Accident Overview
On June 1, 2008, about 1030 eastern daylight time, a Cessna 208B, registration N102VE, operated by Skydive Greensburg, experienced a complete loss of engine power and sustained substantial damage when it nosed over in a cornfield during a forced landing near Greensburg-Decatur County Airport (I34), Greensburg, Indiana. The 14 CFR Part 91 skydiving flight had departed I34 at 1015 with 14 skydivers aboard. The pilot was not injured and all skydivers parachuted safely after the power loss.
Pilot Actions
The pilot, who held a commercial certificate and multiple ratings, reported that the airplane performed normally on the first flight of the day. During the accident flight, while climbing through 7,000 feet msl, he heard an explosion followed by a metal grinding noise from the engine. Vibrations occurred and smoke entered the cabin. He shut off the fuel and performed smoke evacuation procedures, leveling at 5,000 feet with flaps set to 20 for skydiver exit. After the skydivers departed, he retracted flaps and turned off electrical systems. He attempted to land on runway 18 but could not lower flaps due to a tripped circuit breaker; oil on the windshield obscured forward visibility. He executed a forced landing to a cornfield off the departure end of runway 18, where the propeller and left wing impacted the terrain.
Witness and Aircraft Condition
A witness at I34 photographed the airplane as it approached; the photos indicated flaps were fully extended. Post-accident inspection revealed the flap lever in FULL position, indicator near FULL, and actuator in full flaps position. When electrical power was applied from the accident battery, the flap system operated normally with no circuit breaker trip.
Aircraft and Engine Details
The single-engine Cessna 208B (serial 208B0618, 1997) had a Pratt & Whitney PT6-114A engine rated at 675 shaft horsepower. The pilot had 1,089 total hours, with 85 hours in the C-208B. The aircraft total time was 7,221 hours; the engine had 3,075.3 hours since overhaul. The last annual inspection was February 7, 2008.
Engine Examination
The engine was sent to Pratt & Whitney Canada for teardown. Examination revealed the compressor turbine (CT) guide vane ring had impact damage and erosion. The CT shroud had a deep impact mark at 2 o'clock position. The CT disk had rubbed with both CT and power turbine vanes. All CT blades were fractured at varying heights. NTSB materials lab inspection showed creep features, including wrinkling and re-solidified metal, consistent with high-temperature necking.
Service Information Letters
Pratt & Whitney Canada had issued several Service Information Letters (SILs) addressing PT6A CT blade fractures and maintenance practices:
- SIL PT6A-053R3: Emergency Power Lever system
- SIL PT6A-116R2: Borescope inspection with fuel nozzle check
- SIL PT6A-125: CT blade fractures – described conditions leading to blade creep and the importance of correct power settings
- SIL PT6A-146: CT blade maintenance – emphasized fuel nozzle maintenance and borescope inspections for detecting oxidation and sulphidation
These SILs are advisory for Part 91 operators. The mechanic who maintained the airplane for Skydive Greensburg reported no directive to conduct borescope inspections during fuel nozzle maintenance. The aircraft owner from Kapowsin Air Sport stated he was unaware of any requirement for borescope inspections or the pertinent SILs.