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ASN Wikibase Occurrence # 145018
Last updated: 14 November 2019
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Date:30-MAR-2012
Time:09:43
Type:Silhouette image of generic LAMA model; specific model in this crash may look slightly different
Aérospatiale SA 315B Lama
Owner/operator:Trans Aero Helicopters, Ltd
Registration: N929JV
C/n / msn: 2361
Fatalities:Fatalities: 0 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:25 miles from Alva, OK -   United States of America
Phase: En route
Nature:Cargo
Departure airport:Alva, OK (KAVK)
Destination airport:Alva, OK (KAVK)
Investigating agency: NTSB
Narrative:
The helicopter was flying at 300 feet above the ground with an external load when the pilot heard a loud noise from the engine and the rotor rpm began to decay. He jettisoned the load and entered an autorotation. During the flare, the helicopter's main rotor blades contacted the tail rotor drive shaft. Engine disassembly and examination revealed that the turbine casing was deeply eroded by particles that had accumulated in the casing as a result of operating in dusty environments. The erosion caused a crack to develop, and non-uniform overheating of the engine led to the partial melting of the nozzle guide vanes and the rupture of the blade tips in all three turbine stages. Uncontained debris then punctured the turbine casing and shroud. According to the helicopter's maintenance records, the helicopter had operated 68 hours past a 100-hour inspection. The erosion in the engine was likely preexisting since it had been purchased second hand. Further, the records contained no entries pertaining to compliance with the manufacturer's maintenance procedures, by either the current or previous owner, for operations in sandy environments. The current operator reported that they have since complied with the manufacturer’s procedures.
Probable Cause: Failure of the current and previous operators to comply with the manufacturer's maintenance procedures for operation in sandy environments, which resulted in turbine case erosion and the subsequent uncontained engine failure.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20120409X21232&key=1


Revision history:

Date/timeContributorUpdates
13-Apr-2012 12:03 Geno Added
31-Dec-2012 14:58 Anon. Updated [Nature, Damage, Narrative]
01-Oct-2014 08:11 harro Updated [Aircraft type]
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
27-Nov-2017 20:27 ASN Update Bot Updated [Operator, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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