ANA 787 Engines shutdown during landing

[ManaAdaSystem]

Not seen anything about this. Reported by Aviation Herald. Both engines stopped during the landing rollout. Weird!

https://avherald.com/h?article=4c2fe53a&opt=0

[Yaw String]

Case of TCMA logic ?

[Dorf]

You Tube

[Raggyman]

System Manuals

Where can you get the entire systems manual for the 787?

30 years in system design (non avionics) and really interested in how these systems work.

[golfyankeesierra]

“Rollback and shutdown”, eufemism for “both engines failed on landing”
maybe the reason there is not much reaction here. Nobody as shocked as I am?
And how could this even be related to the turbine blades issue? This looks as a new one.
Or is it fake news?

[Maninthebar]

Is it possible that this is related to the issues identified in a recent Boeing release ""Uncommanded Engine Shutdown during Landing Roll Bulletin""

Samchui.com comment:

"It’s worth noting that a bulletin was released by Boeing not so long ago to pilots and maintenance crew about the Thrust Control Malfunction Accommodation (TCMA) system, which prevents risk in an uncommanded high-thrust situation, stating that errors in the landing sequence could cause the system to activate. The errors include a combination of selecting full reverse too quickly before the aircraft has transitioned to ground mode followed by a quick deactivation of reverse thrust. Boeing advises not to apply full reverse too quickly in the bulletin."

[ManaAdaSystem]

Somebody did post a very plausible reason for this dual engine failure. It was related to a bulletin and what not to do when you reverse after landing. Deleted or removed, I don’t know.
Not sure how happy I’m am about engine auto shotdown features on some of the aircraft out there. A damaged but running engine may save your day. No engines will not.

[wiedehopf]

A quote from https://thepointsguy.com/news/boeing...re-on-landing/ :

Boeing did recently release a bulletin regarding the Thrust Control Malfunction Accommodation system (TCMA). The safety system is designed to prevent uncommanded high-thrust situations. In the bulletin, Boeing said that selecting full reverse too quickly upon landing before the aircraft has fully transitioned to ground mode could cause the system to activate. While this bulletin could shed some light on what happened, what actually caused the engines to shutdown won’t be clear until a full investigation is completed.

[KelvinD]

May be of interest:
https://patents.google.com/patent/US6704630B2/en

[Global Aviator]

Let’s not forget the 777 just before the runway...

https://en.m.wikipedia.org/wiki/Brit...ways_Flight_38

[ManaAdaSystem]

As for the engine failure, is this some kind of protection against unintentional engine reverse in the air? Since it is linked to reverse selection before the aircraft is fully in ground mode?

[tdracer]

Originally Posted by ManaAdaSystem

That would be nice! Some weird censoring here at times.
As for the engine failure, is this some kind of protection against unintentional engine reverse in the air? Since it is linked to reverse selection before the aircraft is fully in ground mode?

Assuming the (now deleted post) was correct, and this is an issue with TCMA when combined with an unusual T/R application, it has nothing to do with reverse before being on the ground.
TCMA - Thrust Control Malfunction Accommodation - is something Boeing came up with to address an FAA (and later EASA) concern with Uncontrollable High Thrust (UHT) on the ground. UHT is nothing new - although uncommon (probability of occurance is somewhere between 1/10 million and 1/100 million flight hours), all turbine engine installations have failures that can cause the fuel metering valve to go wide open uncommanded. FADEC has made it less likely, but the potential failure is still there.
UHT was always assumed to be something the flight crew could address by shutting down the affected engine - but then there was an event on a 737-200. Going from memory here, but I think it was 1997, it was either in Egypt or an Egyptian operator (fuzzy memory on that part). Anyway, there was an issue with the JT8D fuel control where the splined shaft that fed N2 speed to the fuel control could wear excessively and start slipping. During takeoff power set, that spline started slipping - the fuel control thought the dropping N2 meant the engine was spooling down and opened the fuel metering valve wide open. The crew saw EGT spike over redlline and aborted the takeoff, but the fuel control didn't respond when they retarded the throttles. The went off the side at low speed - no one was seriously injured or killed, but it was a hull loss.
The FAA (and later EASA) decided this meant that UHT on the ground was catastrophic and therefore every aircraft/engine combination ever built didn't comply with the regulations (25.901(c) - no single failure shall result in an unsafe condition).
It become a long and quite messy story - the FAA ended up issuing partial exemptions for aircraft then in production, but dictated that we needed to address UHT on the ground for future aircraft certs. So starting with the 777-300ER/GE90-115B, Boeing came up with TCMA. In short, when on the ground, if the FADEC determines that the engine is at high power with the throttles at/near idle, and not decelerating, TCMA will shut the engine down. For what should be obvious reasons, TCMA is only active on ground, with quite robust air/ground logic that will default to air if it's not sure.

[ManaAdaSystem]

Thank you for a good explanation of the TCMA system, but in this case it was not working as advertised. If TCMA was the cause of this incident, that is.

[ASH26E]

I wonder what the FAA and EASA will make of the recent Lion Air 737 Max event resulting from the failure of a single AoA sensor in the light of 25.901(c)

[Ian W]

Originally Posted by ASH26E

I wonder what the FAA and EASA will make of the recent Lion Air 737 Max event resulting from the failure of a single AoA sensor in the light of 25.901(c)

I think that is already known. They consider that if the actions for a stab trim runaway had been taken there would have been no problem, just switch off the stab trim with the switches provided for just that purpose. Therefore, more than a single failure was required,

[Luc Lion]

@Ian,
the possible non-conformity of the Lion Air B737 Max with Part 25 is more related to 14 CFR 25.672 than 25.901.
Part 25.672 is specifically for stability augmentation systems.
The issue is not so much single or double point of failure but rather dedicated warning.

Originally Posted by Part 25.672

§ 25.672 Stability augmentation and automatic and power-operated systems.If the functioning of stability augmentation or other automatic or power-operated systems is necessary to show compliance with the flight characteristics requirements of this part, such systems must comply with § 25.671 and the following:

(a) A warning which is clearly distinguishable to the pilot under expected flight conditions without requiring his attention must be provided for any failure in the stability augmentation system or in any other automatic or power-operated system which could result in an unsafe condition if the pilot were not aware of the failure. Warning systems must not activate the control systems.

In the Lion Air accident, the second failure, i.e. not shutting off the electric trim, is linked to the ability of understanding the nature of the problem at stake and understanding that the stability augmentation system is failing.

Luc

[megan]

AVweb report.

All Nippon Airways, Japanese authorities and Boeing are investigating why both engines on a 787-8 shut down simultaneously during rollout at Osaka Itami Airport last week. The engines quit right after the crew selected thrust reversers on touchdown and the aircraft rolled 8,000 feet before coming to a silent stop, according to samchui.com. The crew worked with technical staff for 40 minutes to restart the engines but couldn’t get them going so the plane was towed to the gate. A subsequent inspection revealed no faults with the engines but the website says a service bulletin issued by Boeing warned that mishandling the thrust reverse controls can cause the Thrust Control Malfunction Accommodation system, which guards against inadvertent asymmetrical high thrust situations, to activate. The bulletin reportedly says problem can occur if the thrust reversers are deployed too soon after touchdown.

https://www.avweb.com/eletter/archiv...4235-full.html

[tdracer]

Originally Posted by ASH26E

I wonder what the FAA and EASA will make of the recent Lion Air 737 Max event resulting from the failure of a single AoA sensor in the light of 25.901(c)

To add a bit to what Luc Lion posted, 25.901(c) is specific to propulsion systems - not flight controls (which have their own set of applicable regulations).
No question if TCMA was the cause of the dual shutdown then there is an issue that needs to addressed in the software. There is a quite comprehensive review of the TCMA limits during the flight test program (at least on the 747-8, we had TCMA deactivated for much of the flight test program, until we had enough real engine data to verify we had adequate margins between the TMCA limits and what a normally functioning engine would really do). However it's really hard to anticipate every possible scenario - and it appears that perhaps the pilots on this flight managed to come up with an unanticipated scenario for the Trent engine.

[Smdts]

Is it not possible that a fault occurred in the fuel delivery system during TR deployment and then TCMA performes as designed?

[Luc Lion]

@Smdts : on both engines, simultaneously ?