chopper doctor Posted June 18, 2009 Report Share Posted June 18, 2009 OK, here is whats up. FCU had been changed out about 15 hours ago. Pilot reporting minor compressor stall during start, and starting hot. Engineer tasked to adjust FCU, found it not responding as per usual. Did quick test flight and single engine power checks were ok ( its in a light twin helo) Next day all is well, starts good, pilot goes to take off and can only get 60% Q out of this engine before rotor rpm droops off. WTF i say? check out all lines and linkages, its all good. Decided that after all the probs adjusting this FCU, maybe its time for it to go. New FCU installed by myself......same problem...........engine is good until you pull pitch, 60% Q and 90.5% N1 is all you get, pull more pitch and rotor droops off. Hmmmm, fuel flow limited it seems.....very strange, well, we have a spare governor, lets try that. Same prob. New fuel nozzle, same prob, fuel pump from the other engine, same prob. All lines pneumatic leak checked, all ok. Rigging triple checked ( was not touched during original FCU change) all ok. Running out of ideas here. When you hit 60 % Q it just stops, and when you lower collective, the N1 goes down right away, the torque seems to stick for a second or two, then jumps down to follow the collective input. This A/C had been operating normally before the FCU change. Sorry for the long post, but trying to get all the info out here............... Ideas? suggestions? Quote Link to comment Share on other sites More sharing options...
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