Engine failure caused August 2012 crash of a Bell 407 helicopter in Wabush,
Newfoundland and Labrador
DARTMOUTH, NS, Nov. 28, 2013 /CNW/ - The Transportation Safety Board of Canada
(TSB) today released its investigation report (A12A0085) into the August 2012
engine failure and hard landing of a Bell 407 helicopter in Wabush,
Newfoundland and Labrador.
On 12 August 2012, a Universal Helicopters Newfoundland Limited Bell 407
helicopter was slinging a drill tower approximately 4nautical miles
southwest of Wabush, Newfoundland and Labrador. At around 1p.m. Atlantic
Daylight Time, as the helicopter was approaching the drill base frame, the
engine lost power. The helicopter then immediately descended and yawed to the
left. The engine power loss occurred at an altitude from which a safe landing
could not be assured, resulting in substantial helicopter damage; there was no
post-crash fire. The pilot, who was the sole occupant, sustained minor
injuries and was able to exit the aircraft.
The Bell 407 is powered by a single Rolls-Royce Corporation (RRC) Model
250-C47B turbine engine. A metallurgical examination of the occurrence
helicopter's engine revealed high-cycle fatigue (HCF) striations on 6 turbine
wheel blades. One of these blades had an HCF crack, which propagated about
0.40inches before it separated in overstress. The failure of the first blade
led to a rapid failure of the turbine wheel as the remaining blades separated
in overstress due to impact with blade fragments.
Since April 2002, there have been 3 similar occurrences of HCF blade failure
on part number 6898663 third-stage turbine wheel installed in the Model
250-C47B engines. At the time of this report, RRC has not been able to
specifically identify what engine operating condition, or conditions, cause
the tensile residual stresses to be induced at the blade hub trailing edges.
The TSB is an independent agency that investigates marine, pipeline, railway
and aviation transportation occurrences. Its sole aim is the advancement of
transportation safety. It is not the function of the Board to assign fault or
determine civil or criminal liability.
SOURCE Transportation Safety Board of Canada
Transportation Safety Board of Canada Media Relations 819-994-8053
The TSB is online atwww.tsb.gc.ca. Keep up to date throughRSS,Twitter
@TSBCanada,YouTube,Flickr and ourblog.
To view this news release in HTML formatting, please use the following URL:
CO: Transportation Safety Board of Canada
ST: Newfoundland and Labrador
NI: TRN AIR
-0- Nov/28/2013 14:08 GMT
Press spacebar to pause and continue. Press esc to stop.