ANA 787 Engines shutdown during landing

[Smdts]

I dont know hence the question. Does tcma only shutdown the affected engine or both if it is trying to prevent thrust assymetry?

[tdracer]

Originally Posted by Smdts

I dont know hence the question. Does tcma only shutdown the affected engine or both if it is trying to prevent thrust assymetry?

TCMA only shuts down the engine with the problem. Boeing makes of point of not cross talking information between engines to help protect engine-to-engine isolation.
The intent is not to override anything the pilots are doing, but to deal with an engine that's not responding when the thrust lever is moved to idle.

[punkalouver]

(ANA) has concluded there was no engine failure following a Jan. 17 incident in which both engines on a Boeing 787-8 shut down after it landed at Japan’s Osaka International Airport.

ANA flight NH985 was arriving from Tokyo Haneda Airport with 109 passengers and nine crew members on board. After touching down on the runway and deploying the thrust reversers to slow the aircraft, pilots noticed that both Rolls-Royce Trent 1000 engines had shut down. The 787 completed rolling out and came to a stop about 8,000 ft. down the runway, according to media reports.

The carrier said it conducted a thorough investigation of the aircraft and found no engine failure. It did not assign responsibility for the cause of the shutdown.

“Following a safe landing in Osaka, an appropriate safeguard system on the 787 was activated properly on both engines, triggering the discontinuation of the thrust,” ANA said in a statement. “This system is meant to prevent the aircraft from becoming unstable after landing when thrust is shifted again from reverse to forward. This safeguard system will not be ready for activation unless it detects that the landing gear is on the ground, and an instrument measuring the altitude will not allow maneuver of the thrust reverser during flight.”

Engine manufacturer Rolls-Royce did not immediately respond to a request for information, and Boeing declined to comment.

https://atwonline.com/engines/ana-fi...e5fb9afefca4d2

[tdracer]

Sure sounds like a 'nuisance' TCMA trip on both engines - guessing that the pilots did something very unusual with the thrust levers when transitioning out of reverse.

[nicolai]

Originally Posted by tdracer

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 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

There is also this more recent incident from 2010
https://www.cad.gov.hk/reports/AB-01-2010e.pdf
where small hard particles contaminating the fuel jammed the fuel metering valve at 74% N1 on a Cathay Pacific A330-300 while in flight. The engine only stopped when shut down on the ground.

It's definitely not impossible even today.

[golfyankeesierra]

It is not so the issue that anything can and will fail, more surprising that two supposedly independent systems fail at the same time.

[lomapaseo]

Originally Posted by golfyankeesierra

It is not so the issue that anything can and will fail, more surprising that two supposedly independent systems fail at the same time.

They are not independent when it comes to a common fuel supply as a causal factor

[Onceapilot]

Originally Posted by lomapaseo

They are not independent when it comes to a common fuel supply as a causal factor

Well, if that is the case, I would have thought the authorities should be treating this as seriously as an accident.

OAP

[tcasblue]

Originally Posted by 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. :

Our company sent out a memo talking about this incident stating that it was a TCMA issue with reverse selected just prior to touchdown(if possible), reversers activating upon touchdown with full reverse selected followed a quick cancellation of reverse thrust selection.

[Superpilot]

Originally Posted by Onceapilot

Well, if that is the case, I would have thought the authorities should be treating this as seriously as an accident.

OAP

On this topic I thought it was an AMC design criteria for airplane engines to run from their onside WING tank during takeoff and landing. Not on the 787 aparrently. They can be drawing from centre tanks right on rotation.

[nicolai]

Originally Posted by lomapaseo

They are not independent when it comes to a common fuel supply as a causal factor

Originally Posted by Onceapilot

Well, if that is the case, I would have thought the authorities should be treating this as seriously as an accident.

Perhaps lomapaseo is referring to things such as fuel contamination, incorrect fuel loads, and large-scale fuel leaks that can affect both engines?

[tdracer]

Originally Posted by tcasblue

Our company sent out a memo talking about this incident stating that it was a TCMA issue with reverse selected just prior to touchdown(if possible), reversers activating upon touchdown with full reverse selected followed a quick cancellation of reverse thrust selection.

Some pilots have a very bad habit of lifting the reverse levers prior to touchdown - depending on the air/ground logic to prevent deployment until they actual land. The good news is that, since Lauda, the air/ground protection is good enough that the probability of the reversers actually deploying prior to touchdown is very remote - the bad news is that if there is some sort of latent fault that allows a reverser to deploy, they'll probably crash .
We did a big investigation of this on the 757 years back, where lifting the reverse levers was causing a rash of nuisance fault messages. We instrumented a couple in-service 757s and sure enough, about 1% of the landings they were lifting the reverse levers prior to touchdown - sometimes by as much as 10 seconds

All that being said, I'd be hard pressed to come up a scenario for how doing that could cause a nuisance TCMA trip...

[ManaAdaSystem]

Originally Posted by tdracer

Some pilots have a very bad habit of lifting the reverse levers prior to touchdown - depending on the air/ground logic to prevent deployment until they actual land. The good news is that, since Lauda, the air/ground protection is good enough that the probability of the reversers actually deploying prior to touchdown is very remote - the bad news is that if there is some sort of latent fault that allows a reverser to deploy, they'll probably crash .
We did a big investigation of this on the 757 years back, where lifting the reverse levers was causing a rash of nuisance fault messages. We instrumented a couple in-service 757s and sure enough, about 1% of the landings they were lifting the reverse levers prior to touchdown - sometimes by as much as 10 seconds

All that being said, I'd be hard pressed to come up a scenario for how doing that could cause a nuisance TCMA trip...

On the NG you can select reverse thrust from 10 ft above the runway. Limitations forbids this, but it is possible. Going back 20 years, some of our guys did this on short runways. It works if you know what you are doing, but it’s very easy to end up with a firm landing.
You you manage to select reverse 10 seconds before touchdown, you will hit very hard. 😳

[DType]

SLF here, but I still remember being in reverse thrust for so long on the old/short runway at Edinburgh Turnhouse that I was convinced I must have missed a very sweet touch down, THEN we finally did touch down, quite gently, very far down the runway, and with max braking. Fortunately, the runway was dry! Must have been either a Trident or 111.

[old,not bold]

FWIW, as a tentative technical contribution to the discussion, my Prentice suffered what I now realise was a rollback and shutdown on rollout after an excellent wheelie landing. Exhaustive investigation by the owner established that the flight crew's fuel management had erred to the extent that when the tail went down the gallon or two remaining fuel sloshed to the back of the tank in use, while the pickup was near the front. If the mods feel that this sorry tale does not help this serious discussion, I won't be offended.

[Check Airman]

What’s the advantage to being able to select reverse before you’re on the ground? Without checking my FCOM, I’m almost positive you can’t do that on the A320.

[Herod]

I could be wrong, but I believe on the Trident, the centre engine could not only be selected to reverse while airborne, but it actually went into reverse. Always worth watching the Trident land at Aldergrove.

I recall reading somewhere that one of the early jets (DC8?) could reverse two engines for descent control.

[DaveReidUK]

Originally Posted by Herod

I could be wrong, but I believe on the Trident, the centre engine could not only be selected to reverse while airborne, but it actually went into reverse. Always worth watching the Trident land at Aldergrove.

Unlike the 727, the Trident didn't have a thrust reverser on the centre engine.

[topgas]

The Trident could use reverse thrust for emergency descent, 10,000 ft/min, and before touchdown. The C17 can use reverse thrust on all engines for tactical descents at 15,000 ft/min

[Check Airman]

Thanks. My question was targetted to the 737. Any practical reason to select reverse at 10ft?