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ASN Wikibase Occurrence # 146643
Last updated: 26 September 2021
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Time:15:25 LT
Type:Silhouette image of generic B06 model; specific model in this crash may look slightly different
Bell 206L-1 LongRanger II
Owner/operator:Hevi Lift (PNG) Ltd
Registration: P2-HCY
MSN: 45333
Fatalities:Fatalities: 3 / Occupants: 3
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:30 km SSE of Mount Hagen, Western Highlands -   Papua New Guinea
Phase: En route
Departure airport:Inter Oil Drilling Rig,
Destination airport:Hou Creek near Mount Hagen), PNG
Following an engine surge just before landing at a remote drill site in Gulf Province, maintenance and troubleshooting was carried out by a company engineer on a Bell B206L-1/C30P helicopter, registered P2-HCY (HCY). To rectify whatever had caused the engine surge, two fuel system components were changed at the same time: the fuel control unit and the power turbine governor. The cause of the engine surge was not isolated to one of the components; instead, after both components had been changed, the helicopter was test-run once and considered to be serviceable. The drill site had run out of Jet A-1 fuel, and it is possible the engineer and pilot did not carry out a test-run after each component was changed to save the fuel on board the helicopter; they may also have wanted to save time in the field and return quickly to the company’s base at Mt Hagen, where more thorough checks could be undertaken.

Six minutes after HCY departed on the accident flight, a ‘MAYDAY’ broadcast was heard from HCY which included the words ‘engine failure’. It was reported that the sound of the ENGINE OUT aural warning could be heard in the background of the MAYDAY broadcast. The helicopter’s engine had stopped in flight and it crashed approximately 3 km north east of the departure point, fatally injuring all three on board. No signal was detected from the helicopter’s emergency locator transmitter (ELT) and the wreckage was found 7 days after the accident following an extensive search.

Damage to the main rotors indicated that the rotor system had been in a very low rotational energy state at impact. Damage to the engine indicated its rotation had been consistent with a spool-down cycle at the time of impact. Detailed testing of the engine and fuel system found no pre-existing defects that would have prevented the engine and fuel system from operating as intended.
Three possible explanations for why the engine stopped in flight are considered in this report; they relate to fuel exhaustion and mechanical issues. The AIC was unable to discount any of them on the evidence available, and all three are regarded as possible explanations for the occurrence. However, evidence from the engine driven fuel pump gear set and carbon seals that rely on fuel for lubrication (showing them to be in good condition with no evidence of deficiencies) and reports of a strong smell of fuel downstream of the wreckage several days after the accident together shed doubt on the likelihood of fuel exhaustion being a contributing factor.
Remoteness from the operator’s main base at Mt Hagen is probably, at least in part, why the reason for the engine surge was not established before the helicopter was returned to service. The fuel control unit and power turbine governor were both changed together, the helicopter appeared to be functioning properly, and the accident flight began ─ but it was still not known why the engine had surged the day before. This highlights a procedural deficiency: the helicopter was returned to service without a clear understanding of the malfunction that led to it being grounded. The Bell 206L-4 helicopter Flight Manual stated that a ‘Helicopter should not be operated following any emergency/malfunction procedure or precautionary landing until cause of malfunction has been determined and corrective maintenance action taken.’ While HCY was a Bell 206L-1/C30P, the AIC considers that this is prudent advice for any helicopter or aircraft. If this instruction had been followed it is possible the accident would not have occurred.

The AIC recognises the difficulties that remoteness poses for operators, engineers, and pilots when malfunctions occur far from well-equipped maintenance centres; nevertheless, the AIC recommends that operators should implement procedures to ensure that, wherever they are, aircraft are not returned to service unless corrective maintenance action has been taken on the basis of a full diagnosis of the cause of any malfunction.



Revision history:

07-Jul-2012 01:32 Geo Added
13-Jul-2012 02:39 gerard57 Updated [Source, Damage, Narrative]
20-Jul-2012 14:02 StreetF117 Updated [Registration, Operator]
30-Aug-2014 17:08 Aerossurance Updated [Source, Narrative]
11-Apr-2015 23:20 Dr. John Smith Updated [Aircraft type, Registration, Cn, Location, Nature, Departure airport, Destination airport, Source, Narrative]
22-Apr-2016 17:08 harro Updated [Date, Source, Narrative]
26-Sep-2016 20:34 Aerossurance Updated [Time, Location, Departure airport, Destination airport]
26-Sep-2016 20:35 Aerossurance Updated [Nature, Narrative]

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