Pratt & Whitney has reacted angrily to CFM’s assertions that its Leap-1A engine for the Airbus A320NEO will be up to $4 million cheaper to operate over 15 years than the competing PW1100G on a per aircraft basis.

“Effectively they’re defying the laws of physics and the laws of economics,” says Pratt president David Hess. The geared turbofan has six-fewer stages than the conventionally configured CFM engine. “That’s 25% fewer stages and 2,000 fewer airfoils – or 50% fewer. Plus it runs cooler. So someone needs to explain to me how you take that and translate it into a $3 million to $4 million advantage in terms of net present value,” he adds.

Hess was speaking to Aviation Week on the eve of the Farnborough air show which is expected to see a spate of engine selections and new order announcements associated with the A320NEO. CFM says its Leap-1A on the re-engined Airbus will require 40 less fuel tank refills per year than the PW1100G. This, together with predicted savings from fewer maintenance visits, prompted CFM to say on July 7 that the Leap could be up $4 million cheaper to operate per aircraft over 15 years.

Pratt also stresses that its performance claims for the PW1100G are supported by on-going test experience with the smaller PW1500G variant in development for Bombardier’s CSeries. “Fuel burn looks good – it’s going to meet what we said it will meet,” says Hess. Development is going to plan and although Hess acknowledges that “when you get under the hood there is the usual excitation of a test program, there are no show stoppers.” Pratt also claims the PW1100G will be lighter on the A320NEO, a claim countered by CFM.

Hess remains confident that the geared turbofan has the potential to earn up to $325 billion over the life of the four airliner programs for which it is already launched. The technology is central to Pratt’s large commercial engine business growth strategy which is aimed at doubling revenues to around $24 billion per year by the end of the decade if all goes to plan. “It’s a real number,” says Hess who adds that “coupled with the IAE (International Aero Engines) acquisition this is a transformational period for Pratt & Whitney.”

Pratt is scheduled to reveal details about new leadership changes for the restructured IAE at Farnborough on July 9 following the completion of the sale of the Rolls-Royce share last week.