SQ836 incident

[cscs1956]

Seems more likely to be crew error... But even if it's crew error, that's extremely worrying. An accident is never due to just one reason - it's always issues building up on top of each other - and having a poorly trained crew can be the matter between an incident and an accident. And this is even more pressing considering this has already happened with SQ 6.

Support that, especially after a 13000 ft drop without a clear explanation on root cause.
If the aircraft is not grounded, what happen to the crew?

[FSJZ]

Support that, especially after a 13000 ft drop without a clear explanation on root cause.
If the aircraft is not grounded, what happen to the crew?

Probably grounded too, undergoing investigations and interviews by AAIB and SQ.

[flyguy]

Let's really seriously hope that SIA did do another more through check on 9V-SSF after it came back from Shanghai. And the issue or the undetermined engines shut down is solved. It is very scary for an aircraft to have lost its engines even albeit temporarily for one engine which "relighted" on its own. But still share many in the aviation industry and other pilots' views that after a uneventful engine failure, the protocol is to divert to the nearest airport - and especially in this case, where the aircraft continue it flight for the next 100 mins.

[sgflight]

Guys, please relax and not speculate too much.

Sq have a high level of pilot training and pilots are trained to be very religious to the checks. It's almost systematic that it's a kind to changing a ram card and the computer will still operate nicely.

Excessive turbulence or huge intake of water due rain have been known to cause engine flameout. And re-lighting engine at 39000ft is quite difficult, thus descent down to the range of 20000ft to 25000ft where there is more air to restart engine is common.

Whatever the cause, a good landing is one where we can walk away from and a excellent landing is one where they can also reuse the aircraft. We all pay extra n cash or miles to fly sq not just for its service, but also for that confidence.

[leops1984]

Here is a first-hand account from somebody on the flight:

http://onemileatatime.boardingarea.c...-engine-power/

[boing]

BS cleaner

It's imperative to understand that engine stall and engine shutdown/flameout are two different things. If a dual engine shutdown did occur, the aircraft would lose all power to the cabin and oxygen masks would drop out as the aircraft would be unable to pressurize the aircraft. With a situation as dramatic as this, it would be the headline news all over the news/net as almost everyone with a smartphone is a freelance news reporter nowadays.

And with hundreds of oxygen masks to stow and numerous seat cushions to change, it's impossible the aircraft could have departed in 4 hours. Mind you, we are not even taking into account the various technical checks that would have to be done for a dual engine flameout. The aircraft would be grounded. Period. There's no way an aircraft that experienced dual engine flameout would be allowed to depart on a revenue flight so soon.

The facts I know so far are that the crew saw a weather pattern developing along their route and requested and got approval to deviate from their filed route. Midway through, one engine stalled. While descending, as per SOP, another engine stalled and that's when they issued a "Mayday " call. They managed to get both engines working normally after following the checklists and cancelled their Mayday call.
And after consulting Singapore maintenance, who have direct access to Airbus and RR, decided to continue to PVG. These decisions are not taken lightly and are taken after much deliberations and considerations, taking into account the various real time engine and aircraft parameters they have access to and could study from. So, it's not a matter of two men in the pointy end taking a minute or two to say, " I think we continue " but a room full of engineers studying carefully various manuals and data to give a recommendation to the flight crew.

It's strongly suspected at this time that icing is what caused the engine power loss. Exactly the same as AF447, but instead of the aircraft's pitots getting blocked, the engines pitots get blocked giving erroneous information and the engines computers cannot give the desired thrust. Descending to a lower altitude and warmer air solves the issue by thawing and removing the source of blockage. Tada !, problem solved.

And to those who speculated about fuel problems and crew accidentally shutting down the engines and covering up, with the amount of data being sent and recorded real time at the airline base's maintenance centre, the flight crew cannot simply say "I didn't do it" and walk away. Heck, anyone who watches Air Crash Investigation would know about this.

[shikhargpt]

... the flight crew cannot simply say "I didn't do it" and walk away...

Who's to say they did? I mean, it is still possible that dispatch, RR and Airbus realised it was no fault of the aircraft and that's why it was back in service so quickly. Still could have been a crew mistake, and maybe they are being investigated right now.

[cscs1956]

It's imperative to understand that engine stall and engine shutdown/flameout are two different things. If a dual engine shutdown did occur, the aircraft would lose all power to the cabin and oxygen masks would drop out as the aircraft would be unable to pressurize the aircraft. With a situation as dramatic as this, it would be the headline news all over the news/net as almost everyone with a smartphone is a freelance news reporter nowadays.

And with hundreds of oxygen masks to stow and numerous seat cushions to change, it's impossible the aircraft could have departed in 4 hours. Mind you, we are not even taking into account the various technical checks that would have to be done for a dual engine flameout. The aircraft would be grounded. Period. There's no way an aircraft that experienced dual engine flameout would be allowed to depart on a revenue flight so soon.

The facts I know so far are that the crew saw a weather pattern developing along their route and requested and got approval to deviate from their filed route. Midway through, one engine stalled. While descending, as per SOP, another engine stalled and that's when they issued a "Mayday " call. They managed to get both engines working normally after following the checklists and cancelled their Mayday call.
And after consulting Singapore maintenance, who have direct access to Airbus and RR, decided to continue to PVG. These decisions are not taken lightly and are taken after much deliberations and considerations, taking into account the various real time engine and aircraft parameters they have access to and could study from. So, it's not a matter of two men in the pointy end taking a minute or two to say, " I think we continue " but a room full of engineers studying carefully various manuals and data to give a recommendation to the flight crew.

It's strongly suspected at this time that icing is what caused the engine power loss. Exactly the same as AF447, but instead of the aircraft's pitots getting blocked, the engines pitots get blocked giving erroneous information and the engines computers cannot give the desired thrust. Descending to a lower altitude and warmer air solves the issue by thawing and removing the source of blockage. Tada !, problem solved.

And to those who speculated about fuel problems and crew accidentally shutting down the engines and covering up, with the amount of data being sent and recorded real time at the airline base's maintenance centre, the flight crew cannot simply say "I didn't do it" and walk away. Heck, anyone who watches Air Crash Investigation would know about this.

Is this another speculation or root cause study?

[FSJZ]

Here is a first-hand account from somebody on the flight:

http://onemileatatime.boardingarea.c...-engine-power/

Really interesting and insightful read of his experience. I would say SQ handled this crisis rather well, by not causing undue panic and alarm in the cabin, which would have further complicated matters.

The aircraft made a slight left turn towards the coast, in the event that if power could not be restored, then it would be within the safe distance of an airport. If there was something really dire, then the crew would definitely have diverted to Hong Kong, given that SQ has many flights there and parts or spare aircraft could easily be flown over.

But given that the crew decided to continue the flight, it means that they must be fairly confident that whatever caused the engine flameout or temporary loss of power was a one time occurrence and will not affect the safety of the flight.

A loss of altitude following a dual engine "failure" is normal, as the crew needs to descend at around Mach 0.80 to windmill and restart the engines. If that fails, then the APU will provide bleed air to start the engines. And if that also fails, then the crew will slow down the aircraft to green dot speed to maximize the glide distance and prepare the aircraft for landing or ditching.

The crew would probably have restarted the APU shortly after the engine shutdown, to provide bleed air for cabin pressurization and power to the cockpit and cabin. The IFE would be offline though, as non-vital electronics are shut down to reduce power load.

After the landing in Shanghai, the fact that the engineers on the ground checked the engines thoroughly and signed it off for the return flight means that the technical crew were also fairly certain that the failure was isolated and would not affect the performance of the aircraft whatsoever.

[9V-JKL]

It's strongly suspected at this time that icing is what caused the engine power loss. Exactly the same as AF447, but instead of the aircraft's pitots getting blocked, the engines pitots get blocked giving erroneous information and the engines computers cannot give the desired thrust. Descending to a lower altitude and warmer air solves the issue by thawing and removing the source of blockage. Tada !, problem solved.

Airbus sent out a note to carriers that indicating it was a severe icing related event. But let's wait for SQ's official report.

Btw, love the BS Cleaner title

[sgflight]

Very nice & detailed analysis, thanks!

It's imperative to understand that engine stall and engine shutdown/flameout are two different things. If a dual engine shutdown did occur, the aircraft would lose all power to the cabin and oxygen masks would drop out as the aircraft would be unable to pressurize the aircraft. With a situation as dramatic as this, it would be the headline news all over the news/net as almost everyone with a smartphone is a freelance news reporter nowadays.

And with hundreds of oxygen masks to stow and numerous seat cushions to change, it's impossible the aircraft could have departed in 4 hours. Mind you, we are not even taking into account the various technical checks that would have to be done for a dual engine flameout. The aircraft would be grounded. Period. There's no way an aircraft that experienced dual engine flameout would be allowed to depart on a revenue flight so soon.

The facts I know so far are that the crew saw a weather pattern developing along their route and requested and got approval to deviate from their filed route. Midway through, one engine stalled. While descending, as per SOP, another engine stalled and that's when they issued a "Mayday " call. They managed to get both engines working normally after following the checklists and cancelled their Mayday call.
And after consulting Singapore maintenance, who have direct access to Airbus and RR, decided to continue to PVG. These decisions are not taken lightly and are taken after much deliberations and considerations, taking into account the various real time engine and aircraft parameters they have access to and could study from. So, it's not a matter of two men in the pointy end taking a minute or two to say, " I think we continue " but a room full of engineers studying carefully various manuals and data to give a recommendation to the flight crew.

It's strongly suspected at this time that icing is what caused the engine power loss. Exactly the same as AF447, but instead of the aircraft's pitots getting blocked, the engines pitots get blocked giving erroneous information and the engines computers cannot give the desired thrust. Descending to a lower altitude and warmer air solves the issue by thawing and removing the source of blockage. Tada !, problem solved.

And to those who speculated about fuel problems and crew accidentally shutting down the engines and covering up, with the amount of data being sent and recorded real time at the airline base's maintenance centre, the flight crew cannot simply say "I didn't do it" and walk away. Heck, anyone who watches Air Crash Investigation would know about this.

[cscs1956]

Really interesting and insightful read of his experience. I would say SQ handled this crisis rather well, by not causing undue panic and alarm in the cabin, which would have further complicated matters.

The aircraft made a slight left turn towards the coast, in the event that if power could not be restored, then it would be within the safe distance of an airport. If there was something really dire, then the crew would definitely have diverted to Hong Kong, given that SQ has many flights there and parts or spare aircraft could easily be flown over.

But given that the crew decided to continue the flight, it means that they must be fairly confident that whatever caused the engine flameout or temporary loss of power was a one time occurrence and will not affect the safety of the flight.

A loss of altitude following a dual engine "failure" is normal, as the crew needs to descend at around Mach 0.80 to windmill and restart the engines. If that fails, then the APU will provide bleed air to start the engines. And if that also fails, then the crew will slow down the aircraft to green dot speed to maximize the glide distance and prepare the aircraft for landing or ditching.

The crew would probably have restarted the APU shortly after the engine shutdown, to provide bleed air for cabin pressurization and power to the cockpit and cabin. The IFE would be offline though, as non-vital electronics are shut down to reduce power load.

After the landing in Shanghai, the fact that the engineers on the ground checked the engines thoroughly and signed it off for the return flight means that the technical crew were also fairly certain that the failure was isolated and would not affect the performance of the aircraft whatsoever.

In the previous A380 aircraft door seal case. It was sign off by engineer too!
Interested to know how do ground engineers simulate problem happen above 30,000ft? Or they just pull what ever recorded in the system to analyse?