What happened
On November 28, 2011, an ATR 72-212A operated by Flybe Finland Oy, registration OH-ATL, departed Vaasa for Tallinn. While cruising, thick black smoke began emitting from the aircraft's ACARS thermal printer located in the center pedestal. The flight crew immediately donned oxygen masks and declared a MAYDAY, requesting radar vectors for an emergency landing at Pori Airport.
During the descent, the smoke dissipated, and the crew and passengers assumed the brace position for landing. No injuries were reported following the landing. After the aircraft was parked, it was noted that the smoke had originated from the printer unit.
The investigation
The investigation focused on the source of the smoke, the functionality of the crew's emergency equipment, and the coordination of emergency services. Investigators examined the printer and found a metal paper clip inside the unit, which showed signs of heating. This object had caused a short circuit. The smoke production ceased once the printer's circuit breaker tripped.
Regarding the crew's response, the investigation found that the oxygen masks caused significant communication difficulties between the pilots and between the captain and cabin crew. It was noted that the condition of the oxygen masks used in flight simulators for training did not match the condition of the masks in the actual aircraft. Additionally, the investigation found that the tower controller was not informed of the total number of persons on board prior to landing, as the information was not relayed to the air traffic controller or rescue personnel.
Findings
- The primary cause of the smoke was a short circuit triggered by a metal paper clip inside the ACARS thermal printer.
- Communication was severely hampered by the use of oxygen masks.
- There was a lack of timely information regarding the passenger and crew count provided to the rescue services.
- The operator's post-traumatic stress protocols were found to be insufficient.
Safety action
- The Finnish Transport Safety Agency is recommended to include a subjective condition check of oxygen masks in annual flight simulator inspections.
- Finavia Oyj is advised to re-evaluate the training, implementation, and maintenance of its post-traumatic stress support system.