Boeing and Southwest Airlines have announced the launch of the 737 MAX 7, the third member of the 737 MAX family.

The Dallas-based carrier and launch customer for the 737 MAX program became the first airline to order the 737 MAX 7, when it converted 30 existing orders for Next-Generation 737s into orders for the 737 MAX 7.

Southwest also exercised options to add five more Next-Generation 737-800s to its fleet.

These airplanes, along with the 737 MAX 7s, are part of Southwest’s ongoing effort to improve fuel efficiency and profitability.

The 737 MAX 7 supports Southwest’s expanding fleet modernization effort. Southwest is expected to take its first 737 MAX 7 delivery in 2019.

“We are thrilled to announce that Southwest Airlines and Boeing have entered into an agreement for Southwest to be the launch customer for the Boeing MAX 7 series, with deliveries beginning in 2019,” said Gary Kelly, Southwest Airlines chairman.

“The 737 MAX 7 builds on the strengths of today’s Next-Generation 737-700, incorporating the latest CFM International LEAP-1B engines is expected to reduce fuel burn and CO2 emissions by an additional 12 percent over today’s most fuel-efficient single-aisle airplane.”

The 737 MAX 7 brings the most advanced engine technologies to the world’s best-selling airplane, building on the strengths of today’s Next-Generation 737-700.

The 110-ft long airplane incorporates the latest CFM International LEAP-1B engines to deliver improved efficiency with the most reliability and passenger comfort in the single-aisle market.

The 737 MAX 7 also will extend the range over today’s 737-700 by approximately 400 nautical miles (741 km).