October 21, 2011 (by Asif Shamim) - An Air Force investigation into a crash of an F-16 belonging to the 176th Fighter Squadron concluded that the cause was engine failure.
A Accident Investigation Board (AIB) was setup to investigate the June 7th, 2011 crash of F-16C block 30
, which crashed 57 nautical miles north by northwest of Truax Field, Wisconsin, after the pilot experienced a sudden loss of thrust during the flight back to his home airfield.
The pilot was unable to successfully restart the General Electric F110-GE
-100 engine and subsequently ejected at 1,500 feet resulting in the F-16 impacting into an unoccupied residence in rural Adams County, Wisconsin destroying both the $25 million dollar aircraft and the residence. There were no casualties or civilian injuries.
The accident board found convincing evidence the cause of the mishap was a failure of the power take-off shaft forward main bearing assembly within the Accessory Gearbox. Additional evidence showed inadequate lubrication of the bearing assembly due to a complete or partial blockage of the Accessory Gear Box (AGB) oil supply line with debris caused the engine to malfunction resulting in catastrophic engine failure.
When the engine was examined, investigators found glass-bead media and a small pieces of Teflon in the oil supply line that prevented oil from reaching the bearing assembly. The Teflon on its own probably wouldn't be enough to jam up the supply line, according to the report, but led to clogging when combined with the glass-bead debris.
The glass-bead media was similar to materials used to overhaul accessory gearboxes, used at depot level maintenance in the overhaul and cleaning of the AGB assembly. The accessory gearbox of the crashed F-16 was overhauled in March 2010 and passed all necessary tests, the report said.
The report did not lay blame with either the pilot nor maintenance crewmembers who serviced the aircraft just the day before.