ASN Wikibase Occurrence # 43759
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| Date: | Sunday 1 July 2007 |
| Time: | 19:00 |
| Type: |  Eurocopter AS 350B2 AStar |
| Owner/operator: | Expedition Helicopters |
| Registration: | C-FLUK |
| MSN: | 2767 |
| Year of manufacture: | 1993 |
| Fatalities: | Fatalities: 2 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Bernick Lake, Saskatchewan -
 Canada
|
| Phase: | En route |
| Nature: | Passenger - Non-Scheduled/charter/Air Taxi |
| Departure airport: | Bernick Lake, Saskatchewan |
| Points North Landing, Saskatchewan | |
| Investigating agency: | TSB |
| Confidence Rating: |  Information verified through data from accident investigation authorities |
The pilot of the Eurocopter AS 350 B-2 helicopter (registration C-FLUK, serial number 2767) was ferrying the helicopter, with one passenger, to Points North Landing, Saskatchewan, from a fuel cache located approximately 42 nautical miles (nm) southwest at Bernick Lake. An electronic flight notification was sent by the passenger to another member of his survey company based at Points North Landing, indicating an arrival time of 19:05 central standard time (CST).
When the helicopter did not arrive, the survey company initiated emergency procedures at 19:45. Debris was found the following day floating in Bernick Lake, approximately 25 nautical miles south-west of Points North Landing. The helicopter was found at the bottom of the lake with extensive damage and both occupants sustained serious injuries at water impact, but drowned when the helicopter sank.
The engine's number three bearing failed, resulting in a rearward movement of the power turbine shaft which cut the engine's Py line. As a result, the engine's rotational speed decreased to about ground idle speed, which is insufficient to sustain flight. Since there was no message from the helicopter by the survey technician indicating any emergency condition, it is likely that the power loss occurred quickly and that there was little advance warning of the impending bearing failure.
Findings as to Causes and Contributing Factors
The number three bearing of the engine's power turbine failed and engine power was automatically reduced to about ground idle, requiring the pilot to conduct an autorotation. The bearing likely failed when corrosion pitting occurred during a period where the required storage procedures were not followed.
The pilot conducted a forced landing into the lake because the en route altitude selected was too low to permit an autorotation to shore, because the pilot's response to the engine power loss slowed the establishment of an effective autorotation toward the shore, or because he was attempting to land near the shoreline of the lake in response to the first indication of the impending bearing failure.
The pilot likely misjudged the height of the helicopter above the water and executed the flare and landing prematurely. Premature initiation of the flare would result in the loss of the kinetic energy of the main rotor blades at a height from which the pilot would have been unable to control the water landing.
Finding as to Risk
Although regulations require pilots to fly the helicopter at a distance and height that would enable an autorotation to shore, there is no information provided in the basic flight manual with respect to glide ratios.
Other Finding
Although not a factor in this occurrence, the pressure in the hydraulic accumulators was below specification.
Accident investigation:
 |
|
Sources:
1. http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20080205X00139&key=1
2. http://www.tsb.gc.ca/eng/rapports-reports/aviation/2007/a07c0114/a07c0114.asp
History of this aircraft
Other occurrences involving this aircraft
| 5 November 1998 | C-FHAD | Les Helicopteres Abitibi Ltee | 0 | Bérat (Albanie) |  |
unk |
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 28-Oct-2008 00:45 | ASN archive | Added |
| 08-Jun-2009 03:23 | Anon. | Updated |
| 29-Jun-2014 23:13 | Dr. John Smith | Updated [Time, Aircraft type, Location, Phase, Nature, Departure airport, Destination airport, Source, Narrative] |
| 03-Feb-2016 10:22 | Aerossurance | Updated [Nature, Source, Narrative] |
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