What happened
On 3 October 2000, a Boeing 757-300, registration 4X-BAU, was performing a scheduled public transport flight from Tel Aviv to London Gatwick. During the landing roll on Runway 26 Left, the crew experienced vibrations and heard two distinct loud bangs. Shortly after touchdown, the aircraft's right main landing gear experienced the failure of two tyres.
As the aircraft decelerated, debris from the bursting tyres struck the underside of the right wing, causing a hole in the flap, splitting wing panels, and damaging the engine nacelle and pended components. The crew noted a loss of hydraulic fluid in both the left and right systems. Despite the damage, the aircraft safely vacated the runway via exit Golf Romeo. The runway was temporarily closed for inspection and cleaning of tyre debris.
The investigation
The AAIB examined the aircraft's flight recorders, the damaged airframe, and the failed tyres. The investigation focused on the condition of the tyres and the possibility of foreign object damage (FOD). Examination of the tyres revealed that both the number 7 and number 8 tyres had been destroyed, leaving only the sidewall and bead portions.
Investigators found that the tyre carcasses showed signs of separation consistent with overstress and overtemperature, likely caused by excessive deflection. While a small amount of FOD was noted on the tread of Tyre 7, the primary damage to Tyre 8 was characterized by severe overheating. Additionally, the investigation found that the fusible plugs on Wheel 8 had been insufficiently tightened during maintenance.
Findings
- The primary cause of the tyre failures was operating with underinflated tyres, which led to excessive sidewall flexing, heat generation, and eventual carcass separation.
- The failure of one tyre likely caused the subsequent overloading and failure of its partner on the same axle.
- The aircraft's maintenance records did not show any recent pressure loss, but the lack of a continuous tyre pressure indication system meant that underinflation was not detectable by the crew during pre-flight inspections.
- The presence of loose fusible plugs on the wheel assembly was identified as a potential contributing factor to pressure loss.
Safety action
- Safety recommendation 2002-13: It is recommended that BF Goodrich Aerospace reassess measures to ensure wheel fusible plugs are correctly tightened and consider the need for positive locking.
- Safety recommendation 2002-14: It is recommended that Airworthiness Authorities (such as the JAA and FAA) consider implementing requirements for tyre pressure monitoring and warning systems on aircraft.