Enstrom 280FX, G-VVWW
A few minutes after leaning the fuel mixture the pilot felt a significant engine vibration, shortly after which the low rotor rpm warning horn sounded and the warning light illuminated. The pilot lowered the collective lever and opened the throttle which briefly restored the rotor rpm. The engine rpm continued to decrease and the pilot realised that the helicopter could not maintain level flight and decided to enter an autorotation to land. During the landing flare the tail rotor contacted the ground. Following repair a number of test flights were conducted where full engine power was achieved. It was found that there was an unusual engine-generated vibration which, on examination, was found to have been caused by a partially restricted fuel injector nozzle.
Enstrom 280FX, G-VVWW 04-07.pdf (240.01 kb)