What happened
On 12 August 2019, an Airbus A320, registration EI-DEO, was performing a commercial passenger flight from Dublin Airport to London Heathrow. The flight began with a non-standard engine start procedure because the APU was inoperative; the first engine was started using a ground air supply, and the second was started via a cross-bleed method.
Following this procedure, both members of the flight crew noticed a potent smell of fuel and oil. The crew initially attributed this odor to the engine start process. As the aircraft taxied, the fumes persisted, leading the crew to speculate that the smell might be exhaust from a preceding aircraft. These intermittent odors continued through the departure and climb phases of the flight.
During the approach briefing, the crew noted that they felt they were not performing at their usual standard due to the fumes, though they decided against using oxygen masks at that time. The landing was completed without further incident. After reaching the stand, the crew performed a medical self-assessment and briefly used oxygen masks. A subsequent medical check confirmed that the vital signs of both crew members were normal.
The investigation
Following the event, engineering personnel performed comprehensive fault-finding procedures on the aircraft. Despite these efforts, no specific source for the fuel and oil fumes could be identified. The aircraft subsequently returned to service without any further reports of similar odors.
Findings
- The crew experienced intermittent fuel and oil odors starting from the engine start sequence.
- The crew maintained heightened awareness during the flight but did not utilize oxygen masks during the flight phase.
- No identifiable cause for the fumes was found during technical inspections of the aircraft.
Safety action
- The operator has conducted an internal investigation.
- The operator is currently reviewing the guidance material provided to flight crews regarding smoke and fumes incidents.