What happened
On 6 January 2012, a Gulfstream American GA-7 Cougar, registration G-OOGA, was preparing for a private flight from Andrewsfield Airfield. Following delays caused by a discharged battery, the engines were successfully started with assistance from ground personnel. Before the takeoff roll, the pilot held the aircraft on the brakes while advancing the throttles to 2,000 rpm to verify that engine temperatures and pressures were within limits.
As the aircraft accelerated, the pilot noted that the airspeed indicator was functioning. However, at approximately 70 kt, the aircraft began drifting to the left. Despite the application of full right rudder, the aircraft continued to yaw left. Upon reaching 75 kt, the main wheels struck a hidden ridge on the runway. This impact caused the aircraft to lift off without any elevator input. The aircraft entered a steep nose-up attitude, rolled to the left, and subsequently descended in a tail-down attitude, striking the ground. The pilot attempted to lower the nose and applied full power, but the aircraft impacted the earth. Both the pilot and the passenger escaped without injury.
The investigation
The AAIB examined the wreckage and the flight controls. The investigation established that the rudder controls were fully functional and showed no technical defects. A review of the aircraft's weight and balance indicated that the fuel tanks had been filled to the top tabs, suggesting the aircraft was operating at its maximum all-up weight. However, the exact takeoff weight could not be precisely confirmed due to uncertainties regarding the fuel state at the moment of departure.
Findings
- The aircraft became airborne at an insufficient airspeed.
- The aircraft struck a hidden ridge on the runway during the takeoff roll.
- The aircraft was operating at or near its maximum all-up weight.
- There were no mechanical failures identified in the rudder or engine systems.