SQ B777 Engine destroyed during taxi
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In regards to replacing both engines, which I am positive wouldn't happen, the airline I worked for, would require a test flight of the aircraft after a double engine change, on a 2 engine acft.
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arrival process
There is best practise when it comes to aircraft arrivals on stand.
1. the stand entry guidance is only activated once a sweep of the stand/ramp is completed. The guidance systems indicate to a pilot the stand is clear at that time. The correct aircraft type should be visually checked once activated.
2. The pilot should not enter the stand if the guidance is not on or is showing the incorrect aircraft type.
3. the ground handler or a person named by the airline should be in close proximity to the "Emergency Stop" button which is at ramp level.
This is to safeguard the aircraft should anything happen during the aircraft arrival. ALL new guidance systems including Safedock and Apis have this facility. Even the Old Agnis stands can have this fitted and indeed a lot of airports do. Best practise dictates this manned by a nominated person.
The question that needs to be asked are.
1. why was the guidance turned on ?
2. If it was on why does the airline not have a procedure that enables activation of the "Emergency stop"
1. the stand entry guidance is only activated once a sweep of the stand/ramp is completed. The guidance systems indicate to a pilot the stand is clear at that time. The correct aircraft type should be visually checked once activated.
2. The pilot should not enter the stand if the guidance is not on or is showing the incorrect aircraft type.
3. the ground handler or a person named by the airline should be in close proximity to the "Emergency Stop" button which is at ramp level.
This is to safeguard the aircraft should anything happen during the aircraft arrival. ALL new guidance systems including Safedock and Apis have this facility. Even the Old Agnis stands can have this fitted and indeed a lot of airports do. Best practise dictates this manned by a nominated person.
The question that needs to be asked are.
1. why was the guidance turned on ?
2. If it was on why does the airline not have a procedure that enables activation of the "Emergency stop"
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i'd be so pi@#$d if my luggage had been in there. What is the legal situation for the passengers I wonder? Sorry can't find your suitcase, only bits and pieces?
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I think the main points about replacing both engines is..
It does not take twice as long to replace two engines as it does one engine, so the airplane can be back in service sooner.
If there is any performance improvement package available then a matched pair is obviously the way to go.
An engine does not loose its value by being taken off the plane, it is still worth exactly the same in the engineering bay as it is on the pylon.
A spare engine is an asset to the airline, it is an additional economic utility.
It does not take twice as long to replace two engines as it does one engine, so the airplane can be back in service sooner.
If there is any performance improvement package available then a matched pair is obviously the way to go.
An engine does not loose its value by being taken off the plane, it is still worth exactly the same in the engineering bay as it is on the pylon.
A spare engine is an asset to the airline, it is an additional economic utility.
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Hmmmm.
Twice the labor.
Twice the paperwork (even though paperless)
Test flight required.
Now, I've been away from the industry for a while, but I HAVE NEVER HEARD of any airline changing both engines as a matter of routine practice!
But I'm open to updating...
Twice the labor.
Twice the paperwork (even though paperless)
Test flight required.
Now, I've been away from the industry for a while, but I HAVE NEVER HEARD of any airline changing both engines as a matter of routine practice!
But I'm open to updating...
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It's an SQ 777.
Rolls-Royce and SQ have a joint-venture overhaul facility right there in Singapore (SAESL).
Rest assured, the engine is already torn down and every rotating component is being NDT'ed. Depending on which gas path the FOD took, most likely all the compressor blades are trash...LP, IP and HP. Along with the VIGVs. Each fan blade costs $60K US, BTW.
Turbine blades...who knows. Each one will be FPI'ed to determine if they're "serviceable-used" or scrap. Depending on how many hours are on the blades, some may not be worth keeping in the rotable parts shelf, simply because their life limit would mandate another engine overhaul just to remove the time-expired parts. Ditto all the major bearings.
The inlet duct is part of the basic engine. It will have it's own overhaul and be fitted to another engine when needed.
No double engine changes for crying out loud. For one, it's an SMS issue. Do you really want BOTH engines being replaced on a two-engine aircraft? Never do the same maintenance to both engines at the same time. If, for some reason you MUST do the same mx to both sides, the same person absolutely cannot perform the mx on both sides. In order to reduce the risk of the same mistake being made to both engines and a resulting dual flameout. Basic ETOPs SMS.
Old engines/new engines...they just run at different temperatures to produce the same thrust. Don't they teach that in pilot school?
Rolls-Royce and SQ have a joint-venture overhaul facility right there in Singapore (SAESL).
Rest assured, the engine is already torn down and every rotating component is being NDT'ed. Depending on which gas path the FOD took, most likely all the compressor blades are trash...LP, IP and HP. Along with the VIGVs. Each fan blade costs $60K US, BTW.
Turbine blades...who knows. Each one will be FPI'ed to determine if they're "serviceable-used" or scrap. Depending on how many hours are on the blades, some may not be worth keeping in the rotable parts shelf, simply because their life limit would mandate another engine overhaul just to remove the time-expired parts. Ditto all the major bearings.
The inlet duct is part of the basic engine. It will have it's own overhaul and be fitted to another engine when needed.
No double engine changes for crying out loud. For one, it's an SMS issue. Do you really want BOTH engines being replaced on a two-engine aircraft? Never do the same maintenance to both engines at the same time. If, for some reason you MUST do the same mx to both sides, the same person absolutely cannot perform the mx on both sides. In order to reduce the risk of the same mistake being made to both engines and a resulting dual flameout. Basic ETOPs SMS.
Old engines/new engines...they just run at different temperatures to produce the same thrust. Don't they teach that in pilot school?
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""No double engine changes for crying out loud. For one, it's an SMS issue. Do you really want BOTH engines being replaced on a two-engine aircraft? Never do the same maintenance to both engines at the same time. If, for some reason you MUST do the same mx to both sides, the same person absolutely cannot perform the mx on both sides. In order to reduce the risk of the same mistake being made to both engines and a resulting dual flameout. Basic ETOPs SMS.""
Absolutely,thats been procedure since time began.
Absolutely,thats been procedure since time began.
A buddy who works 777 tells me the event engine was a GE90-115B, not a Trent.
Rather amazingly, he says that based on the borescope, there is minimal damage to the core (fan and nacelle were pretty trashed though) .
However it sounds like they're going to do a completely overhaul regardless...
Rather amazingly, he says that based on the borescope, there is minimal damage to the core (fan and nacelle were pretty trashed though) .
However it sounds like they're going to do a completely overhaul regardless...
A buddy who works 777 tells me the event engine was a GE90-115B, not a Trent.
Rather amazingly, he says that based on the borescope, there is minimal damage to the core (fan and nacelle were pretty trashed though) .
However it sounds like they're going to do a completely overhaul regardless...
Rather amazingly, he says that based on the borescope, there is minimal damage to the core (fan and nacelle were pretty trashed though) .
However it sounds like they're going to do a completely overhaul regardless...
Yep, I stand correct - I should have checked the 21.3 report first: Trent 884. 
Obviously my buddy was mistaken.
Obviously my buddy was mistaken.
Last edited by lomapaseo; 21st Jan 2014 at 12:10.
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Try telling that to the bean counters phiggsbroadband, to the bean counters spares on the shelf are a waste of capital and space, particularly if the space is leased. Only bean counters could calculate an 'Allowable time AOG' awaiting spares. According to the BC the money is better off in the bank earning interest than sitting on shelves in the form of spares, even if it does mean the a/c is grounded for a day or two. The engine may be part of a 'power by the hour' agreement anyway in which case SQ will simply want shot of it and a replacement ASAP.
It may turn out to be an interesting insurance claim though, it will hinge on weather the offending baggage container is legally classified as F.O.D. or not. Difficult to call it F.O.D. when it is simply misplaced on the tarmac but still a part of the necessary equipment for the ground handling of that aircraft. Unless the insurance industry has pre written agreements on such incidents, (this won't be the first!), then I see two sets of underwriters possibly going head to head there.
it is an additional economic utility.
Try telling that to the bean counters phiggsbroadband, to the bean counters spares on the shelf are a waste of capital and space, particularly if the space is leased. Only bean counters could calculate an 'Allowable time AOG' awaiting spares. According to the BC the money is better off in the bank earning interest than sitting on shelves in the form of spares, even if it does mean the a/c is grounded for a day or two. The engine may be part of a 'power by the hour' agreement anyway in which case SQ will simply want shot of it and a replacement ASAP.
It may turn out to be an interesting insurance claim though, it will hinge on weather the offending baggage container is legally classified as F.O.D. or not. Difficult to call it F.O.D. when it is simply misplaced on the tarmac but still a part of the necessary equipment for the ground handling of that aircraft. Unless the insurance industry has pre written agreements on such incidents, (this won't be the first!), then I see two sets of underwriters possibly going head to head there.
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Hi Parabellum, I was just thinking that if the engineering crew did not have a spare engine sitting on their shelves, which they could soon put onto the aircraft, then that aircraft is going nowhere for a very long time whilst they replace individual HP turbine blades.
Perhaps some techy types could give us some figures about the time taken to replace an engine, as opposed to testing and replacing internal parts.
Perhaps some techy types could give us some figures about the time taken to replace an engine, as opposed to testing and replacing internal parts.
Perhaps some techy types could give us some figures about the time taken to replace an engine, as opposed to testing and replacing internal parts.
Depending on the operator and engine (777 engines, due to their size, tend to take a little longer), an engine change is somewhere between 8 and 24 hours. Some operators routinely do engine swaps during an overnight.
I've never heard of an operator opening up an engine core 'on wing', in a shop it's typically a few weeks, depending on the extent of the work. The newer engines can be broken into modules - fan module, compressor module, hot section module, that sort of thing. If only one module needs work, they'll replace that module (day or two) and return the engine to service while the module in question will go into the shop for overhaul.
If the operator doesn't have an available spare, the engine manufacture typically has several 'lease pool' engines available as spares (although it may take a couple days and a very expensive Antonov charter to get it to where its needed).
Depending on the operator and engine (777 engines, due to their size, tend to take a little longer), an engine change is somewhere between 8 and 24 hours. Some operators routinely do engine swaps during an overnight.
I've never heard of an operator opening up an engine core 'on wing', in a shop it's typically a few weeks, depending on the extent of the work. The newer engines can be broken into modules - fan module, compressor module, hot section module, that sort of thing. If only one module needs work, they'll replace that module (day or two) and return the engine to service while the module in question will go into the shop for overhaul.
If the operator doesn't have an available spare, the engine manufacture typically has several 'lease pool' engines available as spares (although it may take a couple days and a very expensive Antonov charter to get it to where its needed).
Rebuilding the engine in situ is not happening.
RR has very specific maintenance procedures and doing HP turbine work outside of the shop is not ok.
So an engine replacement seems unavoidable here.
It would be nice to get an update on this from someone on site.
RR has very specific maintenance procedures and doing HP turbine work outside of the shop is not ok.
So an engine replacement seems unavoidable here.
It would be nice to get an update on this from someone on site.
It would be nice to get an update on this from someone on site.
If it's only fan damage (not internal stuff like HP turbine) many engine repairs are often made on wing after a bird strike.
If the shroud casing bits around the fan blade tips are heavily damaged then it just may end up replaced anyway.
Since I haven't seen a photo it aint worth guessing, about the only thing one might hear from the grapevine is whether it was replaced or not.
tdtracer's unreliable friend
had a very believeable story about the damage so take your pick 