View Full Version : AS350 B2 ENGINE
what may cause the restriction in partial/complete movement of the axial compressor?
alouette
9th Jun 2013, 09:12
Could you be a bit more specific...?
victor papa
9th Jun 2013, 09:45
Be careful! What does your rundown time look like-50%N1 to 0% not using the gauge but monitor the starter gen flange? If low the prosedure is in the Trouble shoot manual to remove comp by comp to determine which one is limiting the free rotation. If none of them and in any case do a boroscope asap. There has been a case or 2 of carbon build up behind the injection wheel leading to no free rotation and obviously if not rectified big problems. If you are in sandy conditions there is a ASB to chk the vibration level due sand build up on the shaft.
This is just general as to little info.
alouette
9th Jun 2013, 12:06
Did someone disassemble the modules before...? I agree on the borescope procedure. You should do one!!!!
sobit
12th Jun 2013, 07:47
thank you.answer appreciated. boroscope done. findings are within limitations. and operated for a flight.IDLE to FLIGHT GATE 340-360 NR the horn was inoperative,hover,all parameters normal, initiated takeoff.at 1000 AGl GONG was heard..over limit detected on VEMD.on inspection it was torque over-limited which we are finding hard to understand. operating altitude of aerodrome 3800 feet. Take-off weight of 1615 kgs only.
please share your thoughts on this.!!
alouette
13th Jun 2013, 02:52
We also operate a B2 with a VEMD, and had similar problems. One day I returned from cargo slinging, and when I released the load, the display indicated an exceedance. When the engineers had a look, the free turbine apparently over sped up to 530 which would have meant that I would have disintegrated in flight. Subsequently, the lead engineer attempted to spin the axial compressor a strange noise was heard. The result was that the engine modules had to be taken apart to ensure that nothing was done improperly at a previous inspection.