F-35B crash-lands in Fort Worth, Texas

[daswp]

USNI said it was during an acceptance flight.

https://twitter.com/i/status/1603469769407139842

Thoughts?

[outlaw162]

One would think the auto-ejection system would have activated sooner.

[steve2267]

Musings (in no particular order):

1. The ejection system worked as advertised. Pretty ding dang close to a true 0-0 ejection.
2. Did not think they (who is they?) practiced SVRL during acceptance testing -- aircraft had forward velocity when it touched down -- was not a pure vertical landing.
3. What caused the sudden pitch forward? Lift fan and/or clutch failure? Or main engine did not stop when commanded, but lift fan did?
4. Engines continued running (could hear the whine of the turbine) right up to ejection (possibly shortly afterwards as well)

[notquiteconfident]

If I was forced to make a guess, it would be lift fan failure. But have to wait for the report, might be completely wrong as I'm hardly an expert.

It appears that the aircraft had yet to be turned over the the Government and Lockheed still owned it, but a Government pilot was the one flying so it will be interesting to see who has to cover the bill.

I'd guess that this aircraft is probably repairable, didn't seem to take that much damage all things considered, and it just so happened to crash at probably the best possible airport to repaired.

[ricnunes]

WOW!

My speculation/2 cents:
- It looks like that either the engine or the lift fan "throttled up" for some reason when the aircraft touched down.

[optimist]

A copy of the video on YouTube: https://www.youtube.com/watch?v=t9GBHNaYzcs

[Prinz_Eugn]

Looks like a pretty big bounce after touching the ground (the first time), wonder if that was a cause or a symptom?

Almost looks like it was throttle lag where the pilot was trying to slow the descent, but too late, and the late thrust picked the aircraft back up into the air. Not sure if that descent rate was anything unusual.

[spazsinbad]

Pilot OK one hopes. Looks like as things go wrong the nosewheel falls off - which is not helpful. Remember the distance of the telephoto video camera from the scene means the sound will lag the video action. Seems pilot delays ejection for a better trajectory? We can only guess about any details I guess. Jet looks repairable at least? A lot happens eh.

Pilot ejects OK from F-35B near White Settlement, Texas 16 Dec 2022 https://www.youtube.com/watch?v=q3z6TeHzJRk

[steve2267]

I am going to go out on a limb here and posit that there was some sort of propulsion failure (duh) at the aft-end of the engine. First, I note that the rate of descent appears to be signifcantly higher than I am accustomed to watching videos of USMC pilots planting a Bee. I suppose it could be an acceptance test test point. Or perhaps the pilot was dealing with a general propulsion system issue from the get go?

At 0:04 of the video, I note some whitish vapor at the aft end of the engine, in the vicinity of the 3-bearing swivel nozzle.

The aircraft has a slightly forward velocity vector component -- it is not coming down absolutely straight.

In Mode 4, the pilot has no direct control over the throttle - i.e. over engine RPM or thrust. He (she) controls vertical descent rate with the stick (inceptor?). Push down to go down, pull up to go up etc. Either the pilot would appear to have a significant "push" forward on the stick, or the motor is not developing the thrust it should resulting in a higher than nominal descent rate. Just after the bounce at 0:14, at approx 0:16 there is a large plume of white smoke out the back end of the aircraft. I can only guess this is no bueno, and potentially related to the propulsion system issues the aircraft / pilot experienced.

Given the rather abrupt nature with which the aircraft pitched forward, and the lag gas turbine engines typically experience when throttling up, I am going to guess this is more likely a fan-related (clutch?) failure rather than a "runaway" throttle command. Even if the engine "ran away", I do not think the resulting thrust imbalance would have been as abrupt was we see here.

FWIW.

(I would not be surprised to find out that I am wrong, but this is the best I can deduce based on the video evidence up to this point in time.)

[sprstdlyscottsmn]

IIRC there is logic to kill the engine on WoW. This clearly didn't happen. Is this the first landing incident of a B?

[steve2267]

IIRC there is logic to kill the engine on WoW. This clearly didn't happen. Is this the first landing incident of a B?

So many questions. So many musings.

I am a wonderin' if the lift fan and/or clutch suffered a catastrophic failure.... OR if that logic did kill the lift fan, but somehow the engine core didn't get the memo.

I do note the large bounce -- I could see the logic killing the lift fan, but perhaps a different engineer or team wrote that kill logic software for the engine core? OR... could we be looking at a difference in lift tail-off for the lift fan (disengage the clutch immediately and you pretty much kill the lift fan lift immediately, but kill the motor and the thrust tail-off of the rear of the turbofan is not so immediate)?

[spazsinbad]

IT is good that the aircraft is relatively intact I assume - so that a good forensic analysis can take place. It does appear that 'something went awry' indeed it did. Some good guesses so far I guess; but hey I'll wait for an accident report - oops sorry MISHAP. Being such a public event we are likely to see something from LM at least about it all soonly soonest?

[charlielima223]

Thank God the pilot survived!

WardCarroll
https://youtube.com/shorts/GIy6XPTa0SI?feature=share

my guess was that after the bounce, there was too much thrust at the rear end causing the nose dive.

[steve2267]

For those following along at home...

Attached is a 4.7MB mp4 video file from Ward Warrol's YouTube post. It appears identical to the cell phone video on Twitter, although I must admit Mr. Carroll's commentary is better than the oohs-aahs-OMGs of the civilian in the Twitter clip. I grabbed a 1024x768 resolution download. This yields pretty decent full screen clarity. With a decent video software player, one can step through frame-by-frame.

[steve2267]

I would take this information with a grain of salt, but from a Facebook group I follow, one fellow posted:

"I got word from an inside source who said this is BF-148 that was slated to go to VMFA-214."