quote:Is the banging & vibration a normal feature of a surge? - and is it normal for an engine to cause the same noises & vibration if the pilot tries to re-start it?
Does anyone know the answer to this?
Also, does anyone (any Heathrow service engineers out there?) know what was actually wrong with this engine? I had a quick look at it as I walked down the front aircraft steps at Manchester, but I couldn't see any obvious sign of damage. Was it just a sticking valve (or something similar)? - or was there any physical damage?
You probably missed the link I posted in the first pages of this thread to
www.fromtheflightdeck.com
which in turn shows all the info about engine failures in general as well as surges from a doucment published by the FAA, including supporting video
Yes for a surge alone the engine will rock and vibrate simply because the surge is localized and rotates backwards to the spinning rotor at about 1/4 rotor speed while at the same time producing pressure pulses at a rate of about 7 per second.. Since the mounts are single point in the top front, this rotating pressure wave causes the engine and pylon to shake and in turn the wing and passengers as well. It's all very short lived until the pilot retards the throttle and reduces the pressures in the engine.
The sparks seen could either be from rubbing of the blades against a case or moe likely a few loose bits in the engine.
Often the F/A s as well as the passengers are not familar with this and it can create some apprehension although it is typically ho-hum to the aircraft.