In article , Todd Pattist
writes
I've also had some pilots tell me they were trained years
ago to use a standard compass
That is, an old fashioned one with pendulous suspension of the magnet
assembly. This type of compass has acceleration errors on east and west
and turning errors on north and south. What may be an "error" in terms
of registering an accurate instantaneous heading, might be turned to
advantage in a case of total failure of gyro instruments. With great
caution, of course, and IMHO not the best answer, see below.
, head south
It is true that a pendulous compass has turning errors on South, and
could be used a sort of turn indicator on that heading.
and steer with
rudders.
No! A good way to get disorientated, IMHO. What is wrong with turning
in the normal way, application of (in this case) small amounts of bank
where necessary. Fly gently, don't get used to coarse use of
unnecessary control inputs. Particularly boots of rudder un-coordinated
with aileron, unless you wish to spin or do aerobatics, of course!.
However, to stay alive in instrument flying, particularly in turbulence,
there is no substitute for proper aircraft-designed gyro instruments.
I taught and examined on what we used to call "limited panel" for many
years, AND IT WORKS, with a bit of practice. That is, instrument flight
using a good old Sperry turn gyro presented through a needle display
("needle, ball, airspeed ... needle, ball, airspeed"). Turn gyros take
little power and normally run on DC, so are well suited to glider use.
People say that instrument flight using only a turn needle is difficult,
But at least it is designed for the job, unlike pendulous compasses, GPS
presentations etc. And what is difficult is limited-panel accurate
pattern turns, approaches etc., with an examiner breathing down your
neck!
Merely keeping the wings about level so as not to enter a spiral dive,
is not difficult. On a safe heading, of course, that is away from known
high ground. Try it in a two-seater with a safety pilot, but make sure
that you are really "under the hood" and are not peeping out to see the
horizon, otherwise you are not really getting proper training that might
get you out of trouble later.
The dear old Link Trainer was pretty good for this training also, but
there aren't many about now except in museums!
Of course even better if your glider has a gyro-driven Artificial
Horizon as well as that rate-gyro. Makes instrument flight for those
not in practice, including me nowadays, reasonably straightforward.
--
Ian Strachan
Lasham Gliding Centre, UK
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