SQ's GE90-115B problems - some light shed

[SQflyergirl]

Seems that the three failures on the 77W's were different.

SQ345's was an engine surge due to a turbine plate failure. Turbine blade corrosion was the root cause apparently.

SQ15's was Transfer Gearbox failure (the gearbox drives the mechanical accessories like fuel and oil pumps plus things like rpm sensors and provides electrical power for attached items like sensors - many engine gauges show blank until the engine starts to turn and provided such power)

SQ334's I'm told was an Accessories Gearbox failure (which surprises me, since on this type of engine an Accessories Gearbox is the same as a transfer gearbox - last I checked the 77W was not a helicopter nor a turboprop where it might be different -*). AFAIK, TGB's and acc gearboxes are the same, but I defer to those here who know the GE90-115B better than I do.

SIAEC and GE are working together to sort it


*quick note: Turboprops and Choppers will have a transfer box to power the rotor or prop and a secondary accesories box for the ancilliaries

[The High Flyer]

SQflyergirl, you are the best!

[EWR]

a turbine plate corrosion already? I thought the plane was only about a year old

[v1rotate]

I think the GE90's the same, but the CF6 definitely has both an Accessory Gearbox and Transfer Gearbox. The accessory gearbox is the one which drives the integrated drive generator, fuel pumps, hydraulic pump, lube oil pump, and air/oil seperator. The transfer gearbox, along with the inlet gearbox and radial drive shaft connects the accessory gearbox to the turbine shaft. I'll see if I can find a diagram showing how this works.

[milehighj]

What were the reg. nos. of the 77Ws concerned?

[HKG1]

I don't know if this means anything or it was just routine maintenance, but as I was taking off earleir today on the SQ 976, I saw 3 777's parked up at their gates at T3 with their right hand engine cowlings open. I assume it was for inspection. I can't remember whether they were 200's or 300's or a mix

Maybe it's just because of the BA 777 incident, but there certainly "seems" to be more issues with the 777 at the moment. A week or so ago I was at BKK and the 777 I was on suffered a APU problem and we were delayed for 40mins. Still one of my favorite planes though.

[flyguy]

seems the engine's turbine corrosion is too early for that considering that the engine/plane is only a year old at best

[v1rotate]

I think the GE90's the same, but the CF6 definitely has both an Accessory Gearbox and Transfer Gearbox. The accessory gearbox is the one which drives the integrated drive generator, fuel pumps, hydraulic pump, lube oil pump, and air/oil seperator. The transfer gearbox, along with the inlet gearbox and radial drive shaft connects the accessory gearbox to the turbine shaft. I'll see if I can find a diagram showing how this works.

Here is a diagram, showing how the Accessory Gearbox and Transfer Gearbox works, taken from a GE CF6-80:

[v1rotate]

What were the reg. nos. of the 77Ws concerned?

SQ334 was 9V-SWA
SQ345 I believe was 9V-SWK. She operated this flight on 15/2.
SQ15 not sure (anyone know the date?)

[Doraemon]

SQ334 was 9V-SWA
SQ345 I believe was 9V-SWK. She operated this flight on 15/2.
SQ15 not sure (anyone know the date?)

I think all 3 flights belong to the same bird, 9V-SWA.

[SQ LPP]

I think all 3 flights belong to the same bird, 9V-SWA.

That is what I heard too.

[v1rotate]

I think all 3 flights belong to the same bird, 9V-SWA.

Ah yes I stand corrected. The SQ345 flight involved left on the 14th, which was indeed operated by 9V-SWA.