In article , Bruce
Hoult writes

It's amazing how hard it is to get *true* no-visual-reference conditions
in IMC.

I've done some flying with a commercial pilot friend doing night freight
runs in small turboprops. Even in the clouds in the middle of nowhere
in NZ you can almost always see some speck of light out of the corner of
your eye, whether a farmhouse or a star, and that gives you roll
information even when you're not looking at the AH. You don't realize
how much this helps until the first time there really *is* nothing out
there.

A reference if you are rolling but for a controlled descent you do not
want to be rolling. More important, what about horizon reference? I
have often seen "false horizons" in cloud layers and at night. They can
be very disorientating. For instance, I got severe "leans" once when
coming off a tanker at night when the lit tanker was in a turn. And
several times when between slanting cloud layers.

Not a glider case, of course, but "beware the false horizon" and
"believe the turn needle" would appear to be good guidance!

Incidentally the title of this thread uses the word "benign". An
accelerating spiral in a slick glider can be anything but benign. It is
not difficult, I imagine, to literally pull the wings off in an attempt
to recover. The rule on "limited panel" unusual attitude recoveries was
"don't pull until you have the turn needle within about Rate 1 of the
centre of the instrument.

--
Ian Strachan

Bentworth Hall West
Tel: +44 1420 564 195 Bentworth, Alton
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