The companies last year announced plans to jointly develop an engine to power midsized commercial passenger aircraft but on Thursday issued separate statements saying the deal was off.
"In October 2011, Rolls-Royce and United Technologies Corp. (UTC) announced their intention to form a new joint venture to develop an engine to power future mid-size aircraft (120-230 passenger aircraft)," Pratt & Whitney said. "Following further discussion and because of the current regulatory environment, the parties have agreed not to proceed with the partnership.
"Pratt & Whitney remains fully committed to this important market segment and will continue independently to invest in, and develop, applications of its geared turbofan engine to power the next generation of mid-sized aircraft."
Rolls-Royce, which stated the same reason for ending the planned partnership, also reiterated its continued commitment to the market segment and its intention to invest in technologies for it.