A fire erupted in the aft end of a Lockheed Martin F-35A during the engine start sequence on 23 September in Mountain Home AFB, Idaho, forcing the pilot to escape, the US Air Force says.

The fire was “extinguished quickly”, but the USAF has not described the extent of the damage. Four servicemen — the pilot and three maintainers — were treated at a hospital as a precaution and were released, the USAF says.

Fires have now damaged at least three production and test copies of the F-35A, including the AF-4 test aircraft in 2011 and the AF-27 production aircraft in 2014. AF-4 returned to flight after the fire caused by a failure of the Honeywell Integrated Power Package. AF-27 remains unflyable due to the 2014 engine fire, which was caused by the airfoils of an integrally bladed rotor rubbing against an abladable strip of material within the fan casing.

The cause of the F-35A fire at Mountain Home remains under investigation, the air force says.

The damaged aircraft was one of seven F-35As from the 61st Squadron at Luke AFB deployed to Mountain Home from 21-24 September. The purpose of the deployment was to train F-35A instructor pilots how to teach techniques for detecting and attacking surface-to-air missile launching systems. The remote Mountain Home base in Southwest Idaho operates a large training range with multiple types of SAM launchers.

In early August, the USAF declared the F-35A operationally capable to perform a limited set of missions. Full operational capability is scheduled to be achieved in about a year.

Source: FlightGlobal.com