What happened
On 15 July 2013, a Fokker F28 Mk 100, registration HB-JVH, was performing a scheduled flight from Zurich to Bristol. During the initial climb, the senior cabin attendant activated the galley ovens to begin food preparation. Shortly after, smoke began emitting from the second oven. Upon opening the oven door, a significant cloud of smoke was released into the cabin.
Simultaneously, the flight crew noticed white smoke entering the right side of the cockpit. In response, the crew instructed the cabin crew to pull the oven circuit breaker, which successfully halted the smoke generation. Due to the presence of smoke in the flight deck, the pilots decided to abort the flight and return to Zurich. The aircraft landed safely at 07:00 UTC, and passengers were allowed to disembark normally as the smoke had cleared.
The investigation
The investigation focused on the technical cause of the smoke and the operational response of the crew. Investigators examined the oven's configuration and the presence of any foreign objects. It was discovered that the aircraft utilized two different oven models: one with a protective rear cover and another with an exposed heating element.
Technical analysis revealed that the smoke was not caused by an electrical short circuit, as the crew had initially suspected, but rather by the carbonization of a plastic film. The investigation also reviewed the crew's use of the electrical smoke emergency checklist and the communication between the flight crew and the ground fire brigade upon landing.
Findings
- The primary cause of the smoke was a plastic film left inside the oven, which came into contact with an exposed heating element.
- The oven in use lacked the necessary tray rack required to protect the heating element from such contact.
- A systemic issue existed where personnel were unaware that two different oven types, requiring different safety precautions, were being operated on the same aircraft.
- The crew's decision to open the oven door contributed to the sudden release of smoke into the cabin.
- While the crew successfully managed the smoke, the investigation noted that the procedures for combating oven smoke were not strictly followed.