(Michael) wrote in message . com...
(Snowbird) wrote
One observation from the recent ASF/FAA vacuum failure study
was that pilots who lost only their AI (electric HSI did not
fail) did not lose control of the airplane, while a significant
number of pilots (same aircraft) lost control when they lost
both. There was no correlation to time in type or total time.

This result suggests to me that it might be a mistake to
extrapolate from "lose AI no problem" to "lose gyros no
problem".

That's somewhat valid. I don't worry about this situation for two
reasons: First, I have dual vacuum pumps, so loss of both gyros
simultaneously is very, very unlikely.

I wasn't so much concerned about your personal setup but about
your posting history, which is to pipe up whenever the subject
of gyro failure (and bad outcomes thereof) are discussed and
say something to the effect of well, I've had a gyro failure in
actual and it was no big deal so contrary to popular opinion I
don't think it's something a proficient pilot needs to sweat
about. (I paraphrase here, and perhaps that wasn't the message
you intended to convey, but it's the message I and, I think,
others, have garnered from your posts)

That's why I think the distinction between a single instrument
failure, and vacuum failure (loss of two instruments) may be
relevant to point out.

I've already made my feelings about flying IMC with a single
dry pump and no backups well known, but in case anyone missed it -
it's stooopid.

Actually, I'm glad to hear you say this. The impression that
I've received from your previous posts is that you believed a
vacuum failure should be no big deal at all to a proficient pilot.
Not a reason to abort the flight, declare an emergency, and
request no-gyro vectors to the nearest ILS, for example (which
is my notion).

If that's not the case, I'm at a bit of a loss as to how to
interpret some of what you've previously posted.

If that is the case, I'm at a bit of a loss as to why you
feel lack of backup is so stupid -- if it's no big deal and any
proficient pilot should be able to cope without breaking a
sweat, why is backup important? If the cause of accidents
following vacuum or gyro failure is lack of proper, recurrant
training, why not just invest in training instead of redundant
instrumentation or vacuum sources--isn't that what you've
suggested in the past when the point has been raised?

The reason I say it's somewhat valid is this - my (admittedly somewhat
limited) experience as an instrument instructor is that most people
miss having the DG a lot more than they miss having the AI.

That's certainly true for me.

[nb this originally referred to "ugly outcomes" to gyro failures
in IMC]
There are currently no "real stats" which prove or disprove
the contention that this ugliness is entirely due to improper
training.

No, but that's the way to bet. It's certainly how my insurance
company is betting - I'm now required to take a full IPC with engine
cuts every year in make and model, regardless of recency of
experience, if I want to keep my relatively low rates.

Apples and oranges to the topic under discussion here, which was
whether the "ugly outcomes" of vacuum failure are entirely due
to improper training.

Unless I'm missing something, there is no requirement that an
IPC necessarily include partial panel work, so it's not clear
to me how your insurance company votes on this topic. The
principle cause of accidents in light twins is not related to
vacuum failure due to redundant systems.

Cheers,
Sydney