More GE woes

[gas path]

Apparently two GE90 operators (SV and AF)suffered IFSDs last week due to hp compressor stage 4 toggle seals letting go which results in the failure of the compressor downstream, this follows on from another operator (CO) who suffered a similar failure a couple of months ago. A fleet wide check has resulted in a number of unscheduled removals.

[Eboy]

I remember when GE was trying to get the GE90 certified with the FAA around '94, they had some technical problems to overcome. I thought they fixed them then. Are these new problems or has this always been an issue with the GE90?

[Mutsy]

There are ongoing inspections on the GE90's 3rd and 4th stage compressor toggles, with the reinspect time dependant on the wear found, with some engines down to 25 cycle reinspects. The tolerances are continually updated as more information comes available, I would expect the limits to change again in the light of the two IFSD's recently. Many more shut downs and I would think that the ETOPS approval will start to be called into doubt.

[cirrus01]

The toggle seal inspections are only to monitor the progress of rubbing.
The root cause is the wear in the VSV bearings, something which I was told that GE have not yet got a fix, and did not expect to be "on top" of the problem for at least two years.

When the wear reaches the current limit , the engine gets pulled, sent back for overhaul and gets put back to the original condition ready for the toggle seals to start wearing again !