On 30 November a Pilatus PC-12 aircraft crashed in Chamberlain SD. I believe there were 12 occupants on the plane, 4 generations of an LDS family from Twin Falls and/or Idaho Falls. I don't recall all the details. Only 2 of the occupants survived the crash.

Discussion of preliminary NTSB report (about 15 minutes):
https://www.youtube.com/watch?v=8S8E4wFSmN0

Short version: There had been bad icing conditions the night before, bad enough to close I-90 to the WY border. Two of the family members spent 3 hours cleaning ice and snow off the aircraft. There was a flight data recorder which also records voice, though a transcript is not available yet. The plane was heavily loaded, though the effect of that on the crash was not in the preliminary report.

What is known so far is that the plane stalled on takeoff, rolled sharply to the left after the stall commenced, which is typical for a full power stall, caused by engine torque. The debris field was only 85 feet long, so the forward speed of the aircraft was quite slow, and the debris field was pointed toward the airport, which may mean the plane was attempting to return to the airport [me: or it could have just spun around in the stall. Needs further analysis]

The narrator read a Pilatus notice that it can take up to 700 feet to recover from a stall, and the plane that crashed was only 400 feet in the air at the time of the stall.

Final report expected about this time next year. That will no doubt go into whether and how much weather/ice or loading or pilot experience were factors.

It should be noted that this was not a professional pilot flying. It was the family patriarch. I know a lot of commercial pilots. They all said that a pro pilot would've have nixed the takeoff. Ice and fog are a deadly combo. Looks like an arrogant, foolish decision to even attempt a takeoff. Guess the magic underwear has a shelf life.

stillanon Wrote:
-------------------------------------------------------
> It should be noted that this was not a
> professional pilot flying. It was the family
> patriarch. I know a lot of commercial pilots. They
> all said that a pro pilot would've have nixed the
> takeoff. Ice and fog are a deadly combo. Looks
> like an arrogant, foolish decision to even attempt
> a takeoff. Guess the magic underwear has a shelf
> life.

If there was not adequate de-icing/anti-icing equipment at the airport, then you are correct, a professional pilot would not have taken off. In fact most regulations would have prevented a takeoff if the aircraft was operating commercially. At the basic level, any ice or snow contamination on the wing is an automatic no-go.

Yeah, having your kids scraping ice off of wings and control surfaces, is not proper de-icing. It was a stupid move. They said they scraped for 2+ hours. Even with chemical de-icing, if it's been more than 20 minutes, depending on temps, commercial planes return to get de-iced again.

At some point you have to wonder if that was a factor. Poor weather conditions, amateur pilot, bad loading factors. Did the patriarch believe that his magic powers of mormon hierarchy lead him to believe they would be blessed and protected? Because nothing else was in their favor.

In a heavy fog, one can easily speculate that the urge to climb faster than the ability of the plane to respond was the major factor (absent mechanical issues) in the reduction of speed until 'lift' vanished.



ETA: it occurs to me that as a non-pilot, I just stated something so obvious as to be laughable.



Edited 1 time(s). Last edit at 01/03/2020 05:04PM by elderolddog.

LOL. Pilot check lists are page after page of "obvious". When something unexpected comes at you out of the blue, the ability to spot the obvious gets severely tested.

The correct response in a potential stall is to lower the nose, lowering the angle of attack of the wings, and picking up airspeed, both good things under the circumstances. The plane had a stick-pusher that would automatically do that if the pilot didn't. That is why I suspect that the plane may have been tail heavy, and it was impossible to lower the nose. Also, it is a T tail plane, so the tail fins are high off the ground, which likely made them difficult to clean off the ice snow.

So, tail heavy, or icy tail - either could have been a lethal problem, and it is entirely possible both conditions were true. It may have been impossible to avoid the stall, no matter the pilot skill. The real skill needed was to say "I don't care what it costs, we're not going anywhere today." That's hard to do.

The plane was loaded to max passengers +1. Some were kids so, maybe the added 2 as one. Plus, guns and ammo from the hunt. But, like you stated, if the stall control recovery is 700 feet and they stalled at 400 feet, the math isn't working in their favor.



Edited 1 time(s). Last edit at 01/03/2020 06:16PM by stillanon.

More and more under-qualified climbers are paying big money to check off their bucket list. They get up high, often having to wait long times on the rope line to get their +/- five minutes and camera shots on the peak. More experienced climbers will turn back, but no, not these yo-yo vainglorious tourists. And so, many of them die, their bodies mummified in the snow.

Moral of the lesson: vanity and hubris are equal-opportunity killers.

Agreed on the above comments. The prudent decision would have been to just wait a day to fly home. That's expensive and people had stuff scheduled, so they didn't want to do that. That's basically why the Challenger space shuttle took off even though the air temps were outside the range the equipment had been tested for. We know how that turned out.

If the plane was overloaded, and especially if it was tail-heavy (center of gravity too far aft) because of all the guns and pheasants, it might have gone down regardless of the weather. The plane was pushing many limits (ice, load, experience) and all three being at the limit makes the other two more likely to end up in a failure mode. Regardless of what the final cause is determined to be, they were pushing (or even exceeding) way too many limits. Flying was a very poor bet under the circumstances, and it turned out to be a losing bet.

But the pheasants got payback. It’s time for another conference talk. Don’t kill the little birds, God will get you.

I used to subscribe to Flying magazine and the NTSB crash reports all too frequently had pilots taking off in conditions they had no business flying in. We lost members of two local families who crashed while flying into icing conditions their aircraft were not equipped to fly in but with a "hot shot pilot" at the controls trying to prove how good they thought they were. Tragic and so sad. Get a hotel and wait it out.

Every time I hear the word "patriarch", my mind translates it as "moron".