What happened
During ground operations, Flight 335, an SD3-60, was cleared to taxi into position and hold behind a departing Boeing 747-400. As the crew of Flight 335 taxied forward of the hold line, the pilot lost control of the aircraft. The intense thrust from the departing heavy jet caused the SD3-60 to be blown into the airport's blast fence.
The investigation
The investigation examined the experience levels of the crew and the aerodynamic stability of the aircraft under high-velocity wind conditions. The pilot in command (PIC) had 44 hours in type, with 10 hours as PIC, and had previously served as a first officer on an ATR-42. The second in command (SIC) had 49 hours in type and transitioned from general aviation.
Investigators queried the manufacturer, Short Brothers, regarding the effects of high-velocity winds on the aircraft. The manufacturer stated that a wind of approximately 70 knots perpendicular to the fuselage could upset the airplane. This specific operational limitation was not documented in the flight manual or provided to the operator.
Findings
- The company's crew pairing policy, which prohibited pairing two low-time crew members together, had been waived by the VP of Flight for this specific positioning flight.
- Critical information regarding the aircraft's susceptibility to perpendicular winds was unavailable to the pilots.