Pratt & Whitney has escalated a legal feud over patent rights on commercial jet engines with rival and partner Rolls-Royce.

Complaints filed on 5 November by P&W parent United Technologies Corp. in both US and UK courts allege patent infringement by Rolls. Specifically, P&W accuses Rolls of copying swept turbine blade technology covered under a 1995 patent on the Trent 900 and 1000 engines.

Using the same argument, P&W also has asked the US International Trade Commission to block Boeing from importing the Trent 1000, which powers the 787.

The new lawsuit follows a separate patent infringement dispute between Rolls and P&W. In August, Rolls sued P&W for violating patent rights with the company's PW1000G geared turbofan and the GP7200, an engine developed between General Electric and P&W.

P&W counter-sued in September, arguing that the Rolls patent is "invalid and unenforceable". The latest patent infringement complaint was filed as an amendment to P&W's original counter-suit.

The legal battle comes as the rivals and partners in the commercial engine business position for the powerplants developed for the next-generation of narrowbodies.

Rolls and P&W participate in the International Aero Engines, a joint venture that includes Germany's MTU and Japanese Aero Engines, to produce the V2500 turbofan.

P&W's PW1000G geared turbofan is designed to capture market share in the single-aisle market, where currently the V2500 competes against the CFM International CFM56.

Rolls was not immediately available to comment on P&W's patent infringement complaint.

Source: Air Transport Intelligence news