What happened
On April 15, 2005, a Ryanair Boeing 737-800, registration EI-DAC, was operating a commercial passenger flight from London Stansted to Murcia San Javier Airport. The aircraft was carrying 59 passengers and 6 crew members.
After landing on runway 23, the aircraft was taxiing toward taxiway H when a wheel well fire warning alarm activated in the cockpit. The flight crew immediately stopped the aircraft and issued two mayday calls to the Murcia control tower. Due to the lack of external visual confirmation of the fire and the persistent cockpit warning, the crew decided to initiate an emergency evacuation.
All four main doors were used to deploy slides, and the aircraft was evacuated in approximately 30 seconds. Upon the arrival of emergency services, no smoke, fire, or elevated temperatures were detected on the aircraft. The warning was subsequently determined to be false.
The investigation
The investigation focused on the origin of the fire warning and the crew's decision-making process. Investigators examined the aircraft's fire detection system, which utilizes a sensor in the wheel well to trigger audible and visual alarms if temperatures exceed a specific threshold.
Technical inspections of the sensor and the control module revealed no defects, and the electrical connections were found to be in good condition. The investigation also reviewed the aircraft's maintenance history, noting that a similar false warning had occurred the previous day, April 14, 2005. The airline had previously performed maintenance on the detector connectors and inspected the fleet for potential causes related to runway deicing fluids.
Findings
- The wheel well fire warning was spurious, as no actual fire or heat source was present.
- The crew followed established emergency procedures by stopping the aircraft and initiating an evacuation when the fire could not be visually verified.
- The aircraft's fire detection system was functioning according to its design, but the incident was part of a pattern of intermittent false warnings.
- Maintenance efforts by the operator, including cleaning and replacing connectors, had not prevented the recurrence of the false alarm.