On 2008-04-24, Brian wrote:
Depends on what you mean by "the impossible turn". If you mean turning back
at 200 AGL, yeah, that one's pretty much impossible. If you mean 600 AGL,
it's pretty much possible in the average aircraft. (Hell, that's pattern
altitude at EFD!) The line lies somewhere in between.

It is statements like this that get pilots killed.

It's statements like 'never turn, always land straight ahead' that also
gets pilots killed. There are plenty of airfields where going straight
ahead is quite possibly the worst option, and the best survivability
options are at least a 120 degree turn away from whatever point you're
at when at 600' AGL.

The only thing you can do is use the best judgement at the time. You get
one chance - it may be wrong. Sometimes, trying to turn back might be
wrong. Sometimes doing anything *other* than trying to turn back might
be wrong.

In gliders, every glider pilot is taught "the impossible turnback" from
200 feet (which, in the typical low performance training glider, is
about equal to turning back at 600 feet in a C172). We actually train
for it for real - there's no other way to do it - the instructor will
eventually pull the bung on you at around 200ft. It's an essential skill
because power failures (rope or cable breaks) are a lot more frequent
than engines quitting on a single. Doing it off a simulated winch launch
failure is quite exciting - we tend to do that at about 400 ft though
because it's an extremely critical manoevre, since you're pitched up at
50 degrees or so and any delay equals a low altitude stall. The ground
looks really, really close when you pitch down steeply to quickly regain
your airspeed and can see nothing but green in front of you. The really
important bit about this training though is you're not taught it as an
absolute. The mantra is to first do what it takes to maintain airspeed,
then quickly decide on a course of action. The course of action could be
any of several possibilities - can you get down on the remaining runway?
Can you turn back? Is what's in front of you landable? Land to the side?
Which way is the wind going? (If there's a crosswind aloft, this affects
the decision on which way you're going to turn: you should have already
decided turn direction in the 'eventualities' part of the checklist
before the slack is even taken up on the cable or tow rope).

The answer is as always training, and having a plan. Think of the
eventualities just as you line up - if you lose power at point X, what
should you do. At point Y, what should you do? What about point Z?

--
From the sunny Isle of Man.
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