Video of the incident, photographs of the immediate aftermath, statements of first responders, and my personal inspection of the crash site. The aircraft went down almost perpendicular and all nonmineral remnants of passengers and cargo were consumed. Perhaps professionals are better equipped for that kind of assesment but I don’t see how. As the vernacular goes, it was at most a smoking hole.
From the images in the docket, while the aircraft was completely destroyed by fire, the metal seat frames wouldn’t be completely destroyed and you can see where all the seats are in relation to each other. You’ve likely got remains strapped in each seat to identify who was sitting where (it’s not a pretty thought, but I doubt the bodies were complete consumed by fire). In a small aircraft like the P210, there’s really only the aft baggage compartment for luggage and maybe a shoulder bag stowed somewhere forward.
beat by Dr Strangelove…
I appreciate the insight. It’s not what I’ve been waiting 2 years to hear, but I guess it is what it is.
I agree with txtumbleweed that the weight and balance was not the direct cause of the accident. The cause was the pilot’s seat sliding backwards and therefore being unable to keep the aircraft in a nose-down configuration. But the weight and balance exacerbated the problem. The seat might not have slid back otherwise, or the aircraft might have been trimmed well enough that the pilot could have recovered.
Exactly, you can forget to lock your seat, or fuck up your CG calculation, but not both. It’s just hard to believe he did that.
The seats aren’t too different from manual car seats. You pull on a spring-loaded lever and can move the seat fore and aft. But the mechanism can fill up with crud, and the pins can get bent, so it can seem like it’s locked when it is just barely holding in place. And the aircraft was known to have problems in this regard, recommending an extra stop.
It’s not forgetting to lock the seats; it’s just not verifying that they are solidly locked in place.
I get it. It’s just hard to accept. These were all known things. Gross takeoff weight is a known thing, center of gravity for the aircraft is known and well-documented, the seat rollback issue was known and well-documented thing. He was known to be a detail-oriented guy with 7 years of piloting experience, it’s just hard for me to imagine how he messed all this up with his daughter and family friends onboard.
When you have done most of your flying alone or with an instructor, it can take a lot of your attention to have several passengers, especially if they are family or friends traveling to the field with you, probably asking a lot of questions. For most of our flying we just get into the mindset that more fuel is safer, and I think the weight and balance is a completely understandable oversight, even for a diligent and careful person.
And it’s not clear to what extent the seat locking issue was a mistake vs a design flaw or even mechanical failure. As you said, absent something else going wrong, the weight and balance oversight would likely not have caused an accident. I think he likely would have realized en route, burning fuel would then have helped, and his wife could have swapped places with the 33lb bag to improve C of G.
I’m so sorry for the loss of your friends.
He probably wouldn’t have even noticed. By itself, the weight mainly affects climb performance–but this was a pretty high performance aircraft, and it wasn’t a hot day, and they were not much above sea level. So it’s doubtful that would have been a problem. And the CoG was just a little behind the limits for max payload, though it’s unclear what they should have been at the actual weight. Still–probably a case of needing close to max trim, but not totally uncontrollable.
I appreciate the insight. Yes, I think of him with his newly upgraded aircraft, excited to impress people, distracted by questions, thinking it’s just another single-engine like he’s accustomed to, but with better performance. He might forget the trim or underestimate the torque roll but it’s hard to imagine him messing up a purely numbers function like weight and balance. But it’s always the basic things that get us in in life, isn’t it.
I don’t know if this excess beyond maximums would be noticeable vs maximums, but the difference in performance compared to what he was accustomed to without passengers would have been noticeable. So I think as he focused on flying and thinking about the performance of the aircraft it would quickly have occurred to him that he forgot to do the weight and balance.
Certainly the difference between just the pilot and main tanks full vs. a full passenger load plus all aux tanks full would be noticeable. I just doubt that it would have seemed to have abnormally bad performance. It might have felt peppier overweight than a 172 would have been under the best of conditions!
But remember that we’re not talking about a situation where he did a weight and balance calculation but made an error in the arithmetic. I’m not suggesting that aircraft performance would allow him to infer weight or C of G with any accuracy. I’m just saying that as soon as he starts focusing on the aircraft and thinking about performance it’s quickly going to occur to him that he forgot to do weight and balance. And then, as a fairly experienced pilot, he will immediately realize that he’s probably overweight and at risk of C of G aft of limits.
I see. Yes, that’s certainly possible. Though one has to account for normalization of deviance–something like “well, we’re definitely overweight, but the plane handles fine, so it’s probably not worth turning around”. Even very smart and diligent people can fall into this trap.
Turning around and landing certainly isn’t a good idea, since burning fuel will reduce weight. If there’s no bad weather ahead, in this situation I think I’d just continue as planned, have the person in the aft seat move into the middle row, and just try to maneuver as gently as possible on the eventual approach and landing. I might divert to a field with less traffic / better weather.
I’m not sure what tank controls the plane has, but preferentially pulling from the transfer tank would have had the most effect here. It has about 3x the moment arm of the main tanks. They probably could have gotten an acceptable CoG before going under the max gross weight.
In this case there wasn’t any time for any of that. It happened on takeoff. Video is available if you google “zac summers pdk crash twitter”. The video quality isn’t great but you can see they were airborne for maybe all of 5 seconds before it stalled and crashed.
So here’s another detail I’m struggling with, the more I think of it. Snipping some text to put these sections in contrast (bolding mine)
So we know for a fact there was no secondary lock. We’re implying that the primary lock either failed or wasn’t engaged, suggesting that the seat was entirely free to roll far enough aft that the 5’8" pilot couldn’t actuate the controls. That unfortunately happens often enough that it’s a well-known and uncontroversial issue. We’re claiming this based on the seat supposedly being witness-marked in the aft position at impact. But something’s off about that:
Can you see the problem here? We’re saying that the seat freely rolled back after rotating maybe 20 degrees nose-up. Fair enough. But the analysis claims that the seat was witnessed-marked as being in the aft position even after nosing over and impacting terrain at ~50 degrees inverted). It’s hard to buy that the free-rolling death seat somehow remained in the fully aft position even after an inverted nosefirst impact.
I’m not getting at any sort of conspiracy theory here. For 2 years I’ve been waiting for the complete report to drop, with a high expectation of pilot error. I just wanted to know what he missed. The impact didn’t leave much intact evidence to go on, the security video was poor quality. If they reported inconclusive results, I’d grudgingly understand and accept. But I feel like they couldn’t determine what happened, and used some rough weight estimates combined with reports of similar situations to throw together a reasonable conclusion, a serviceable cautionary tale about how to avoid similar incidents: don’t take off overweight, be mindful of CG for pax and cargo, consider fuel distribution, always lock your seat and check it thoroughly.
I believe the overweight estimate. I could believe a CG issue or seat rollback, but I could also believe the investigator just threw together a reasonable story to close it out.
Do planes of this size carry a “black box”? That would record what input the pilot is giving to the controls, and with how cheap accelerometers are nowadays, I’d expect that the recorder would also track the plane’s response to those controls. Put those together, and you could probably reconstruct the plane’s total mass and moment of inertia tensor.
As for “I can’t believe the pilot would make mistakes like that”, isn’t that going to be true of every crash? We know with certainty that the plane crashed. That isn’t supposed to happen, and it happens only very rarely. That means that, every time a plane crashes, you can be sure that someone (or something, or both) screwed up, way beyond normal parameters.
Speaking as someone who’s been in two small plane crashes, this is so very true. My father, the master of small details and attentiveness and with decades of flying under his belt, lost focus for a few crucial moments as we neared the ground, and we crashed. Fortunately we both survived, but it was a long and painful recovery.
My other crash (in an ultralight) was the result of me not following my instincts but rather following the instructions given to me by my father in law (airline captain and ultralight instructor) when caught in a sudden crosswind at low altitude. No huge damage there, fortunately.