What happened
On October 23, 2004, at approximately 12:40 UTC, a Boeing 707-330C, registered as PP-BSE, was preparing for a cargo flight from Eduardo Gomes International Airport (SBEG) in Manaus, Brazil, to Guarulhos (SBGR). During the takeoff roll on runway 10, the right main landing gear suffered a structural collapse.
The failure caused the right trunnion support rib to fracture, which subsequently punctured the upper skin of the right wing. This structural breach caused the aircraft to tilt, forcing the number 4 engine to make contact with the runway surface, which immobilized the aircraft. The crew successfully aborted the takeoff and shut down the engines. All three crew members—the pilot, co-pilot, and flight mechanic—evacuated the aircraft without injury.
The investigation
CENIPA investigators examined the wreckage and the maintenance history of the aircraft. Laboratory analysis of the remaining portions of the right main landing gear trunnion support rib by the Institute of Aeronautics and Space (IAE) revealed that a significant pre-existing crack had developed, leading to a final failure due to overload.
The investigation also reviewed the applicability of Boeing Alert Service Bulletin (ASB) 3510. While the bulletin originally required the removal of the landing gear for inspection, a subsequent Boeing instruction (IN 001) allowed the inspection to be performed without removal. The investigation noted that the aircraft had been involved in a previous landing accident in September 2003, where the right wing tip touched the ground, potentially subjecting the landing gear structure to excessive stress and initiating the fatigue crack.
Findings
- The primary cause of the collapse was a structural failure of the right main landing gear trunnion support rib due to a pre-existing crack that reached a critical size.
- The inspection method permitted by Boeing's updated instructions (allowing inspection without gear removal) was insufficient to detect the internal and external cracks within the support rib.
- A previous landing incident in 2003 likely contributed to the structural fatigue by subjecting the gear to abnormal loads.
- There were identified deficiencies in the operator's emergency training, specifically regarding the use of the main door escape rope during an evacuation.
Safety action
CENIPA issued several safety recommendations following the investigation:
- To the Civil Aviation Department (DAC): Re-evaluate the granting of inspection extensions for B700 aircraft, considering factors such as flight hours and cycle history.
- To the operator (BETA): Establish clear evacuation procedures for using the main door escape rope and evaluate crew performance regarding emergency evacuation procedures.