Boeing has released the most detailed information yet on the changes it is considering for a proposed 737 upgrade powered by advanced turbofans. Meanwhile, Airbus expects its engineering teams to complete their initial evaluations of what will be required for a similar upgrade to the A320 at the end of next month.
Speaking to Flight International at the ISTAT appraisers conference in Orlando, Florida in March, Boeing Commercial Airplanes vice-president marketing Randy Tinseth explained: "We think we're going to need a new pylon, a new nacelle, strengthening of the wing and potential strengthening of the wing-box."
To accommodate the larger nacelles of the advanced turbofans under evaluation - including the CFM International Leap X and Pratt & Whitney PW1000G geared turbofan - Tinseth says Boeing is studying some "minor modifications around the nose landing gear, still to be determined". However, he says that the company "doesn't want to" and "won't have to" make changes the main landing gear.
While Tinseth says that the study so far has not turned up "any show stoppers", before committing to a launch, the airframer will "keep diving deep on the technical side and make sure that we're absolutely confident that we'll be able to go forward from a technical perspective".
Airbus's chief operating officer customers John Leahy was also at ISTAT, and he stressed the proposed re-engined A320 family will be "an option to the existing airplane" rather than a replacement programme.
Airbus's management expects to receive a report by the end of April from 14 engineering teams studying various impacts of re-engining, including the impact on the leading edge of the wings and thrust reversers.
Leahy says that the upgraded family will feature the airframer's recently launched "sharklet" winglets, and is also likely to need a strengthened wing.
Alongside the re-engined 737, Boeing (like Airbus) continues to study an all-new aircraft and Leahy warns his rival that should an upgraded A320 go ahead, it would be a huge mistake for Boeing to announce a new clean-sheet design.
He says that if Boeing were to introduce a new aircraft in the 2017 or 2018 timeframe, such an aircraft would only slightly modify current technology, and would not have the 20- to 30-year staying power necessary to ensure commercial success of an aircraft programme.
Leahy is holding high-level meetings this week to continue discussions of the re-engine, and says if Airbus firms up plans to launch the product, it would be introduced as an option for customers at the end of 2015.
The Airbus executive continues to press IAE partners P&W and Rolls-Royce to resolve their differences and agree to offer a geared turbofan type engine for the A320. He reiterates his position from last year, that Airbus has no interest in a standalone offering of P&W's GTF. "We want the two [P&W and R-R] to sit down and iron out their differences," says Leahy, who adds that if P&W and IAE "can't get their act together, they can't get their act together".