How to get rid of that autopilot

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pelmet
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How to get rid of that autopilot

Post by pelmet » Thu Nov 29, 2018 12:47 pm

"C-GMLS, a privately registered Cessna 340A aircraft, was conducting an approach at Ponoka Industrial (Labrie Field) (CEH3), AB with only the pilot on board. The pilot missed the first approach due to autopilot malfunction issues, and decided to do a forced landing during the go-around due to the autopilot that would not disconnect as needed. As the forced landing in a field was executed, the aircraft struck a tree during the slide. The aircraft was substantially damaged, and the pilot walked away with a serious injury."

I wonder if simply turning off the electrics would possibly save the day strictly in terms of regaining control of the aircraft.

Any opinions?
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Bacunayagua
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Re: How to get rid of that autopilot

Post by Bacunayagua » Thu Nov 29, 2018 1:00 pm

Interesting situation.

I always make it a point of familiarizing myself with the location of the more "critical" CBs, incase simply turning off the unit/ electronics isn't doing the job. That being said, I never found it difficult to overpower the A/P servos in small planes. As a matter of fact, I think it is part of the certification process that they be easily overpowered, no? Maybe someone can correct me on that. I remember when I used to fly similar sized/weight Cessnas, moving the controls around when the A/P was engaged was part of the A/P systems check while still on the ground.
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MUSKEG
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Re: How to get rid of that autopilot

Post by MUSKEG » Thu Nov 29, 2018 2:00 pm

I believe turning off the avionics master would do the job. Quick and easy.
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TeePeeCreeper
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Re: How to get rid of that autopilot

Post by TeePeeCreeper » Thu Nov 29, 2018 2:07 pm

MUSKEG wrote:
Thu Nov 29, 2018 2:00 pm
I believe turning off the avionics master would do the job. Quick and easy.
Yep, loosing all your primary flight desplays rather than disconnecting the AP or pulling the AP breaker sounds like a GREAT idea while in IMC!
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J31
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Re: How to get rid of that autopilot

Post by J31 » Thu Nov 29, 2018 2:15 pm

pelmet wrote:
Thu Nov 29, 2018 12:47 pm
"C-GMLS, a privately registered Cessna 340A aircraft, was conducting an approach at Ponoka Industrial (Labrie Field) (CEH3), AB with only the pilot on board. The pilot missed the first approach due to autopilot malfunction issues, and decided to do a forced landing during the go-around due to the autopilot that would not disconnect as needed. As the forced landing in a field was executed, the aircraft struck a tree during the slide. The aircraft was substantially damaged, and the pilot walked away with a serious injury."

I wonder if simply turning off the electrics would possibly save the day strictly in terms of regaining control of the aircraft.

Any opinions?
A Cessna cabin class twin crashed because the pilot could not turn the autopilot off!

I think the issue was mostly a lack of knowledge and poor or no training.
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oldtimer
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Re: How to get rid of that autopilot

Post by oldtimer » Sat Dec 01, 2018 9:25 pm

There are at least 2 foolproof ways of disconnecting an autopilot. One is a switch on the autopilot controller that is marked OFF. Then there is the big red button on the control column marked OFF that when pushed, shuts off the autopilot. Sounds to me the pilot needs some Special Hight Intensity Training (SHIT) if you get my drift.
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Lightchop
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Re: How to get rid of that autopilot

Post by Lightchop » Sun Dec 02, 2018 3:00 pm

Bacunayagua wrote:
Thu Nov 29, 2018 1:00 pm
Interesting situation.

I always make it a point of familiarizing myself with the location of the more "critical" CBs, incase simply turning off the unit/ electronics isn't doing the job. That being said, I never found it difficult to overpower the A/P servos in small planes. As a matter of fact, I think it is part of the certification process that they be easily overpowered, no? Maybe someone can correct me on that. I remember when I used to fly similar sized/weight Cessnas, moving the controls around when the A/P was engaged was part of the A/P systems check while still on the ground.
In the Ho you just give it a sharp yank and the AP disconnects. Not good for the system but in an emergency it would do the trick.
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Zaibatsu
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Re: How to get rid of that autopilot

Post by Zaibatsu » Mon Dec 03, 2018 10:27 am

It probably saved his life.

I shudder to think of a private pilot staying on instruments hand flying an aircraft while fighting a runaway autopilot.
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switchflicker
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Re: How to get rid of that autopilot

Post by switchflicker » Mon Dec 03, 2018 12:41 pm

oldtimer wrote:
Sat Dec 01, 2018 9:25 pm
There are at least 2 foolproof ways of disconnecting an autopilot. One is a switch on the autopilot controller that is marked OFF. Then there is the big red button on the control column marked OFF that when pushed, shuts off the autopilot. Sounds to me the pilot needs some Special Hight Intensity Training (SHIT) if you get my drift.
I think we sued to call that the B R B.
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co-joe
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Re: How to get rid of that autopilot

Post by co-joe » Thu Dec 06, 2018 2:44 pm

That's a head scratcher. Couldn't disconnect the autopilot...so he tried to land in a field? Give that man a drug test. Give him two just to be sure.
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FlyGy
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Re: How to get rid of that autopilot

Post by FlyGy » Fri Dec 07, 2018 7:25 am

Last summer my Cherokee trim switch decided to short out and transit to full pitch up while on climb out. Although I could control the aircraft, it isn't something I'd be able to do for very long. The red button made life much easier as I turned around to land.

Edit for detail.

While the switch was smoking I couldn't physically move the trim wheel against the force of the motor. With my master shut off I was able to manipulate my trim wheel and land normally.
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Last edited by FlyGy on Fri Dec 07, 2018 7:59 pm, edited 1 time in total.

pelmet
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Re: How to get rid of that autopilot

Post by pelmet » Fri Dec 07, 2018 8:48 am

FlyGy wrote:
Fri Dec 07, 2018 7:25 am
Last summer my Cherokee trim switch decided to short out and transit to full pitch up while on climb out. Although I could control the aircraft, it isn't something I'd be able to do for very long. The red button made life much easier as I turned around to land.
Interesting experience. I wonder if an autopilot disconnect switch could have some sort of malfunction like this and not disconnect. Or some single point failure closer to the autopilot itself.

Any avionics types around here?
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