USAF Inspects KC-135s After Discovering Falsified Certifications

The U.S. Air Force has inspected and cleared its KC-135 fleet after the service discovered falsified certifications at a main technical repair shop.

An October memorandum from Air Mobility Command (AMC), verified by Aviation Week, identified the risk with the aircraft’s stabilizer trim actuator (STA) assemblies. The memorandum impacted KC-135s in AMC, along with U.S. Air Forces in Europe, Pacific Air Forces, Air Education and Training Command, Air Force Reserve Command and the Air National Guard.

Specifically, the memorandum from AMC’s director of operations says the potential quality concerns are linked to “falsified test certifications at the 309 [Commodities Maintenance Group].

“Testing discrepancies and a reported inflight trim issue indicate possibility of degraded STA performance over time on affected aircraft,” the memo says.

The memorandum is dated Oct. 20, and marked as a controlled unclassified information special interest item for aircrews.

An Air Force Materiel Command (AFMC) spokesperson says the same shop that was linked to the falsified test certifications self-discovered the issue. No aircraft were found to have been affected, with all KC-135s passing the required on-aircraft maintenance and operational checks.

“The Air Force has taken necessary actions to address all concerns with the testing procedures … and has made the required process, tooling and personnel changes to ensure all STAs are tested properly and in accordance with technical data,” AFMC says.

The KC-135’s STA has primary and auxiliary brakes designed to prevent aerodynamic loads from moving the aircraft’s horizontal stabilizer. A failure of both primary and auxiliary brakes in the STA could potentially cause a jammed stabilizer scenario, the memo says.

AMC consulted with the KC-135 program office, Boeing engineering, Reserve and National Guard safety and the KC-135 flight test community on the issue and issuing the 60-day inspection order.

“These measures are designed to proactively identify and address potential STA-related issues, ensuring the continued safety and reliability of the aircraft,” the memorandum says.

The Air Force has 376 KC-135s, both R and T variants, across its components.