Hmm. Is it possible there’s some system that cuts lift power once the landing gear detects contact? Sorta like the spoilers on commercial jets that only deploy when the main landing gear is compressed and the wheels spinning. Maybe such a system cut lift fan power but “forgot” to do the same for the main nozzle.
or the clutch mechanism snapped. I can’t see a reason for the pilot to eject. I suspect there was some noise(s) that sounded like internal parts looking for a summer home.
I’d expect exactly that sort of “weight on wheels” thrust-dumping system. Once you’re certain you’re on the ground you want to stop flying & settle all the weight on the gear as quickly as possible net of avoiding wild fore / aft or left / right transients.
But the aft nozzle is pure engine exhaust. The only way to cut its thrust is to reduce the engine fuel flow and let the engine RPM decay towards idle RPM. Which takes time. The front fan is driven by a shaft that is clutched to the engine’s main shaft. Which affords near-instant disconnection followed by very very quick spool down & thrust decay.
But more logically for a normal landing you’d expect the lift fan and engine to stay clutched together as the engine RPM drops so thrust from both engine exhaust and from the forward lift fan decay together as the engine shaft slows. Once you;re idling and almost all the weight is on the gear, then you can declutch the lift flan, close its upper & lower doors, and realign the aft nozzle aftwards for normal taxi. IOW, do the whole “transformer toy” conversion.
Clearly the airplane ended up with very unbalanced thrust fore/aft. Which began at/after the initial gear touchdown and lasted through all the wild gyrations. And was just returning to a balanced minimum thrust as the pilot ejected.
By the time the seat was moving the whole airplane had settled down and we saw it stayed settled down. At the time a second or two earlier when he decided to bail out the airplane was still gyrating and he was probably concerned it was going to end up on its back. So once it was moving towards a level attitude he assumed the position & pulled the handle as quickly as he could.
It’s easy to forget a) how disorienting all this is, and b) that what did happen was not fore-ordained to happen. Based on what was knowable at the time he decided to punch, it may have been pretty obviously the smart(est) thing to do.
We also don’t know what his written guidance says. There may be none, there may be a lot. As we saw a few years ago in an F-22 accident and I explained then about F-16s, many low-speed ground accidents are not reliably survivable. Better to jump out. The emergency procedures guidance reflects this bias. The F-35 is IMO probably similar. I know that I don’t know for sure.
Well, you could swivel it aft, too. You’d get some forward thrust, but maybe not all that much total impulse.
That’s true. Disorientation moves at the speed of light in an airplane. which is another reason for 2 people in the cockpit. 1 to fly the plane, one to work through an emergency.
When you’re trying to make a spot vertical touchdown the last thing you want to a sudden application of forward thrust as you make ground contact.
Two heads are definitely better than one. Except when things are progressing too fast to coordinate. In that scenario better to have one person. They may well misdiagnose or screw up while trying to keep up with a fast-changing scenario, but the only person they’re hurting / killing is themselves.
I’d say the second to last thing. The actual last thing you want is what happened here 
.
Good point. Touche!
I must admit I was wondering the same thing, but it’s very much a case of 20-20 hindsight I guess. As already stated, at the time that decision was made, the pilot had no way of knowing that 2 seconds later the plane would settle right way up and stop moving. I also wondered if the pilot waited until the nose of the plane swivelled away from the busy road before pulling the handle, but given what has already been posted, probably not. Though it would be a damn shame to stick the landing, only to be immediately run over by a truck.
The video may be misleading, but to me it looked a relatively soft landing for such a low altitude 'chute deployment - hopefully no serious injuries.
I thought of something else today while sitting in class.
Typically the weight-on-wheels systems have switches on all the gear legs. These systems typically consider the airplane airborne until all 3 gear are at least partly compressed by aircraft weight. This avoids going to ground mode while the pilot is still flying the nosegear down towards the runway after the mains touch down.
But the nosegear of this airplane was wrecked as one of the very first events of the accident sequence. Perhaps at that point the input from the nose gear switch(es) was lost and the airplane switched back to in-air mode or had never even left in-air mode. And while in in-air mode, the engine will be throttled to maintain the output necessary to roughly hold the aircraft’s weight.
A prototype F-22 was lost in a landing accident caused by a similar confused air-vs-ground transition.
IIRC the test pilot made a poor but certainly should-have-been-tolerable landing. When the gear compressed, the flight controls switched instantly to ground mode. Which exacerbated the bounce. The pilot inputs to counteract that lagged slightly and just then the airplane got airborne again and the controls switched instantly to air mode. This quickly got divergent as the gains & neutral position of the tail were quite different in the two modes. Also IIRC after a couple of increasing gyrations the pilot realized this was getting out of hand, just let go, chopped the throttle, and thumped hard back onto the ground which folded the gear and the airplane slid to a stop on its belly. All in about 5 seconds flat, plus the ensuing slide to a halt.
The eventual fix was to slowly blend the gains & neutral position between air mode and ground mode over a few seconds and only start that transition after some short delay after the air/ground sensor changed its output.
Oops.
Interesting. That seems plausible as a theory.
Seems like it would be a bad design, but is it possible the lift fan and main engine use different conditions for what they consider ground mode? Say, the lift fan using the front gear only (which maybe got wedged into a ground state after the bounce), but the main nozzle requiring all three gear, or just the main gear?
Anything is possible in software. But your idea seems an implausibly illogical design. We’re getting pretty far out on a limb here; lots of guesswork that may be utterly up the wrong tree.
That does sound like a very plausible scenario. I would have thought the engineers thought about what would happen if a plane bounced from a hard landing or even a wind gust.
Hope the pilot lived, but this isn’t going to help his or her career in any event, I should think.
It still counts as a good landing. And it was likely a mechanical issue anyway so the plane wasn’t so damaged that they couldn’t figure out what the problem was. Given the history of test pilots/planes I’d say it was a 9 out of 10 on the success scale.
It totally depends on the nature of the incident. For all we know, he did an amazing job just getting the plane onto the ground in one piece. Ejecting on the ground wasn’t necessarily a bad decision - he may have thought the thing was on fire or otherwise still capable of flipping over or killing him in some other way. Maybe he had fire warnning lights across the board. We don’t know yet.
Agree in general.
It’s unlikely from what we see that the pilot caused the mishap. Many people have ejected from bad airplanes, been not too badly injured and gone on to have long successful careers. It’s not quite like the Navy where if the ship is damaged the Captain & XO are fired before the bilge is even pumped dry.
The pilot’s job was performing acceptance tests on new jets rolling off the assemlby line that Lockheed was handing off to the military. A rather rarified job. I’d expect to find this is a senior pilot with experience, qualifcations, and ribbons out the wazoo.
But to be clear, if this does turn into a problem the pilot caused, they’ll be out of that line of work pretty quickly.
I’ve not been able to find any update on who the pilot was/is or how they are doing medically.
Keep your seatbelts buckled, folks:
Well think about it, if a pilot experienced with the F-35 has a problem, what are the newly minted ones going to do? He may have uncovered a “gotcha” scenario that needs some reprogramming.