FAA issues directive for UH-1H driveshafts replacement or overhaul

The US Federal Aviation Administration (FAA) has issued an airworthiness directive, published in the Federal Register on 21 January, which will require the inspection or replacement of main driveshafts on certain Huey UH-1H helicopters.

Effective from 25 February 2022, the directive applies to all aircraft of this type that are equipped with a KAflex main driveshaft with the part number SKCP2180-1, SKCP2281-1, SKCP2281-1R, or SKCP2281-103 installed.

It requires the establishment of a limit to replace the driveshafts, and one-time and repetitive inspections. Main driveshafts, which have accumulated 5,000 or more total hours in service (TIS), must also be replaced or overhauled before further flights.

The airworthiness directive could create significant costs for aerial firefighters

The FAA says that the directive will affect approximately 384 helicopters in the US registry. It estimates that:

• Replacement will cost US$54,085 per aircraft (including one work-hour and $54,000 parts cost)
• Overhaul will cost $38,085 per aircraft (including one work-hour and $38,000 for parts costs).

If requested, operators may be issued with Alternative Methods of Compliance (AMOC), pending approval by the FAA’s Delegation Systems Certification Office (DSCO) branch.

UH-1H helicopters are routinely used by many aerial firefighting agencies across the US, including in the states of Montana, Washington and California.