US Army quickly grounds 400 Apache helicopters after realizing drive system upgrade might cause potentially deadly ‘internal failure’

The US Army has grounded the majority of its Apache attack helicopters after it was discovered an upgrade made them unsafe to fly. The AH-64E Apache is one of the most iconic aircraft in the US military, but it also has a reputation for being one of the most dangerous vehicles to fly, with what’s described as a high “mishap” rate.

Now Stars and Stripes is reporting that Army brass has imposed an “immediate” pause in flight operations after they realized that Apaches with “improved drive system transmissions” were susceptible to mechanical failure.

The report quotes an internal investigation that concluded that “some AH-64E [improved drive system] main transmissions can experience an internal failure resulting in loss of accessory gearbox drive, which can result in loss of tail rotor thrust, electrical power, and hydraulics.”

Questions remain about this “upgrade”

As per Task & Purpose, 400 Apaches have been grounded out of the approximately 700 in the Army’s possession, and nobody seems to know when they will be able to fly again. But that may come as a relief to their pilots and crew, as 2026 has not been a stellar year for the aircraft.

So far there have been four serious incidents involving Apaches this year. The first happened in March, when an AH-64E crashed during a training exercise at Fort Rucker in Alabama, injuring two crew members. In April, a “maintenance issue” mid-flight resulted in an unplanned landing in rural Alabama, and there was another in May, with an unscheduled emergency landing in a rice field south of Seoul, Korea.

The most recent, and most serious, incident took place outside Fort Hood on August 12, 2026, with a crash that killed the Apache’s two pilots. An Army official later stated (via military.com) that investigators had eliminated the known AH-64E transmission issue as a factor in this crash, but grounded training flights for a week. That was lifted on schedule, but is now back in place.

Historically, the Apache has had a higher “mishap” rate than other aircraft, though its defenders argue that this is down to it being used for demanding missions involving low and fast flight, combined with a high workload during conflicts. It’s also difficult to deny its proven combat effectiveness.

However, the immediate grounding of the majority of the Army’s Apaches suggests that something has gone awry with this “upgrade.” Here’s hoping whatever the problem is can be resolved before these crashes claim the lives of those on board.