On Sun, 10 Sep 2006 07:28:36 +0200, Mxsmanic
wrote:

RK Henry writes:


But it doesn't work like that in the real world. The airplane
inherently imparts accelerations that are inconsistent with the
indications of the instruments.

Which ones?

In one common exercise, referred to as Recovery from Unusual
Attitudes, the instructor, or eventually a FAA-designated pilot
examiner, will ask the hooded student to look down or conceal his
eyes. With the student unable to see what is going on, the instructor
will take the airplane through a series of maneuvers calculated to
disrupt the student's inner ear equilibrium. Once that has been
accomplished, the student is asked to look at the instruments and take
over control the airplane. Immediately, the student will notice that
the airplane's attitude is seriously out of whack. He has to recognize
what's wrong and fix it. The challenge is complicated by the fact that
the previous maneuvering has given rise to inner ear equilibrium
sensations that conflict with the instruments. He may level the wings
but still have a sensation that the airplane is continuing to roll. He
may bring the nose to the horizon but experience a sensation that the
airplane is continuing to pitch up or down.

It's a little like the game that kids play of sitting in an office
chair and spinning round and round until they're dizzy. Great fun when
you're a kid, not so much fun if the sensations trick you into taking
improper actions with the airplane. You just have to learn to ignore
the sensation through sheer mental willpower.

Part of the training process is learning to ignore the
sensations and trust the instruments.

That rather conflicts with the preceding statement, doesn't it? If
the instruments don't accurately indicate accelerations, why trust
them?

The thing is, the instruments should be trusted over the sensations of
the inner ear, but they can't be trusted completely. Another facet of
instrument training is understanding the limitations of the
instruments. One example is precession errors. All gyroscopic
instruments exhibit this behavior to some extent. You may roll into an
intensive series of maneuvers and after rolling level may discover
that the attitude gyro no longer indicates "up." It's slightly tilted.
From the other instruments, you deduce that it's the AI that is wrong
and that the airplane is actually level. The AI will right itself
after a short time, but you have to understand the instrument in order
to not be tricked into following its incorrect indication in the
meantime. Similarly, most of us fly airplanes in which we have to
reset the directional gyro regularly to keep it in agreement with the
magnetic whiskey compass. Otherwise it eventually drifts off to
indicate some heading that has little basis in reality.

And then sometimes the instruments perversely decide to fail. During
instrument training, expect the instructor to pull out a piece of
paper, or a suction cup thingy, to cover one, or more, or maybe even
all of the instruments. Then instead of looking at the attitude gyro,
you're deducing the state of your airplane based on what's left,
including airspeed, changes in altitude, and maybe even just sound.
You'll then be asked to perform some maneuvers to demonstrate your
ability to compensate for the lost information.

Instrument flying doesn't come from the instrument panel, it comes
from between the pilot's ears. It's a mental process, which is why so
many people seem to find it so difficult. It isn't about making the
instruments do something, it's about making the airplane do something.
It's about challenging the forces of nature and prevailing, and
celebrating your triumph with your beverage of choice at some pleasant
spot hundreds of miles from where you started. It's about seeing and
doing things you've never done before.

Which raises an interesting question: Who here has seen a glory?

RK Henry