737 Flashcards
PTU
The PTU helps supply additional volume of hydraulic fluid needed to operate the autoslats and leading edge flaps and slats at the normal rate when system B engine-driven hydraulic pump volume is inoperative. The PTU uses system A pressure to power a hydraulic motor-driven pump, which pressurizes system B hydraulic fluid. The PTU operates automatically when all of the following conditions exist:
● System B engine-driven pump hydraulic pressure drops below limits.
● Airborne.
B737-700 ● Flaps are less than 15 but not up.
B737-800 ● Flaps not up.
Landing Gear Transfer Unit
The purpose of the landing gear transfer unit is to supply the volume of hydraulic fluid needed to raise the landing gear at the normal rate when system A engine-driven pump volume is lost. The system B engine-driven pump supplies the volume of hydraulic fluid needed to operate the landing gear transfer unit when all of the following conditions exist:
● Airborne.
● No. 1 engine RPM drops below a limit value.
● Landing gear lever is positioned UP.
● Either main landing gear is not up and locked
Standby Hydraulic System
● Thrust reversers
● Rudder
● Leading edge flaps and slats (extend only)
● Standby yaw damper
FEEL DIFF PRESS
Excessive differential hydraulic pressure is sensed in the elevator feel computer.
SPEEDBRAKES EXTENDED light
IN FLIGHT:
NG and MAX- The speed brake lever is beyond the ARMED position, and TE flaps extended more than flaps 10, or radio altitude less than 800 ft.
MAX- Thrust levers are above idle with the speed brake extended beyond the ARMED position
ON THE GROUND:
– SPEED BRAKE lever is in the DOWN detent, and
– Ground spoilers are not stowed
VOR, DME, and ILS Tests
VOR With a VOR frequency tuned and a course of 000 selected:
● VOR fail flag appears first, then functional test (FT) appears in outboard
display, upper outboard corner.
● Course deviation, bar scale, and TO/FROM indicator biases out of view.
● Course deviation, bar scale, and TO/FROM indicator re-appears.
DME
● Shows DME fail flag.
● DME displays dashes.
● Normal DME distance displayed.
ILS With an ILS tuned and a course selected within 90° of aircraft heading:
● G/S and LOC fail flags appear.
● Pointers display one dot up and one dot left.
● Pointers then display one dot low and one dot right.
● Pointers then return to normal.
Crew Oxygen Test
Audio Selector Panel ………………………………………… Set
Mask/Boom Switch (as installed) …………………………….. Mask
Note: If the audio control panel does not have the Mask/Boom switch, the
oxygen mask is activated with either the Reset/Test lever during the
test process, or when the O2 mask access panel doors are opened
during use.
Interphone Mic Select Switch ………………………………….. ON
Audio Selector Panel/Speaker Volume………………………… Adjust
Normal/100% Switch ……………………………………….. 100%
TEST/RESET Switch …………………………………. Push and Hold
Verify that the yellow cross shows momentarily in the flow indicator.
Emergency/Test Selector……………………………. Push and Hold
Continue to hold the TEST/RESET switch down and push the EMERGENCY/TEST
selector for five seconds. Verify that the yellow cross shows continuously
in the flow indicator.
Verify that crew oxygen pressure does not decrease more than 100 psi.
If the oxygen cylinder valve is not in the full open position, any of the
following can occur:
● Pressure can decrease rapidly
● Pressure can decrease more than 100 psi.
● Pressure can slowly increase back to normal.
Release the TEST/RESET switch and the EMERGENCY/TEST selector. Verify
that the yellow cross does not show in the flow indicator.
Push-to-Talk Switch………………………………………….. I/C
While holding the reset-test lever down and pushing the emergency/test
selector, simultaneously depress the push-to-talk switch and check an
oxygen flow sound through the flight deck loudspeaker or headset. Then
release all switches.
PSEU
Light:
● On the ground—
– A fault is detected in the PSEU, or
– An overwing exit flight lock fails to disengage when commanded
● In flight—
– Inhibited from thrust lever advance for takeoff until 30 seconds after landing
The PSEU monitors the following systems:
● Takeoff configuration warnings
● Landing configurations warnings
● Landing gear
● Air/ground sensing (6, 2 on each gear)
(+ Engine control, stall warning, anti-ice, cabin pressurization…)
The PSEU light, OVERHEAD system annunciator, and MASTER CAUTION light illuminate automatically for a single fault in certain redundant systems, also known as “simple fault.” However, in this case, these lights illuminate only after a landing. The PSEU light extinguishes when a parking brake is set, or when both engines are turned off.
Landing Gear Warning Horn
Gear not down & locked…
Depends on flap position, altitude and thrust lever angle
Cannot be silenced flaps greater than 10 or below 200
Nose Wheel Steering
NORM- hydraulic system A
ALT- hydraulic system B
Tiller: 78° turn
Rudder pedals: 7° turn
Alternate Brakes
If HYD SYS B fails, Hydraulic System A automatically supplies an alternate source of pressure for the main landing gear brakes.
Autobrakes INOP
Antiskid available, but paired wheels
Alternate brakes stop wheel rotation before gear retraction into wheel well
Brake Accumulator
Pre-charged to 1000 psi
HYD SYS B charges the accumulator to normal operating pressure 3000psi (3500 max psi)
Provides several brake applications or parking brake application
ANTISKID
When the system detects a skid, the associated antiskid valve reduces brake pressure until skidding stops.
NORM brakes: individual
ALT brakes: pairedg
Both normal and alternate brake systems provide:
- Antiskid
- locked wheel
- touchdown
- hydroplane protection.
Antiskid protection is available even with loss of both hydraulic systems.
ANTISKID INOP- Illuminated (amber)—A system fault is detected by antiskid monitoring system.
Autobrakes will also be INOP.
Speed trim
SPEED TRIM FAIL Indicates failure of a single FCC channel when MASTER CAUTION light recall is activated and light extinguishes when Master Caution System is reset.
designed to improve flight characteristics during operations with a low gross weight, aft center of gravity, and high thrust when the autopilot is not engaged.
trims the stabilizer using the autopilot stabilizer trim.
As the aircraft speed increases or decreases from the trimmed speed, the stabilizer is commanded in the direction to return the aircraft to the trimmed speed…this increases control column forces.
STS operates most frequently during takeoffs, climbs, and go-arounds.
Elevator Jam Landing Assist
MAX— When a jam occurs in the aft elevator control mechanism, both control columns have a limited range of motion. During approach and landing, the Elevator Jam Landing Assist System uses the flight spoilers for small changes to the flightpath. To activate the system: - switch ON - flaps extended - autopilot disengaged.
