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The U.S. Army is progressing through inspections of a subset of its Boeing AH-64E fleet that has been grounded due to faults in the helicopter’s transmissions, prioritizing units based on mission needs.
The Army announced Oct. 2 it had directed an immediate pause in flight operations of AH-64Es equipped with the Improved Drive System (IDS) transmissions for inspections and corrective actions. This followed an ongoing technical and airworthiness assessment of the IDS transmission, which included information from prior safety of flight actions, inspections, maintenance reports and engineering analysis.
The Army did not specify how many helicopters were affected, and Maj. Gen. Phillip “Cain” Baker, the commander of the Army’s Aviation Center of Excellence, said Oct. 14 it impacts one type of IDS system. Another subset of the AH-64E fleet with a separate, enhanced version of the IDS is not affected.
The process is expected to take months, though Baker says some of the helicopters have returned to flight.
“We’re going through full inspections on the Apaches, which we’ve announced,” he says. “That’s based off of prioritization . . . based off of mission requirements.”
The first unit was inspected starting “a couple of months ago,” he says. The Army has applied a maintenance procedure coordinated through Boeing, Aviation and Missile Command and the Army’s airworthiness office.
“The grounding was really to get the aircraft inspected,” Baker says.
Defense One first reported in May 2026 that the newly discovered issue with the Apache’s IDS transmission was impacting the fleet, causing a loss of accessory gearbox drive that in turn could cause a loss of tail rotor thrust, electrical power and hydraulics. A root cause was under investigation. At the time, there had been three AH-64E crashes or hard landings within the prior three months.
The Army in 2018 stopped accepting deliveries of AH-64Es and conducted a fleetwide inspection and retrofit of strap pack “mega-nuts” that connect rotor heads to the airframe. The service also grounded the AH-64E in December 2013 because of a transmission problem.
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