F-35 accident Fort Worth 15/12/22 - pilot ejected ok

[SpazSinbad]

Boring vertical landings. USMC F-35Bs Vertical Landing aboard JS Izumo 03 Oct 2021

You Tube

[safetypee]

Spaz, the video illustrates my question above.

If the 'stick' controls up and down - 'throttle' controls fore and aft; then how is the constant pitch attitude maintained.

[Fortissimo]

Originally Posted by safetypee

If the 'stick' controls up and down - 'throttle' controls fore and aft; then how is the constant pitch attitude maintained.

Based on the previous descriptions in the thread, the pitch attitude will be commanded by the FBW system and achieved by managing the output from one of the two downward thrust sources. It would be a reasonable guess that the attitude will be aimed at putting all 3 wheels on the deck at the same time. Perhaps an F-35 driver can enlighten us if this is wide of the mark.

[SpazSinbad]

Originally Posted by safetypee

Spaz, the video illustrates my question above.
If the 'stick' controls up and down - 'throttle' controls fore and aft; then how is the constant pitch attitude maintained.

POST 69 Video Wizzer Wilson explains the aircraft computer controls the F-35B in hover with the pilot just accurately positioning it.

You Tube

[SpazSinbad]

Eleven [out of 33] F-35 fighters grounded after US crash 25 Dec 2022 https://www.jpost.com/breaking-news/article-725763 "...the IDF and Lockheed Martin, who manufactures the F-35, pointed out that it is not certain that the Israeli F-35A has the same problem. Rather, they emphasized that the grounding, which only applies to 11 aircraft out of a much larger fleet of F-35s and other planes, was taken as a precaution...."

[gums]

Salute!

To answer the question about pitch attitude, I'll describe short as I can what I saw here when the Bee did a go around from an approach with all the doors open and what looked like normal pitch maneuvering. Was #3 behind an A and a C. So my guess is the flight was a demo for some brass.

The A and C landed and the Bee went up to downwind just like a normal plane with all doors open. It turned base and flew to the runway just like basic planes do, and at 100 feet or so leveled, slowed and went into a hover. Plane maintained perfectly level and the pilot rotated the heading 90 deg one way then back. Once more go around after it gained speed and this time came in a bit slower than I suspect a normal landing would be and with minimal flare plopped onto the runway, then turned off after about 300 feet or so.

So the part about the control laws blending in and out according to the speed seems to describe what I saw that day.

Gums sends...

[SpazSinbad]

Spoiler

 

 

Spoiler

 

 

Pentagon grounds some F-35s after ejection on Texas runway



Pentagon grounds some F-35s after ejection on Texas runway (defensenews.com) 28 Dec 2022
"...A source familiar with the program, who spoke on the condition of anonymity because they were not authorized to discuss details of the incident, said the JPO’s initial assessment found that a propulsion system issue led to the Dec. 15 crash of the hovering F-35B, which has now led to broader groundings in the fleet. The source said that, in guidance to the services, the JPO said a failure of atube used to transfer high-pressure fuel in the fighter’s F135 engine prompted the office to update its safety risk assessments. The JPO also told the services that jets with fewer than 40 hours of flying are affected, this source said...."

[Stuff]

Israel have apparently grounded their F-35As as a result of the Fort Worth crash so whatever went wrong might not be isolated to the B model.

https://eurasiantimes.com/us-israel-...rash-in-texas/

[gums]

Salute!

Rumor on the street over in the States is a problem with a fuel line or other component that is pressurized and has several functions. Remember, this is "rumor network". So could be a component they are looking at that is common on the engine, regardless of the A,B or C.

Gums sends...

[tdracer]

Originally Posted by gums

Salute!

Rumor on the street over in the States is a problem with a fuel line or other component that is pressurized and has several functions. Remember, this is "rumor network". So could be a component they are looking at that is common on the engine, regardless of the A,B or C.

Gums sends...

Seeing the same reports as gums - high pressure fuel line on the engine (likely part of the fuel control - e.g. FADEC).
BTW, saw an article yesterday that said the "aircraft ejected the pilot". Now, given the accuracy of reporting, I'm inclined to take that with a grain of salt. But if it is in fact correct, it would suggest the ejection was automatic, not commanded by the pilot.

[RAFEngO74to09]

Lots of new still photos in this video

F-35s Grounded Again Following Ft. Worth Crash - YouTube

[megan]

Interesting cloud of smoke at 1:50 in the above video, wonder what it might infer.

[SpazSinbad]

Reason for the swift descent? Smoke gets in your eyes.

[Compass Call]

Never realised that the canopy was built in two pieces.

[SpazSinbad]

Probably not here now but anyway: http://www.flightglobal.com/blogs/th...%20Studies.pdf

[Compass Call]

SpazSinbad
Thanks for the info.

[Video Mixdown]

Originally Posted by Compass Call

Never realised that the canopy was built in two pieces.

I thought it was a one-piece moulding that is cut in half (by MDC?) during the ejection sequence.

[tdracer]

Originally Posted by SpazSinbad

Reason for the swift descent? Smoke gets in your eyes.

Not familiar with the specifics of the F135 engine, but it's standard design practice on jet engines that the high-pressure fuel doesn't only go into the burner - it's used as muscle for various actuators such as variable vanes and bleeds, etc. - so lots of fuel lines snaking their way around the engine. Typical pressure downstream of the fuel metering unit is around 300 psi - so any crack in a fuel line is going to result in a large fuel leak - not only do you have a big risk of fire if a line fails, you lose muscle pressure to the various actuators. In other words, bad things are likely to happen.
Smoke (or flames) is a pretty common indicator...

[SpazSinbad]

Originally Posted by Video Mixdown

I thought it was a one-piece moulding that is cut in half (by MDC?) during the ejection sequence.

Pictures always better than words that are not specific enough probably. Pic no longer at this URL so posted here to show canopy with MDC on the F-35A. There is the canopy metal bowframe [that is integrated with the canopy - I guess this is a cause for confusion - X-35A had a TWO piece canopy] in front of the pilot and the canopy as visualised in the previous - above - image graphic. http://www.jsf.mil/images/gallery/sd...5testa_100.jpg

Quote from previous graphic: F-35 Canopy Design Description 2009 LM
- Transparency is Single Piece Formed & Stretched Acrylic
- Thick Windscreen is Fwd of the Bowframe & Transitions to Thinner Transparency Section Aft
- CTOL & CV Canopy Designs are Common & Windscreen Design is Tri-variant Common
- Flexible Linear Shape Charge Bonded to IML [Inner Mould Line] to Facilitate Pilot Escape
http://www.flightglobal.com/blogs/th...%20Studies.pdf [no longer there]

[Rigga]

Originally Posted by SpazSinbad

Reason for the swift descent? Smoke gets in your eyes.

The smoke also appears forward of, and external to, the jet pipe - so could come from anywhere inside the airframe. I would suspect the fan drive system from the meagre evidence so far.