Boeing 737 Next-Generation (737NG) is a twin engine narrow body aircraft manufactured by Boeing. The 737NG is upgraded version of 737 Classic model. Currently 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. Upgraded and re-engined models in development as the 737 MAX series will eventually supplant the 737NG.
The Boeing Next-Generation 737 is powered by two CFM56-7B engines. Two CFM56-7B engines supply thrust for the airplane and also supply power for Electric, Hydraulic and Pneumatic System. The CFM56-7B is a high bypass ratio, two spool, turbo fan engine. The CFM56-7B operates through a FADEC (Full Authority Digital Engine Control) system. The CFM56-7B uses “On Condition Maintenance” concept, that means engine has no periodic overhaul schedules. Engine can remain installed on aircraft until something important occurs or when lifetime limits of parts are reached. For this reason monitoring and maintaining 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.