Aerospace observers view Boeing's latest new-aircraft decision timeline as another delay to an already lengthy process, a development that could reflect the project's complexity.
"A lot of people were taken by surprise," says aerospace analyst Richard Aboulafia of news that Boeing's decision to launch the so-called New Mid-market Airplane (NMA) will not come until 2020.
The industry must now undergo more "waiting and waiting" to learn the future of a concept Boeing has discussed for years, adds Aboulafia, vice-president at consultancy Teal Group.
“It feels and looks like a delay. One has wonder why Boeing is doing this," says Addison Schonland, partner at consultancy AirInsight Group.
The industry had been expecting Boeing to decide this year whether to launch the NMA, a concept for a widebody aircraft with 200-270 seats and range of 4,000-5,000nm (7,400-9,300km).
The NMA would fill a hole in Boeing's production lineup – sitting in a category roughly between 737 Max 10s and 787-8s. Boeing has described the concept as having true transatlantic capability, replacing aging 757 and 767s and enabling airlines to launch new mid-demand, mid-range routes.
But on 30 January Boeing chief executive Dennis Muilenburg reset those expectations. This year's decision will be whether to "offer" the NMA, he specified. That means Boeing can wrangle up launch customers.
The actual launch decision will come in 2020, assuming the company's board of directors approves the offer decision, Muilenburg says.
He characterised the double-decision process as Boeing's standard procedure for new aircraft programmes, but also stressed Boeing remains committed to an entry-into-service of 2025.
"It's a two-step decision process as we've always done with commercial airplanes," he says.
George Dimitroff, head of valuations at FlightGlobal's Flight Ascend Consultancy, stops short of calling Boeing's newly-disclosed timeline a delay. The move gives Boeing time to find customers and further define the aircraft, he says.
"The decision to offer means they can effectively start selling it, but they are giving themselves another year before they actually commit to building it,' Dimitroff says. "They clearly want to be sure they can kick it off with some large order commitments (even if letters of intent) before they start investing serious money in design and testing."
Making the final call in 2020 might also reflect the complexities of the project, Aboulafia says.
For starters, Boeing faces the challenge of building a twin-aisle aircraft that has the production and operational economics of a single-aisle model – no easy feat, Aboulafia notes.
Another challenge could be identifying a suitable engine and engine maker, he adds, noting that the world's prime engine manufacturers are now working through their own struggles. Those struggles have included technical problems with new models and delivery delays.
Challenges aside, Boeing's delays come when moving fast would seem imperative.
The 757s still in service are rapidly approaching retirement, and Airbus has been aggressively pitching its longer-range A321LR as replacement. That aircraft has range and seating capacity similar to the 757's, but with modern efficiency.
"The 757 replacement [window] is closing," says Aboulafia.
Airlines worldwide still operates 352 757s and 431 767s in passenger configurations, according to Flight Fleets Analyzer.
"The replacement need for 757/767, especially in the US, is the most pressing requirement for the NMA," says Dimitroff. "The longer they take, the more the opportunity to offer NMA as a viable replacement for 757s and 767s reduces."
Though news of the 2020 launch decision came as surprise to many, whether potential airline customers were caught unaware remains unknown.
American Airlines, Delta Air Lines and United Airlines declined to comment about Boeing's timeline.
"We are pleased to see that Boeing continues to move forward with the programme and look forward to learning more about the potential for the aircraft," says United.
Aboulafia suggests airlines may not have been in the dark.
"The one thing Boeing does well is talk to customers," he says.