What happened
On 15 October 2019, an ATR 72-212A, registration EC-MPI, operated by Canarias Airlines, was performing a commercial takeoff from runway 12 at Tenerife North Airport (GCXO) bound for Gran Canaria. As the aircraft approached rotation speed, the crew heard an unusual noise from the right side accompanied by intense vibrations. Upon observing abnormal parameters for the right engine, the crew successfully aborted the takeoff maneuver.
The aircraft vacated the runway via taxiway E4 and returned to the parking stand. While the 46 passengers and crew were uninjured and disembarked normally, a subsequent inspection revealed scratches and damage to the aft section of the fuselage. Additionally, airport officials recovered various metal fragments from the runway and near taxiways E1 and E2, which had been ejected from the engine exhaust during the incident.
The investigation
Investigators examined the right engine, a Pratt & Whitney Canada PW127M, to determine the source of the mechanical distress. Metallographic and spectroscopic analyses were performed on the recovered fragments. The investigation also reviewed maintenance records and the implementation of existing service bulletins regarding turbine blade durability.
Technical analysis of the fractured components revealed that the material itself was free of pre-existing defects. However, the investigation found that the engine had not yet been updated with a specific part number recommended in a previous service bulletin, which was intended to improve resistance to corrosion.
Findings
- The engine failure was initiated by a fatigue fracture of a single blade in the second stage of the power turbine (PT2).
- This initial failure led to the subsequent overload fracture of several additional blades.
- The investigation noted that operating in environments prone to salinity or contamination can decrease the service life of these power turbine blades.
- At the time of the event, the engine had not yet been updated with the newer, more corrosion-resistant blade part number recommended by the manufacturer.