Incident Overview
On June 27, 2016, at approximately 1430 eastern daylight time, an Enstrom 208FX helicopter, registration N518EG, experienced an engine fire while preparing for departure from Ottawa Executive Airport (Z98) in Zeeland, Michigan. The helicopter was being used for an instructional flight under 14 Code of Federal Regulations Part 91, operated by Blue Sun Air, LLC. Day visual meteorological conditions prevailed at the time.
Sequence of Events
According to the flight instructor, the student pilot was on his first flight. After completing a preflight inspection, they started the helicopter's engine and prepared for takeoff. Before increasing collective pitch, the instructor noticed the panel lights flicker and smelled smoke. Around the same time, ground personnel were observed running toward the helicopter. Both the instructor and student exited the helicopter, and ground personnel extinguished an engine fire. The flight instructor and student pilot were not injured, and the helicopter sustained minor fire damage.
Examination Findings
An examination by a Federal Aviation Administration (FAA) inspector revealed that the exhaust pipe had separated from the engine turbocharger. The helicopter sustained damage to the engine access door, electrical wires, and smoke/thermal damage to the engine compartment.
The turbocharger, exhaust clamp, and scavenge pump were sent to the National Transportation Safety Board (NTSB) Materials Laboratory in Washington, DC for further examination.
The materials laboratory reported that the band clamp assembly consisted of a strap portion and two U-shaped retainers. The bottom end of each U-shaped retainer was joined by several spot welds to the inner side of the strap portion. Examination of the band clamp assembly showed that the two U-shaped retainer portions had fractured at the spot weld locations.