Flight Details
The pilot in command (PIC) and second-in-command (SIC) completed a positioning flight, picked up passengers, and continued to the destination airport. During the en route phase, cockpit voice recorder (CVR) data indicated the PIC expressed a desire to complete the flight quickly, arriving before another aircraft also en route, presumably to please the passengers. The PIC compared the flight to an automobile race. The airplane’s overspeed warning activated multiple times during descent.
Approach and Landing
The crew elected a straight-in visual approach. Throughout final approach, the airplane was high and fast, as noted by the SIC’s airspeed callouts. When the SIC suggested S-turns, the PIC stated they were unnecessary. An electronic voice recorded by the CVR repeatedly provided “sink rate” and “pull up” warnings, indicating an unstable approach, but the crew continued. The airplane touched down about 1,000 feet down the 4,200-foot runway.
After touchdown, the PIC reported that wheel brakes, thrust reversers, and ground air brakes did not function. However, witness and video evidence showed thrust reversers deployed shortly after touchdown. Tire skid marks indicated wheel braking occurred throughout the ground roll, increasing heavily during the final 1,500 feet when the antiskid system activated. The ground air brakes did not deploy. The airplane overran the runway, coming to rest about 400 feet past the departure end in marshy terrain, resulting in substantial damage to the fuselage and wings.
Post-Accident Examination
The switch controlling automatic deployment of the ground air brake system was found in a position that should have allowed deployment. No preaccident mechanical malfunction was found in the hydraulic system, wheel brakes, thrust reversers, weight-on-wheel switches, or air brake switches. The ground air brake deployment logic required both throttle levers below 18° (throttle lever angle). Post-accident testing of throttle lever position microswitches showed the left microswitch normal, but the right microswitch produced abnormal electrical current/resistance during initial testing. When touched and manipulated manually, resistance tested normal. The investigation could not determine whether this intermittent resistance prevented ground air brake deployment, as testing was inconclusive.
Landing performance calculations indicated that without ground air brakes, the ground roll exceeded the available runway from the touchdown point. Mobile phone video showed a quartering tailwind of about 10 to 15 knots during landing, exceeding the manufacturer’s 10-knot tailwind limitation, which would have further increased the actual ground roll distance.
During the approach, the crew received several indications of instability. Both pilots had opportunities to initiate a go-around, which would have been appropriate. However, external pressures to complete the flight quickly likely influenced their decision to continue.
Probable Cause
The flight crew’s continuation of an unstable approach and the failure of the ground air brakes to deploy upon touchdown, both of which resulted in the runway overrun. Contributing was the crew’s motivation and response to external pressures to complete the flight as quickly as possible to accommodate passenger wishes and the crew’s decision to land with a quartering tailwind that exceeded the airplane’s limitations.