The upcoming Boeing 737 Max 10 has reached firm design configuration, the company announced at the Singapore Airshow Wednesday. The milestone ushers in the start of the program’s detailed design phase, as the company looks toward first delivery in 2020 to one of 18 customers that have committed to 416 of the airplanes since its launch at last year’s Paris Air Show.

Boeing vice president of marketing Randy Tinseth noted that although a small proportion of the new orders and commitments represent transfers from another Max derivative, most notably the Max 9, most were completely new, suggesting that the Max 10 has not significantly cannibalized demand for the smaller variant.

“We see a place for both the 9 and the 10, depending on the customer,” said Tinseth. “The 10 plugged a hole that we had, and that hole was we didn’t have as many seats as the [Airbus] A321.”  

Addressing the demand mix for the Max family, Tinseth estimated that between 60 and 65 percent of orders will go to the baseline Max 8; 20 to 25 percent to the Max 9 and 10; and roughly 10 percent “on the lower end of that market,” namely the Max 7.

The Max 10 incorporates a pair of fuselage plugs to extend the Max 9’s length by 66 inches. Other changes include a levered main landing gear, minor wing changes to accommodate the 777-style landing gear and a four-inch-wider mid-exit door to allow for the extra 12 passengers, bringing maximum capacity to 230. Boeing claims it delivers 5 percent better trip cost and 5 percent lower seat-mile cost than the A321LR.

In terms of the family’s production, Tinseth noted that the Max 10 forced “a little bit” of a change in plans to accommodate the airplane’s introduction into the existing line in 2020, right about the same time rates increase to 57 a month. He also reported that Boeing might need to raise rates beyond that to address the company’s growing oversold position.

“We’re going to watch it very closely and figure out what happens in terms of what we call meltaway. But if those numbers don’t go away, we’ll have to think very seriously about [raising rates beyond 57],” said Tinseth.