What happened
On February 9, 2010, a Boeing 737-7EH, registration PR-GEA, operated by Varig Linhas Aéreas S.A., departed from Salvador (SBSV) bound for Rio de Janeiro (SBGL). The aircraft was carrying 101 passengers and 6 crew members on a scheduled passenger flight.
While climbing through 4,000 feet, the crew heard a loud bang followed by significant vibration. The Exhaust Gas Temperature (EGT) indicator for the right engine displayed a failure warning. Following established procedures, the crew executed the necessary checklists and initiated an emergency return to Salvador. The aircraft successfully performed a single-engine landing on runway 10. There were no injuries to the passengers or crew, and the aircraft sustained no damage.
The investigation
CENIPA conducted an investigation into the engine failure. A subsequent inspection of the engine led to its removal and a detailed teardown at a GE Celma S.A. facility. Investigators discovered a large amount of metal debris (swarf) within the lubrication system. Laboratory analysis confirmed that the debris originated from the engine's bearings. Further examination by GE Aviation identified that the failure was caused by the failure of bearing number 4 on the engine's main shaft.
Findings
- The primary cause of the incident was the failure of the number 4 bearing on the right engine's main shaft.
- The degradation of this bearing released metal particles into the lubrication system, which caused the observed vibrations and the EGT warning.
- The investigation concluded that the premature failure of the bearing may have been due to a manufacturing defect.
Safety action
CENIPA issued several safety recommendations following the investigation:
- To GE Celma S.A.: Determine the specific cause of the bearing failure.
- To Varig Linhas Aéreas S.A.: Monitor the detailed analysis of the damaged bearing being conducted by GE Aviation.
- To ANAC: Disseminate the investigation report to all operators of the 737-7EH and monitor the bearing analysis to determine if an Airworthiness Directive (AD) is required from the engine's primary certification authority.