What happened
On 28 November 2016, an Airbus A320-214, registration G-EZWX, was performing a scheduled passenger flight from Edinburgh to Hamburg. Approximately 11 minutes into the climb, while passing FL230, the flight crew detected smoke and fumes within the cockpit. In response, the crew donned oxygen masks, and the ECAM displayed an avionics smoke alert. The commander declared a MAYDAY and diverted the aircraft to Newcastle Airport.
During the descent, the crew performed the required smoke/fumes checklists. The smoke eventually began to dissipate. However, the crew experienced significant difficulties establishing two-way communication with the cabin crew via the interphone system, with it taking approximately three minutes to successfully brief the cabin manager. The aircraft landed at Newcastle without further incident, though fumes were still detectable during the post-landing inspection.
The investigation
The investigation focused on the source of the smoke and the breakdown in cabin communications. Technicians traced the fumes to the overheating of a cockpit additional electrical supply static inverter located in the avion and electronics bay. This specific unit was part of a known batch of 2,058 units containing a faulty capacitor.
Regarding communications, the AAIB examined the operation of the cabin interphone system. It was found that the co-pilot's attempt to brief the cabin manager failed because the manager could not hear the transmission, leading the manager to hang up the handset. The investigation also identified that the crew lacked specific knowledge regarding how to re-establish a connection to an active emergency call after a handset had been reset.
Findings
- The smoke was caused by the overheating of a capacitor within the static inverter.
- The operator was unaware of a manufacturer's technical publication and a vendor service bulletin that recommended replacing the faulty capacitor.
- The operator's maintenance software did not include technical follow-up notices (TFUs) for routine review.
- Communication delays occurred because the cabin crew were not trained on how to reconnect to an emergency interphone call after disconnecting their handset.
- The aircraft was part of a series of failures, with this being the eleventh such incident involving this component type reported to the manufacturer.