One of the reports that I read said that someone thought they “heard lightning” (not sure how that works) and they did fly through a storm shortly before the crash, so maybe it was a thunderstorm?

I know, that’s why I said slight chance. Anything is possible. For it to auger in like that would have to be something totally catastrophic, they didn’t even have time to make a radio call. Even the DC10 example that you linked was able to make a controlled crash landing.

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Pretty cool huh? Typically on the airframe side they also protect critical systems in the event that the engine doesn’t fully contain the damage. I worked on a business jet program where we reinforced the fuselage adjacent to the engines with Kevlar for greater impact resistance.

I recall having to do engine and tire burst tests on the 777. The tire burst caused a systems redesign to move stuff around in the wheel wells. Ahh, the joys of concurrent design-build technology!

Very sad about the crew in this airplane. I hope to goodness it wasn't intentional..

One of the reports said "Last recorded data was a -29,500 fpm descent. " About .44 Mach so probably not a sonic boom.

There are a lot of scenarios bandied about on several forums from full trim tab down, which would allow them some steerage, to loads shifting aft causing a deep stall (don't see this one as high potential) to uncontained engine shrapnel. Hopefully they can get the FDR and CVR to put the pieces together and see what really happened.

I agree with the point you’re making. I gave those examples only to show that uncontained engine failures have resulted in damage beyond what was predicted through the certification process.

With the United accident, keep in mind that the failure of the #2 engine left them with symmetrical thrust on #1 and #3 that they could use to compensate for the loss of flight controls. A 2 engine aircraft would be a very different situation.

That speed calculation only works if they were headed straight down. any other decent angle and there would be a descent ratio to take into account.

True, but the video shows a near vertical decent and the debris area is small indicating an impact from vertical.

There is a airworthyness directive (is that right) to do with the bellcrank shear rivits form 2014.

There have been a couple other incidents in the past. 2001 there were two where suspected ice interfered with the elevators and this one in 2001.

CNN.com - NTSB investigates 767 elevator problem - March 28, 2001

That was my first thought.

No radio call.
No (apparent) attempt to salvage.
vertical impact.

It's a possibility, and wouldn't be the first time.
That was my second thought, along with the possibility of explosive cargo of some sort, which has also happened before. The rules are certainly more strict in that regard these days, but I imagine plenty of the items banned from air cargo still slip through the cracks and make it onto planes.

No radio call would not be surprising if it was something catastrophic that caught them by surprise.

I could see cargo being an issue, especially if it were a pallet of batteries where one shorted. Might explain the lightning or thunder noise.

Sounds like they are dredging the impact area to find the boxes.

One of the TV interviews after the crash from a nearby resident said he heard the engines screaming like he's never heard. Don't know if it was because they were so much closer to the ground or because they were overspeeding or whatever aero turbines do.

They did not intentionally put it into the water per se (as in trying to avoid a populated area..) . That's just where they happened to be when either they had a control malfunction (trim runaway, tail broke off, etc) or someone pushed the yoke over and held it there. If they had any kind of engine problem, they would have glided down or maybe even stalled it before they hit the ground but the alt/speed tapes show a different story. They were cruising along at 6,000 ft and told to descend to 3,000 ft. As soon as they started down, it went into a dive and 23 seconds later they hit the ground. I doubt it was a load shift as these planes carry those big aluminum cans and there is really no room for them to move and they made it that far and were in the most gentle part of the flight regime. Hopefully they find the boxes soon..

While flight crew intentionally crashing aircraft is not unprecedented, I think a sudden control surface issue is far more likely.

The reports of a sound like thunder are interesting. I think people were just hearing the plan crash. What sort of cargo would an Amazon delivery flight be carrying that could explode and take down an aircraft? I find that far fetched. There is always the very, very remote possibility of an act of terror, but it seems like a rather lame way to strike.

We all know nothing, most of all me....

Not sure how to properly embed video's, but this was a famous cargo shift from a few years ago.
https://youtu.be/lksDISvCmNI

https://www.youtube.com/watch?v=lksDISvCmNI

Here ya go. Astonishing video.


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Yeah, I'm familiar with that crash.. That was a 4 ton Humvee like vehicle that broke loose on T/O (pitch up) and severed all the connections between the cockpit and the elevator. Atlas planes carry ULDs or pallet freight (basically aluminum big cans filled with boxes) stacked in line from one end to the other and they have a RGD (rigid cargo door) in the front where shifting cargo cannot go through. Plus they were in a very gentle phase of flight in the way of pitch angle. (the cargo would have had to shift violently forward to cause a nose down attitude). Of course all of this is speculation as we await the findings of the black boxes. (which are actually orange!)

This sounds like full power applied as if trying to recover from a stall.

Ive got a bunch of flight time in a 767 as well as a few other large aircraft. It is not easy to get one of those planes in a steep dive, even from a stall. They just dont do that. And to do it intentionally with power on the engines would take a huge amount of nose down trim and stick force. A cargo fire would be my worst case speculation. They tend to escalate rapidly. Very interested to find out the cause.

Wouldn't a cargo fire leave a smoke trail? The crash video does not show a smoke trail.

My dad was an Air Force pilot for cargo planes. C-124 C-47 and C-54 and just a little in C-130. He often talked about the importance of a good load-master crewman. Dad was on an assignment with a Marine unit as just an observer. They had a tank as cargo. Dad was taking notes on their operation. The tank broke some restraints, and started moving around. They almost crushed a few crew, but they got it strapped down and made an emergency landing. It was almost a major incident, and dad wrote up the entire event and several careers were likely ended. He said they had some poor procedures, and he spent several weeks helping write new procedures. He said it was the scariest incident he had in an airplane.