On Thursday, the Department of Defense announced it has awarded Rolls-Royce Corp a $83.7 million "modification" to a firm-fixed-price contact previously awarded to the company (for $150.9 million) in March of 2012 .

The contracts in question, both the original March contract and the current one, procure from Rolls-Royce V-22 AE1107C turboshaft engines used to power V-22 Osprey tiltrotor aircraft operated by the U.S. Navy and U.S. Air Force.

In the previous contract, the order was for 232 engines for the Navy, and 33 additional engines for the USAF. Yesterday's modification adds 34 engines to the Navy's order (266 in all), and four to the Air Force's (now 37).

Work on the engines covered by the new modification is to be completed in December 2014; however, the original contract stated that it would not be completed until October 2017. Thus, the possibility of additional modifications -- and additional sales for Rolls-Royce -- in future years would appear to remain open.