The longest-range variant of the Boeing 737 MAX range, the 737-7, has finally secured certification from the Federal Aviation Administration (FAA), seven years later than originally planned. The certification comes after significant changes were made to the model’s engines and cockpit alert systems.
The 737-7 was originally meant to enter into service in 2019 with Southwest Airlines as the launch customer, but those plans were derailed following two tragic crashes of the slightly larger 737MAX-8 variant involving a Lion Air jet in 2018 and then an Ethiopian Airlines aircraft just months later in 2019.
In the aftermath of those accidents, the FAA carried out a complete reset of how it approved new aircraft models, but that wasn’t the only reason it took so long for the 737-7 to secure certification.
In 2021, the 737-7 program suffered a major setback when engineers discovered that running the engine anti-ice system continuously on the CFM-manufactured LEAP-1B engines caused excessive heat buildup that could weaken the inlet structure and potentially shed debris.
Boeing and CFM had to redesign elements of the engine, but just when that work was complete, a Boeing 737MAX-9 operated by Alaska Airlines suffered a mid-cabin exit door plug blowout shortly after takeoff.
Thankfully, no one was seriously injured in that accident, but the incident refocused the FAA’s attention on Boeing’s quality controls.
In the end, it took nearly a decade for the 737-7 to be certified, with the FAA saying that the process “reflects years of sustained work to resolve complex technical issues and complete a thorough review of the airplane’s design and supporting safety analyses.”
A statement from the FAA added: “Throughout the process, the FAA performed or directly reviewed significant work involving flight controls, system safety assessments, human factors, flightcrew alerting, and other novel, complex, or safety-critical areas, while also requiring testing, design changes, and additional analysis where necessary.”
Boeing’s chief executive, Stephanie Pope, said the incredibly lengthy certification timeline “validates the rigor of our airplane’s design and recognizes the determination and resilience of our 737 MAX development team.”
The 737-7 (which dropped the MAX title following the Lion Air and Ethiopian Airlines crashes) is the smallest but longest-range variant of the 737MAX family. The aircraft is able to fly up to 3,800 nautical miles, around 8.5% further than the 737MAX-8.
In a typical two-class configuration, the 737-7 can accommodate between 135 and 160 passengers, whereas the 737MAX-8 can accommodate up to 180 passengers in a two-class configuration.
The 737MAX-8 was the first of the MAX family to be certified in 2017, followed by the MAX-9 in 2018. The 737-7 was next to be certified when the entire certification process was upended.
Southwest Airlines has ordered more than 300 Boeing 737-7 aircraft, with the model being described as “pivotal to Southwest’s long-term fleet modernization strategy.”
