B737-300/400/500 General Familiarization Course

.POWER PLANT

Overview

The airplane is powered by two CFM56 turbofan engines mounted below the wing. The engines are

individually supported in strut-mounted nacelles with mounts designed to absorb thrust, vertical and side

loads and to allow growth of the engine due to thermal expansion.

Engine components and accessories are accessible for maintenance and service operations by use of hinged

removable fan cowl panels, hinged removable fan duct cowl and thrust reverser halves, and a removable

forward fairing, Engine Cowling, for description of the fan cowl panels and forward fairing, Fan Thrust

Reverser System, for description of the fan duct cowl and thrust reverser halves.

The major components installed on each engine in addition to the basic engine accessories include the

constant speed drive, generator, hydraulic pump, and starter.

The engine is a dual-rotor, axial flow turbofan of high compression ratio and high bypass ratio. The engine

incorporates two multistage turbine-driven compressors utilizing concentric shafting. The integrated fan and

low pressure compressor, consisting of one fan stage and three compressor (booster) stages is driven by a

four-stage low pressure turbine. The nine-stage high pressure compressor is driven by a single-stage high

pressure turbine.

The engine starting system provides the means for rotating the high pressure rotor (HPR) to establish airflow

through the engine. Rotation of the HPR drives the engine fuel pump and main engine control and delivers

metered fuel under pressure to the combustion chamber. The ignition system is a high energy capacitor

discharge system consisting of two electrically and physically independent circuits serving separate igniter

plugs.

The engine includes a complete self-contained oil system for lubrication and cooling of internal parts. Thrust

reverser mechanisms are utilized at the engine fan discharge to provide a means of further decelerating the

airplane during its landing roll. Various remote transmitting devices are installed on the engine to provide

indication in the flight compartment of engine performance and condition.

A vent and drain system is mounted on the engine to collect and discharge drain fluids overboard.

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