What happened
On April 24, 2012, at approximately 16:40 UTC, a Beechcraft 58, registration PR-JHM, operated by Fretax Táxi Aéreo, was performing a passenger transport flight from Belo Horizonte to Guarulhos. The flight proceeded normally until the landing phase at Aeródromo Governador André Franco Montoro (SBGR).
During the landing roll, approximately 300 meters after touchdown, the aircraft experienced intense vibrations on the right side. This vibration was caused by the right main landing gear tire becoming detached from the wheel hub. The resulting mechanical stress caused the right main landing gear to unlock, leading the aircraft to veer sharply to the right. The aircraft exited the runway pavement and came to a stop on the adjacent grass area, oriented approximately 180 degrees from its original landing direction. The aircraft sustained substantial damage, but all four occupants—two crew members and two passengers—remained uninjured.
The investigation
The CENIPA investigation focused on the mechanical failure of the right main landing gear assembly. Investigators examined the tire and found no evidence of excessive wear, cuts, or punctures on the outer tire casing. However, an inspection of the inner tube revealed significant cuts.
While the inflation valve remained intact, suggesting the tube had not slipped within the tire, the investigation considered the manufacturer's maintenance manual for the Goodyear tires. The manual specifies that inner tubes should not be reused, as they can expand by up to 25% during service. The investigation explored the hypothesis that a previously used inner tube was installed in a new tire. Such a mismatch can cause the tube to fold, leading to a catastrophic failure under pressure.
Findings
- The right main landing gear tire detached from the wheel hub due to a failure of the inner tube.
- The reuse of a previously used inner tube in a new tire likely caused the tube to fold and subsequently rupture.
- The failure of the inner tube led to the tire detaching from the hub, creating vibrations that caused the right main landing gear to unlock.
- Aircraft maintenance procedures regarding tire and tube replacement were a contributing factor.