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ENGINES & APU

737

Flight Manual

Sec. 6.7 TOC-1

Continental

ENGINES & APU TABLE OF CONTENTS

Rev. 11/15/02 #41

ENGINES SYSTEM DESCRIPTION ...................................................... 1 GENERAL......................................................................................... 1 >>@ POWER MANAGEMENT CONTROL (PMC).................... 2 BCD ELECTRONIC ENGINE CONTROL (EEC) ...................... 2 EEC Normal Mode .................................................................... 3 EEC Alternate Mode.................................................................. 3 Structural Limit Protection......................................................... 3 >>@ IDLE RPM ........................................................................... 4 BCD IDLE OPERATION ............................................................. 4 >>@ POWER PLANT SYSTEM SCHEMATIC .......................... 5 BCD POWER PLANT SYSTEM SCHEMATIC .......................... 6 ENGINE FUEL SYSTEM.................................................................. 7 ENGINE OIL SYSTEM ..................................................................... 8 >>@ ENGINE FUEL AND OIL SYSTEM SCHEMATIC ............. 9 BCD ENGINE FUEL AND OIL SYSTEM SCHEMATIC........... 10 ENGINE START SYSTEM............................................................. 11 Abnormal Start Protection (Ground Starts Only) ................... 12 IGNITION SYSTEM........................................................................ 12 BCD AUTO-RELIGHT .............................................................. 13 INFLIGHT STARTING.................................................................... 13 >>@ ENGINE START AND IGNITION SYSTEM SCHEMATIC ............................................................... 14 BCD ENGINE START AND IGNITION SYSTEM SCHEMATIC ............................................................... 15 THRUST REVERSER.................................................................... 17 THRUST REVERSER SCHEMATIC............................................. 19 AIR BLEED SYSTEM..................................................................... 20 Compressor Section................................................................ 20 Fan Bypass / Bleed Air ............................................................ 20 >>@ ENGINE AND FUEL FLOW INDICATORS..................... 21 >>@ ENGINE OIL AND VIBRATION INDICATORS................ 24 >>@ ENGINE START SWITCHES .......................................... 26 >>@ ENGINE REVERSER, PMC AND LOW IDLE................. 27 BCD PRIMARY AND SECONDARY ENGINE INDICATIONS ............................................................................. 28 BCD AUTOTHROTTLE LIMIT, THRUST MODE DISPLAY AND TOTAL AIR TEMPERATURE............................................ 29 BCD N1 INDICATIONS ............................................................ 30 BCD THRUST REVERSER INDICATIONS ............................ 32

ENGINES & APU Sec. 6.7 TOC-2 Rev. 11/15/02 #41

737

Continental

Flight Manual

THERMAL ANTI-ICE INDICATION ................................. 32 EGT INDICATIONS.......................................................... 33 ENGINE FAIL ALERT ...................................................... 35 N2 INDICATIONS ............................................................ 36 CROSSBLEED START INDICATION............................. 36 FUEL FLOW / FUEL USED INDICATIONS.................... 37 CREW ALERTS ............................................................... 38 ENGINE OIL INDICATIONS ............................................ 39 ENGINE VIBRATION INDICATIONS .............................. 40 ENGINE START SWITCHES.......................................... 41 ENGINE PANEL............................................................... 42 ENGINE CONTROLS ...................................................... 44 APU SYSTEM DESCRIPTION ............................................................. 47 GENERAL....................................................................................... 47 APU OPERATION.......................................................................... 49 APU START ................................................................................... 50 APU FUEL ...................................................................................... 50 APU SHUTDOWN ......................................................................... 50 APU COMPONENTS..................................................................... 51 APU AUTOMATIC LOAD SHEDDING .......................................... 51 >>@ APU SCHEMATIC ............................................................ 52 APU CONTROLS AND INDICATORS................................................. 53 BCD APU .................................................................................. 55

BCD BCD BCD BCD BCD BCD BCD BCD BCD BCD BCD BCD

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 1

Continental

ENGINES SYSTEM DESCRIPTION

Rev. 11/15/02 #41

GENERAL >>@ The aircraft are equipped with two CFM56-3 high bypass ratio turbofan engines rated at 20,000 pounds of takeoff thrust.

BCD The aircraft are powered by two CFM56-7 engines. B Takeoff thrust rating is 24,200 lbs. CD Takeoff thrust rating is 26,300 lbs.

The engine is dual rotor assembly consisting of a fan rotor (N1) and a compressor rotor (N2). The N1 rotor consists of a single stage fan and a three stage booster section connected by a through shaft to a four-stage low pressure turbine. The N2 rotor is a nine-stage axial flow compressor connected by a through shaft to a single-stage high pressure turbine. The first four stages of the compressor are variable. The compressor delivers highly compressed air to the annular combustor where the fuel / air mixture is ignited. The resulting high energy gasses drive the turbines, producing the power to turn the fan, the compressor and the accessories. Thrust is the combined forces produced by accelerated fan air and rapidly expanding high velocity combustion gasses. Fan air and combustion gasses exit through separate nozzles at the rear of the engine. >>@ The Main Engine Control (MEC) schedules fuel to provide the thrust called for by the Forward Thrust Lever setting in the flight deck. This fuel flow is further refined electronically by the Power Management Control (PMC) without moving the Forward Thrust Levers.

BCD The Hydro-Mechanical Unit (HMU) and the Electronic Engine Control (EEC) combine to meet the thrust requirements called for by the forward thrust lever setting. The EEC meters fuel through the HMU for both forward and reverse thrust.

A sliding sleeve, fixed vane thrust reverser system is installed which redirects bypass fan air to aid in stopping the aircraft.

ENGINES & APU Sec. 6.7 Page 2 Rev. 11/15/02 #41

737 Continental

Flight Manual

> >@ POWER MANAGEMENT CONTROL (PMC) The thrust control system consists of a hydro-mechanical MEC unit and a PMC unit mounted on each engine. The PMC is an electronic system with limited authority over the MEC. The PMC uses MEC power lever angle, N1 speed, inlet temperature and pressure to adjust, or trim, the MEC to obtain the desired N1 speed. The PMC adjusts fuel flow as a function of thrust lever angle. The PMC provides a constant thrust climb feature once the thrust lever is set at the beginning of climb. Thus, when thrust is set for the climb, the PMC automatically maintains that thrust throughout the climb profile with no further thrust lever adjustments. If the thrust lever is repositioned, the PMC maintains the setting corresponding to the new thrust lever angle. The PMC includes failure detection and annunciation modules, which detect PMC failures and provide a signal to the crew. For detectable failure conditons, the PMC schedules a slow N1 drift over approximately 30 seconds and illuminates the PMC INOP light, the ENG system annunciator light and the MASTER CAUTION lights. For a PMC failure, the PMC can be selected OFF by a switch on the aft overboard panel. The engine speed is then controlled by the hydromechanical MEC only. The PMC INOP light is suppressed below starter cutout engine speed (46% N2 RPM).

BCD ELECTRONIC ENGINE CONTROL (EEC)

Each engine has a full authority digital EEC. Each EEC has two independent control channels and automatically switches channel if the operating channel fails. With each engine start or start attempt, the EEC alternates between control channels. The EEC uses thrust lever inputs to automatically control forward and reverse thrust. N1 is used by the EEC to set thrust in two control modes; normal and alternate. Manual selection of the control mode can be made with the EEC switches on the engine panel.

ENGINES & APU

737

Flight Manual EEC Normal Mode

Sec. 6.7 Page 3

Continental

Rev. 11/15/02 #41

In the normal mode, the EEC uses sensed flight conditions and bleed air demand to calculate N1 values. The EEC compares commanded N1 to actual N1 and adjusts fuel flow to change engine speed until actual N1 equals commanded N1. The full rated takeoff thrust for the installed engine is available at a thrust lever position less than the forward stop. Fixed or assumed temperature reduced takeoff thrust ratings are set at thrust lever positions less than full rated takeoff. If the thrust lever is advanced to the forward stop, the EEC limits thrust to the maximum certified thrust rating for current conditions. EEC Alternate Mode The EEC can operate in either of two alternate modes, soft or hard. If required signals are not available to operate in the normal mode, the EEC automatically changes to the soft alternate mode. When this occurs, the ALTN switch illuminates and the ON indication remains visible. In the soft alternate mode, the EEC uses the last valid flight conditions to define engine parameters. Thrust rating shortfalls or exceedences may occur as flight conditions change. The soft alternate mode remains until the hard alternate mode is entered by either retarding the thrust lever to idle or manually selecting ALTN with the EEC switch on the aft overhead panel. Note: Loss of either DEU results in a loss of signal to both EECs. The EEC ALTN lights illuminate and each EEC reverts to the alternate mode to prevent the engines from operating on a single source of data.

When the hard alternate mode is entered, the EEC reverts to the alternate mode thrust schedule. Hard alternate mode thrust is always equal to or greater than normal mode thrust for the same lever position. Maximum certified thrust rating can be exceeded. If the hard alternate mode is entered by reducing the thrust lever to idle while in the soft alternate mode, the ALTN switch remains illuminated and the ON indication remains visible. When ALTN is selected manually, the ON indication is blanked. Structural Limit Protection The EEC provides N1 and N2 redline overspeed protection in both normal and alternate modes. The EGT limit must be observed by the crew because the EEC does not provide EGT redline exceedence protection.

ENGINES & APU Sec. 6.7 Page 4 Rev. 11/15/02 #41 > >@ IDLE RPM There are two engine idle speeds, low idle and high idle. The minimum engine speed for all flight phases is high idle, which varies with flight conditions. As temperature and airspeed decrease, high idle speed also decreases. The average high idle setting is approximately 32% N1. To reduce braking activity, engine idle speed is reduced to low idle, approximately 22% N1, four seconds after touchdown. The four second delay is provided to enhance engine speed acceleration for reverse thrust.

737 Continental

Flight Manual

BCD IDLE OPERATION

The EEC automatically selects approach idle, flight minimum idle, and ground minimum idle. Ground minimum idle is selected for ground operations and flight minimum idle is selected for most phases of flight. Approach idle is selected in flight if flaps are in landing configuration or engine anti-ice is ON for either engine. Approach idle improves engine acceleration time for go-around. Approach idle is maintained until after touchdown, when ground minimum idle is selected. In flight, if a fault prevents the EEC from receiving flap or anti-ice signals, approach idle schedule begins below 15,000 feet MSL.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 5

Continental

Rev. 11/15/02 #41

> >@ POWER PLANT SYSTEM SCHEMATIC

FAN AIR 5TH STAGE BLEED AIR 9TH STAGE BLEED AIR BOOSTER FAN COMBUSTOR TURBINES

COMPRESSOR

ACCESSORIES OIL PUMP FUEL PUMPS GENERATOR GENERATOR DRIVE STARTER TACHOMETER HYDRAULIC PUMP

THRUST REVERSER ENGINE IDLE CONTR0L ENGINE FUEL SYSTEM POWER CONTR0L

AIR DRIVEN STARTER

COCKPIT CONTROLS & INDICATORS

ENGINE START & IGNITION SYSTEM FROM ENGINE INDICATING SYSTEM FROM ELECTRICAL SYSTEM

FROM PNEUMATIC SYSTEM

37318001

FROM FUEL SYSTEM

ENGINES & APU Sec. 6.7 Page 6 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD POWER PLANT SYSTEM SCHEMATIC

ENGINES & APU

737

Flight Manual ENGINE FUEL SYSTEM

Sec. 6.7 Page 7

Continental

Rev. 11/15/02 #41

>>@ Fuel is delivered to the engines at pressures and flow rates required to obtain desired engine thrust. Fuel leaves the fuel tank and enters through the main engine fuel shutoff valve. The engine fuel shutoff valve is electrically controlled by the Engine Start Lever and the Engine Fire Warning Switch. When the engine fuel shutoff valve is closed, the FUEL VALVE CLOSED light located on the forward overhead panel illuminates dim. Fuel passes from the first stage of the engine driven fuel pump through a fuel / oil heat exchanger to a filter. Provisions are made to bypass the heat exchanger or the filter in the event of failure or blockage. Illumination of the FILTER BYPASS light indicates an impending bypass of the fuel filter due to contamination. The second stage of the fuel pump provides high pressure fuel to the MEC. As the fuel leaves the second stage, a portion of the fuel is diverted to run the hydro-mechanical portion of the MEC. This fuel is filtered again and then routed through the fuel heater a second time. The fuel heater uses engine oil to heat the fuel of the MEC for anti-icing purposes. The MEC in conjunction with the PMC uses thrust lever angle, fan inlet pressure and temperature, N1 RPM and N2 RPM to meter the correct amount of fuel to the combustor. Fuel flows from the MEC through the MEC fuel shutoff valve. The MEC shutoff valve is mechanically controlled by the Engine Start Lever. A fuel flow transmitter measures the rate of fuel flow from the MEC.

BCD Fuel is delivered under pressure from fuel pumps located in the fuel tanks. The fuel flows through a fuel spar shutoff valve located at the engine mounting wing stations. The fuel passes through the first stage engine fuel pump where pressure is increased.

It then passes through two fuel / oil heat exchangers where IDG oil and main engine oil heat the fuel. A fuel filter then removes contaminants. Fuel automatically bypasses the filter if the filter becomes saturated. Before the fuel bypass occurs, the fuel FILTER BYPASS alert illuminates on the upper display unit. The second stage engine fuel pump adds more pressure before the fuel reaches the Hydro-Mechanical Unit (HMU). To meet thrust requirements, the EEC meters fuel through the HMU. The spar fuel shutoff valve and engine fuel shutoff valve allow fuel flow to the engine when both valves are open. The valves are open when the engine fire warning switch is in and the start lever is in IDLE. Both valves close when either the start lever is in CUTOFF or the engine fire warning switch is out. SPAR VALVE CLOSED and ENG VALVE CLOSED lights located on the overhead panel indicate valve position.

ENGINES & APU Sec. 6.7 Page 8 Rev. 11/15/02 #41

737 Continental

Flight Manual

Fuel flow is measured after passing through the engine fuel shutoff valve and is displayed on the upper display unit. Fuel flow information is also provided to the FMS. ENGINE OIL SYSTEM >>@ Oil from the individual engine tank is circulated under pressure, through the engine to lubricate the engine bearings and accessory gearbox. Oil quantity is displayed on the Oil Quantity Indicator located on the center instrument panel. The oil system is pressurized by the engine driven oil pump. The oil leaves the oil pump, passes through an oil filter, and continues to the engine bearings and gearbox. Sensors for the oil pressure indicator and the LOW OIL PRESSURE light are located downstream of the oil filter, prior to engine lubrication. The oil is returned to the oil tank by means of engine driven scavenge pumps. From the scavenge pumps the oil passes through a scavenge filter. Should the filter become saturated with contaminants, oil automatically bypasses the filter. Prior to the oil bypassing the filter, the OIL FILTER BYPASS light, located on the center instrument panel, illuminates. Scavenge oil temperature is sensed as the oil returns to the oil tank, and is displayed on the Oil Temperature Indicator located on the center instrument panel. The oil then passes through the fuel / oil heat exchanger where it is cooled by engine fuel to maintain proper oil temperature prior to returning to the oil tank.

BCD Oil from the individual engine tank is circulated under pressure, through the engine to lubricate the engine bearings and accessory gearbox. The oil quantity indicator, oil temperature indicator, oil pressure indicator and LOW OIL PRESSURE alert are all located on the upper display unit.

The oil system is pressurized by the engine driven oil pump. Oil from the pump goes to the engine bearings and gearbox. Sensors for the oil temperature indicator, oil pressure indicator and LOW OIL PRESSURE alert are located downstream of the oil pump prior to engine lubrication. Oil is returned to the oil tank by engine driven scavenge pumps. From the scavenge pumps oil passes through a scavenge filter. If the filter becomes saturated with contaminants, oil automatically bypasses the filter. Prior to the oil bypassing the scavenge filter, the OIL FILTER BYPASS alert illuminates on the upper display unit. Prior to returning to the oil tank, the oil passes through the main engine oil cooler where it is cooled by engine fuel to maintain proper oil temperature.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 9

Continental

Rev. 11/15/02 #41

> >@ ENGINE FUEL AND OIL SYSTEM SCHEMATIC

ENGINES & APU Sec. 6.7 Page 10 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD ENGINE FUEL AND OIL SYSTEM SCHEMATIC

ENGINES & APU

737

Flight Manual ENGINE START SYSTEM

Sec. 6.7 Page 11

Continental

Rev. 11/15/02 #41

Pressurized air, a pneumatic starter, and electrical power are required for starter operation. The engines may be started with air from the APU, from a ground source, or by using engine crossbleed. >>@ The Engine Start Switch GRD position uses DC power from the battery bus to *command the engine bleed air valve closed, open the starter valve and allow pressure from the pneumatic manifold to rotate the starter. When the starter valve opens, the amber START VALVE OPEN light, located on the center instrument panel, illuminates. The starter is a turbine-type air motor which rotates the N2 compressor through the accessory drive gear system. When the engine has accelerated to 25% N2 RPM, and with the Engine Start Lever advanced to the IDLE position, which completes the ignition circuit, the MEC supplies fuel to the combustor and the fuel ignites, resulting in an engine start. At cutout speed (46% N2 RPM), power is interrupted to the start switch-holding solenoid, allowing the Engine Start Switch to return to the OFF position, *the engine bleed air valve to return to the selected position and the starter valve to close. During an engine shutdown, the start switch holding-solenoid is held in the cutout position until engine speed falls below 30% N2 RPM. The starter should not be re-engaged until engine speed has decreased below 20% N2 RPM.

BCD In the GRD position, the engine start switch uses battery power to close

the engine bleed air valve and open the start valve to allow pressure to rotate the starter. When the start valve opens, an amber START VALVE OPEN alert is provided on the upper display unit. The starter rotates the N2 compressor through the accessory drive gear system. When the engine accelerates to the recommended value (25% N2 or max motoring), moving the engine start lever to the IDLE position opens the fuel valves on the wing spar and engine, and causes the EEC to supply fuel (via the HMU) and ignition to the combustor where the fuel ignites. Initial fuel flow indications lag actual fuel flow by approximately two seconds, therefore, during engine start, an EGT rise may occur before fuel flow indication. At starter cutout speed (approximately 56% N2), power is removed from the start switch holding solenoid. The engine start switch returns to OFF, the engine bleed air valve returns to the selected position and the start valve closes. * On all B737 aircraft delivered after November 1988.

ENGINES & APU Sec. 6.7 Page 12 Rev. 11/15/02 #41

737 Continental

Flight Manual

Abnormal Start Protection (Ground Starts Only)

BCD During ground starts, the EEC monitors engine parameters to detect

impending hot starts, EGT start limit exceedances, and wet starts. These protection features do not function during inflight starts. If an impending hot start is detected by a rapid rise in EGT or EGT approaching the start limit, the white box surrounding the EGT digital readout flashes. The flashing white box resets when the start lever is moved to CUTOFF or the engine reaches the idle N2. If the EGT exceeds the starting limit, the EGT display, both box and dial, turn red. The EEC automatically turns off the ignition and shuts off fuel to the engine. The alert terminates and the display returns to white when EGT drops below the start limit. Following engine shutdown, the EGT box turns red to remind crew of the exceedance. A wet start occurs if the EGT does not rise after the start lever is moved to IDLE. If a wet start is detected, the EEC turns off the ignition and shuts off fuel to the engine 15 seconds after the start lever is moved to IDLE. IGNITION SYSTEM Two high energy AC systems are provided. With the Engine Start Switch in the GRD position, the starter valve opens, *the engine bleed air valve closes and the selected igniter(s) are energized when the engine start lever is placed to IDLE. The CONT position is used for takeoff and landing, and prior to turning on engine anti-ice. This affords extra protection, through the selected igniter(s) against flameout in the event that birds or ice are ingested, or inlet airflow is suddenly disrupted for any reason during the more critical stages of flight. The FLT position energizes both igniters when the engine start lever is placed to the IDLE position. It is used for air starts and for flight in severe turbulence, moderate to severe icing, and in moderate to heavy precipitation, hail or sleet. powered by the AC transfer bus, provides single high energy ignition to the left igniter. IGN R, powered by the AC standby bus, provides single high energy ignition to the right igniter. * On all B737-300/-500's delivered after November 1988.

IGN L,

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 13

Continental

Rev. 11/15/02 #41

BCD AUTO-RELIGHT

An auto-relight capability is provided for flameout protection. Whenever the EEC detects an engine flameout, both igniters are activated. A flameout is detected when an uncommanded rapid decrease in N2 occurs, or N2 is below idle RPM. INFLIGHT STARTING Two methods of starting an engine inflight are available, windmill and crossbleed.

BCD None of the ground start protection features are functional during inflight start.

Note: At low N2 values, the oil scavenge pump may not provide enough pressure to return oil to the tank, causing a low oil quantity indication. Normal oil quantity should be indicated after start.

If crossbleed starting is required, the X-BLD START indication is displayed above the N2 dial. This indication is based on aircraft altitude, airspeed and N2.

ENGINES & APU Sec. 6.7 Page 14 Rev. 11/15/02 #41

737 Continental

Flight Manual

> >@ ENGINE START AND IGNITION SYSTEM SCHEMATIC

AIR DRIVEN STARTER MANUAL CONTROL HANDLE

START VALVE OPEN

GRD

ENGINE BLEED AIR VALVE S STARTER VALVE

BATTERY BUS

OFF CONT FLT

SWITCH HOLDING RELAY

HIGH N 2 LOW N 2

STARTER CUTOUT SWITCH

FROM PNEUMATIC SYSTEM

COMBUSTOR

BOTH GRD OFF CONT IGN FLT IGN L R

ENGINE START

IDLE CUTOFF

MEC

1

FROM FUEL SYSTEM

GRD IGN L BOTH IGN R

AC TRANSFER BUS

OFF CONT FLT

IDLE CUTOFF

LEFT IGNITER

GRD

IGN L BOTH IGN R

RIGHT IGNITER IDLE CUTOFF CONDITION:

AC STANDBY BUS

OFF CONT FLT

BLEED AIR FUEL

37318003

ENGINE BEING STARTED N2 ROTATION BELOW STARTER CUTOUT SPEED.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 15

Continental

Rev. 11/15/02 #41

BCD ENGINE START AND IGNITION SYSTEM SCHEMATIC

ENGINES & APU Sec. 6.7 Page 16 Rev. 11/15/02 #41

737 Continental

Flight Manual

INTENTIONALLY LEFT BLANK

ENGINES & APU

737

Flight Manual THRUST REVERSER

Sec. 6.7 Page 17

Continental

Rev. 11/15/02 #41

Each engine is equipped with a hydraulically operated thrust reverser, consisting of left and right translating sleeves. Aft movement of the reverser sleeves causes blocker doors to deflect fan discharge air forward, through fixed cascade vanes, producing reverse thrust. The thrust reverser is for ground operations only and is used after touchdown to slow the aircraft, reducing stopping distance and brake wear. Hydraulic pressure for the operation of engine No. 1 and engine No. 2 thrust reversers comes from hydraulic systems A and B, respectively. If hydraulic system A or B fails, alternate operation for the affected thrust reverser is available through the standby hydraulic system. When the standby system is used, the affected thrust reverser will deploy and retract at a slower rate and some thrust asymmetry can be anticipated. The thrust reverser can be deployed when either radio altimeter senses less than 10 feet altitude, or when the air / ground safety sensor is in the ground mode. Movement of the reverse thrust levers is mechanically restricted until the forward thrust levers are in the IDLE position. When reverse thrust is selected, an electro-mechanical lock releases, the isolation valve opens and the thrust reverser control valve moves to the deploy position, allowing hydraulic pressure to unlock and deploy the reverser sleeves. An interlock mechanism restricts further movement of the reverse thrust lever until the reverser sleeves have approached the deployed position. When either reverser sleeve moves from the stowed and locked position, the REVERSER UNLOCKED light, located on the Center Instrument Panel, illuminates. As the thrust reverser reaches the deployed position, the Reverse Thrust Lever can be raised to detent No. 2. This position provides adequate reverse thrust for normal operations. When necessary, the reverse thrust lever can be pulled beyond detent No. 2, providing maximum reverse thrust. Downward motion of the Reverse Thrust Lever past detent No. 1 will command the reverser to stow. Once the thrust reverser is commanded closed, the control valve moves to the stow position allowing hydraulic pressure to stow and lock the reverser sleeves. After the thrust reverser is stowed, the electro-mechanical lock engages and the isolation valve closes. The REVERSER light, located on the Aft Overhead Panel, illuminates when the thrust reverser is commanded to stow and extinguishes 10 seconds later when the isolation valve closes. Any time the REVERSER light illuminates for more than approximately 12 seconds, a malfunction has occurred and the MASTER CAUTION and ENG SYSTEM annunciator lights illuminate.

ENGINES & APU Sec. 6.7 Page 18 Rev. 11/15/02 #41

737 Continental

Flight Manual

When the reverser sleeves are in the stowed position, an electro-mechanical lock and a hydraulically operated locking actuator inhibit motion of each reverser sleeve until reverser extension is selected. Additionally, an auto-restow circuit compares the actual reverser sleeve position and the commanded reverser position. In the event of incomplete stowage or uncommanded movement of the reverser sleeves toward the deployed position, the auto-restow circuit will open the isolation valve and command the control valve to the stow position directing hydraulic pressure to stow the reverser sleeves. Once the auto-restow circuit is activated, the isolation valve remains open and the control valve is held in the stowed position until the thrust reverser is deployed or until corrective maintenance action is taken.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 19

Continental

Rev. 11/15/02 #41

THRUST REVERSER SCHEMATIC

ENGINES & APU Sec. 6.7 Page 20 Rev. 11/15/02 #41 AIR BLEED SYSTEM Compressor Section The N1 compressor, or booster section, produces low temperature, low pressure air and delivers it to the N2 compressor which produces high temperature, high pressure air. The single stage fan, which is an extension of the first stage of compression, produces very large volumes of bypass air. Each compressor section is driven by its own separate turbine at its own best speed. The high pressure compressor (N2) is governed by the MEC / EEC while the fan and low pressure compressor (N1) is driven by its turbine and is free to select the best speed to ensure optimum airflow. This airflow matching feature allows the compressor sections to adjust themselves automatically throughout the operating range of the engine. It also minimizes interstage bleeding preventing stalls and surges, and with the front and rear rotor sections working in harmony, the compression ratio can be increased without decreasing efficiency. Fan Bypass / Bleed Air Fan bypass air is used for thrust reversal, generator drive and generator cooling as well as bleed air cooling. Fifth stage bleed air is used for the Environment Control and Anti-Ice systems. However, at low thrust settings, fifth stage air pressure is inadequate, so ninth stage bleed air is used. When fifth stage air pressure becomes adequate, a crossover from ninth to fifth stage air is made.

FAN AIR GENERATOR DRIVE AND GENERATOR COOLING AIR CONDITIONING PRECOOLER

737 Continental

Flight Manual

5TH STAGE OR 9TH STAGE BLEED AIR AIR CONDITIONIING & WING ANTI-ICE ENGINE ANTI-ICE HYDRAULIC SYS TANK PRESSURE WATER SYSTEM PRESSURE

37318005

AIR BLEED SYSTEM

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 21

Continental

Rev. 11/15/02 #41

> >@ ENGINE AND FUEL FLOW INDICATORS

ENGINES & APU Sec. 6.7 Page 22 Rev. 11/15/02 #41 <

REVERSER UNLOCKED

737 Continental

Light (amber) Flight Manual

Illuminated ­ Indicates the thrust reverser is unlocked. =

N1 RPM

Indicator

· ·

Indicates fan speed in percent of RPM. Used as the primary thrust setting reference.

> N1 Manual Set Knob Push In ­ The cursor is set by input signal from the Flight Management Computer (FMC). · The lower digital display is blank.

Pull Out ­ Disables the FMC input signal. Rotate ­ Sets the desired N1 RPM in the lower digital display. · The cursor moves to the corresponding position on the outer scale. ? Warning Light (red) Illuminated ­ Indicates the limit for the engine parameter displayed has been reached or exceeded. · Remains illuminated until the engine parameter is reduced below the limit.

@ Exhaust Gas Temperature (EGT) Indicator · A · B Indicates turbine exhaust gas temperature in degrees C. Indicator

N2 RPM

Indicates high pressure compressor speed in percent of RPM. Switch (spring loaded to the RATE position)

FUEL FLOW RESET

­ Resets the fuel used display on both Fuel Flow Indicators to zero.

RATE ­

The digital display on both Fuel Flow Indicators shows rate of fuel consumption. ­ The digital display on both Fuel Flow Indicators shows total fuel consumed per engine since last reset.

USED

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 23

Continental

Rev. 11/15/02 #41

C Fuel Flow (RATE / USED) Indicator Pointer ­ Indicates the RATE of fuel flow in pounds per hour X 1000 at all times. Digital Display ­ With the FUEL FLOW switch in the RATE position, indicates rate of fuel flow in pounds per hour X 1000. · · With the FUEL FLOW switch held in the USED position, indicates the amount of fuel used in pounds X 1000 since last reset. With the FUEL FLOW switch held in the RESET position, the fuel USED display returns to zero.

ENGINES & APU Sec. 6.7 Page 24 Rev. 11/15/02 #41

737 Continental

Flight Manual

> >@ ENGINE OIL AND VIBRATION INDICATORS

ENGINES & APU

737

Flight Manual < Oil Quantity Test Switch

Sec. 6.7 Page 25

Continental

Rev. 11/15/02 #41

Press ­ Oil Quantity Indicators move toward zero during test. =

START VALVE OPEN

Light (amber)

Illuminated ­ Indicates the engine starter valve is open and air is being supplied to the air driven starter. >

OIL FILTER BYPASS

Light (amber)

Illuminated ­ Indicates an impending bypass of the scavenge oil filter. ?

LOW OIL PRESSURE

Light (amber)

Illuminated ­ Indicates engine oil pressure is at or below the red radial. @ Oil Pressure Indicator · · Indicates engine oil pressure in psi. The yellow band is only valid at takeoff thrust. Oil pressure is unregulated and is primarily a function of engine speed (N2).

Note:

A Oil Temperature Indicator · B · · · Indicates engine oil temperature in degrees C. Indicator

OIL QUANTITY

Indicates engine oil quantity in gallons.

C Airborne Vibration Monitor Indicates engine vibration level in the fan section of the engine.

D Off Index Mark (blue) Indicator pointer moves to the Off Index Mark if the system is inoperative.

ENGINES & APU Sec. 6.7 Page 26 Rev. 11/15/02 #41

737 Continental

Flight Manual

> >@ ENGINE START SWITCHES

< Engine Start Switch

GRD

­ (solenoid held, spring-loaded to OFF) Opens the starter valve. Closes the engine bleed air valve. Provides high energy ignition to the selected igniter(s) when the Engine Start Lever is moved from CUTOFF to IDLE. ­ No Ignition.

· ·

OFF

­ Provides high energy ignition to the selected igniter(s) with the Engine Start Lever in IDLE.

CONT

­ Provides high energy ignition to both igniters when the Engine Start Lever is in IDLE.

FLT

·

The Ignition Select Switch is bypassed when the Engine Start Switch is in FLT.

= Ignition Select Switch

IGN L BOTH IGN R

­ Selects the left igniter for use on both engines. ­ Selects both igniters for use on both engines. ­ Selects the right igniter for use on both engines.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 27

Continental

Rev. 11/15/02 #41

> >@ ENGINE REVERSER, PMC AND LOW IDLE

<

REVERSER

Light

Illuminated ­ One or more of the following has occurred: · · · The isolation valve or the thrust reverser control valve is not in the commanded position. The thrust reverser sleeve position sensors are in disagreement for more than two seconds. The auto-restow circuit has been activated.

= Power Management Control (PMC) Switch

ON

­ (ON in view ­ white) Indicates the PMC is selected ON.

INOP (INOP

in view ­ amber) Indicates the PMC is inoperative when engine speed is above 46% N2, or the PMC is selected OFF. >

LOW IDLE

Light (amber)

Illuminated ­ The thrust lever for either engine is near idle and the MEC on either engine is not commanded to maintain high idle RPM inflight. · The speed of either engine is below 25% N1 inflight.

If an Engine Start Lever is in CUTOFF, the light is deactivated.

ENGINES & APU Sec. 6.7 Page 28 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD PRIMARY AND SECONDARY ENGINE INDICATIONS

< Primary Engine Indications = Fuel Quantity Indications Refer to Section 6.12, Fuel. > Secondary Engine Indications ? Hydraulic Indications Refer to Section 6.13, Hydraulics.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 29

Continental

Rev. 11/15/02 #41

BCD AUTOTHROTTLE LIMIT, THRUST MODE DISPLAY AND

TOTAL AIR TEMPERATURE

< Autothrottle Limit (A/T LIM) Indication Illuminated (white) ­ The FMC is not providing the A/T system with N1 limit values. The A/T is using a degraded N1 thrust limit from the related EEC. = Thrust Mode Display Displayed (green) ­ The active N1 limit reference mode. With N1 manual select knob on engine display control panel in AUTO, active N1 limit is displayed by reference N1 bugs. Active N1 limit is normally calculated by FMC. Thrust mode display annunciations are: · · · · · · · ·

R-TO

­ reduced takeoff ­ reduced climb TO ­ takeoff CLB ­ climb CRZ ­ cruise G/A ­ go-around CON ­ continuous ---- FMC not computing thrust limit

R-CLB R-TO does not indicate the type of reduced takeoff. The N1 limit may be reduced due to the entry of an assumed temperature, a takeoff thrust derate or a combination of both assumed temperature and takeoff thrust derate.

Note:

> Total Air Temperature (TAT) Indication Displayed (label ­ cyan, temp ­ white) ­ total air temperature (degrees C).

ENGINES & APU Sec. 6.7 Page 30 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD N1 INDICATIONS

<

N1 SET AUTO

Outer Knob

­

· · · ·

1

Both reference N1 bugs set by FMC based on N1 Limit page and Takeoff Reference page. Displays reference N1 bugs at active N1 limit for A/T. ­ Both reference N1 bugs and readouts manually set by turning N1 SET inner knob. Has no effect on A/T operation. or 2 ­ Respective N1 reference bug and readout manually set by turning N1 SET inner knob. Has no effect on A/T operation. Inner Knob (spring-loaded to center)

BOTH

· · =

N1 SET

Rotate ­ Positions reference bugs N1 bug(s) and readouts when N1 SET outer knob is set to BOTH, 1, or 2. > Reference N1 Bugs Displayed (green) ­ With N1 SET outer knob in AUTO, 1, 2 or BOTH position. ? N1 Redlines Displayed (red) ­ N1% RPM operating limit.

ENGINES & APU

737

Flight Manual @ N1 Command Sectors

Sec. 6.7 Page 31

Continental

Rev. 11/15/02 #41

Displayed (white) ­ Momentary difference between actual N1 and value commaned by thrust lever position. A N1 RPM Readouts (digital) Displayed (white) ­ Normal operating range. Displayed (red) ­ · · Operating limit exceeded. On ground after engine shutdown, red box indicates an inflight exceedance has occurred.

B Reference N1 Readouts Displayed (green) ­ Manually set N1% RPM: · · · Set with N1 SET inner knob when N1 SET is in BOTH, 1, or 2 position. Blank when N1 SET outer knob in AUTO position. ---- When N1 SET outer knob in AUTO and FMC source invalid.

C N1 RPM Indications Displays N1% RPM: · · Displayed (white) ­ Normal operating range. Displayed (red) ­ Operating limit exceeded.

ENGINES & APU Sec. 6.7 Page 32 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD THRUST REVERSER INDICATIONS

< Thrust Reverser (REV) Indications Displayed (amber) ­ Thrust reverser is moved from stowed position. Displayed (green) ­ Thrust reverser is deployed.

BCD THERMAL ANTI-ICE INDICATION

< Thermal Anti-Ice (TAI) Indications Displayed (green) ­ Cowl anti-ice valve(s) open. Displayed (amber) ­ Cowl anti-ice valve is not in position indicated by related engine anti-ice switch.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 33

Continental

Rev. 11/15/02 #41

BCD EGT INDICATIONS

< Exhaust Gas Temperature (EGT) Redlines Displayed (red) ­ Maximum takeoff EGT limit. = Exhaust Gas Temperature (EGT) Amber Bands Displayed (amber) ­ Lower end of band displays maximum continuous EGT limit. > Exhaust Gas Temperature (EGT) Start Limit Lines Displayed (red) ­ N2 less than 50%. ? Exhaust Gas Temperature (EGT) Readouts (digital) Displayed (white) ­ Normal operating range (degrees C).

BC

Displayed (amber) ­ Maximum continuous limit exceeded; color change inhibited for up to 5 minutes during takeoff or go-around.

D

Displayed (amber) ­ Maximum continuous limit exceeded. · · Color change inhibited for up to 5 minutes during takeoff or goaround (normal operation). Color change inhibited for up to 10 minutes during takeoff or goaround (when an engine out condition occurs within the first 5 minutes of the inhibit).

Displayed (red) ­ Maximum takeoff limit or start limit exceeded.

ENGINES & APU Sec. 6.7 Page 34 Rev. 11/15/02 #41

737 Continental

Flight Manual

On ground, after engine shutdown, red box indicates an exceedance has occurred. EEC senses conditions that may lead to hot start during ground starts (blinking white box). @ Exhaust Gas Temperature (EGT) Indications Displayed (white) ­ Normal operating range.

BC

Displayed (amber) ­ Maximum continuous limit exceeded; color change inhibited for up to 5 minutes during takeoff or go-around.

D

Displayed (amber) ­ Maximum continuous limit exceeded. · · Color change inhibited for up to 5 minutes during takeoff or goaround (normal operation). Color change inhibited for up to 10 minutes during takeoff or goaround (when an engine out condition occurs within the first 5 minutes of the inhibit).

Displayed (red) ­ Maximum takeoff limit of start limit exceeded.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 35

Continental

Rev. 11/15/02 #41

BCD ENGINE FAIL ALERT

< Engine Fail (ENG FAIL) Alert Displayed (amber) ­ · · · · · Engine N2 below sustainable idle (less than 50%); and Engine start lever in IDLE position.

Alert remains until ­ Engine N2 above sustainable idle (50% or greater); or Start lever moved to CUTOFF; or Engine fire warning switch pulled.

ENGINES & APU Sec. 6.7 Page 36 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD N2 INDICATIONS

< N2 Redlines Displayed (red) ­ N2% RPM operating limit. = N2 RPM Indications Displays N2% RPM · · Displayed (white) ­ Normal operating range. Displayed (red) ­ Operating limit exceeded.

> N2 Readouts (digital) Displayed (white) ­ Normal operating range. Displayed (red) ­ · · Operating limit exceeded. On ground, after engine shutdown, red box indicates an inflight exceedance has occurred.

BCD CROSSBLEED START INDICATION

< Crossbleed (X-BLD) START Indication Displayed (magenta) ­ Crossbleed air recommended for inflight start. Displayed when airspeed is less than required for a windmilling start.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 37

Continental

Rev. 11/15/02 #41

BCD FUEL FLOW / FUEL USED INDICATIONS

<

FUEL FLOW RATE ­ USED

Switch (spring-loaded to RATE)

Displays fuel flow to engine.

­

· · ·

Pointer and shading are removed. Displays fuel used since last reset. After 10 seconds, display automatically reverts to fuel flow. Note: If switch is activated longer than 30 seconds, fuel used readout is deactivated for remainder of flight.

RESET

­

· · ·

Pointer and shading are removed. Resets fuel used to zero. Displays fuel used momentarily, decreases to zero, then displays fuel flow.

= Fuel Flow (FF) Readout (digital) Displayed (white) ­ Fuel flow to engine with FUEL FLOW switch in RATE position (pounds per hour x 1000). > Fuel Flow (FF) Dial / Index Markers & Digits (white) Displayed (white) ­ Fuel flow to engine with FUEL FLOW switch in RATE position (pounds per hour x 1000). ? Fuel Used (FU) Readout (digital) Illuminated (white) ­ Displayed when FUEL FLOW switch moved to USED or RESET .

ENGINES & APU Sec. 6.7 Page 38 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD CREW ALERTS

<

START VALVE OPEN

Alert Illuminated (amber) ­ · · Steady ­ Respective engine start valve open and air is supplied to starter. Blinking ­ Uncommanded opening of start valve. Alert is displayed and solid amber boxes are displayed in unannunciated positions for that engine. All three boxes blink for 10 seconds, then alert remains on steady and solid amber boxes are removed. (See Note)

=

Alert Illuminated (amber) ­

LOW OIL PRESSURE

· ·

Steady ­ Oil pressure at or below red line. Blinking ­ With a condition of low pressure. Alert is displayed and solid amber boxes are displayed in unannunciated positions for that engine. All three boxes blink for 10 seconds, then alert remains on steady and solid amber boxes are removed. (See Note)

>

OIL FILTER BYPASS Alert Illuminated (amber) ­

· ·

Steady ­ Indicates an impending bypass of scavenge oil filter. Blinking ­ With an impending bypass. Alert is displayed and solid amber boxes are displayed in unannunciated positions for that engine. All three boxes blink for 10 seconds, then alert remains on steady and solid amber boxes are removed. (See Note) Note: Blinking is inhibited: · · · During takeoff from 80 knots to 400 feet RA, or 30 seconds after reaching 80 knots, whichever occurs first. During landing below 200 feet RA until 30 seconds after touchdown. During periods when blinking is inhibited, alerts illuminate steady.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 39

Continental

Rev. 11/15/02 #41

BCD ENGINE OIL INDICATIONS

< Oil Pressure (OIL P) Indication Displays engine oil pressure (psi). · · · Displayed (white) ­ Normal operating range. Displayed (amber) ­ Caution range. Displayed (red) ­ Operating limit reached.

= Low Oil Pressure (OIL P) Redline Displayed (red) ­ Oil pressure operating limit. > Low Oil Pressure (OIL P) Amber Band Displayed (amber) ­ Low oil pressure caution range beginning at red line: · · Variable depending on N2% RPM above 65% N2. Amber band not displayed below 65% N2.

? High Oil Temperature (OIL T) Redline Displayed (red) ­ Oil temperature operating limit. @ High Oil Temperature (OIL T) Amber Band Displayed (amber) ­ Oil temperature caution range.

ENGINES & APU Sec. 6.7 Page 40 Rev. 11/15/02 #41

737 Continental

Flight Manual

A Oil Temperature (OIL T) Indication Displays oil temperature (degrees C): · · · Displayed (white) ­ Normal operating range. Displayed (amber) ­ Caution range reached. Displayed (red) ­ Operating limit reached.

B Oil Quantity (OIL Q) % Readout Displays usable oil quantity as a percentage of full quantity. Note: Indicated oil quantity may decrease significantly during engine start, takeoff and climb out. If this occurs, engine operation is not impacted and the correct oil quantity should be indicated during level flight. An oil quantity indication as low as zero is normal if windmilling N2 RPM is below approximately 8%.

Note:

BCD ENGINE VIBRATION INDICATIONS

< Vibration (VIB) Pointer Displays (white) ­ Engine vibration level.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 41

Continental

Rev. 11/15/02 #41

BCD ENGINE START SWITCHES

<

ENGINE START GRD

Switches

­ Opens start valve. Closes engine bleed valve. For ground starts, arms selected igniter(s) to provide ignition when engine start lever is moved to IDLE. For inflight starts, arms both igniters to provide ignition when engine start lever is moved to IDLE. Releases to OFF at start valve cutout. ­ Ignition normally off. Both igniters are activated when engine start lever is in IDLE and: - - - An uncommanded rapid decrease in N2 occurs or, N2 is between 57% and 50 % or, In flight ­ N2 is between idle and 5%.

· · · · ·

OFF

· ·

CONT

­

· ·

FLT

Provides ignition to selected igniters when engine is operating and engine start lever is in IDLE. In flight ­ provides ignition to both igniters when N2 is below idle and engine start lever is in IDLE. ­ Provides ignition to both igniters when engine start lever is in IDLE.

= Ignition Select Switch

IGN L BOTH IGN R

­ Selects the left igniter for use on both engines. ­ Selects both igniters for use on both engines. ­ Selects the right igniter for use on both engines.

ENGINES & APU Sec. 6.7 Page 42 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD ENGINE PANEL

<

REVERSER

Lights

Illuminated (amber) ­ One or more of following has occurred: · · · · = Isolation valve or thrust reverser control valve is not in commanded position. One or more thrust reverser sleeves are not in commanded state. Auto-restow circuit has been activated. A failure has been detected in synchronization shaft lock circuitry. Lights

ENGINE CONTROL

Illuminate (amber) ­ Engine control system is not dispatchable due to faults in system. Light operates when: · · Engine is operating and, Aircraft on ground and: - - Below 80 kt prior to takeoff or, Approximately 30 seconds after touchdown.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 43

Continental

Rev. 11/15/02 #41

> Electronic Engine Control (EEC) Switches

ON

­ In view (white) Indicates normal control mode is selected. Engine ratings calculated by EEC from sensed atmospheric conditions and bleed air demand. When ON is not in view, the EEC has been manually selected to the alternate mode. ­ In view (amber)

· · ·

ALTN

· ·

Indicated EEC has automatically switched to alternate control mode or it has been selected manually.

EEC

provides rated thrust or higher. Both ON and ALTN may be in view if EEC has automatically switched to soft alternate mode. EGT limits must be observed in both normal and alternate control modes.

Note: Note:

ENGINES & APU Sec. 6.7 Page 44 Rev. 11/15/02 #41

737 Continental

Flight Manual

BCD ENGINE CONTROLS

< Forward Thrust Levers ­ · · Controls engine thrust. Cannot be advanced if the reverse thrust lever is in the deployed position.

= Reverse Thrust Levers ­ · · Controls engine reverse thrust. Cannot select reverse thrust unless related forward thrust lever is at IDLE. Reverse thrust lever is blocked at reverse idle position until related thrust reverser is more than 60% deployed. Movement of reverse thrust lever into reverse thrust engages locking pawl preventing forward thrust lever from moving. Terminating reverse thrust removes locking pawl and restores forward thrust lever movement ability.

Note: Note:

ENGINES & APU

737

Flight Manual > Engine Start Levers

IDLE

Sec. 6.7 Page 45

Continental

Rev. 11/15/02 #41

­ Energizes the ignition system. Electrically opens engine fuel shutoff valve in the wing leading edge, outboard of the pylon. Mechanically opens the Main Engine Control (MEC) shutoff valve. Energizes ignition system through EEC. Electrically opens spar fuel shutoff valve in the wing leading edge, outboard of the pylon. Electrically opens engine-mounted fuel shutoff valve via the EEC. ­

>>@ · · · · · ·

BCD

CUTOFF

>>@ · · · · Closes the engine fuel shutoff valve in the wing and the MEC shutoff valve. Ignition system is de-energized. Closes both spar and engine fuel shutoff valves. De-energizes ignition system.

BCD

ENGINES & APU Sec. 6.7 Page 46 Rev. 11/15/02 #41

737 Continental

Flight Manual

INTENTIONALLY LEFT BLANK

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 47

Continental

APU SYSTEM DESCRIPTION

Rev. 11/15/02 #41

GENERAL The Auxiliary Power Unit (APU) is a self-contained, gas turbine engine installed within a fireproof, sound-reducing compartment located in the tail of the aircraft. The APU supplies bleed air for the engine starting or air conditioning / heating. An AC generator provides an auxiliary AC power source. Exhaust gases are dumped overboard through a sound reducing, air cooled exhaust duct. >>@ Air for cooling and compression is routed to the APU through a diffuser duct from an automatically operated door located on the right side of the fuselage. Electrical power from the aircraft battery and fuel from the No.1 tank are used to start and operate the APU. The battery switch must be on for all APU starts and for all ground operations. Positioning the battery switch to OFF, while the aircraft is on the ground, will cause an automatic shutdown. In flight, positioning the battery switch to OFF after APU start causes no automatic shutdown.

BCD

Air for compression routes to the APU through an automatically operated air inlet door located on the right side of the fuselage. Air for APU cooling enters through a cooling air inlet above the APU exhaust outlet. This air circulates through the APU compartment, passes through the oil cooler and vents through the exhaust outlet. Electrical power from No. 1 transfer bus or the aircraft battery and fuel from the left manifold are used to start the APU. With AC power available, the starter / generator uses AC power to start the APU. With no AC power the starter / generator uses battery power to start the APU. The start / generator only uses very high voltage 3 phase AC power therefore, the AC or DC sources must be converted to be compatible with the starter / generator. The battery switch must be on for all APU operations (start, ground, flight). Moving the battery switch to OFF (ground or flight) causes an automatic shutdown because of power loss to the Electronic Control Unit (ECU).

ENGINES & APU Sec. 6.7 Page 48 Rev. 11/15/02 #41

737 Continental

Flight Manual

ENGINES & APU

737

Flight Manual APU OPERATION

Sec. 6.7 Page 49

Continental

Rev. 11/15/02 #41

Engine speed and Exhaust Gas Temperature (EGT) are automatically controlled by the fuel control unit. Control air input is provided to the fuel control unit through a solenoid-operated three-way control valve. This enables the fuel control unit to maintain the required ratio of fuel flow to control air pressure. The control air pressure is changed by the combined acceleration / load control thermostat in response to EGT changes. When electrical load and bleed air extraction combine to raise the EGT above acceptable levels, the bleed air valve will modulate toward the closed position. In the event of an overtemperature, the bleed air valve will close rapidly but the APU will continue to run without initiating an auto shutdown. >>@ APU starts and operates up to its maximum altitude of 35,000 ft. The APU can supply bleed air for a single air conditioning pack on the ground or in flight. Both generator busses can be powered from the APU generator on the ground but only one generator bus may be powered in flight. One electrical bus and one air conditioning pack may be powered up to 10,000 ft. One electrical bus or one air conditioning pack may be powered from 10,000 ft. to 17,000 ft. One electrical bus only may be powered from 17,000 ft. to 35,000 ft.

BCD

The APU starts and operates up to the aircraft maximum certified altitude of 41,000 ft. The APU supplies bleed air for both air conditioning packs on the ground and one pack in flight. Both transfer busses can be powered on the ground or in flight. Both electrical power and bleed air are supplied up to a maximum altitude of 10,000 ft. Bleed air alone can be supplied up to 17,000 ft. Electrical power alone can be supplied up to 41,000 ft.

ENGINES & APU Sec. 6.7 Page 50 Rev. 11/15/02 #41 APU START The automatic start sequence begins by moving the APU switch momentarily to START from the OFF position. This initiates opening of the air inlet door. When the APU inlet door reaches the full open position the start sequence begins. After the APU reaches the proper speed, ignition and fuel are provided. When the APU is ready to accept a bleed air or electrical load the APU GEN OFF BUS light illuminates. If the APU does not reach the proper speed with the proper acceleration rate within the time limit of the starter, the start cycle automatically terminates. >>@ The start cycle may take as long as 135 seconds. If the start fails or the APU GEN OFF BUS light fails to illuinate by the end of the start cycle, a system failure has occurred and the OVERSPEED light illumiantes. BCD The start cycle could take as long as 120 seconds. If the start fails or the APU GEN OFF BUS light fails to illuminate by the end of the start cycle, a system failure has occurred and the FAULT light illuminates. Operate the APU for one full minute before using it as a bleed air source. This one-minute stabilization is needed to extend the service life of the APU. APU FUEL Fuel to start and operate the APU comes from the left side of the fuel manifold when the AC fuel pumps are operating. If the AC fuel pumps are not operating, fuel is suction fed from the No. 1 tank. During APU operation, fuel is automatically heated to prevent icing. With the APU operating and AC electrical power on the aircraft busses, operate at least one fuel boost pump to supply fuel under pressure to the APU. APU SHUTDOWN >>@ Operate the APU for one full minute with no bleed air prior to shutdown. This cooling period is needed to extend the service life of the APU. BCD When the APU switch is moved to OFF, a 60-second time delay is met automatically. Moving the APU switch to OFF trips the APU generator, closes the APU bleed air valve and extinguishes the APU GEN OFF BUS light. An immediate shutdown can also be accomplished by pulling the APU fire switch.

737 Continental

Flight Manual

ENGINES & APU

737

Flight Manual APU COMPONENTS

Sec. 6.7 Page 51

Continental

Rev. 11/15/02 #41

>>@ Automatic protection for EGT exceedance, overspeed, high oil temperature, low oil pressure, and other system faults is provided by a three way control valve, speed switches, pressure switches, and fuel control unit.

BCD An Electronic Control Unit (ECU) monitors and controls the APU. Automatic shutdown protection is provided for overspeed conditions, low oil pressure, high oil temperature, APU fire, fuel control unit failure, EGT exceedance, and other system faults monitored by the ECU. The ECU automatically controls APU speed through the electronic fuel control. If speed or EGT exceed acceptable levels with the APU providing electrical load only, some electrical load is shed. When electrical load and air extraction raise the EGT above acceptable levels during engine starting, electrical load shedding occurs prior to reducing bleed air. When electrical load and air extraction raise the EGT above acceptable levels other than during engine starting, the inlet guide vanes move toward a closed position, reducing bleed air extraction while maintaining electrical load.

APU AUTOMATIC LOAD SHEDDING > No automatic galley load shedding provided.

>@ Galley electrical loads will automatically be shed should the total aircraft electrical power requirements exceed design limits with only the APU generator providing electrical power. The galley power switch will trip to the OFF position. BCD In flight, if the APU is the only source of electrical power, all galley busses are automatically shed. If electrical load still exceeds design limits, both main busses automatically shed until the load is within design limits. On the ground, the APU attempts to carry a full electrical load. If an overload condition is sensed, the APU sheds galley busses first and then both main busses until the load is within limits.

ENGINES & APU Sec. 6.7 Page 52 Rev. 11/15/02 #41

737 Continental

Flight Manual

> >@ APU SCHEMATIC

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 53

Continental

Rev. 11/15/02 #41

APU CONTROLS AND INDICATORS >

ENGINES & APU Sec. 6.7 Page 54 Rev. 11/15/02 #41

737 Continental

Flight Manual

< APU LOW OIL QUANTITY / MAINT Light (blue) Illuminated ­ APU oil quantity is insufficient for extended operation. · Light is disarmed when the APU switch is in the OFF position.

= APU LOW OIL PRESSURE Light (amber) Illuminated ­ APU oil pressure is low causing the APU to initiate an automatic shutdown (after the start cycle is complete). · · Light is illuminated during start until the APU oil pressure is normal. Light is disarmed when the APU switch is in the OFF position.

> APU HIGH OIL TEMP / FAULT Light (amber) Illuminated ­ APU oil temperature is excessive, causing the APU to initiate an automatic shutdown. · Light is disarmed when the APU switch is in the OFF position.

? APU OVERSPEED Light (amber) Illuminated ­ APU speed is excessive, causing the APU to initiate an automatic shutdown. · · Light illuminates if an APU start is aborted prior to reaching governed speed, but extinguishes following a normal start. Light illuminated during APU shutdown indicates overspeed shutdown protection is lost.

@ APU Generator AC Ammeter · Displays APU generator load current.

A APU Switch ­ Normal position when the APU is not running. Positioning the switch to OFF with the APU running, initiates an APU shutdown.

OFF ON

­ Normal position with the APU running.

START

(Momentary) ­ Positioning the APU switch from OFF to START and releasing it to ON initiates an automatic start sequence.

ENGINES & APU

737

Flight Manual

Sec. 6.7 Page 55

Continental

Rev. 11/15/02 #41

BCD APU

< APU Maintenance (MAINT) Light Illuminated (blue) ­ APU maintenance problem exists: · · APU may be operated. Light is disarmed when APU switch is in OFF.

= APU Exhaust Gas Temperature (EGT) Indicator Displays APU EGT.

EGT

indicator remains powered for 5 minutes after shutdown.

ENGINES & APU Sec. 6.7 Page 56 Rev. 11/15/02 #41 > APU OVERSPEED Light Illuminated (amber) ­ · · · · APU RPM limit has been exceeded resulting in an automatic shutdown. Overspeed shutdown protection feature has failed a self-test during a normal APU shutdown. If light is illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes. Light is disarmed when the APU switch is in OFF position.

737 Continental

Flight Manual

? APU FAULT Light Illuminated (amber) ­ · · · A malfunction exists causing APU to initiate an automatic shutdown. If light is illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes. Light is disarmed when APU switch is in OFF position.

@ APU LOW OIL PRESSURE Light Illuminated (amber) ­ · · · · A

APU OFF

During start until the APU oil pressure is normal. Oil pressure is low causing an automatic shutdown (after start cycle is complete). If light is illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes. Light is disarmed when APU switch is in OFF position. Switch ­ Normal position when APU is not running. Positioning switch to OFF with APU running trips APU generator off the bus(es), if connected, and closes APU bleed air valve. APU continues to run for a 60 second cooling period. APU air inlet door automatically closes after shutdown. ­ Normal position when APU is running.

·

·

ON

(momentary) ­ Positioning APU switch from OFF to START and releasing it to ON, initiates an automatic start sequence.

START

737

Flight Manual

Continental

LIST OF EFFECTIVE PAGES

PAGE * * * * * * * * * * * * * * * * * * * * * * * * * * 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 DATE 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02

ENGINES & APU Sec. 6.7 LEP-1 Rev. 11/15/02 #41

PAGE

DATE

PAGE

DATE

* TOC-1 11/15/02 * TOC-2 11/15/02 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02 11/15/02

* LEP-1 * LEP-2

*

Asterisk indicates page(s) revised or added by the current revision.

ENGINES & APU Sec. 6-7 LEP-2 Rev. 11/15/02 #41

737 Continental

Flight Manual

INTENTIONALLY LEFT BLANK

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