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Loss of vacuum pump, VMC on top, leads to a fatal crash

He had no other gyro instruments, it seems



Administrator
Shoreham EGKA, United Kingdom

I think he had the old style needle and ball. The trouble is in a V-tail Bonanza, in any turbulence, it just waves side to side like a metronome in level flight (the V tails especially like to wag their tails in any turbulence). Add to that the Bonanza is slippery and neutrally stable in roll and if you’re not 100% on your game with partial panel flying, it will quickly lead to a bad outcome.

My thoughts for a gyro failure in the Bonanza if IMC were unavoidable would be slow down and make the plane draggy (gear down provides a lot of drag) if possible. Of course if it’s hard IMC for hundreds of miles this isn’t possible but when I was flying the club’s Bonanza, I didn’t live in the kind of place (Houston) where it tended to be hard IFR for hundreds of miles (and if it was you didn’t want to fly in it due to the thunderstorms).

Last Edited by alioth at 20 Dec 09:45
Andreas IOM

I have had 3 in-flight vacuum failures, one in actual IMC with a 7-800 ft ceiling. I had no passengers to distract me, I was in familiar airspace, the airplane was very stable, and I had a turn coordinator, not the old basic turn indicator. I found the hardest ting was not to look at the useless DI all the time, and while my heading was way off several times during approach manoeuvring, I managed to keep the dirty side down and never banked more than rate 1. I can imagine how difficult it would be to handle partial panel in a V-tail Bonanza with the old type turn indicator only.

huv
EKRK, Denmark

You must have, at the very least, post-it notes with you to cover the failed instruments. If you don’t, it is almost impossible to ignore the instruments that you have spent so many years learning to bet your life on.

When I train people on the sim, whatever the exercise, I always throw in a vacuum failure at some stage and they always die. A real failure is nothing like the way it is trained on the aircraft. In the aircraft you cover the AI and DGI and it’s all obvious and easy. In reality, as they say in the video, the pump runs down slowly, the vacuum decreases slowly, the gyros run down slowly and by the time it is obvious that you have a problem you may already be in a spiral dive.

And vacuum pumps do fail. It really is a critical single point of failure.

The potential safeguards are:

  • A rate-based autopilot, such as the STEC. This means that you always have either autopilot or AI.
  • Glass, with a vacuum backup
  • Electric backup AI
  • Two vacuum pumps feeding independent systems including a second AI

Personally, I think that anyone doing a lot of IMC should do one of these things. The cheapest is probably the electric backup AI.

EGKB Biggin Hill

And add to that a completely independent attitude indicator via Stratus/Stratux/Etc..

ATPL / IFR Instructor
Europe

Timothy’s advice is wise with an independent electrical AI being, for most GA planes, the most practical.
In the USA, many pilots in Experimental Aircraft are using this

Rochester, UK, United Kingdom

A-EFIS successfully.
Being so cheap, it is something that perhaps all of us should have on our phones?

Rochester, UK, United Kingdom

This is relevant to all planes with analog instruments; I have that backup system which uses the intake manifold in the Bonanza, but additionally, with the WAAS update I had a Flightstream 210 installed which provides an independent certified attitude information to the garmin pilot app. This can make a difference.
What he should have done is while in VMC, request a straight and level descend, lower the gear, stabilize a 500ft/min descend and then fly it through the clouds using the turn and bank indicator.

Last Edited by EuroFlyer at 20 Dec 12:40
Safe landings !
EDLN, Germany

Many of us already have the necessary emergency tool → on their Apple phone. Up to iOS11 there is a level in the compass.app, iOS12 and up it moved to the measure.app. It is not perfect, but I guess may save your a### in case of. As my iPhone is mounted on an XGRIB in the cockpit, we leveled it during my last check ride and tried using it as backup device – it does work surprisingly well.

Last Edited by at 20 Dec 12:51

I died many times on this using flight sim and radom failures, unless you hide that problematic AI, cross checking is not enough you will certainly crash it just a matter of how long it takes in units of hours…

I guess a backup AI on iphone gyros will do the job for a short non precision decent?

Last Edited by Ibra at 20 Dec 12:34
ESSEX, United Kingdom
36 Posts
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