Virgin Atlantic Flight 024

Virgin Atlantic Flight 024 was a regularly scheduled Virgin Atlantic passenger flight from Los Angeles, California, to London, United Kingdom. On 5 November 1997, the Airbus A340 was forced to make an emergency landing at London Heathrow Airport after the left main landing gear failed to deploy. During the crash landing, the aircraft was damaged and later repaired. Of the 114 passengers and crew aboard, 7 were lightly injured.

Aircraft
The aircraft involved was an Airbus A340-311, registered G-VSKY with manufacturer serial number 016. It made its first flight on 3 November 1993 and was delivered soon after to Virgin Atlantic on 21 January 1994. At the time of the accident, the aircraft had flown 19,323 hours. It was fitted with four CFM International CFM56-5C2 low-bypass turbofan engines.

Incident
At 05:09 GMT (21:09 local time), flight VS024 departed from runway 24L in Los Angeles after a 19-minute delay. While climbing, the crew noticed that the landing gear was slow to retract. Later, during a routine in-flight systems scan, it was noted that the brake temperature sensor on the inboard rear wheel of the main landing gear had failed, but the flight was otherwise uneventful.

At 15:04 GMT, while on final approach to Heathrow Runway 27L, the crew received an aural "Gear not safe" alert after deploying the landing gear, upon which the crew elected to go around and return to a holding pattern.

The crew decided to fly near the ATC tower to have a controller visually identify a problem. It was found that the left main landing gear was stuck in a partially deployed position. The crew tried to complete several manoeuvres to free the landing gear without success. The crew planned to touch the runway with the right main landing gear and immediately go around, hoping to shake the landing gear up. The idea was not attempted as it was too dangerous and the pilots were inexperienced in such an action.

When the crew realized that it was impossible to deploy the left main landing gear, the passengers and airport were prepared for an emergency landing. At 16:08 the captain realized the aircraft was nearly out of fuel and declared "Mayday". The crew aimed to land the plane on runway No. 27L, believing the lopsided aircraft would turn away from airport facilities once on the ground and towards empty space.

Per SOP, all four engines are to be powered down. The captain decided to start shuttering the outermost engines first (engines 1 and 4), followed by the inner most pair (engines 2 and 3)

As the aircraft came to land, engine 4 struck the runway and the last landing gear burst. Soon after, engines 1 and 2 also struck the ground, bursting into flames. Once the aircraft veered to the left, passages were evacuated, seven of which who suffered minor injuries.

Cause
The reason of the incident were the following factors:


 * Full deployment of the left main landing gear was prevented because the unrestrained end of the No. 6 brake torque rod became trapped in the keel beam structure within the gear bay. It jammed the landing gear in a partially deployed position.
 * The torque pin that had connected the No. 6 brake torque rod to the wheel brake had disengaged during the landing gear was retracted after takeoff from Los Angeles, allowing the unrestrained rod to pivot freely about the retained end.
 * The torque pin and its retaining assembly had been subject to higher axial and torsional loads than predicted during aircraft braking in service. These loads were the result of elastic deformation of the wheel axle, brake, and torque rod, and due to assembly without the correct axial clearance as a result of prior undetected displacement of the associated bushes. The precise mode of failure of the retaining assembly bolt, nut, and cotter, could not be ascertained in the absence of these parts.
 * This design of wheel brake assembly had satisfactorily passed the related wheel brake structural torque test. However, the latter contained no requirement to use a representative axle or other means to reproduce the axle deflections which occur during aircraft braking in service. As a result, the inspection did not require post torque test strip assessment of brake assemblies, in turn resulted in an over stressing deformation which produced component failure.

Aftermath
The aircraft sustained considerable damage, including to three engines and the landing gear. Runway 27L was damaged after the landing gear tires burst.