The incident occurred on July 22, 1966, at RAF Lyneham Air Force Base (Chippenham, UK) while maintaining a Lightning F53 supersonic interceptor aircraft. It was caused by the actions of the aircraft technician, who agreed with the flight crew of the plane, but which were beyond the authority of the ground service team. The incident itself seriously endangered the safety of the aircraft and the airfield’s infrastructure and put the lives of airbase personnel and residents of nearby communities at risk.
The accident involved an aircraft designated XM135, the second serial produced copy of the latest British fighter-interceptor manufactured by English Electric. The aircraft had problems with its electrical inverter, which in turn caused the onboard instruments to shut down during takeoff and switch them to a backup power source. Given the temporary absence of test pilots and the urgent need for troubleshooting, one of the flight engineers was asked to fly the aircraft independently during test runs on the runways at the airfield, which was necessary to pinpoint the malfunctions. In addition to allowing an unqualified employee to operate complex military equipment, there were deliberate actions that limited the aircraft’s functionality. It created a potential danger to the aircraft technician in the cockpit and to the military personnel around him (Haltonians, 2021). Among such assumptions was the absence of external protection for the cockpit (a canopy) due to the lack of radio communication between the temporary pilot and the rest of the ground crew.
The aircraft technician did not have any protection prescribed for the pilot, which included such items as a helmet, flight suit, and pilot’s oxygen-supply equipment. Also, the fighter’s landing gear was fixed in test mode. The aircraft technician had to fly the plane a short distance of 30-40 yards at high engine speeds. During the second attempt to accelerate the aircraft, the engineer accidentally pulled one of the levers controlling engine speed to its limit, activating the afterburner and activating takeoff afterburner mode. The fighter had a feature that allowed for an emergency deactivation of this mode, but the technician in the cockpit at the time did not have the necessary qualifications.
With his flying license and ability to fly small piston engine airplanes, the aircraft technician was able to get the fighter into the air to avoid crashing after the end of the runway. The unsanctioned takeoff also risked a collision with a refueling truck and a de Havilland Comet passenger plane, which was taking off from the airfield at the time (Haltonians, 2021). Already in the air, the technician managed to switch off the engine afterburner and decided to eject, which, however, proved impossible since the ejection system of the aircraft was in ground mode, which did not allow its use. The technician decided to land the plane, but not having sufficient piloting skills, he was able to do it only from the third approach. On landing itself, the aircraft sustained damage to the fuselage and gear struts because the landing followed the landing procedure typical to the temporary pilot for piston aircraft with tail gear.
Before and during the incident, a significant number of safety and personnel access rules were violated. Despite the high level of training of the airbase’s flight and ground crews, there was negligence and carelessness that resulted in a severe emergency within the boundaries of the airfield as well as the surrounding area (Haltonians, 2021). Throughout the entire incident, a chain of errors and breaches of safety regulations can be discerned, which ultimately led to the situation described above. First of all, an unqualified person was allowed to operate the aircraft, which would not have happened if the base flight officers and the aircraft technician themselves had followed basic safety principles and technical regulations. The next link in the future emergency situation was the unpreparedness of the ground crew, and the airfield control room for possible accidents at the facility since the “pilot” had no protective equipment and some mechanisms and elements of the aircraft were blocked or dismantled. An essential factor in this situation was also the poor coordination between the various service units at the airfield, which was evident from the continued regular operation of all base units from the unintentional activation of the fighter’s afterburner mode until it took off. Also, having access to technical documentation for the soldier and being able to communicate with qualified military pilots, the person responsible for the incident did not have the required knowledge that could have stopped the situation before takeoff. As the last mistake of the mechanic, who for a short time was the pilot of a supersonic jet, one can define a completely wrong choice of landing angle, which, however, is instead a consequence of panic and was performed intuitively.
Summarizing the information provided above, one can conclude that seemingly insignificant mistakes made by the ground crew during ground handling of an aircraft can pose a significant danger. The primary driving cause of the incident described was human error, which caused a series of safety violations and then led to number of errors and mistakes that endangered a significant amount of human and material resources. An emergency situation could have been prevented at any stage up to takeoff mode if the ground crew had complied with the requirements specified in the safety manuals or had alerted higher command. That, in turn, with knowledge of the intent to conduct unauthorized and unsafe testing, could have stopped it from happening and prevented the incident.
Haltonians, T. O. (2021). Wing Commander “Taffy” Holden’s inadvertent flight in Lightning XM135. The Old Haltonians. Web.