The troubles with aircraft XM135 were holding up the closure of the unit, and at the time of the incident, no test pilot was available for another week. A pilot from
RAF Boscombe Down, who was involved in previous tests, suggested Holden perform the test himself because it involved only ground taxiing for 30 to 40 yards at a time. For each test, Holden was to test a different electrical configuration, rev up the engine to high RPMs, then cut the engine and apply the brakes. Holden was to communicate by hand signals with his support crew on a Land Rover, which would coordinate the next test with the control tower. Holden was not wearing a helmet and had no radio. The canopy of the aircraft was removed for the electrical wires running out of the cockpit. The landing gear was locked in a down position in a test mode. After the Lightning was in position, Holden carried out the first test as expected, moving the aeroplane . However, in a subsequent test, Holden unintentionally pushed the throttle past the afterburner gate. Once the afterburner was engaged, disengaging it required pushing the gate keys behind the throttle, which Holden was inexperienced in operating. The Lightning gained speed quickly and just missed a fuel tanker that was crossing the runway in front of Holden. The Lightning crossed the main runway as a mid-takeoff
de Havilland Comet passed over the Lightning. Holden was then running out of runway, so he pulled the stick back and took off. Following takeoff, Holden managed to disengage the afterburner after feeling for the gate keys. Holden considered ejecting; however, that was not possible because the ejection seat was in inert ground mode. On his first two landing attempts, his speed and height were wrong and Holden aborted both. Holden, who vaguely recalled that the landing speed for the Lightning was 150 knots, took a wide circuit around Lyneham and attempted to land in the opposite direction of the runway, running away from the village. In Holden's final flare, he adopted the attitude used in a
taildragger aircraft of his earlier training. This resulted in a
tailstrike, the rubber tail bumper of the Lightning hitting the concrete, breaking, and detaching the cable of the
drogue parachute used for assisting braking. Braking hard, Holden managed to bring the Lightning to a stop about one hundred yards before the end of the runway. Holden was airborne for 12 minutes. ==Aftermath==