What happened
On August 12, 2013, an Airbus A320-214, registration G-EZTC, was performing a takeoff from runway 35R at Milan Malpensa Airport, bound for Lisbon. During the takeoff roll, portions of the left engine's fan cowl doors became detached. The flight crew was alerted to the situation via radio by a pilot of another aircraft on the ground who observed the open cowling, as well as by cabin crew and passengers who noticed the abnormal noise and visual separation of the components.
The crew declared an intention to return to Malpensa, requesting landing priority. Due to the fuel load and necessity of the return, the aircraft performed an overweight landing on runway 35L. During the landing roll, while using maximum reverse thrust on both engines, additional parts of the same engine cowling detached. The aircraft subsequently taxied to the parking stand, where all 175 persons on board (including 6 crew members) were evacuated normally. There were no injuries.
The investigation
The ANSV investigation focused on the mechanical failure of the fan cowl doors and the resulting structural impact. The investigation examined the aircraft's flight data, cockpit voice recordings, and the physical condition of the airframe. Investigators analyzed the damage to the fuselage, which included 44 impact points resulting in punctures, deformations, and scratches. The separation of the cowling also caused damage to 10 passenger windows, the left engine pylon structure, the left wing slats and spoilers, and the vertical stabilizer leading edge.
Findings
- The primary cause of the event was the separation of the left engine fan cowl doors during the takeoff and landing phases.
- The separation of the cowling parts caused extensive secondary damage to the aircraft's fuselage, wing, and engine pylon.
- The investigation identified technical and organizational factors related to maintenance practices and the verification of the cowling latching system.
- The loss of the cowling doors occurred during high-stress phases of flight (takeoff and landing roll) where aerodynamic forces were significant.