Unfallbericht:Peace Air Ltd. Flight PE905 departed Grande Prairie (CYQU) at 10:40 MST on the first leg of a scheduled run to Fort St. John (CYXJ), Fort Nelson, BC, and Grande Prairie.
|Datum:||Dienstag 9 Januar 2007|
British Aerospace 3112 Jetstream 31
|Triebwerk:|| 2 Garrett TPE331-10UG-513H|
|Besatzung:||Todesopfer: 0 / Insassen: 2|
|Fluggäste:||Todesopfer: 0 / Insassen: 10|
|Gesamt:||Todesopfer: 0 / Insassen: 12 |
|Konsequenzen:|| Written off (damaged beyond repair)|
|Unfallort:||Fort St. John Airport, BC (YXJ) ( Kanada)
|Flugphase:|| Landung (LDG)|
|Betriebsart:||Inländischer planmäßiger Passagierflug|
|Flug von:||Grande Prairie Airport, AB (YQU/CYQU), Kanada|
|Flug nach:||Fort St. John Airport, BC (YXJ/CYXJ), Kanada|
Air traffic control (ATC) cleared the flight to maintain 12 000 feet above sea level (asl), and to hold on the TAYLOR non directional beacon (NDB), which forms the final approach fix for the instrument landing system (ILS) approach to runway 29 at St. John. At 11:09, Flight PE905 was cleared for an ILS approach to runway 29. The first approach was discontinued due to the aircraft being too high on the final approach leg, and clearance was given to return to the TAYLOR NDB at 6000 feet. At 11:23, ATC cleared the flight for another ILS approach to runway 29. The second approach was conducted as a full procedure with the outbound leg extended to ensure that the aircraft was positioned to follow the correct vertical approach profile.
The final approach course was flown with a flap setting of 20º and at the company standard operating procedure (SOP) recommended airspeed of 130 knots. At approximately 300 feet above ground level, the first officer informed the captain that he had the ground in sight. The approach lights were visual shortly thereafter. The captain discontinued his instrument scan and confirmed the appearance of the approach lights. The captain made the decision to land, and called for the full flap setting of 35º. The first officer diverted his attention to setting flaps, and to the Vref reference cards clipped to the instrument panel. When he looked up, the aircraft was almost on the ground, but short of the runway. There was insufficient time to warn the captain.
The aircraft initially touched down in a nearly wings-level attitude, 320 feet short of the threshold in about 16 inches of packed snow. The left main gear contacted the surface first, followed by the right main gear, and then the nose wheel. The aircraft then struck the last set of approach lights, bounced slightly, and touched down again 180 feet short of the threshold. After sliding through the threshold lights, the aircraft came to rest on the right edge of the runway, 380 feet beyond the threshold. The right main gear had broken off, and the nose gear had collapsed rearward. Both propellers were damaged by ground contact. The aircraft was equipped with a belly-mounted cargo pod, which supported the fuselage during impact.
Probable Cause:FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. A late full flap selection at 300 feet above ground level (agl) likely destabilized the aircraft's pitch attitude, descent rate and speed in the critical final stage of the precision approach, resulting in an increased descent rate before reaching the runway threshold.
2. After the approach lights were sighted at low altitude, both pilots discontinued monitoring of instruments including the glide slope indicator. A significant deviation below the optimum glide slope in low visibility went unnoticed by the crew until the aircraft descended into the approach lights.
FINDING AS TO RISK:
1. The crew rounded the decision height (DH) figure for the instrument landing system (ILS) approach downward, and did not apply a cold temperature correction factor. The combined error could have resulted in a descent of 74 feet below the DH on an ILS approach to minimums, with a risk of undershoot.
1. The cockpit voice recorder (CVR) was returned to service following an intelligibility test that indicated that the first officer's hot boom microphone intercom channel did not record. Although the first officer voice was recorded by other means, a potential existed for loss of information, which was key to the investigation.
Official accident investigation report
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Grande Prairie Airport, AB to Fort St. John Airport, BC as the crow flies is 164 km (103 miles).