The Federal Aviation Administration approved Boeing's new stretched-737 MAX to enter service after a 6-year delay amid intense scrutiny from regulators.

Oct. 21 (UPI) -- The Federal Aviation Administration approved Boeing's 737-10, a stretched variant of its fourth generation 737 MAX family of narrow-bodied aircraft, clearing the way for the company to begin the first deliveries in the next few months of more than 1,500 orders.

Boeing said in a news release Tuesday that its newest and largest 737 MAX had completed a comprehensive certification process that included almost 1,000 test flights and "extensive safety assessments and design reviews."

The company said that the MAX 10 brought with it new safety technology, including an improved Angle-of-Attack system, set to become standard across the 737 MAX family, and was the first be certified to the full extent of the 2020 Aircraft Certification, Safety, and Accountability Act that mandates enhanced documentation of safety assessments and human factors evaluations.

"Completing the certification program clears the path for us to deliver a Boeing airplane that will set a new standard in commercial aviation. The 737-10 offers greater capacity, longer range and the best seat economics in its class, a platform that will create more value and opportunities for airlines around the world," said Boeing Commercial Airplanes President and CEP Stephanie Pope.

Regulatory clearance follows a six-year delay from when the aircraft was scheduled to enter service, including an eleventh-hour call over an issue with the navigation system issue that FAA officials eventually determined was not a safety concern.

The saga drew criticism of the U.S. system of aircraft certification from Transportation Secretary Sean Duffy who told CNBC that while safety was of the utmost importance, the system was hurting America's global competitiveness.

"It takes Boeing, to certify an aircraft in Europe, about half the time, less than half the time that it does in the U.S. You have China now playing to take over in aviation. We have to certify aircraft more quickly if we're going to compete as Americans," said Duffy.

The certification delay was due to regulators looking very closely at the 10 following after fatal crashes of earlier MAX variants crashes in 2018 and 2019 that killed more than 300 people led to MAX fleets being grounded worldwide for more than a year and briefly in 2024 after an emergency exit blew out on an Alaska Airlines 737 MAX in Oregon.

Customers for the 10, which is longer enabling it to carry 230 passengers, 12 more than the previous version, include American Airlines, United Airlines, Delta Air Lines and Alaska Airlines, which said it planned to use the extra space to fit lie-flat seats on some of its 737 MAX 10s.