Backup gyros - which do you trust?

There is one IFR flight school that gives the student the introduction to
the AI during their first briefing in the first hour...
Instructor: "See, that's the AI... See how it gives you both pitch and
bank."
Student: "Yes, that's really nice."
Plonk goes the sink stopper...
"That's the last time you will see it until your check ride, son.!"

Denny

"Aaron Coolidge" wrote in message
...
In rec.aviation.owning Roy Smith wrote:
: David Megginson wrote:
: But once you're established, do you find it easier to hold pitch using
: the ASI?

My big, ugly, AN horizon has been working reliably for decades... Makes you
kinda wonder...

Denny

"Michael" wrote in message
om...
Sydney Hoeltzli wrote
What do you think of the conclusions?

Aaron Coolidge writes:

In rec.aviation.owning Roy Smith wrote:

: David Megginson wrote:
: But once you're established, do you find it easier to hold pitch using
: the ASI?

: Not really. When I'm doing partial panel work, I find I miss the DG
: much more than I miss the AI.

I totally agree with Roy here. I also don't use the AI as much as some. I too
fly pitch using the ASI, although I use the AI as a reference to set pitch
during level-offs. I too miss the DG more than the AI in partial panel
work. I do fly a fixed-gear Cherokee, though.

Note that I wrote "ASI", not "AI", so it might be that all three of us
agree.


All the best,


David

--
David Megginson, , http://www.megginson.com/

"Sydney Hoeltzli" wrote in message
...
Michael wrote:

2) since 2 AIs weren't enough to keep the plane upright (combined
with 2 turn and banks, 2 of every other instrument), require
passenger planes to have 3

Yes, that's the recommendation. IMO it's unmitigated crap. First
off, AI's should not be failing at an average of less than 300 hours.
Second, there were still two good PNI's (basically HSI's) and
turn&slip indicators. But could the pilots use them? Probably not
because "This technique, commonly referred to as 'limited panel' (see
paragraph 1.5.3.2) does not form part of a professional pilot's
recurrency training and testing."

You Have Got To Be Kidding.

Are you serious? Yes, I missed that. Are they asserting this
shocking hole in proficiency training is widespread?

I think you're barking up the wrong tree here. Classic teaching of
partial/limited panel involves covering an instrument and then continuing to
fly without it. In the case of the Bandeirante accident, that wasn't the
issue. There was still a perfectly serviceable AI in the panel, and a pilot
sitting in front of it. The issue was identifying the failed instrument in a
complex cockpit environment.

The chances of being left with no working AI in the panel of a transport
aircraft (which starts with 3 AIs) but still having the instrumentation to
fly partial panel are so remote that it's not worth the time to train on it.
That time is better spent on other exercises, one of them *recognition* of
instrument failure.

For GA aircraft the situation is different. The probability of ending up
with a TC but no AI is much higher, and controlling the aircraft
successfully without it is easier. That makes it well worth the practice.

Julian Scarfe

Julian Scarfe wrote:

I think you're barking up the wrong tree here. Classic teaching of
partial/limited panel involves covering an instrument and then continuing to
fly without it. In the case of the Bandeirante accident, that wasn't the
issue. There was still a perfectly serviceable AI in the panel, and a pilot
sitting in front of it. The issue was identifying the failed instrument in a
complex cockpit environment.

I'm not sure I'm barking up the wrong tree.

Possibly practicing flying partial panel makes little sense. OTOH,
practicing partial panel *does* teach which combinations of instruments
can be used to provide the same information as the missing AI.

Surely this is relevant to obtaining and maintaining a good
crosscheck -- and wouldn't good crosscheck be the key to identifying
the failed instrument in a "complex cockpit environment"?

BTW, my reading of the accident report is that they weren't
certain but what both AIs had failed -- something that was certainly
within statistical likelihood given the low MTBUR

Cheers,
Sydney

I have a Garmin 196. It has a simulated instrument
panel page on it that is pretty accurate. It would be
the tie breaker in the event of confusion over what
the gyro instruments were saying.


"Sydney Hoeltzli" wrote in message
...
Julian Scarfe wrote:

I think you're barking up the wrong tree here. Classic teaching of
partial/limited panel involves covering an instrument and then
continuing to
fly without it. In the case of the Bandeirante accident, that wasn't
the
issue. There was still a perfectly serviceable AI in the panel, and a
pilot
sitting in front of it. The issue was identifying the failed instrument
in a
complex cockpit environment.

I'm not sure I'm barking up the wrong tree.

Possibly practicing flying partial panel makes little sense. OTOH,
practicing partial panel *does* teach which combinations of instruments
can be used to provide the same information as the missing AI.

Surely this is relevant to obtaining and maintaining a good
crosscheck -- and wouldn't good crosscheck be the key to identifying
the failed instrument in a "complex cockpit environment"?

BTW, my reading of the accident report is that they weren't
certain but what both AIs had failed -- something that was certainly
within statistical likelihood given the low MTBUR

Cheers,
Sydney

I played with that page on the 196 yesterday in moderately gusty
conditions... You have to be smooth on the controls, make your correction
and then wait for the unit to update... Flown that way it is useable and I
suspect that I could fly an approach with it in real conditions (an ILS to
minimums would be hairy).. The work load is significantly higher than with
the gyros..

But, if you do not wait for the screen to update you get into a world of
hurt... Since it was nice and bumpy I put the hood on and then flew it like
I was panicky - rapid, big,. inputs - It only took about 30 seconds to get
out of sync, with the ship laid over on it's side, whereupon I had the fun
of recovering from an unusual attitude... Other than the speed having
gotten further into the yellow arc than I like it was good exercise... About
this time the controller came on and asked me to say intentions - uh, oh,
busted!

Denny

"Roger Tracy" wrote in message
...
I have a Garmin 196. It has a simulated instrument
panel page on it that is pretty accurate. It would be
the tie breaker in the event of confusion over what
the gyro instruments were saying.