Incident Overview
On a demonstration flight at Dunsfold, a HS-125-600B jet commenced takeoff from runway 07 at 1611 hours with two pilots and seven passengers. Prior to the takeoff roll, no birds were observed as a hazard. However, the aircraft followed standard bird strike precautions by operating with landing lights, strobe lights, and navigation lights on.
Bird Encounter
As the aircraft began its takeoff roll, witnesses noticed a large flock of birds rising from the grass verge north of the eastern runway end. The birds were apparently disturbed by an incoming Harrier aircraft taxiing west along the perimeter track, approximately 120 meters north of and parallel to the runway. The flock ascended in a dense formation and wheeled south across the runway as the HS-125 became airborne. Simultaneously, a second bird flock rose from the center of the aerodrome and flew north.
Engine Power Loss
The aircraft became airborne shortly before the halfway point of the runway. The commander reduced power from 100% to between 98% and 96% and ordered the undercarriage raised when the aircraft, at 50 to 100 feet altitude and approximately 150 knots, encountered one or both bird flocks. The commander heard and felt a series of bangs as birds struck the aircraft. Ground witnesses heard high-power engine noise followed by one to three muffled sounds (described as explosions, bangs, thumps, booms, or whoofs), then cessation of high-power engine noise. Simultaneously, balls of flame lasting one to three seconds appeared at the rear of each engine. After the accident, remains of 11 dead lapwings (Vanellus vanellus) were found about 1,170 meters from the runway start. The largest bird weighed 303 grams with a 61 cm wingspan.
Forced Landing
Neither pilot noted abnormal instrument readings, but the commander sensed an immediate decrease in acceleration, attributing it to complete loss of power on both engines. He also suspected some bangs were due to engine surging. He reduced climb attitude to maintain flying speed, partially reduced throttles, then reopened to full throttle without perceiving any thrust increase. He decided on a forced landing straight ahead, called for undercarriage extension and full flaps, closed throttles, and lowered the nose for approach. The aircraft touched down on main wheels about 180 meters before the runway end at an estimated 120 knots. After lowering the nosewheel, he applied full wheel brakes throughout the landing run.
Overrun and Collision
The aircraft overran the runway and continued straight across grass fields and through hedges, then struck a ditch on the west side of the A281 road, about 285 meters beyond the runway end. The impact ruptured and detached the entire undercarriage. The aircraft bounced across the road at an estimated 85 knots, striking and demolishing a passing private Ford Cortina. All six occupants of the car were killed. The aircraft slid on its underside for about 150 meters across a field beyond the road. Shortly before stopping, the commander closed the high-pressure fuel cocks. Noticing light behind him, he assumed fire and ordered immediate evacuation. The forward entry door was opened upon stopping, and all nine occupants evacuated safely before fire spread.