Update on PC12 inflight breakup in FL

SpiraMirabilis said:
Can't even imagine the "stuff" you'd have to fly through to break up a PC-12, they're built pretty solidly.
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I don't think the airplane broke up because of the weather, I think it broke up because of the post autopilot disengagement whifferdills.

I am going to guess he got it too slow in the climb, got the shaker (which would disengage the a/p), didn't do anything to recover, which led to a pusher activation. Instead of letting the pusher do its thing and recovering, he pulled back on the yoke ala Colgan 3407 and things got exciting. Having very little instrument experience, and probably being in the clouds at the time didn't help the situation.

Very sad story, but sadly one we've heard many times before, and will hear again in the future.
 
Groundpounder said:
I don't think the airplane broke up because of the weather, I think it broke up because of the post autopilot disengagement whifferdills.

I am going to guess he got it too slow in the climb, got the shaker (which would disengage the a/p), didn't do anything to recover, which led to a pusher activation. Instead of letting the pusher do its thing and recovering, he pulled back on the yoke ala Colgan 3407 and things got exciting. Having very little instrument experience, and probably being in the clouds at the time didn't help the situation.

Very sad story, but sadly one we've heard many times before, and will hear again in the future.
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That wouldn't really be cause for a breakup though. There's plenty of videos that show the pc-12 stalls and spins real nicely.
 
Somewhere in one of the links associated with the report it states the airplane was 300+ knots prior to structural failure.
 
Stomp16 said:
What leads you to this conclusion/guess? What factual info are you basing your assumptions on?
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Well, I'm an ass. Found the actual NTSB report on line, which had more info than the other articles I read, and it specifically stated there was no pusher activation....

A radar performance study indicated that the airplane did not enter an aerodynamic stall, and according to the CAWS log entries, there was no record that the stick pusher activated before the departure from controlled flight.
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http://www.ntsb.gov/AviationQuery/brief.aspx?ev_id=20120607X54234&key=1
 
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Groundpounder said:
See my edited post.....I jumped to conclusions a little too quickly.....sorry.
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No worries, thanks for posting the link. For some reason, it will open the report if linked in a post, but I can not directly get it from NTSB.gov. I think it might be firewall issues at the hotel I'm at right now.
 
I read through the NTSB report - my CFII mentioned that I should read it last night when we were talking about IMC flight after a sim lesson.

Do A/Ps just disengage on their own? The report doesn't say that for obvious reasons, but the fact that he tested it immediately after makes me wonder if he tested it because he didn't like/believe what it was doing or....something?

The lesson I'm taking away at the moment is reinforcement of the primary rule: fly the airplane. No matter what. Fly the airplane.
 
killbilly said:
I read through the NTSB report - my CFII mentioned that I should read it last night when we were talking about IMC flight after a sim lesson.

Do A/Ps just disengage on their own? The report doesn't say that for obvious reasons, but the fact that he tested it immediately after makes me wonder if he tested it because he didn't like/believe what it was doing or....something?

The lesson I'm taking away at the moment is reinforcement of the primary rule: fly the airplane. No matter what. Fly the airplane.
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Autopilots will kick off if they're unable to do what you're requesting them to do, commonly due to excessive control forced being required. On the last plane I flew, that meant gusty crosswinds in IMC while coupled to an ILS.
 
killbilly said:
Do A/Ps just disengage on their own? The report doesn't say that for obvious reasons, but the fact that he tested it immediately after makes me wonder if he tested it because he didn't like/believe what it was doing or....something?
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I read elsewhere the PC 12 has an issue with the AP kicking off in turbulace. Can anybody verify that?
 
Some APs are very sensitive. Mine is a KAP-140 in a C-172 and it sometimes disengages when I start down at the OM. There's always the audible tone and mechanized callout "AUTOPILOT," so you'll clearly recognize that YOU'RE flying the airplane now, not George.
 
The PC-12 autopilot will kick off in moderate turbulence, especially if there is something out of rig. But, while the report makes no mention of the stick shaker, if the airplane was in pusher ice mode, he'd have gotten the shaker at 109 knots, which is what the report states as the speed at which the a/p kicked off. The shaker will disengage the autopilot.
 
tomokc said:
Some APs are very sensitive. Mine is a KAP-140 in a C-172 and it sometimes disengages when I start down at the OM. There's always the audible tone and mechanized callout "AUTOPILOT," so you'll clearly recognize that YOU'RE flying the airplane now, not George.
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Unless you're doing 120KIAS, I think you have a servo or computer issue. Is it a 2001 or newer 172?
 
Why would you put your entire family on an airplane with you at the helm, with such little experience? Very unfortunate for them.
 
Just reading how low time the guy was, how little time he had in the Pilatipus, how his sim partner said he was behind the plane at Simcom...





And...that he couldn't control an airplane with the autopilot off and went full aft on the controls 175 knots above maneuvering speed in a spiral dive.

It has all the hallmarks of a modern Bonanza/doctor saga.
 
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