On April 20, 1993, a Douglas C-47 Skytrain (DC-3) (registration N8056) operated by Phoenix Air Group was involved in an aviation accident near Zephyrhills, United States of America during takeoff. No fatalities were reported. Investigators recorded the probable cause as: The pilot-in-command's failure to maintain best single-engine rate-of-climb speed which resulted in a forced landing. A factor which contributed to the accident was a possible exhaust system clamp failure. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).
During initial climb at about 400 feet, the crew detected smoke and a left engine fire warning. After shutting down the left engine, the aircraft could not maintain altitude, resulting in a forced landing in a field. Examination revealed fused fire detection elements and burned hydraulic lines.
Incident Narrative
The pilot reported that during initial climb at approximately 400 feet above ground level, the crew detected a burning odor followed by light smoke in the cabin. Visual inspection showed both engines appeared normal. The odor and smoke intensified, and the left engine fire warning light illuminated. The crew shut down the left engine and feathered its propeller. The pilot increased power on the right engine, but the airplane was unable to climb or maintain airspeed. A forced landing was executed with the landing gear and flaps retracted into a field.
Investigation Findings
Examination of the left engine revealed that the lower fire detection elements were fused and broken free, and the hydraulic lines were burned through. The pilot speculated that an exhaust clamp may have broken, allowing a segment of exhaust to scorch the cowling and activate the fire warning system.
The probable cause determined by the investigation was the pilot-in-command's failure to maintain best single-engine rate-of-climb speed, which resulted in a forced landing. A contributing factor was a possible failure of the exhaust system clamp.