Estado:	Final
Fecha:	23 ABR 2003
Hora:	18:02
Tipo:	Beechcraft 99A
Operador:	Transwest Air
Registración:	C-FDYF
Numéro de série:	U-110
Año de Construcción:	1969
Motores:	2 Pratt & Whitney Canada PT6A-27
Tripulación:	Fatalidades: 0 / Ocupantes: 2
Pasajeros:	Fatalidades: 0 / Ocupantes: 4
Total:	Fatalidades: 0 / Ocupantes: 6
Daños en la Aeronave:	Anulado
Consecuencias:	Written off (damaged beyond repair)
Ubicación:	11 km (6.9 milles) de Prince Albert, SK (Canadá)
Fase:	Aproximación (APR)
Naturaleza:	Vuelo Doméstico Programado
Aeropuerto de Salida:	Saskatoon Airport, SK (YXE/CYXE), Canadá
Aeropuerto de Llegada:	Prince Albert Airport, SK (YPA/CYPA), Canadá
Número de Vuelo:	602

Descripción:
The aircraft was approximately 4000 feet asl when the crew selected the flaps for the approach to Prince Albert. A bang was heard from the rear of the fuselage. The aircraft commenced an uncommanded pitch-up to a near-vertical attitude, then stalled, nosed over, and began a spin to the left. The crew countered the spin but the aircraft continued to descend in a near-vertical dive. Through the application of full-up elevator and the manipulation of power settings, the pilots were able to bring the aircraft to a near-horizontal attitude. The crew extended the landing gear and issued a Mayday call, indicating that they were conducting a forced landing. The aircraft struck a knoll, tearing away the belly cargo pod and the landing gear. The aircraft bounced into the air and travelled approximately 180 metres, then contacted a barbed-wire fence and slid to a stop approximately 600 metres from the initial impact point.

FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. During flight, the horizontal stabilizer trim actuator worked free of the mounting structure, and as a result, the flight crew lost pitch control of the aircraft.
2. During replacement of the horizontal stabilizer trim actuator, the upper attachment bolts were inserted through the airframe structure but did not pass through the upper mounting lugs of the trim actuator.
3. The improperly installed bolts trapped the actuator mounting lug assemblies, suspending the weight of the actuator and giving the false impression that the bolts had been correctly installed.
4. Dual inspections, ground testing, and flight testing did not reveal the faulty attachment.

Fuentes:
» CBC