Incident Description
While in flight, the fire detection light for the #2 engine illuminated. The captain promptly declared an emergency and initiated a return to the departure airfield. Upon landing, an emergency landing was conducted, followed by an emergency slide evacuation of the crew and passengers.
Investigation Findings
Post-incident inspection revealed no damage to the aircraft and confirmed that no actual fire had occurred. Examination of the engine's fire detection system identified a failed Systron Donner fire detector, part number 4361. The exact cause of the failure could not be determined.
Conclusion
The incident was caused by a malfunctioning fire detector, resulting in a false alarm. The crew's response to the emergency warning was appropriate, ensuring the safety of all occupants.