Apache Helicopters Grounded: Why South Korea Halted All 36

The Republic of Korea Army has kept its entire fleet of 36 Boeing AH-64E Apache Guardian attack helicopters on the ground since early October for inspections of a suspected transmission defect. That makes South Korea at least the third operator to halt flights of the type since the U.S. Army ordered its own pause on October 2. Army spokesperson Captain Bae Seok-jin disclosed the measure at a press briefing on November 10, stating that the grounding followed a U.S. military safety advisory concerning a transmission component and that American authorities had begun phased technical inspections. No date was given for a return to flight, with Bae stating: “Operations will resume sequentially based on the inspection results.” The disclosure highlights how a fault in a single American drive system now constrains frontline attack helicopter fleets from the United States to Taiwan and the Korean Peninsula at the same time.

The U.S. Army’s order applies to AH-64Es fitted with the Improved Drive System transmission, reportedly around 400 of its roughly 700 E-model Apaches, and covers every active duty and National Guard unit flying them. Army officials indicated in early October that the inspections were likely to take months, with units being prioritised by mission need. An internal Army safety review earlier in the year reportedly found that the transmission could fail internally and cause a loss of tail rotor thrust, electrical power and hydraulics. Army safety records also list four major AH-64E mishaps in the last fiscal year, one of them a catastrophic transmission failure. The whole Apache fleet had already been briefly grounded in August after an older model crashed at Fort Hood, Texas, on August 12, killing both pilots, although the Army has stated that the transmission did not cause that loss.

Taiwan grounded its own Apaches after a U.S. technical notification on gearbox risks, with Defence Minister Wellington Koo confirming the measure on October 29 without saying how long it would last. The Republic of China Army has since relied on older AH-1W SuperCobra and OH-58D helicopters for readiness missions. The island received 30 AH-64Es in five batches, the last six arriving in 2014, and its forces are also waiting on delayed F-16 Block 70 deliveries from the same American industrial base. Seoul insists that its own readiness is intact, with routine training suspended but the helicopters kept available for immediate launch in an emergency, with Bae stating: “There are currently no issues with our readiness or operational posture.” More than five weeks without training flights will nevertheless erode crew proficiency on the Korean Army’s most capable anti-armour platform, particularly if the inspections run as long as American officials have suggested.

South Korea took delivery of its 36 AH-64Es by 2017, and its plan for a second batch of 36 was effectively abandoned in July 2025 after the National Assembly cut that year’s funding from 10 billion won to 300 million won. The estimated unit price had risen from 44.1 billion won for the first batch to 77.3 billion won for the second, and the money was redirected towards combat drones and unmanned systems, while the domestic Marine Attack Helicopter built on the Marineon airframe has since completed development. Israel has shown similar caution over the type’s cost, having signed for only 12 AH-64Es with deliveries not expected until the early 2030s.