Pipistrel SINUS 912 near West Palm Beach, FL — 2018-08-12

Final reportERA18LA214

Date: 2018-08-12
Location: West Palm Beach, FL, USA
Airport: F45
Aircraft: Pipistrel SINUS 912
Registration: N467L
Category: Glider
Highest injury: None
Fatalities: 0
Phase of flight: Takeoff roll

Probable cause

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

NTSB narrative

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.