P & A for Performance
How many times have you had someone, usually an instructor or some crusty old captain looking condescendingly down over their reading glasses, remind you that power plus attitude equals performance?
If you are anything like me, in my formative years as a pilot, I heard it many, many times…and now I find myself on the other end of the conversation, looking over at a young student pilot struggling to control what to him or her feels like an out of control aeroplane with a mind of its own. Frustration permeates their expression and through broken work-cycles and instrument scans, I can see them grabbing and applying information spasmodically – hoping for an elusive clue from the aeroplane telling them what is going wrong.
In situations where a pilot feels as if the aeroplane is getting away from him or her, the application of a known attitude and a known power will result in a known performance. It may take some time for the aeroplane to settle into the desired performance, and adjustments may need to be done to achieve the exact numbers the pilot is after, but as a first step in correcting what the aeroplane is doing, it is really the only step the pilot should take.
What are we actually talking about here? Before even getting in your aeroplane to go flying, you must know the required attitudes and powers for various configurations. For example, with the downwind attitude trimmed out, setting 21”/2200 rpm results in a performance of level flight at 110kias, whilst cruising requires 22”/2300 rpm at cruise attitude, giving 125kias (these are of course generic numbers that may mean absolutely nothing to your specific aeroplane type!)
Knowing these figures means you have a base to start from. In your aeroplane, as you anticipate the level out at your planned cruise altitude, you know exactly the attitude at which you are going to place the nose of the aircraft, and as you achieve this attitude, you know exactly the power you are going to set. As the aeroplane settles, hold the attitude and trim out the forces. Then do a lookout, and check performance. Height? If off, adjust attitude to correct and re-trim. Speed? Don’t rush into playing with your power; allow the aeroplane to settle at a given speed before adjusting. Let it stabilise, and then adjust. Often I see students glance at the speed, see it fast, and immediately adjust power to fix. However, the aeroplane was still settling at the speed for the attitude and power set. Reducing power too quickly only causes the speed to reduce more, resulting in stabilising too slow, and a further adjustment of power and consequently trim. Unnecessary work caused by rushing the initial power adjustment.
Setting a known attitude and power must be applied when things are getting out of hand. If on downwind the student pilot feels as if they are falling behind the aircraft with too much to do and not enough time to do it in, the first step is to fly the aeroplane: set the required attitude and power, trim and set up corrections to achieve by the base turn point the required height, speed and position. Only once this is done, then do the admin – checks etc. Taking the time once you realise that things are getting out of hand to fly the aeroplane and trim will actually create more time as less brain power is required to fly the aeroplane, and more can be devoted to other requirements.
It also works when things get really out of hand. Just because you may be flying a large airliner at high altitude, backed up by many systems designed to stop you stalling or over-speeding the jet, doesn’t mean that attitude and power can be forgotten. As long as you have a valid attitude reference and power (or thrust) instruments, an aeroplane will fly even though the pilot may have no idea at what speed they are at. So, confronted by simultaneous over-speed and stall warnings, conflicting speed information and confusing aircraft malfunction alerts; the act of returning to the basics, setting a known attitude and a known power for the altitude and required speed, will force the aircraft to settle into that known performance, buying vital time to investigate, diagnose and correct the malfunctions occurring. In a situation such as this, knowledge of the aircraft, plus good cockpit discipline and CRM is vital. Bypass the basics, (setting attitude and power) and you will not even get to the point of investigation.
As my airliner burns fuel, subsequently becomes lighter and we climb, I always have an idea of the attitude required and the power (thrust) setting needed in case the flight station gets noisy and the screens go dark. If that does happen, my job as the pilot is to fly. And that means setting an attitude, a power and if need be, doing nothing else until I know the aeroplane is flying and I can direct my attention to the problem at hand. A light aircraft is no different. Talk to your instructor and make sure you understand the attitude and power relationship at various stages of flight for your aircraft type. Happy flying!