Description

On 23 July 2011, a Boeing 737-300 being operated by Jet2.com on a passenger flight from Leeds/Bradford to Paris CDG experienced violent vibration from the main landing gear at touch down in normal day visibility on runway 27R at a normal speed off a stabilised approach. This vibration was accompanied by lateral acceleration that made directional control difficult but the aircraft was kept on the runway and at a speed of 75 knots, the vibrations abruptly stopped. Once clear of the runway, the aircraft was stopped and the engines shutdown prior to a tow to the gate. None of the 133 occupants were injured.

Investigation

An Investigation was carried out by the French Bureau d'Enquêtes et d'Analyses (BEA). It was found that the right main landing gear had suffered severe damage, especially to the lower torsion link. Flight Data Recorder (FDR) data showed that the recorded lateral load factor during the initial deceleration had reached 0.41g at 80 knots and the recorded amplitude had reached 0.8g at 90 knots. Deviation from the runway centreline was found to have reached a maximum of 10 metres.

The flight was the first one following overnight scheduled replacement of the main landing gear at the Operator’s own base maintenance facility. It was found that the hydraulic line to the shimmy damper on the right main landing gear had not been reconnected after the new gear assembly had been fitted and that the specified post replacement function checks carried out on jacks did not engage the shimmy dampers and so the anomaly was not detected prior to release to service. It was concluded that undamped vibrations during landing had quickly weakened the lower torsion link until it failed suddenly.