Release #99-112, November 12, 1999


The Army announced today that its Apache helicopter fleet (AH 64 A & D) will undergo a one time inspection of accessory gearboxes. The accessory gearbox is a component of the transmission.

The June 1, 1999 crash of an Israeli Air Force AH-64 prompted the Army's inspection order. The Israeli accident was caused by dual failure of both the primary and secondary sprag clutches in the accessory gearbox.

U.S. Army AH-64s have experienced six such failures, all of which occurred on the ground. The cause of the clutch failure is unknown, but engineering analysis indicates that the clutches are experiencing wear. The Army and Boeing are working to determine exactly what causes the wear, and what can be done to prevent it.

In the meantime, all 743 AH-64 Apaches will be inspected to determine--by serial number--the number of flight hours on their accessory gearboxes. Gearboxes with more than 1,000 flight hours will be replaced. The inspection will take place as soon as practical but prior to the aircraft's next flight and no later than one week from notification.

Unaffected aircraft will be returned to flight status immediately.

Similar to the recent hanger bearing assembly inspection, this is an Army-Industry team effort to get the Apache fleet returned to flight operations as quickly as possible.

For further information, contact Army Public Affairs, (703) 697-7591.