What happened
On 25 February 2019, an Airbus A320-214, registration G-EZOI, was operating a commercial passenger flight from Edinburgh to Bristol. Before departure, the cabin manager alerted the crew to an unusual noise coming from an avionics vent fan. After assessing the situation and noting no other symptoms, the commander elected to proceed with the flight while monitoring the noise.
During the cruise phase, the noise intensified and the aircraft began to vibrate. The crew contacted maintenance operations to request assistance upon arrival at their destination. As the aircraft began its descent near Birmingham, a heavy burning smell permeated the flight deck. The crew immediately donned oxygen masks and diverted the aircraft to Birmingham Airport. During this period, an ECAM message indicating a vent extract fault appeared, and the crew followed the necessary procedures to manage the situation. The aircraft landed safely without further incident, and no 0 injuries were reported among the 178 passengers or 6 crew members.
The investigation
Investigators examined the avionics ventilation system, specifically the blower and extract fans. While the blower fan was found to be fully operational, the extract fan showed significant damage. The investigation established that the extract fan had seized, with visible wear on the rear flange and the front bearing. The rotor was also found to be damaged.
Findings
- The primary cause of the smoke and vibration was worn bearings within the avionics extract fan.
- The failure of the extract fan led to the release of fumes into the flight deck.
- The crew had identified the initial symptom of an unusual noise prior to takeoff but continued the flight as no other indications were present at that time.