What happened
On July 26, 2008, a privately owned Socata TB10, registration JA4106, departed Nagasaki Airport for a familiarization flight to Saga Airport. Shortly after taking off from Runway 32, the pilot noticed a burning odor and white smoke entering the cockpit. While the crew attempted to return to the airport for an emergency landing, the aircraft's performance degraded significantly.
As the aircraft entered the traffic pattern, a large amount of smoke entered the cockpit, and air traffic controllers observed streaks of smoke and orange flames emanating from the rear of the aircraft. Unable to maintain sufficient altitude or thrust, the aircraft turned toward the water and ditleched in Omura Bay, approximately 200 meters east of the runway. The impact resulted in the destruction of the aircraft. Of the three pilots on board, one person died, one sustained serious injuries, and one sustained slight injuries.
The investigation
Investigators examined the wreckage of the Socata TB10 and analyzed the engine components. The inspection revealed that the left-hand front manifold had detached from the exhaust pipe, along with a connecting pipe. This failure allowed hot exhaust gases to escape into the engine compartment, igniting the engine cowlings and nearby hoses. The investigation also reviewed maintenance records, which indicated that routine inspections were limited to external checks and did not include the removal of engine cowlings.
Findings
- The primary cause of the accident was the detachment of the left-hand front manifold and connecting pipe, which released hot exhaust gases into the engine compartment.
- This release of gas initiated a fire that burned the cowlings and hoses.
- Hot exhaust gases and smoke entered the carburetor, which prevented the engine from producing the thrust necessary to maintain flight.
- A contributing factor was the excessive tightening of a clamp on the connecting pipe, which created cracks that eventually failed due to corrosion and stress.