Final Report: Crew miscalculated Falcon's weight

 - December 31, 2008, 7:33 AM

Dassault Falcon 900, Santa Barbara, Calif., June 10, 2007–The Safety Board blamed the Falcon accident on the erroneous gross weight calculation and improper trim setting by the captain, which resulted in the airplane’s failure to rotate at Vr as expected and the captain’s decision to abort the takeoff at high speed. The first officer had entered a takeoff gross weight of 45,500 pounds on the takeoff and landing distance card with the V-speeds for that weight (V1 at 116 knots and Vr at 129 knots); he did not compute the center of gravity. The actual weight was 46,481 pounds and the V speeds were 118 knots for V1 and 131 knots for Vr. The stabilizer trim was set at -5.5 degrees, while the correct setting for the calculated c.g. would have been between -7 and -7.5 degrees.

On takeoff, the first officer called V1, then Vr. The captain got no response when he pulled back on the yoke. With the speed in the upper 130-knot range he relaxed the yoke, then pulled aft again, and again there was no response. He aborted the takeoff and the airplane hit a berm 580 feet past the end of the runway.

Later simulator testing revealed that at the accident takeoff configuration (stabilizer trim set to -5.5 degrees and V speeds set for 45,400 pounds), there was a delay of two to four seconds from the time the yoke was pulled back to the time the airplane reacted. With the trim set to -7.0 degrees and the V speeds set for 46,480 pounds, there was no delay in airplane response to elevator input.

No one was injured.