What happened
On 24 October 2013, a BAE 146 RJ85, registration EI-RJW, was undergoing maintenance at Norwich International Airport. The aircraft was in the middle of a post-installation power assurance check on its number three engine. Approximately three minutes into a full-power soak period, a fire warning light illuminated within the cockpit.
Maintenance personnel positioned outside the aircraft observed an active fire. In response, the operator shut down the engine, activated the fire handle, and discharged the engine fire suppression system. Following the activation of the fire suppression system, the operator and three engineers evacuated the aircraft. While the fire was visible between the fan cowl doors and the jet pipe fairing, it was located in an area that could not be reached by extinguishers. The fire had extinguished itself by the time the fire service arrived on the scene.
The investigation
An engineering examination of the engine revealed that the fire originated in the fuel manifold area near the combustion chamber casing. Investigations into the fuel manifold assemblies, conducted by the manufacturer, determined that the leak was caused by loose fittings located between the fuel supply lines and the manifolds. While the manifolds themselves were found to be in serviceable condition, the specific reason the fittings had loosened remained undetermined. It was noted that because the engine had been in storage before its installation, it was unlikely that the loosening occurred while the engine was mounted on the wing.
Findings
- The fire was caused by the ignition of fuel leaking from fittings between the fuel supply lines and the manifolds.
- The fire resulted in only superficial heat damage to the engine and the nacelle.
- The fire protection systems within the engine nacelle functioned as intended, successfully containing the fire to its immediate zone.