zero/zero
June 14, 2025, 19:46:00 GMT
permalink Post: 11901769

Quote:

Originally Posted by Shep69

This to me makes more sense; perhaps I`ve got it wrong but in the video the trailing edge flaps definitely look up. Maybe there`s more and they weren`t.

On a flap 5 takeoff the FMS could be programmed to select climb power at flaps 1 which would seem like an apparent loss of thrust. Same as for F15 to F5 or further.

OTOH any castastophic failure which left the gear down would have essentially left the flaps where they were. They are hydraulically activated with electrical backup but it`s wayyyyy slow.

Climb Power is programmed as an altitude in the FMC, usually 1000' but sometimes higher for noise abatement, which in this case they wouldn't have reached.

In some instances, the TO derate is so significant that the selection of climb power moves the thrust levers forward. AMD is sea level with a long runway, so can imagine it would be a fairly low power take off.

Subjects: None

zero/zero
July 11, 2025, 22:24:00 GMT
permalink Post: 11919911

Anyone who has flown the 777/787 (imagine the 737 is similar) probably recognises that the movement of those switches has a very easily identifiable audio signature.

Given the sensitivity of the CVRs, I would imagine it would be a very simple task in the full report to compare that to the unlikely scenario of the switches being in some halfway house and slipping to cut-off to to rotation or g-forces etc

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches

zero/zero
July 11, 2025, 22:43:00 GMT
permalink Post: 11919938

Quote:

Originally Posted by A340Yumyum

Well, it\x92s narrowed it down to 3 possibilities:

Action slip
SAIB NM-18-33
Intentional.

The SIAB relates to defective throttle units at the point of installation (on a different but related aircraft). I might be onboard with that theory if maintenance happened to have replaced the unit a day or 2 before the incident. But it's a tough sell that a defective switch that's used literally on every flight had flown for 2 years without someone noticing and snagging that the locking mechanism wasn't working

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Action slip SAIB NM-18-33 Special Airworthiness Information Bulletin

zero/zero
July 17, 2025, 16:01:00 GMT
permalink Post: 11924488

I wondered if he had incorrectly assumed that the EAFRs wouldn't record after both engines were shut down (as per the Jetu 2216 crash) and so it would be harder for investigators to pin down who was responsible.

That makes the timing more logical because doing it in the cruise would record who had left the flight deck beforehand.

Although closer to the ground risks increased chance of survivability, it does massively increase the startle for the other guy and lowers the chance of being able to successfully intervene.

Subjects: None

zero/zero
July 17, 2025, 16:47:00 GMT
permalink Post: 11924518

Quote:

Originally Posted by BrogulT

Do pilots need to know that? Is it covered in training? I imagine there are a lot of technical details on modern planes that the pilots don't necessarily know about. And I'm not referring to MCAS.

It is covered as part of groundschool. But that is potentially a long time ago and it is not a system that's used, talked about or covered as part of sim refresher training.

Of course when something like this happens everyone suddenly becomes an expert (like MCAS), but if you did a straw poll of line pilots at my airline 6 weeks ago you probably would have gotten a fair few confused looks

Subjects: None

zero/zero June 14, 2025, 19:46:00 GMT permalink Post: 11901769	Quote: Originally Posted by Shep69 This to me makes more sense; perhaps I`ve got it wrong but in the video the trailing edge flaps definitely look up. Maybe there`s more and they weren`t. On a flap 5 takeoff the FMS could be programmed to select climb power at flaps 1 which would seem like an apparent loss of thrust. Same as for F15 to F5 or further. OTOH any castastophic failure which left the gear down would have essentially left the flaps where they were. They are hydraulically activated with electrical backup but it`s wayyyyy slow. Climb Power is programmed as an altitude in the FMC, usually 1000' but sometimes higher for noise abatement, which in this case they wouldn't have reached. In some instances, the TO derate is so significant that the selection of climb power moves the thrust levers forward. AMD is sea level with a long runway, so can imagine it would be a fairly low power take off. Subjects: None
zero/zero July 11, 2025, 22:24:00 GMT permalink Post: 11919911	Anyone who has flown the 777/787 (imagine the 737 is similar) probably recognises that the movement of those switches has a very easily identifiable audio signature. Given the sensitivity of the CVRs, I would imagine it would be a very simple task in the full report to compare that to the unlikely scenario of the switches being in some halfway house and slipping to cut-off to to rotation or g-forces etc Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches
zero/zero July 11, 2025, 22:43:00 GMT permalink Post: 11919938	Quote: Originally Posted by A340Yumyum Well, it\x92s narrowed it down to 3 possibilities: Action slip SAIB NM-18-33 Intentional. The SIAB relates to defective throttle units at the point of installation (on a different but related aircraft). I might be onboard with that theory if maintenance happened to have replaced the unit a day or 2 before the incident. But it's a tough sell that a defective switch that's used literally on every flight had flown for 2 years without someone noticing and snagging that the locking mechanism wasn't working Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Action slip SAIB NM-18-33 Special Airworthiness Information Bulletin
zero/zero July 17, 2025, 16:01:00 GMT permalink Post: 11924488	I wondered if he had incorrectly assumed that the EAFRs wouldn't record after both engines were shut down (as per the Jetu 2216 crash) and so it would be harder for investigators to pin down who was responsible. That makes the timing more logical because doing it in the cruise would record who had left the flight deck beforehand. Although closer to the ground risks increased chance of survivability, it does massively increase the startle for the other guy and lowers the chance of being able to successfully intervene. Subjects: None
zero/zero July 17, 2025, 16:47:00 GMT permalink Post: 11924518	Quote: Originally Posted by BrogulT Do pilots need to know that? Is it covered in training? I imagine there are a lot of technical details on modern planes that the pilots don't necessarily know about. And I'm not referring to MCAS. It is covered as part of groundschool. But that is potentially a long time ago and it is not a system that's used, talked about or covered as part of sim refresher training. Of course when something like this happens everyone suddenly becomes an expert (like MCAS), but if you did a straw poll of line pilots at my airline 6 weeks ago you probably would have gotten a fair few confused looks Subjects: None

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