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armagnac2010
Posts: 158
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 12:45 pm

Assuming this involves thrust malfunction logic (which is very likely), it might be worth reminding the background.

Thrust control malfunction is a logic imbedded in the aircraft systems (usually, the FADEC) crosschecking the thrust requirement to the thrust actually delivered by the engine. This was deemed essential as performances are computed assuming a ‘clean’ engine failure; ie the failed engine will deliver no thrust/torque. This assumption is defeated if the engine keeps delivering 60% or 120% (for instance) of the required thrust and such conditions may actually result in runway overrun during a rejected take-off. Engine delivering 120% thrust can also cause lateral controllability issues. Such conditions can happen as a result of failures in the engine control systems (FMV HMU etc.).

To address this, Thrust Control Malfunction (TCM) were introduced. The actual implantation varies among aircraft and engine manufacturers. Typical logics are ground only (weight on wheel on, usually), and inhibited (interlocked) if one engine is already failed. The actual thrust check depends upon each manufacturer (engine and aircraft).

What has been seen in other cases, including the ANA 787, where events during which the thrust comparison detected a problem (false warning, possibly resulting from corrupted / loss signal), triggering the logic as soon as the aircraft was detected on the ground. It affected both engines simultaneously, preventing the interlock logic to limit TCM to a single engine only.

The logic needs to be fixed, but it is not a critical safety issue, considering is needs another rare event to have serious consequences
 
AaronPMI
Posts: 18
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 4:09 pm

BrianDromey wrote:
zeke wrote:
FlapOperator wrote:
If this is a pilot un-commanded software issue, it’s significant.


These sort of things happen...


Lauda Air 004 being one of the most deadly. I don't think it has ever been certain, but it is presumed that the left thrust reverser deployed in flight.

https://en.wikipedia.org/wiki/Lauda_Air_Flight_004


Well, the pilot stated "Oh reversers deployed" so it is more than a presumable cause.
 
LDRA
Posts: 394
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 4:35 pm

armagnac2010 wrote:
Assuming this involves thrust malfunction logic (which is very likely), it might be worth reminding the background.

Thrust control malfunction is a logic imbedded in the aircraft systems (usually, the FADEC) crosschecking the thrust requirement to the thrust actually delivered by the engine. This was deemed essential as performances are computed assuming a ‘clean’ engine failure; ie the failed engine will deliver no thrust/torque. This assumption is defeated if the engine keeps delivering 60% or 120% (for instance) of the required thrust and such conditions may actually result in runway overrun during a rejected take-off. Engine delivering 120% thrust can also cause lateral controllability issues. Such conditions can happen as a result of failures in the engine control systems (FMV HMU etc.).

To address this, Thrust Control Malfunction (TCM) were introduced. The actual implantation varies among aircraft and engine manufacturers. Typical logics are ground only (weight on wheel on, usually), and inhibited (interlocked) if one engine is already failed. The actual thrust check depends upon each manufacturer (engine and aircraft).v

What has been seen in other cases, including the ANA 787, where events during which the thrust comparison detected a problem (false warning, possibly resulting from corrupted / loss signal), triggering the logic as soon as the aircraft was detected on the ground. It affected both engines simultaneously, preventing the interlock logic to limit TCM to a single engine only.

The logic needs to be fixed, but it is not a critical safety issue, considering is needs another rare event to have serious consequences


I am curious, if you have both engines out, wouldn't that mean hydraulics and electrical power source are lost as well? How long does the hydraulic accumulator and the on-board battery last, while actively using brakes and nose wheel steering? Or does APU automatically comes on on a CS300?
 
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armagnac2010
Posts: 158
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 4:54 pm

Per applicable part 25 regulation, the aircraft is supposed to remain fully controllable in case of total engine flame out. The ground case is no issue compared to the flight case. Critical functions are nose wheel steering and braking.

The APU is probably not automatic, and in any case I doubt it would have time to provide any service before the aircraft stops on the runway.
 
ILNFlyer
Posts: 685
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 5:07 pm

sgbroimp wrote:
This fuel savings business is really getting extreme, no? First taxi on one engine, now taxi on none!


What really gets my gourd is that the pax have to get out and push. You would think after all the bag fees we wouldn't have to do this :)
 
VV
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 5:22 pm

Polot wrote:
armagnac2010 wrote:
Transport Canada is in charge of the Airbus A220, not EASA.

That doesn’t prevent EASA from grounding the plane if they want (they are not going to).

Transport Canada just has the lead over certification. EASA is still in charge of the A220’s airworthiness in Europe.


Correct.

I do not know why there's so much Canadianism here.
 
Interflug74
Posts: 47
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 5:41 pm

oldannyboy wrote:
I had a car, a lovely one at that (and yes, a Mercedes, not a Yugo!), with that same clever fuel-saving 'auto cut-off' system....it liked to shut itself off when going downhill, if the a/c was on. I have some really interesting memories of losing engine, power assisted steering, and servo-braking, all in one go while cruising at 150km/h on a motorway....


i bet, your q-tip car was kaputt. these days a mercedes works well only, if it is an S class. sad
 
hivue
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Fri Jul 16, 2021 7:32 pm

In the case of QF32 the #1 engine, due to control wiring cut following the #2 engine failure, didn't get the request from the pilots to shut down, and it took an hour and lots of foam and water from the fire crew to bring it under control. In the present case the pilots did not request the engines to shutdown but they did anyway. I guess the "FA" in FADEC means exactly what it says.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
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armagnac2010
Posts: 158
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Sat Jul 17, 2021 7:22 pm

VV wrote:
Polot wrote:
armagnac2010 wrote:
Transport Canada is in charge of the Airbus A220, not EASA.

That doesn’t prevent EASA from grounding the plane if they want (they are not going to).

Transport Canada just has the lead over certification. EASA is still in charge of the A220’s airworthiness in Europe.


Correct.

I do not know why there's so much Canadianism here.


No, this is incorrect. Just have a look at ICAO Airworthiness Manual (doc 9760), it is very clear. Among others, chapter 9.2.1.2 reads:

"Furthermore, it is also essential that the type design organization and the State of Design be kept informed
of service difficulties. The type design organization, receiving this kind of information from all operators of the type of
aircraft, is in the best position to develop recommendations to solve the problems of the aircraft in service. The State of
Design, being the certificating authority of the type of aircraft, will, if necessary, make these recommendations mandatory
and initiate changes to the airworthiness requirements, if appropriate."

The State of operator and the State of registry can certainly take action, if deemed necessary, and technically justified. This is however highly unusual and the few recent cases were all related to FAA failing to make due diligence.

(but Ok - ICAO is headquartered in Montreal - those pesky Canadians are everywhere:).
 
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AirKevin
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Sun Jul 18, 2021 12:48 am

BrianDromey wrote:
zeke wrote:
FlapOperator wrote:
If this is a pilot un-commanded software issue, it’s significant.


These sort of things happen...


Lauda Air 004 being one of the most deadly. I don't think it has ever been certain, but it is presumed that the left thrust reverser deployed in flight.

They determined that it did, they just never figured out why it did.
Captain Kevin
 
VV
Posts: 2352
Joined: Sat Feb 13, 2016 1:03 pm

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Sun Jul 18, 2021 11:14 am

armagnac2010 wrote:
VV wrote:
Polot wrote:
That doesn’t prevent EASA from grounding the plane if they want (they are not going to).

Transport Canada just has the lead over certification. EASA is still in charge of the A220’s airworthiness in Europe.


Correct.

I do not know why there's so much Canadianism here.


No, this is incorrect. Just have a look at ICAO Airworthiness Manual (doc 9760), it is very clear. Among others, chapter 9.2.1.2 reads:

"Furthermore, it is also essential that the type design organization and the State of Design be kept informed
of service difficulties. The type design organization, receiving this kind of information from all operators of the type of
aircraft, is in the best position to develop recommendations to solve the problems of the aircraft in service. The State of
Design, being the certificating authority of the type of aircraft, will, if necessary, make these recommendations mandatory
and initiate changes to the airworthiness requirements, if appropriate."

The State of operator and the State of registry can certainly take action, if deemed necessary, and technically justified. This is however highly unusual and the few recent cases were all related to FAA failing to make due diligence.

(but Ok - ICAO is headquartered in Montreal - those pesky Canadians are everywhere:).


I thought airworthiness is more than just the certificate.
 
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armagnac2010
Posts: 158
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Sun Jul 18, 2021 1:20 pm

VV wrote:
armagnac2010 wrote:
VV wrote:


I thought airworthiness is more than just the certificate.


And you are correct.

From a type design point of view, airworthiness includes issuance of the type certificate and continued operational safety / continued airworthiness, to ensure the assumptions made during the certification are fulfilled. A typical outcome of the COS process are corrective actions, including Airworthiness Directive issuance. As detailed knowledge of the design and certification are required, this is under the responsibility of the state of design.

The other aspect of airworthiness is to ensure individual airframes are conform to the type design. This is the responsibility of the operator, under the oversight of the state of registry and/or state of operator (if they differ). This includes maintenance, compliance to AD, configuration management, etc. and one important aspect is to ensure in-service events are provided to the OEM and state of design.

This A220 event appears more design related than maintenance related.
 
benbeny
Posts: 250
Joined: Thu Nov 03, 2016 1:44 pm

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Sun Jul 18, 2021 5:52 pm

hivue wrote:
In the case of QF32 the #1 engine, due to control wiring cut following the #2 engine failure, didn't get the request from the pilots to shut down, and it took an hour and lots of foam and water from the fire crew to bring it under control. In the present case the pilots did not request the engines to shutdown but they did anyway. I guess the "FA" in FADEC means exactly what it says.

Should we limit the FA part and take Boeing control philosophy to allow pilots to do anything they deemed necessary?
 
VV
Posts: 2352
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 6:42 am

The incident of both engines simultaneously shut down uncommanded on ground does not seem to be a major problem.
Don't get me wrong, it is an issue that needs to be understoof and corrected. It may also require a deeper investigation into how the system is designed.

This second part is the one that may be of concern because someone might open a can of worms. I am not saying that thee is a can of worms, but there is a potential that benign issues would be found in the software somewhere.

The other point is that the investigation and the potential modification will cost some money and time for a program that is still losing money until 2026 or so.

This is not a criticism, but only an comment on what could potentially happen.
In the end it could be a nothing burger.
 
boerje
Posts: 54
Joined: Tue Jan 09, 2018 9:16 am

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 8:28 am

peterinlisbon wrote:
ikolkyo wrote:
An Air Baltic Bombardier C-Series CS-300, registration YL-AAQ performing flight BT-139 from Riga (Latvia) to Copenhagen (Denmark), landed on Copenhagen's runway 04L when both engines automatically shut down automatically. The aircraft rolled out, the crew managed to steer the aircraft clear of the runway. The aircraft was subsequently towed to the apron.

The aircraft is still on the ground in Copenhagen about 4 days later.

http://avherald.com/h?article=4ea5172d&opt=0


Reminds me of this ANA 788 incident a couple years ago.
http://avherald.com/h?article=4c2fe53a&opt=0


That sounds like a great feature. They should add it to more aircraft. It's just what you need when over central London on approach to Heathrow, for example.


BA38 tested this feature and it did not end well.
 
Virtual737
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 9:12 am

Was it a shutdown or an update and shutdown? Sometimes the latter can take a while to get things back online. Is the shutdown feature handily placed in the Start menu?
 
RR757
Posts: 18
Joined: Fri Mar 13, 2009 11:16 pm

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 11:15 am

avier wrote:
I'm guessing it's the new fuel saving technique. The last I heard, they were shutting down one engine after vacating the runway. Now, shutdown both engines right when the wheel comes in contact with the runway surface.

This is worrying to hear. The flight crew surely must be in ultimate control of both engine’s on/off switch?
 
VV
Posts: 2352
Joined: Sat Feb 13, 2016 1:03 pm

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 12:28 pm

RR757 wrote:
avier wrote:
I'm guessing it's the new fuel saving technique. The last I heard, they were shutting down one engine after vacating the runway. Now, shutdown both engines right when the wheel comes in contact with the runway surface.

This is worrying to hear. The flight crew surely must be in ultimate control of both engine’s on/off switch?


As long as they are not shutdown simultaneously during cruise it should be okay, although it could be a very effective way to save fuel.
 
SwissCanuck
Posts: 284
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 12:36 pm

RR757 wrote:
avier wrote:
I'm guessing it's the new fuel saving technique. The last I heard, they were shutting down one engine after vacating the runway. Now, shutdown both engines right when the wheel comes in contact with the runway surface.

This is worrying to hear. The flight crew surely must be in ultimate control of both engine’s on/off switch?


No, they are not. Google FADEC, but as with most things in 2021 the "ultimate control" lies with a computer.
 
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zeke
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 1:01 pm

SwissCanuck wrote:
No, they are not. Google FADEC, but as with most things in 2021 the "ultimate control" lies with a computer.


This is incorrect, FADEC is controlled via the engine master switch. Those of us that are older will remember Hydromechanical units shutting engines down as well.

FADEC has provided much higher reliability, better diagnostics, better fuel economy, higher thrust ratings that could otherwise be achieved.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
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lightsaber
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Mon Jul 19, 2021 1:07 pm

zeke wrote:
SwissCanuck wrote:
No, they are not. Google FADEC, but as with most things in 2021 the "ultimate control" lies with a computer.


This is incorrect, FADEC is controlled via the engine master switch. Those of us that are older will remember Hydromechanical units shutting engines down as well.

FADEC has provided much higher reliability, better diagnostics, better fuel economy, higher thrust ratings that could otherwise be achieved.

No to mention a FADAC has an insanely fast reboot time. I cannot break NDA and say, but under 50ms.

Lightsaber
10 months without TV. The best decision of my life.
 
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AirKevin
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Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Tue Jul 20, 2021 12:18 pm

boerje wrote:
peterinlisbon wrote:
ikolkyo wrote:


That sounds like a great feature. They should add it to more aircraft. It's just what you need when over central London on approach to Heathrow, for example.


BA38 tested this feature and it did not end well.

I think that was the point.
Captain Kevin
 
basspaul
Posts: 69
Joined: Fri Jan 26, 2018 8:18 pm

Re: Air Baltic A223 - Both engines automatically shutdown on touchdown

Tue Jul 20, 2021 7:36 pm

LDRA wrote:

I am curious, if you have both engines out, wouldn't that mean hydraulics and electrical power source are lost as well? How long does the hydraulic accumulator and the on-board battery last, while actively using brakes and nose wheel steering? Or does APU automatically comes on on a CS300?


The brakes on the A220 are purely electric and the battery system has enough reserves to actuate them. Reserve capacity in a aircraft's hydraulic system is a well understood concept, I doubt BBD got it wrong.

It is possible that this incident did reveal a logic error in the software somewhere. Let us hope that if it is, that is a truly "1 in a billion event". Let the experts figure it out.

If it's water ingress into wiring or components, I'm sure Airbus is already well aware and looking into it. Water ingress with the doors open on rainy days is always a PITA for airframers.

Of course we want to never have incidents like this, but when it is discovered via a near miss, our industry often gets the lesson learned incorporated.

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