Boeing aims to firm the configuration of its 737 Max family in 2013 as the final phase of the wind-tunnel testing begins in the USA and UK. Meanwhile, the airframer is confident it will rack up significant orders for the re-engined twinjet during 2012.

Speaking at the Singapore air show, Boeing's vice-president marketing Randy Tinseth said that the final wind-tunnel test sessions begin next week: "The aircraft will go into high-speed testing in Seattle at our transonic wind-tunnel. We're going to take a model to Farnborough to do low speed testing [in QinetiQ's UK facility]," he said.

"We expect that testing to conclude and be evaluated by the middle of this year, and then next year we'll be looking at firming up the configuration of the aircraft," he added.

Tinseth said that the first 737 Max will fly in 2016 and deliveries will follow in 2017, however he declines to reveal which of the three models (7, 8, or 9) will be the lead variant. "We've not yet shared that detail," he said.

The major change on the new family is the installation of the CFM Leap-1B advanced turbofan, which will have a fan diameter 18cm (7in) greater than the current 737NG's CFM56-7. Tinseth says that Boeing and CFM are "set on the engine" and rules out any change to the fan diameter. "We've worked with GE and CFM and we're going to have a slightly smaller core compared to the competition, so we've really optimised for the airframe for the right airplane efficiency."

Other changes on the new 737 include improved aft-body aerodynamics to reduce drag, a new nacelle and pylon; higher weights; airframe, wing, empennage and main landing gear structural strengthening; extended nosegear (by "4-5in" for engine ground clearance); a modified fuel system; and flightdeck and systems revisions.

Tinseth said the changes will reduce fuel burn per seat on the 737 Max 8 by 11% over today's similarly-sized 737-800.

Boeing intends to certificate the new family as derivatives of the current 737NG (which is itself classed as a derivative of the original 737-100/200 introduced in 1968), said Tinseth: "We're working with the regulatory agencies today but our plans are that this would be a derivative".

More than 1,000 737 Max orders and commitments have been placed from 15 customers, of which 250 are firm from two airlines - Southwest (150) and Norwegian (100). Three other customers have been revealed: American Airlines (100), Aviation Capital Group (35) and Lion Air (201).

Tinseth declines to specify how many of these commitments Boeing expects to firm up this year, but is bullish about the Max's near-term sales prospects: "I don't think there's any question that 2012 is going to be the year of the Max. We're working very closely not only to make those commitments into firm orders but also looking for new commitments," he said.

Source: Air Transport Intelligence news