Accident
On 2 July 2015 at 1733 hrs, a Viking Air (De Havilland) DHC-6-300 aircraft, registration 8Q-MAN, crashed into the sea approximately 3 km southeast of Kuredu (KUR). The aircraft was operating a charter flight under visual flight rules (VFR) from Komandoo (KOM) to Kuredu, carrying 11 passengers.
Sequence of Events
According to the operating crew, the aircraft was on final approach northwest bound to land at KUR. At approximately 400 feet, when the flaps were selected to the fully down position, the aircraft pitched up and began vibrating. The pilot flying (PF) could not control the aircraft and requested the pilot in command (PIC) to take over. The aircraft was in a nose-high attitude when the PIC assumed control. The stall warning light illuminated. The PIC applied full left rudder, moved the control column forward, and placed the power levers to idle. The aircraft did not respond. The flaps were then moved to the fully up position. The PIC regained some control, but the aircraft continued turning right and losing height, impacting the sea before full control could be reestablished.
Evacuation
On initial impact, the left float detached. The aircraft bounced and landed on the right float, causing it to also detach, though it remained trapped between the airframe and engine for several minutes. With both floats detached and the right float still trapped, the aircraft stayed afloat long enough for all 11 passengers and 3 crew to evacuate without injury. The aircraft then began tilting left, water rushed inside, and it sank.
Investigation
The Aircraft Accident Investigation Committee (AICC) was notified at 1750 hrs the same day. Investigation began immediately, with inspectors arriving at the scene at 2300 hrs, about five and a half hours after the accident.
Probable Cause
The investigation identified the following causes:
- a. The aircraft was operated outside the centre of gravity limitations on the sector in which the accident occurred.
- b. Load distribution errors went undetected because mass and balance calculations were not carried out in accordance with approved procedures prior to the accident flight.
- c. The co-pilot (PF) was not alerted to the impending stall as she neither saw the stall warning light illuminated nor heard the aural stall warning.
- d. The PIC was not able to gain control of the aircraft because the developing stall was not recognized and incorrect recovery procedures were applied.