What happened
On July 26, 2006, at approximately 18:00 UTC, an Airbus A320-212, registration G-MONX, operated by Monarch Airlines, departed from Faro Airport, Portugal, bound for Manchester, United Kingdom. The flight was carrying 145 passengers and 7 crew members.
During the initial climb phase, while the aircraft was passing 3,000 feet with an indicated airspeed of 320 knots, the crew heard a loud bang followed by intense vibrations. The Electronic Centralized Aircraft Monitoring (ECAM) system indicated a failure of engine #1. The vibration levels reached the maximum scale of 9.9. In response, the pilots followed established emergency procedures, which included shutting down the engine and activating the fire extinguishing system as a precaution. The crew declared a 'Mayday' and requested emergency services for the landing. After holding for approximately 2 and 20 minutes to consume fuel and complete checklists, the aircraft landed safely on runway 28. The landing was performed in a one-engine inoperative configuration and at a weight exceeding the maximum certified landing mass, following manufacturer-approved procedures.
The investigation
The GPIAAF investigation focused on the mechanical failure of the CFM56-5A3 engine. The engine was removed and sent to GE Aircraft Engine Services, Ltd. for detailed analysis. The inspection revealed extensive internal damage. The investigation examined the condition of the fan, bearings, gearbox, and compressor/turbine sections. Additionally, the investigators reviewed the applicability of existing service bulletins and the airline's maintenance records.
Findings
- The primary cause of the incident was the fracture of a High Pressure Turbine (HPT) blade. The separation of this blade triggered a sequence of destruction across various engine components.
- The failure of the HPT blade caused significant damage to the High Pressure Compressor (HPC) rotor, the Low Pressure Turbine (LPT), and the engine's internal bearings and gearbox.
- A contributing factor was the non-observance of Service Bulletin SB 72-0692, which had been issued by CFM International in September 2004. This bulletin recommended the removal and replacement of HPT blades to prevent material fatigue and separation due to high temperatures. At the time of the incident, the engine had not undergone the recommended actions.
- The investigation confirmed that the crew performed correctly, following all appropriate checklists and emergency procedures.
- The aircraft's airworthiness certification and the crew's licenses and rest periods were all found to be in compliance with regulations.