B747 CHAPTER 32

32

1.               L/G USE HYD1, 4 BUT IF NOT AVAIL ALTERNATE EXTENSION SYS WHICH IT IS AN ELEC ACTUATOR UNLOCK AND L/G EXT BY GRAVITY

2.               NOSE AND BODY (DOORS AND GEARS) AND STEERING USE HYD1

3.               WING USE HYD4

4.               DOORS CAN RELEASE BY A CABLE  OPERATED BY A HANDLE

5.               STEERING IS MAX 7 DEG BY PEDAL AND 70 DEG BY TILLER

6.               STEERING USE HYD1 IF L/G LEVER DOWN

7.               BODY GEAR TURN IN OPPOSITE DIRECTION OF NOSE

8.               MAIN GEAR MUST TILT 7 DEG BY A POSITIONING ACTUATOR AFTER LIFT UP

9.               4 AMBER TILT LIT  ON P4 WILL ON IF ANY GEAR NOT TILT

10.            A PRESS REDUCING VLV IN BODY W/W REDUCES PRESS TO 2000 PSI TO ALLOW GEAR UN-TILT IN GND

11.          WING GEAR HAS A MECH LOCK TO ENSURE TILT IN HYD FAIL

12.          L/G IND:

                     GEAR DOWN LIT (GREEN): WILL ON IF ALL GEARS DOWN/LOCK 

                     GEAR LIT (RED): WILL ON IF DISCREPANCY BETWEEN HANDLE

                            AND GEARS POS ALSO IN TRANSITION

                     DOOR OPEN LIT (RED): WILL ON IF ANY DOOR OPEN

13.            THERE ARE 2 L/G SELECTOR VLV IN BODY W/W:

                                                                   R/H: FOR WING GEARS

                                                                   L/H: FOR NOSE, BODY AND STEERING

14.            L/G LEVER POS:

                           UP: IT’S LOCKED BY A SOLE, CAN BE UP IF TILT AND STRAIGHT

                           OFF: HYD CUT

                           DOWN: GEAR SELECTOR VLV OPERATED

15.            ALT GEAR EXT SW:

                                      EXT: MUST 5 TO 10 SEC HELD THEN ARM FOR MORE THAN 90 
                                               SEC TO ENSURE POWER APPLIED

                                      ARM: SPRING LOADED TO ARM

                                      OFF

16.            ALT WING L/G DO NOT EXT IF DOOR OPEN < 40 DEG

17.            ALT NOSE EXT DRIVE UNIT IS IN PRESS AREA (MEC)

18.            2 LOGIC MODULE FOR L/G (PRIMARY AND ALTERNATE) IN MEC ARE NOT I/W EACH OTHER AND USE SEPARATE SENSORS

19.            PROX SW’S GO TO PRIME MODULE EXCEPT NOSE LOCK

20.            REED SW’S GO TO ALT MODULE EXCEPT NOSE UPLOCK AND MAIN GEARS D/L

21.            HANDLE POS GOES TO PRIME MODULE ONLY

22.            GEAR RED LIT AND STEADY HORN IF GEARS NOT D/L IN LAND CONFIG (FLAP IN LAND RANGE AND THR LEVER IDLE)

23.            IN FLT BRAKE DONE BY HYD4 FROM METERING VLV IF LEVER UP

24.            IF PARK BRK ON A/S WILL OFF AND ITS S/O VLV CLOSED TO TRAP HYD FOR PEDAL LOCK

25.            BRK RESERVOIR USED FOR AUTO BRK AND TOUCH DOWN PROTECTION

26.            TOUCH DOWN PROTECTION: A/S GIVES FULL RELEASE TO PREVENT BRK AT T/D

27.            NORMAL BRK USES HYD4 AND RESERVE BRK USES HYD2

28.            BRK ACC IS ONLY ON HYD4