WASHINGTON (AP) -- The Pentagon says it has awarded defense contractor Lockheed Martin Corp. a contract worth up to $7.4 billion to upgrade the systems in the Air Force's F-22 Raptor fighter jet.
The contract calls for Lockheed to develop system upgrades, add new capabilities and enhance the performance of the aircraft.
The Pentagon says one company was solicited for the contract and one submitted a proposal, which suggests only Lockheed vied for the lucrative contract.
Earlier this year, the Air Force temporarily grounded its entire fleet of Raptors for more than four months after concerns over its oxygen-supply system had prompted a larger examination of the stealth fighter.
The Air Force returned its Raptors to flight in September.