Accident Overview
On April 16, 2015, at approximately 2245 mountain daylight time, a Fairchild SA227-AC twin-engine airplane, registration N2691W, operating as Key Lime flight 168, experienced an uncontained engine failure while climbing near Rifle, Colorado. The aircraft was substantially damaged. The pilot, the sole occupant, was not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 135 as a cargo operation in dark night instrument meteorological conditions, with an instrument flight rules flight plan filed.
Event Sequence
The airplane departed Garfield County Regional Airport (RIL) at 2237, destined for Denver International Airport (DEN). During the climb, while still well below the tops of nearby mountains, the pilot reported hearing a "bang" followed by a complete loss of power and engine fire indications from the right engine. After executing the appropriate emergency checklist items, the pilot declared an emergency and diverted to Grand Junction Regional Airport (GJT). The aircraft executed an instrument approach and landed at 2311 without further incident.
Post-Accident Examination
Examination of the aircraft after landing revealed that the second stage turbine rotor from the right engine had separated. One portion of the rotor exited through the left side of the engine and nacelle structure, penetrated the right side of the fuselage, and came to rest inside the fuselage wall. Other portions of the separated rotor exited through the right side of the engine. Thermal damage was observed on the engine and inside the nacelle structure, but no evidence of a sustained fire was found in that area.
Further examination of the turbine engine identified fatigue cracks on the second stage turbine rotor disk. The rotor disk had accumulated 3,901.4 hours and 4,143 cycles at the time of the failure.