Enstrom 280FX, G-MHCK
Following a normal start-up, the pilot lifted the helicopter into a hover when he noticed a burning smell and saw smoke coming from the area around the engine. He reported that the helicopter then lost power and he landed back on the helipad. Both the pilot and passenger exited the aircraft without injury. An exhaust pipe from the turbocharger was found detached which had allowed exhaust gases to heat the aircraft skin, leading to the smoke and fire. The exhaust pipe was maintained ‘on-condition’ and was visually inspected one and a half hours flying prior to the accident. Metallurgical examination of the exhaust pipe showed that it had failed due to intergranular cracking around the weld connecting the flange to the main tube. It is probable that the cause of the intergranular cracking was due to sensitisation of the austenitic 321 stainless steel during welding. The manufacturer’s agent advised that there have been no previous reported incidents of the failure of the exhaust pipe.
G-MHCK 10-05.pdf (356.58 kb)