Boeing B737 Study Material

1. DIFFERENCES B737 CL & NG
Conversion Course
Jakub Muránsky
AirExplore

2. Airplane General, Emergency Equipment,
Differences- Principal Dimensions

3. Airplane General, Emergency Equipment,
Differences- Principal Dimensions

4. Airplane General, Emergency Equipment,
Differences
• gallies are powered from transfer busses rather than
generator busses
• hot water is now available in all lavatories
• interior and exterior forward airstairs control panels
• normal operation of the airstairs requires only AC
power

5. Lighting Systems
Retractable Landing Lights (NG)
Outboard lights (CL)
• Retractable landing lights have
been repositioned from the
outboard flap track fairing to
the lower fuselage
Logo Lights
• Logo lights have been
repositioned from each wingtip
to the top of each horizontal
stabilizer

7. Lighting Systems
Retractable lights (NG)
• RETRACT- outboard landing lights are
retracted and extinguished
• EXTEND - outboard landing lights are
extended and extinguished
• ON- outboard landing lights are
extended and illuminated
FIXED LANDING Light Switch (NG)
Inboard lights (CL)
• OFF- inboard landing lights are
extinguished
• ON-in board landing lights are
illuminated

8. Exits annunciatior panel
• On NG OVERWING EXIT light has been added
• Another procedure how to open overwing exit

9. Airplane General, Emergency Equipment,
Differences
Galleys
• Electricity for the galleys is supplied from the airplane transfer
buses
• 737-400 supplies it from the generator busses
• CAB/UTIL switch added
Water System
• The system is pressurized when the left engine or APU is
running on the ground or by either engine in flight
• Waste quantity indicator was added
• NG does not use filtered waste liquid for flushing

12. Airplane General, Emergency Equipment,
Differences
• Some external
hatches has been
changed

13. Airplane General, Emergency Equipment,
DifferencesForward Airstair
Interior Control
• An white STAIRS OPER light replaces an amber
STAIRS OPERATING light on the interior
control panel
• On NG normal operation requires only 15V
AC power
• On CL normal operation required both AC and
DC power
Exterior Control
• Normal mode - AC + DC power required
• Stby mode – DC power required

14. Pressurization System
• DCPCS instead of CPCS
• Modifications of the pressure controller schedule
and pressure relief valve values to compensate for a
new 41 ,000 foot certified ceiling
• Replacement of ADUs with ADIRUs
• The addition of a motorized overboard exhaust valve
• Modifications of the bleed air duct pressure indicator
and cabin/flight placard
• FLT/GND switch disappeared
• CAB ALT window has been removed

15. Pressurization System
Cabin Pressure Controller
• Cabin altitude is rate-controlled up to a cabin altitude of
8,000 feet at the airplane maximum certified ceiling of
41,000 feet
• The airplane maximum certified ceiling was 37,000 feet on
CL models
• The air data computers in earlier 737 models has been
replaced by ADIRU
• The ADIRUs provide ambient static pressure, baro corrected
altitude, non corrected altitude and calibrated airspeed to
both automatic controllers
• The ADIRUs receive barometric corrections from the
Captain's and First Officer's Barometric Reference Selectors

17. Pressurization System
Pressurization Outflow
• Cabin air outflow is controlled by the outflow valve and the
overboard exhaust valve
• The flow control valve has been replaced with a motorized
overboard exhaust valve

19. Pressurization System
• differential pressure of 8.35 psi above 37,000 feet has been
included to compensate for the increased maximum certified
ceiling of 41 ,000 feet
• The maximum differential pressure limit increased from
8.65psi to 9.1psi
• Deviations from flight altitude may cause the pressure
differential to go as high as 8.45 psi to maintain a constant
cabin altitude

20. Anti-Ice, Rain
• Replacement of the rain repellent bottled solution
with a permanent rain repellent coating on the
windows

21. Anti-Ice, Rain
Windshield Wiper Selector Panel
• Selectors functions the same as in earlier 737 models
however there are seperate selectors for each windshield
wiper

22. Anti-Ice, Rain
• Probe Heat Panel
• Switches and lights function the same as in earlier 737 models
however all reference to "Pitot Static Heat" is changed to
"Probe Heat„
• Auto function of probe heat switches
• CL models are equipped with 4 pitot probes and 6 static
probes
• NG models have 3 pitot probes and 6 static ports

23. Anti-Ice, Rain
• Probes and sensors have
been relocated and modified
• Pitot probes, the total air
temperature probe and the
alpha vanes are electrically
heated
• Static ports are not heated

27. Anti-Ice, Rain
• The amber COWL ANTI-ICE light illuminates only for excessive
pressure in the duct leading from the cowl anti-ice valve to
the cowl lip
• Temperature sensors found in prior models have been
removed
• Thermal Anti-Ice lndication on upper DU

28. Anti-Ice, Rain
• The wing anti-ice system does not include the leading edge
flaps or the new outboard leading edge slat
• WAI with/without GRD TEST

29. Automatic Flight
• Minimum speed reversion is
available in the 737-800
when the AlT is OFF and the
AFDS is in the ALT ACQ mode
• Minimum speed reversion is
not available in prior models
under these circumstances

30. Automatic Flight
• After lift-off, the AlT remains in THR HLD until 800
feet RA
• In prior models, the A/T remained in THR HLD until
400 feet RA was reached and approximately 18
seconds had elapsed since lift-off
• This does not allow A/T to move towards
commanded N1 if TO/GA was pressed bellow this
height
• A/T moves only reference bugs to GA N1

31. Electrical
Main architecture changes:
• replacement of the engine driven generators with
engine integrated drive generators (IDGs)
• new AC system architecture which permits power
sources to power transfer buses more directly
• the bus transfer system is replaced by a bus tie
system using bus tie breakers (BTBs)
• elimination of generator busses
• new DC system architecture

32. Electrical
• the following lights have been added
• an amber ELEC Light
• an amber TR UNIT Light
• an amber BAT DISCHARGE Light
• new standby system architecture
• APU capability of suppling both AC transfer busses in
flight
• generators come on line automatically if the APU is
either shut down or fails (automatic generator on-
line feature)

33. Engine Generators
• electrical power is provided by two engine integrated
drive generators (lDG)
• generator and drive in a common housing - no need
for a separate generator drive unit (CSD) found on
prior 737 models
• IDG supplies its own bus system in normal operation
and also supplies opposite side bus system loads
when one IDG is inoperative
• An amber DRIVE amber caution light has been added
• An integral electro-mechanical disconnect device
provides for complete mechanical isolation of the IDG

36. AC Power System
• APU generator can supply power to both AC transfer buses on
the ground or in flight
• A second AC ground service bus has been added
• bus tie breakers instead of alternate transfer relays
• Generator busses disappeared
• If the APU is either shutdown down or fails, the engine
generators will automatically be brought onto their respective
transfer buses

38. AC Power System
• single generator operation - system is designed to shed
electrical load incrementally based on actual load sensing
• APU is only source of electrical power - all galley busses will
automatically be shed

39. DC Power System
• the DC standby bus is powered directly from the TRs rather
than through DC bus 1 in normal operation
• transfer bus 1 is now a backup source of power for TR3
• A cross bus tie relay replaces the TR3 disconnect relay found
in prior models
• The external DC power receptacle found in prior models has
been removed

40. Standby Power System
• If the Standby Power Switch is in
the AUTO position, automatic
switching from normal power
sources to the altemate power
source is provided both in flight
and on the ground
• automatic switching from normal
to alternate power source occurs
if either AC transfer bus 1 or the
power source for DC bus 1 Ioses
power

42. Engines, APU
• CFM56-7 engines replace CFM56 -3 engines found on prior
models
• CFM56-7 engines produce 18,500 to 27,000 pounds of thrust
while CFM 56-3 engines produce 18,500 to 23,500 pounds of
thrust
• AXE NGs CFM56-7B26 can be drated for 26K, 24K and 22K
• AXE CL CFM56-3C22 has an option only for 22K rating
• CDS and DUs replaces all engine indications from prior models
• N1 set, fuel flow and MDF controls on engine display control
panel

44. Electronic Engine Control (EEC)
• two independent control channels and EEC automatically
switches channel if the operating channel fails
• N1 is used by the EEC to set thrust in two control modes:
normal and alternate
• uses sensed flight conditions and bleed air demand to
calculate N1 values
• compares commanded N1 to actual N1
• Additional ENGINE CONTROL and EEC lights on aft overhead
engine panel
• A dual-channel electronic engine control unit (EEC) regulates
each engine, performing the functions of the PMC used on
prior models, and additional functions not performed on prior
models

45. EEC
EEC functions include:
• providing abnormal ground start protection to include
protection for hot starts, EGT start limit exceedance and wet
starts
• monitors autothrottle and pilot inputs to set engine thrust
• supplying engine indications, except oil quantity and engine
vibration
• providing redline overspeed protection
• setting approach, flight minimum and ground idle
• arming the igniters selected by the ignition select switch
• operates in a normal, soft alternate and hard alternate mode

46. EEC
• On ground EEC monitors hot
starts, EGT start limit
exceedances, and wet starts
• Hot start – EGT box start to
flash, later becomes red
• Wet start – ignition is stopped
and fuel is stopped to flow
into engine after 15s

47. EEC Normal Mode
• uses sensed flight conditions and bleed air demand to
calculate N1 values
• compares commanded N1 to actual N1
• If the thrust lever is advanced to the forward stop, the
EEC limits thrust to the maximum certified thrust rating
for current conditions
• The EEC provides N1 and N2 redline overspeed
protection in both normal and alternate modes
• EEC does not provide EGT redline exceedance protection
• The EEC automatically selects ground minimum idle,
flight minimum idle, and approach idle

48. EEC Alternate Mode
• two alternate modes, soft or hard
• SOFT - ALTN switch illuminates and the ON indiction remains
visible. In the soft alternate mode, the EEC uses the last valid
flight conditions to define engine parameters. Thrust rating
shortfalls or exceedances may occur as flight conditions
change
• HARD - thrust is always equal to or greater than normal mode
thrust for the same lever position
• Maximum certified thrust rating can be exceeded

49. EEC Alternate Mode
• If hard mode is entered by reducing the thrust lever to idle
while in the soft alternate mode, both the ALTN switch
illuminates and the ON indication remains visible
• If ALTN is selected manually, the ON indication is blanked

50. Engines, APU
• the main engine control (MEC) has been replaced with a
hydro mechanical unit (HMU) which is controlled by the EEC
• an IDG fuel-cooled oil cooler has been added the fuell oil
system
• modification to the start and ignition system - starter cutout
speed increased to approximately 56%
• modification of the inflight start envelope

51. Engines, APU
• Pop-up feature if there is exceedance of parameters displayed
on the lower DU
• During battery start only N1, N2 and oil quantity are available
until EEC generator does reach speed of 15%
• ENG FAIL message is displayed if respective engine N2 drops
bellow 50% and start lever is in IDLE

52. Engine Fuel System
• Additional fuel spar shutoff valve
located at the engine mounting
wing stations and an engine fuel
shutoff valve
• SPAR VALVE CLOSED and ENG
VALVE CLOSED lights located on
the overhead panel

53. Engine Start System
• In flight two methods available: windmill and crossbleed
• X-BLD START indication is displayed above the N2 dial

54. APU
APU main differences:
• APU start and operation ceiling increased to 41,000 feet
• the APU can supply both transfer busses in flight
• the APU can supply both air conditioning packs on the ground
• power sources for APU start modified
• battery switch must be ON for APU operation on the ground
and in flight

55. APU
• DC operated fuel pump operates automatically during start
and APU operation when the APU fuel control unit senses low
pressure
• APU generator AC ammeter moved to electrical panel
• APU switch OFF position has an automatic 60 second
shutdown delay
• new electronic control unit (ECU)
• modified automatic load shedding logic

56. Fire Protection
• Fire switch closes both spar fuel shut-off valve and
engine fuel shut-off valve
• All other functions remain the same

57. Flight Controls
• flight spoilers have increased from two per wing to
four per wing
• ground spoilers have decreased from three per wing
to two per wing

58. Flight Controls
• LE slats have increased from three per wing to four per wing

59. Flight Controls
• an elevator transfer mechanism has been added
• In the event of an elevator jam, the transfer mechanism
allows the control columns to be physically separated
• Whichever column moves freely after the breakout will
provide adequate elevator control
• If the jam occurs during the takeoff or landing phase higher
forces are required to generate sufficient elevator control to
rotate for takeoff or flare for landing

60. Flight Controls
• a single electric motor is now used for autopilot and main
stabilizer trim controlled either by autopilot trim or stabilizer
trim switches
• On prior models, the autopilot trim and main trim each used a
separate motor

61. Flight Controls
• trim authority for each mode of trim has been modified as
follows:
• B737-800:
main electric trim:
flaps retracted: 3.95 – 14.5 units
flaps extended: 0.05 – 14.5 units
autopilot trim: 0.05 – 14.5 units
manual trim: -0.2 – 16.9 units

62. Flight Controls
• B737-400:
main electric trim:
flaps retracted: 2.8 – 12.5 units
flaps extended: 0.25 – 12.5 units
autopilot trim: 0.25 – 14.0 units
manual trim: 0 – 17.0 units

63. Flight Controls
• the airspeed range for speed trim has been modified from
100- 300 KlAS to 100 KlAS - Mach 0.50

64. Flight Controls
• a standby yaw damper system has been added
• Both yaw dampers are controlled through Stall Management
Yaw Damper (SMYD) computers
• main rudder power control unit (PCU) and standby rudder
PCU
• YAW DAMPER switch remains in the ON position until the B
FLT CONTROL switch is positioned to OFF or STBY RUD - then
the YAW DAMPER switch disengages and the YAW DAMPER
switch cannot be reengaged
• Can be reengaged during manual reversion and stby system
powers stby yaw damper

65. Flight Controls
• In prior models, gust damping
is not provided by the yaw
damper and all yaw damper
functions are lost with the loss
of hydraulic system B

66. Flight Controls
• stall management/yaw damper
(SMYD) computers have been added
which control primary and standby
yaw dampers

67. Flight Controls
• On prior models, if wheel spin up is not detected, the
speedbrake lever will move to the UP position and all spoilers
will deploy only after the right main landing gear strut
compresses
• On 737-800 if this occur the speed brake lever moves to the
UP position and flight spoiler panels deploy automatically
when the air/ground system senses the ground mode (any
gear strut compresses) When the right main landing gear strut
compresses, the mechanical linkage opens the ground spoiler
shutoff valve and the ground spoilers deploy

68. Flight Controls
• trailing edge flaps are now double slotted instead of triple
slotted

69. Flight Controls
• flap load relief has been added for the flaps 30 position
• When the flaps are set at 40 the TE flaps will:
retract to 30 if airspeed exceeds 163 knots
• reextend when airspeed is reduced below 158 knots
• When the flaps are set at 30 the TE tlaps will:
retract to 25 if the airspeed exceeds 176 knots
reextend when airspeed is reduced below 171 knots
• SFP option on NG

70. Flight Controls
• a flap/slat electronics unit (FSEU) has been added which
provides:
• trailing edge flap asymmetry and skew detection and
protection
• leading edge slat skew detection for slats 2 through 7
• There is no skew detection for the outboard slats 1 and 8, or
for the LE flaps

72. Flight Controls
• In prior models, asymmetry detection for TE flaps was
provided by a comparator in the flap gauge
• When the FSEU detects a TE asymmetry or skew condition the
FSEU:
• closes the TE bypass valve
• displays a needle split on the flap position indicator
• When the FSEU detects a LE skew, or a LE device does not
move to the commanded position, the LE FLAPS TRANSIT light
remains illuminated

73. Flight Controls
• uncommanded motion protection for leading and trailing
edge devices only for NG models
Leading Edge Uncommanded Motion
• In addition, to prevent uncommanded motion from occurring
on the LE devices during cruise, the FSEU maintains pressure
on the retract lines and depressurizes the Extend and Full
Extend lines

74. Flight Controls
• Trailing Edge Uncommanded Motion
• TE flaps:
• move away from the commanded position
• continue to move after reaching a commanded
position, or move in a direction opposite to that
commanded
• The FSEU shuts down the TE flap control by closing the flap
bypass valve
• The flap shutdown cannot be reset by the flight crew and they
must use the alternate flap system to control TE flaps
• The shutdown is indicated by the flap indicator disagreeing
with the flap lever position. There is no flap needle split

76. Flight Instruments and Displays
• DU and CSD replaces EIS and CRT indications

77. Flight Management, Navigation
• Magnetic variation between 82°N and 82°S is stored in each
IRS memory of 737-800
• On 737-400 magnetic variation between 73°N and 60°S is
stored in the IRS memory

78. Flight Management, Navigation
• Dual scanning DME, which was an option on 737-400, is
standard for 737-800
• This allows for removal of the AUTO/MANUAL switch from
VHF NAV tuning panel
• Dual scanning DME consists of two DME interrogators, each of
which rapidly altemates between the manually tuned
frequency (VOR/ILS) and an automatically tuned frequency
(for FMC use)

79. Flight Management, Navigation
• 737-the FMC receives fuel data from the fuel quantity
indicating system
• Fuel quantity values are displayed on the PERF INIT page and
on PROGRESS page 1/3

80. Flight Management, Navigation
• VNAV operation with an inoperative Fuel Quantity Indicating
System on NG:
• FMC uses the last known quantity for subsequent
performance data
• VNAV remains valid/engaged
• the CDU message "VERIFY GW AND FUEL" is displayed
• the fuel line on the PERF INIT page 1/2 changes to dashes
• MAN is shown by the fuel weight to indicate that fuel quantity
input is failed and data has to be entered manually
• the CDU message "VERIFY GW AND FUEL" is displayed every
30 minutes to remind the pilot to update fuel weight.

81. Flight Management, Navigation
• FMC Takeoff and Climb
• LNAV can be now selected on the ground
• displays a white LNAV on the FMA if within engagement
criteria (point within 5°of RWY HDG)
• LNAV couples to the flight plan at 50ft and bank is limited to
8° bellow 200ft and 30° above

82. Flight Management, Navigation
• FMC Cruise
• On NG models engine out information is now informative only
permitting VNAV operation with engine out
• Engine out entries cannot be executed
• On CL models execution after engine out entries made VNAV
inoperative

83. Flight Management, Navigation
VNAV Cruise and Speed Descent Profile
• OM-HEX - VNAV ALT mode feature
• VNAV SPEED mode is entered when in VNAV and above
computed profile
• On CL models VNAV PATH remains engaged and speed may
increase up to Vmo/Mmo

84. Flight Management, Navigation
CDU
• A NAV STATUS page has been added
• A NAV OPTIONS page has been
added
• Two GPS receivers installed making
GPS part of the FMC navigation
solution on NG models
• Dual FMC installed which permits
operation with the FMC as the sole
navigation source

85. Flight Management, Navigation
• Automatic V-Speed computation has been added
On OM-GEX:
• a PLAN/FUEL prompt allows fuel predictions, during preflight,
before actual fuel is known
• ABEAM POINTS prompt creates and displays points on the
new DIRECT-TO route which are abeam the wayponnts
bypassed by the route modifications

86. Fuel System
• On CL models center fuel pumps have check valve
commanded to open at lower pressure than maintank fuel
pumps
• On NG higher output pressure from center pumps is delivered
in order to deplete center tank first
• On NG spar fuel shutoff valves are located at the engine-
mounting wing stations and they are DC motor operated from
the hot battery bus
• Another logic for scavenge jet pump operation

87. Fuel System
• Overwing refueling caps have disappeared from NGs
• 25% increase in fuel tank capacity

88. Hydraulics
• Another refill limits
• There is only one standpipe in B reservoir on NG models
• Another limit for ballance line on NG and CL

89. Landing Gear
• Dual green lights indication on NG
• Viewers has been removed like could
be found on CL
• Antiskid control switch has been
removed
• Wheel well protection from spinning
wheel damage
• The autobrake system may be armed
after touchdown

90. Landing Gear
• Both normal and alternate brake systems provide skid, locked
wheel, touchdown and hydroplane protection
• Touchdown and Iocked wheel protection added to the
alternate brake system on NG models
• Autobrake disarm light logic has been changed during
unintentional setting RTO during landing

91. Landing Gear
• NG - The air/ground system receives logic signals from six
sensors, two on each landing gear
• CL - logic was received from a teleflex cable on the right main
landing gear and sensors located in the nose gear

92. Warning Systems
• Takeoff Configuration Warning
Another trigger feature has been addeed - Spoilers NOT down
with the speedbrake lever in the DOWN position

93. Warning Systems
• Landing Gear Configuration Warnings
• Thrust levers are retarded to idle, the landing gear indicator
lights will illuminate red only when RA is less than 800 feel
AGL
• Flaps 1 to 10 also requires a RA less than 800 feel AGL when
either or both thrust levers are near idle for the warning horn
to sound

94. Warning Systems
Proximity Switch Electronic Unit (PSEU) monitors the
following systems:
• Takeoff Configuration Warnings
• Landing Configurations Warnings
• Landing gear
• Air/ground sensing
The PSEU light is inhibited:
• in flight
• when the thrust lever is advanced forward
• for 30 seconds after landing

95. Warning Systems
• Mach/ Airspeed Warning System
• NG - ADIRUs transmit a signal to the aural warning module
which activates the clacker
• CL - the mach/airspeed warning system operated form a
mechanism internal to each pilot´s mach/airspeed indicator

96. Warning Systems
• Stall Warning System Inputs
• Allowance for anti-ice systems usage
• Minimum maneuvering speed, flap maneuvering speed

97. Warning Systems
• Some NG are equipped with predictive windshear function
coupled with weather radar
• In fleet OM-GEX, OM-HEX