Stalling for Time
Ever heard the saying “prevention is better than the cure”? In this post I would like you, the student pilot, to try and apply that saying to your flying, specifically with respect to the stall.
Now, every time I briefed a stalling exercise while a military instructor, I would ask the student whether the most important aspect of a stalling exercise is to fly a perfect stall recovery, or to recognise the symptoms and indications of an impending stall, and prevent it from occurring in the first place. Invariably, the answer would be the perfect recovery is most important. I however, disagree. Why? Well, prevention is better than the cure. If a pilot recognises and prevents a stall from occurring in the first place, the full standard stall recovery is never needed.
Of course, prevention does not work 100% of the time, and so knowing how to recover from a stall is an essential skill. My second point is that the recovery need never be perfect. The perfect stall recovery is one that recovers the aircraft with minimal height loss. In a real stall situation, finesse and perfection is not needed – the application of the correct recovery techniques, in the correct order is. Do this and recover the aircraft and you have completed a successful stall recovery.
Practice stalling requires knowledge of what is happening to the aeroplane and specifically the aerofoil holding you in the sky. For that I suggest you talk to your instructor and get out your PPL notes: I won’t go into it here. One thing I will emphasise is the recovery depends not on setting a particular attitude but on un-stalling the wing, something I will return to next month.
So recognition of the stall symptoms and indications. Think about it – low airspeed, not necessarily decreasing; a high nose attitude, something that may be very difficult to notice if already at a high angle of bank or an unusual attitude; sloppy and unresponsive controls; light buffet increasing to heavy buffet at the onset of the stall, may be masked by turbulence; and finally the stall warning, if fitted to your aircraft. As you can see the indications above are very easily demonstrated when entering a practice stall, wings level, knowing what it is you are looking for. But my comments also reveal that in everyday operations, the indications may be masked by the aeroplane and what is happening at the time. For example, when turning base on a flapless circuit, if the pilot inadvertently flies through the centreline and increases the angle of bank, and hence G, to ‘pull’ the nose of the aircraft onto final, the high AOA of the wing, easily seen in the practice case by a high nose attitude, will be masked by the angle of bank. Further, the pilot in this case is likely not looking at the aircraft attitude – instead concentrating on where he/she wants to go. Another example is levelling out and forgetting to put the power up after the descent – often due to a high workload or distraction. In these cases it is often one of the more ‘minor’ indications (sloppy controls or the light buffet) that alerts the pilot a stall is imminent.
Keep it in the back of your mind that a real stall in an aeroplane is not a deliberate event. It is the result of the pilot’s mismanagement of workload, resulting in distraction and forgetting to fly the aircraft, or an inappropriate manoeuvre. In both of these situations the classic ‘major’ stall indications are often forgotten or hidden.
If at any time during a heavy workload or an abrupt and unexpected manoeuvre any of the above indications are felt or noticed, the incipient stall recovery must be immediately initiated. This is different from the standard stall recovery. In a standard recovery the wings are stalled – therefore AOA must be decreased to regain lift. In an incipient recovery the wings are still producing lift – they are simply getting close to the stalling angle of attack. So there is no need to lower the attitude to unstall the wings. Simply hold the attitude, apply takeoff power, and roll wings level when accelerating. Once back under control, fly the aircraft – attitude, heading, airspeed – and work out what happened. Preventing a stall is much easier than the cure.