Boeing workers in Renton today witnessed a milestone when the company debuted its first 737 Max 9.

With its debut, the Max 9 joins the 737 Max family, the fastest-selling airplane in Boeing history. The larger Max 9 can carry up to 220 passengers and has a flight range of 3,515 nautical miles.

In the coming weeks — following a series of system checks — the Max 9 will enter its final phase of flight testing to examine and assess the airplane’s operational characteristics and overall performance.

“The 737 Max team continues to do a fantastic job getting us to these important milestones right on schedule,” Keith Leverkuhn, vice president and general manager of the 737 Max program, said in a press release. “Our primary focus is delivering an aircraft that has the legendary reliability our 737 customers depend on, plus the optimized flexibility and range capability they desire.”

The Max 9 is scheduled to enter service in 2018.