On 13 September, an Airbus A320-200 being operated by Canadian airline Skyservice on a domestic passenger charter flight from Toronto to Edmonton was departing in day Visual Meteorological Conditions (VMC) when, after a “loud bang and shudder” during rotation, evidence of left engine malfunction occurred during initial climb and the flight crew declared an emergency and returned for an immediate overweight landing on the departure runway which necessitated navigation around several pieces of debris, later confirmed as the fan cowlings of the left engine. There were no injuries to the occupants.
An Investigation was carried out by the Canadian TSB. It was found that prior to release to service for the incident flight, the aircraft had been at the Company maintenance facility overnight for some minor inspection and parts replacement work including the replacement of an oil-scavenge line on the left engine, an IAE V2500. This work was found to have been commenced by the night shift but been completed after handover to the day shift.
Prior to flight departure, the First Officer, who was to be PNF, carried out the pre-departure walk round check and found no discrepancies.
Following the loud bang and simultaneous shudder, an ECAM aural warning sounded but information on the ECAM MFD remained suppressed until the aircraft reached 1500 feet agl after which numerous messages began to display. It was noted that suppression of ECAM messages deemed ‘non-critical’ is a design feature which applies above 80 knots and below 1500 feet agl. The aircraft commander flew the aircraft with the autopilot and flight director off and the left engine at the ECAM-commanded power setting of idle. One of the passengers informed a flight attendant of the fan cowl loss, which was relayed to the flight deck. The remainder of the flight was uneventful except for the encounter with debris on the runway during the landing roll.
Damage to the aircraft was found to have been substantial. Both inboard and outboard left hand engine fan cowlings had sheared off just below the attachment points, the inner one breaking into several large pieces. The engine pylon was damaged at the fan cowl attachment points and there was impact damage to the left wing leading edge slats.
The Investigation ‘Findings as to Causes and Contributing Factors’ were as follows:
- The left-engine fan cowlings were closed, but the latches were intentionally not locked. This situation led to the aircraft departing with the fan cowls unlocked, resulting in damage to the aircraft.
- Standard operating procedures and maintenance practices were not adhered to, leading both the day shift maintenance supervisor and the aircraft commander to believe that the engine was secure.
- The verbal handover during night to day maintenance shift transfer was inadequate. As a result, the day shift maintenance supervisor was not made effectively aware of the need to complete clamping the oil-scavenge line and secure the left-engine fan cowlings during his shift.
- During separate walk round checks prior to the incident flight, neither of two maintenance staff or the First Officer noticed that the fan cowling latches were not fastened.
- The positioning of the fan cowling caution placard is inadequate, in that it is not easily seen when the fan cowlings are closed and unlatched.
It was noted that Safety Action taken during the Investigation by the Operator included the comprehensive changes in their maintenance procedures. It was also noted that Transport Canada had issued a Service Difficulty Alert targeted at all operators of large jet transport aircraft in Canada not just Airbus types powered by IAE V2500 engines. Transport Canada also issued guidance to operators in respect of fan cowl security. No Safety Recommendations were therefore issued.
The Final Report of the Investigation was released on 25 September 2001 and may be seen in full at SKYbrary bookshelf: Aviation Investigation Report A00O0199