Japan probe finds screw error caused AW139 hoist cable to drop during test

Japan's Transport Safety Board has released findings on an incident involving a Leonardo AW139 helicopter operated by Honda Airways for the Saitama Disaster Prevention Air Squadron. The helicopter, registered JA03FD, lost its hoist cable and an attached test weight during a check flight at Honda Airport in Kawajima on 17 February 2024.

The flight followed replacement of the aircraft's hoist cable the previous day. Standard procedure calls for a load test using weights up to 272 kilograms, hung from the cable's hook, to confirm the hoist works correctly at maximum capacity. The crew included two pilots, an air squadron officer acting as hoist operator, and a mechanic supervising as instructor.

The first test stage went as planned. Ground crew attached a 136-kilogram weight while the helicopter hovered at roughly 50 feet. The aircraft then climbed to about 340 feet, and the operator began extending the cable to its full length of around 300 feet, intending to verify that it would stop automatically at that point.

Instead, as the cable neared full extension, it detached along with the attached weight, falling to the ground near a taxiway. The JTSB traced the failure to a maintenance fault involving a screw placed incorrectly during the cable replacement. The report extract available does not detail the full mechanical sequence linking that error to the release.

No injuries were reported. The Board's report, issued 25 May 2025, is meant to inform maintenance practices for hoist systems on similar helicopter types used in search-and-rescue operations.