Background
A Learjet 23 (serial number 23-45A) was prepared for a flight with a passenger aboard. A lineman noted that the parking brake was set prior to the flight. The aircraft was approximately 430 lbs over its maximum weight limit.
Accident Sequence
The flight crew began takeoff on a 5,147-foot runway with a 10-knot crosswind. A witness reported that the aircraft rotated for takeoff about 4,500 feet down the runway and lifted off approximately 50 feet later. After becoming airborne, the aircraft remained low and slow, at an altitude of 20 to 60 feet above ground level (AGL). It then began to bank (rock) left and right while in a nose-high attitude, settled, struck trees, and crashed about 200 feet beyond the runway.
One observer stated that the aircraft went out of control before impact, while another described it as being "in or on the edge of stalled flight."
Examination Findings
Post-accident examination of the aircraft revealed rotational damage occurred in both engines during impact. The braking system showed evidence that the parking brake control valve was partially engaged; the brake torque tube exhibited heat blueing.
On this early model Learjet, the parking brake had to be released by first depressing the brake pedals. The pilot's handbook did not address this procedure. On later models (serial numbers 23-050 and up), the parking brake needed only to be moved to the 'off' position.
The investigation indicated that the pilot in the left seat had training on later models (Learjet 24/25), but only a biennial flight review was noted in the Model 23. The company dispatcher stated that no training would have been performed for the accident flight.