The Boeing 737 is a narrow-body aircraft produced by Boeing Commercial Airplanes at its Renton Factory in Washington. Developed to supplement the 727 on short and thin routes, the twinjet retains the 707 fuselage cross-section and nose with two underwing turbofans. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with Lufthansa. The lengthened 737-200 entered service in April 1968. It evolved through four generations, offering several variants for 85 to 215 passengers.
The -100/200 original variants were powered by Pratt & Whitney JT8D low-bypass engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984, the 737 Classic -300/400/500 variants were re-engined with CFM56-3 turbofans and offered 110 to 168 seats.
Introduced in 1997, the 737 Next Generation (NG) -600/700/800/900 variants have updated CFM56-7s, a larger wing and an upgraded glass cockpit, and seat 108 to 215 passengers. The latest generation, the 737 MAX -7/8/9/10, powered by improved CFM LEAP high bypass turbofans and accommodating 138 to 204 people, entered service in 2017. Boeing Business Jet versions are produced since the 737NG, as well as military models.
As of December 2019, 15,156 Boeing 737s have been ordered and 10,571 delivered. Actual backlog stands at 4,398 when including “additional criteria for recognizing contracted backlog with customers beyond the existence of a firm contract”.
Initially, its main competitor was the McDonnell Douglas DC-9, followed by its MD-80/MD-90 derivatives. It remained the highest-selling commercial jetliner until surpassed in total orders by the Airbus A320 family in October 2019. The current 737 MAX, designed to compete with the A320neo was grounded worldwide in March 2019 following two fatal crashes.
Boeing 737 MAX groundings
In March 2019, the Boeing 737 MAX passenger airliner was grounded worldwide after 346 people died in two crashes, Lion Air Flight 610 on October 29, 2018 and Ethiopian Airlines Flight 302 on March 10, 2019. Ethiopian Airlines immediately grounded its remaining MAX fleet. On March 11, the Civil Aviation Administration of China ordered the first nationwide grounding, followed by most other aviation authorities in quick succession. The U.S. Federal Aviation Administration (FAA) publicly affirmed the airworthiness of the airplane on March 11, but grounded it on March 13 after receiving evidence of accident similarities. By March 18, all 387 aircraft, which served 8,600 flights per week for 59 airlines, were barred from service.
In November 2018, a week after the Lion Air accident, Boeing revealed that a new automated flight control, the Maneuvering Characteristics Augmentation System (MCAS), which it had not explained in crew manuals or training, could force the aircraft into nosedives. Boeing and the FAA required a supplement to crew manuals to describe a flight recovery procedure. In December 2018, the FAA privately predicted that MCAS could cause more accidents, but assumed the updated manual would suffice until Boeing fixed the system.