What happened
On October 18, 2023, a Boeing 737-800 operating a charter flight was taxiing from its parking position to runway 18 at Frankfurt Main. During the taxi, tire marks were left on the taxiway, which were later identified as belonging to the aircraft.
As the aircraft accelerated during its takeoff roll, the flight crew observed a visible rightward tilt and significant damage to the landing gear. Following the procedures outlined in the Quick Reference Handbook (QRH) for a rejected takeoff, the crew decided to abort the takeoff at a speed of 88 knots IAS. The aircraft sustained light damage to the airframe, and damage was also noted to the airfield surface.
The investigation
The BFU investigation focused on the condition of the main landing gear tires and the sequence of events leading to the failure. Investigators examined the aircraft's maintenance records, specifically the "48 Hours Check" performed by a qualified mechanic. The investigation also reviewed the lighting conditions at the time of the event, noting that it was night and that diffuse lighting and shadows made it difficult to identify tire pressure irregularities or damage during the initial walkaround.
Findings
- The primary cause of the incident was that tire number 3 had insufficient pressure, which resulted in it carrying very little of the aircraft's load.
- Because of the low pressure in tire 3, tire number 4 was forced to support the entire load of the right main landing gear.
- It is highly probable that tire number 4 already possessed an underlying structural weakness, such as material fatigue, internal carcass breakage, or delamination, which significantly reduced its ability to handle the increased load.
- Nighttime lighting conditions and shadows near the right main gear hindered the crew's ability to detect the pressure drop during pre-flight inspections.