Boeing is examining a re-engined 737, but says it will not be rushed into a launch decision to counter the Bombardier CSeries or any A320 upgrade from Airbus.
Like Airbus, Boeing is examining an upgraded version of its single-aisle twinjet, re-engined with an advanced turbofan such as the CFM International Leap-X or Pratt & Whitney PW1000G.
"We continue to look at ways to improve the 737 further and re-engining is one option," said Boeing Commercial Airplanes vice-president for marketing Randy Tinseth, speaking to ATI in London last week.
Tinseth says that a technical feasibility study into the installation of a new engine on the 737 confirms that "it will work", but will require a lot of effort.
He adds that the CSeries and the increasing likelihood of a move by Airbus are not putting pressure on an early decision from Boeing. "There is no reason to rush [into a decision], we'll wait until the right time," he says.
While Bombardier claims that the all-new CSeries will retain a strong appeal and 10% lower operating costs, even against re-engined versions of existing single-aisles, Tinseth points to factors that might work against it.
"You have to take into account the [lower] transition costs of a re-engined derivative for an airline, and risks involved with an all-new design," he says.
But Tinseth expects Bombardier to be a strong competitor as it works hard to build its slim CSeries orderbook, which stands at just 50 aircraft with under three years to go to until first flight.
"This is either going to be the shortest production span in history or Bombardier will have to get more sales," he says. "I think they'll figure out how to get customers, and be very aggressive."
Airbus has progressively pushed back its expected in-service date for any all-new single aisle to the mid-2020s, but Boeing continues to plan for a potentially earlier arrival.
"We are working to ensure that we have the technologies in place to have a single-aisle replacement late this decade," says Tinseth. "Customers have been very specific with what they want: 15-20% better than today's aircraft."
While emerging engine technology is a key factor contributing to this improved performance, Tinseth says that airlines want the 15-20% improvement in all areas, including maintenance costs, noise and range.