect” whose intensity and length of time depends largely on what expectation the pilot had of such an event. For most of us it is a total surprise and it leads to a pause of three to five seconds before the pilot does anything.
What the pilot does next can vary between an instinctive pulling back on the control column. possibly to keep airborne or possibly as part of common human reaction at times of very extreme stress to adopt the foetal position! The pilot in the incident to which this article refers was also a glider pilot and possibly his glider training in the matter of cable breaks caused him to push forward and assume the gliding attitude.
The fundamental problem occurred in the few seconds left when he failed to determine to keep the aeroplane flying at all costs. He says that he never looked at the airspeed indicator but got out a MAYDAY and looked for the best place to put down.
Hindsight is a marvellous thing and we can all sit in our armchairs and imagine that in those same circumstances we would have done things differently, but we need to remind ourselves that the person complacently sitting in that chair is an entirely different creature from the person suddenly stressed to beyond the limit with only split seconds to react instinctively.
The statistics tell us that in this power loss situation many of us are so taken aback that we forget to do the only thing that is going to save us. Which is to keep the aircraft flying above all else. Instead we search for some ideal landing spot, probably not within actual gliding distance and possibly involving some extreme manoeuvre. We seize upon making radio calls, tightening our straps, turning off electrics and fuel: all desirable actions but worthless if we fail to fly the ‘plane all the way to the ground.
Our best defence against these sorts of consequences is to make it an invariable practice just before take-off to self-brief around what we are going to do if there is loss of power on climb out. Whatever you may decide to do in detail is far less important than the essential importance of preparing your mind for the possibility of power loss. When it happens that will reduce the startle effect and make you far more likely to recognise your essential priority: keep it flying!
A Met after-cast revealed that this was a day of Carb Ice at any time. The Continental engine is particularly prone to carb ice, and the relatively short taxy from the hold to the threshold, about one minute, was sufficient to create ice. The pilot could have taxied with Carb Heat ON or he could have done another run up before take-off with carb heat, but he was not aware of the high risk of carb ice on that apparently unexceptional day. Perhaps the best approach is always to assume a significant risk of carb ice unless current conditions are obviously not prone. Remember that carb ice can be prevalent on a warm day just as much as cold one: the essential factor is the humidity.
Looking back, the pilot in this case (who happily survived the resultant crash) warns us all that the nose down attitude which is right for a practice forced landing with the engine ticking over is not necessarily sufficient for best glide speed with the engine stopped and the propeller generating significant drag.
Only a frequent check on the airspeed will tell you if you if the speed is where it needs to be if you are to survive. The pilot regrets that his aircraft did not have a stall warner. He now recommends that your initial response to EFATO should be to put the control column/yoke well forward and beyond the normal gliding position. He also warns that the mind-set that it can never happen to you is a serious mistake. Airline Cabin Crew start their brief with, “In the unlikely event of an accident ...”, but pilots would do much better to regard a power loss on take-off as being distinctly likely - and prepare themselves accordingly.