The US Air Force could spend up to $16 billion over the next several years on further upgrades for the Lockheed Martin F-22.
It could also award some of the business to the manufacturer's competitors.
The dollar value was disclosed in a 26 January acquisition notice calling for bidders to compete for the follow-on Raptor enhancement, development and integration (FREDI) contract.
Lockheed was awarded the original multi-year REDI deal in 2004, but now the USAF is inviting its competitors to bid for the work too.
© Master Sgt Kevin Gruenwald/US Air Force
The last of 187 F-22s will be delivered to the USAF in early 2012, but the service plans to spend about $500 million annually for the next several years on planned upgrades. It is upgrading the F-22's radar and computer, adding more capable missiles and making the stealth aircraft easier to maintain.
At the same time, the USAF also plans to transition the F-22's sustainment programme "to a more organic support concept", the acquisition notice says.
Lockheed has been managing the F-22's maintenance system under a performance-based logistics (PBL) deal, which is designed to generate cost savings over time but locks the government into a long-term support deal.
But the USAF and other government agencies have decided to scale back the use of such PBL contracts. Instead, more maintenance work is being assigned in government depots, while other upgrade and sustainment tasks are split among several contractors.