Questions continue to swirl on the feasibility of the timeline put forward by Boeing for its proposed New Mid-market Airplane (NMA), with some questioning whether the aircraft will be ready by 2025.

"I'm not so sure it'll show up in the 2024-25 period," said Andrew Levy, chief financial officer of United Airlines, on the NMA in an interview with FlightGlobal on the sidelines of an industry conference in San Diego earlier in March.

As a result, the Chicago-based carrier is not building its fleet plan around the proposed widebody being available by 2025, he says. United is looking at nearer-term alternatives, including the Airbus A321LR and Airbus A330-800neo, to replace some of its 128 Boeing 757s and 767s, two models that the NMA is designed to replace.

Such a move by United would be a blow to Boeing, as the airline is a long-standing loyal customer that has long sought a new aircraft in the NMA's market segment.

Levy is not the only one skeptical of Boeing's timeline. Avolon chief executive Domhnal Slattery, speaking at the conference, said a green light from the airframer's board this year is critical to meeting the 2024-25 deadline. He added that key design decisions, especially cargo capacity which is a key selling point in Asia, still need to be made.

Boeing says the NMA will be an aircraft family seating 220-270 passengers with a range of around 5,000nm (9,260km) and trip costs roughly 40% better than current generation widebodies.

The timeline doubts largely stem from the availability of the needed engine technology for the proposed widebody. Boeing can deliver an airframe and wings by the deadline based on historical precedents.

CFM International, Pratt and Whitney (P&W) and Rolls-Royce are all competing to supply engines to the NMA. CFM has not provided details of its proposed architecture, P&W plans a scaled up version of its geared turbofan (GTF) and Rolls-Royce the so-called UltraFan with a reduction gear.

The thrust range for the NMA engines will be between 40,000-50,000lb, an area that has been neglected since the early 1980s, according to Boeing.

All three engine manufactuers are tight lipped about the status of their NMA engines that, coupled with some of the delays meeting deadlines for current aircraft programmes, raise questions about their ability to deliver on time for the proposed Boeing widebody.

Randy Tinseth, vice-president of marketing at Boeing Commercial Airplanes, said "things are coming together" on the configuration and performance of the aircraft, during a briefing at the conference. When asked about views on the proposed 2024-25 timeline, which he affirmed, he says customers have indicated that they are "happy" with it.

"Now, it's about closing the business case," says Tinseth.

Boeing delivered the 777 in five years and the 787 in eight years after launching the respective programmes. The airframer says it will apply the lessons learned with the 787, which entered service three years late, on the NMA suggesting that it will deliver in less than eight years from launch.

United could be a key customer for the NMA. The proposed widebody will have the size and range to replace longer-haul 757s and 767s, two models that the airline has identified as its top near-term fleet renewal decision.

The carrier operates 77 757-200s and -300s with an average age of 20.1 years, and 51 767-300ERs with an average age of 20.7 years, Flight Fleets Analyzer shows. The airline assumes a 30-year life for aircraft.

Other airlines are also looking at options other than the NMA to replace 757s and 767s. American Airlines is considering just two alternatives to replace its 22 767-300ERs: the A330-800neo and Boeing 787-8, a source familiar with American’s fleet plans told FlightGlobal in San Diego.

While refurbishing and continuing to operate the 767s, which Fleets Analyzer shows have an average age of 19 years, is also an option for the Fort Worth-based carrier, the source did not mention the NMA as a possible alternative.

"They're good aircraft, they still have a lot of useful life," said Doug Parker, chairman and chief executive of American, on the 767 in an interview with Airline Business earlier this year.

Delta Air Lines has also expressed interest in the NMA, with chief executive Ed Bastian reportedly telling employees in February that the carrier hopes to launch the aircraft.

Atlanta-based Delta operates 127 757s with an average age of 20.5 years and 80 767-300ERs with an average age of 20.7 years, Fleets Analyzer shows.

Additional reporting by Sophie Segal and Stephen Trimble

Source: Cirium Dashboard