Originally Posted by
DaveUnwin
We had a pro-turn letter into GASCo FSM after I ran a feature on turnbacks; - this was my response.
The Editor replies “I’m afraid that I’m firmly on Captain Laming’s side regarding turn backs. Firstly, when you practice a turn back, you’re already expecting it. If the engine ever stops for real, you will lose valuable time, height and energy due to the ‘startle’ factor, as you’ll be reluctant to immediately accept that the engine has actually failed. Secondly, if you do manage to complete a swift 180° reversal before reaching the ground your problems are far from over. Not only are you significantly displaced from the runway but you may well have a considerable tailwind. Always remember that the kinetic energy possessed by the aircraft as it crashes is E=1/2mv2, or half the mass multiplied by the speed squared when you hit whatever you hit. Let’s assume your aircraft stalls at 50kt. Straight ahead into a 20kt wind means you will crash at 30kt, which is eminently survivable. Turn downwind in the same scenario and your impact speed has more than doubled. Remember E=1/2mv2? The impact forces have increased exponentially, not linearly, and the probability of survival reduced accordingly.”
Captain Scribble "A strong headwind on take off or long runway" also make a very good case to go straight ahead! Finally, I honestly believe practicing a turnback is very different from a real one. How much residual thrust is a Hawk's engine putting out at idle, for example? There must be a considerable difference between a seized jet and an idling one, no? One must be adding some thrust, the other drag Then there's the startle factor. Its very very different from 3-2-1-here we go! Finally, as a very experienced airman once told me "when practicing turnbacks it doesn't matter how many times you get it right, you'll only get it wrong once."
All agreed. Totally. But when does a turn back become acceptable? A few years ago, after a catastrophic engine failure, I flew one quite successfully, thus saving me, my student & the aeroplane. It is what I had been trained to do. A forced landing would have almost certainly lost the aeroplane. Now, though I totally agree with everything you wrote, there comes a time when a turnback can work. So what makes it viable? My engine failure was at about 2500 feet with a good 10 knots down the active runway. Still insufficient to land back on the active runway, but landing down wind on a 6000 foot runway worked. BTW, I taught turnbacks at Chivenor and most worked. But of course I ensured the parameters were sufficient before I closed the throttle. With a seized engine, I probably would have ended up pulling the yellow & black handle.
Incidently, I agree the 'startle factor' using up precious time & height. My student was flying that day & froze. I think I waited half a milli-second before taking control & turning.