Pipistrel SINUS 912 N467L accident near West Palm Beach, Florida

Probable cause

The fatigue failure of the exhaust system manifold, which resulted in a ground fire after landing.

NTSB analysis

The private pilot of a motor glider was taking off when he noticed the engine sounded "a little rough"; as he turned downwind, he started to smell smoke. He reported that he shut down the engine and returned for an uneventful landing. When the motor glider stopped, the pilot noticed flames below the right door; the flames grew and eventually consumed and destroyed the airplane. Postaccident examination of the wreckage revealed that the exhaust manifold had various cracks on the tubing. Examination of the exhaust manifold revealed the fracture and cracking of the exhaust system manifold tubes was due to fatigue. The fatigue cracks on the exhaust manifold were progressive in nature and had likely been present for some time before the accident, allowing exhaust gasses to begin escaping into the engine compartment before reaching the muffler assembly. It is likely that the exhaust gases caused a flammable condition the that resulted in a ground fire after landing.

Text from the NTSB. Open the NTSB docket for ERA18LA214 for the full record.