Boeing 737 is a twin-engine narrow-body aircraft manufactured by Boeing.

The 737 continued to evolve into many variants but still remains recognizable as the 737. These are divided into four generations but all are based on the same basic design.

Boeing 737 family

  • 737 Original series (first generation) – launched in 1965.
  • 737 Classic series (second generation) – launched in 1979.
  • 737 NG series (third generation) – launched in 1993.
  • 737 MAX series (fourth generation) –  launched in 2011.

The Boeing 737 Original is the name given to the -100/200 and -200 Advanced series of the Boeing 737 family.

The Boeing 737 Classic is the name given to the 737-300/400/500 series after the introduction of the -600/700/800/900 series of the Boeing 737 family.

Boeing 737 NG

The 737NG is an upgraded version of the 737 Classic model. The Boeing 737 Next Generation, abbreviated as 737 Next Gen or 737NG, is the name given to the main models 737-600/700/800/900 series and the extended range -700ER/900ER variants of the Boeing 737 family.

Currently, the 737NG series includes three variants (737-700/800/900) and can seat between 149 and 220 passengers. The Boeing 737NG’s primary competition is with the Airbus A320 family aircraft.

737 NG Technical Specs

737-700 737-800 737-900
Seats (2-class)126162178
Maximum seats149189220
Length33.6 m (110 ft 4 in)39.5 m (129 ft 6 in)42.1 m (138 ft 2 in)
Wingspan35.8 m (117 ft 5 in)35.8 m (117 ft 5 in)35.8 m (117 ft 5 in)
Height12.5 m (41 ft 3 in)12.5 m (41 ft 3 in)12.5 m (41 ft 3 in)

The Boeing Next-Generation 737 is powered by two CFM56-7B engines.


The CFM56-7B is the exclusive engine for the Boeing Next-Generation single-aisle airliner. The CFM56-7B engine is a high by-pass, axial flow, dual rotor, two-spool, advanced technology turbofan engine. It is supported by the aircraft’s wing pylon.

Two CFM56-7B engines supply thrust for the airplane and also supply power for the Electric, Hydraulic, and Pneumatic systems. The CFM56-7B is a high bypass ratio, two-spool, turbofan engine. The CFM56-7B operates through a FADEC (Full Authority Digital Engine Control) system. The CFM56-7B uses the “On Condition Maintenance” concept, which means the engine has no periodic overhaul schedules. The engine can remain installed on aircraft until something important occurs or when lifetime limits of parts are reached. For this reason, monitoring and maintaining the health of the engine is very important, for that different types of tools are available which are:

  • Engine performance trend monitoring
  • Borescope inspection
  • Lubrication particles analysis
  • Engine vibration monitoring system

The AlliedSignal 131-9(B) auxiliary power unit (APU) is installed on Boeing 737NG aircraft. APU supplies electrical and pneumatic power to other airplane systems.

Boeing 737 MAX

The Boeing 737 MAX is the name given to the main MAX 737-7/8/9/10 series and high-density MAX 200 variant of the Boeing 737 family. It is offered in four main variants, typically offering 138 to 230 seats and a range of 3,215 to 3,825 NM (5,954 to 7,084 km). The 737 MAX 7, MAX 8 (including the denser, 200-seat MAX 200), and MAX 9 replace the 737-700, -800, and -900 respectively. The further stretched 737 MAX 10 has also been added to the series. The main development was to re-engine with CFM LEAP-1B very high bypass ratio.

737 MAX Technical Specs

737 MAX 7737 MAX 8737 MAX 9737 MAX 10
Seats (2-class)138 – 153162 – 178178 – 193188 – 204
Maximum seats172210220230
Range nm (km)3,850 (7,130)3,550 (6,570)3,550 (6,570)*3,300 (6,110)*
Length35.56 m (116 ft 8 in)39.52 m (129 ft 8 in)42.16 m (138 ft 4 in)43.8 m (143 ft 8 in)
Wingspan35.9 m (117 ft 10 in)35.9 m (117 ft 10 in)35.9 m (117 ft 10 in)35.9 m (117 ft 10 in)
EngineLEAP-1B from CFM InternationalLEAP-1B from CFM InternationalLEAP-1B from CFM InternationalLEAP-1B from CFM International
210 seats: 737-8-200*one auxiliary tank*one auxiliary tank

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