ASN Wikibase Occurrence # 322248
| Date: | Saturday 21 January 2006 |
| Time: | 14:20 |
| Type: |  Cessna 208B Grand Caravan |
| Owner/operator: | Sonicblue Airways |
| Registration: | C-GRXZ |
| MSN: | 208B0469 |
| Year of manufacture: | 1995 |
| Engine model: | Pratt & Whitney Canada PT6A-114A |
| Fatalities: | Fatalities: 3 / Occupants: 8 |
| Aircraft damage: | Destroyed, written off |
| Category: | Accident |
| Location: | 20 km SSE of Port Alberni, BC -
 Canada
|
| Phase: | En route |
| Nature: | Passenger - Scheduled |
| Departure airport: | Tofino Airport, BC (YAZ/CYAZ) |
| Vancouver International Airport, BC (YVR/CYVR) | |
| Investigating agency: | TSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
En route from Tofino to Vancouver, the pilot issued a mayday and wanted to divert to Port Alberni Airport, BC (YPB). The aircraft did not make it and crashed in the woods, some 10 km from the airport.
CONCLUSIONS
FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. The engine lost power when a compressor turbine blade failed as a result of the overstress extension of a fatigue-generated crack. The fracture initiated at a metallurgical anomaly in the parent blade material and progressed, eventually resulting in blade failure due to overstress rupture.
2. The combination of aircraft position at the time of the engine failure, the lack of equipment enabling the pilot to locate and identify high terrain, and the resultant manoeuvring required to avoid entering instrument flight conditions likely prevented the pilot from attempting to glide to the nearest airfield.
FINDINGS AS TO RISK:
1. Single-engine instrument flight rules (SEIFR) operations in designated mountainous regions have unique obstacle risks in the event of an engine failure. Canadian equipment requirements for such operations do not currently include independent terrain mapping, such as terrain awareness and warning systems (TAWS).
2. Airline operators are not currently required to conduct any additional route evaluation or structuring to ensure that the risk of an off-field landing is minimized during SEIFR operations.
3. Pilots involved in commercial SEIFR operations do not receive training in how to conduct a forced landing under instrument flight conditions; such training would likely improve a pilot's ability to respond to an engine failure when operating in instrument meteorological conditions (IMC).
4. Mean time between failure (MTBF) calculations do not take into account In Flight Shut Downs (IFSDs) not directly attributable to the engine itself; it may be more appropriate to monitor all IFSD events.
5. The design of the Cessna 208B Caravan fuel shutoff valves increases the risk that the valves will open on impact, allowing fuel spillage and increasing the potential for fire.
Accident investigation:
 |
|
Sources:
CADORS Number: 2006P0080
Location
Revision history:
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