Lockheed Martin has received a $12.7 million contract modification to supply the final batch of automatic backup oxygen supply (A-BOS) systems for the US Air Force's F-22 Raptor fleet.

"This is the last of the A-BOS kits for fleet retrofit," Lockheed says. "There are no cost plus award fee or time and material line items in the contract."

The contract includes 72 retrofit kits for operational aircraft, two for test aircraft, trainer kits, support equipment and spares, according to a Department of Defense (DoD) announcement. The total cumulative face value of the overall contract is $5.1 billion, the DoD says.

The money comes from the Pentagon's 2012 and 2013 research and development and aircraft procurement accounts, with the retrofit work expected to be completed by 30 May 2015.

The 186 remaining F-22s in the USAF arsenal are being retrofitted with an A-BOS after a 2011 grounding due to a series of physiological incidents that were ultimately attributed back to malfunctioning upper pressure garments.

One of the ensuing recommendations following the series of investigations after those incidents was to add an A-BOS to the fighter, in addition to the originally installed manual emergency oxygen supply.

Source: Flight International