Push and hold TEST (or SET/TEST) button, as applicable, on height indicator. Observe that height indicator indicates 100 |10 feet and warning flag appears on height indicator. IF -
NOTE: Antenna bonding problems usually cause a system to malfunction only during flight. The usual in-flight indications are intermittent warning flag and erratic (flickering) altitude indication from approximately 400 feet alti-tude to the pointer stow altitude. The system will usually self-test prop-erly during flight. On the ground, warning flag and altitude indication
will usually be normal. When antenna bonding is suspected as the cause ofthe system malfunction, refer to 34-33-03, LRRA Antennas - Approved Repairs.
Observe that rising runway display in ADI is retracted from view, and RWY flag is in view. IF -
NOT OK
OK ADI DISPLAY NOT CORRECT - Replace ADI (34-41-05) and perform specified test. Ref 34-31-00 A/T for ground test conditions that allow vertical movements of rising runway symbol on ADI.
EFFECTIVITY
CONFIG 1
AZ ALL
799 Page 102
IB 406-499
Apr 25/88
34-33-00
3. LRRA Systems No. 1 or 2 (Cont)
Release test button. Set DH index on height indicator to zero feet and press and hold test button again. Slowly move DH index up in altitude. Verify DH light (if not marked INOP) on height indicator and DH light on ADI illuminate when DH setting equals test altitude of 100 |10 feet. IF -
EFFECTIVITY
CONFIG 1
AZ ALL
799 Page 103
IB 406-499
Apr 25/88
34-33-00
4. _________________
LRRA System No. 3
Prepare system for trouble shooting as described in par. 2. At receiver-transmitter, press and hold TEST/STATUS switch/lamp and check that LRRA-3 annuncia-tor on center instrument panel P2 indicates red. Release switch and observe annun-ciator indicates black. IF -
NOT OK
Replace annunciator assembly. 3 indicator on P2 panel to change from red to black) -LRRA-3 ANNUNCIATOR FAILURE (indicated by failure of LRRA-transmitter (34-33-02) and perform specified test. IF -lamp to light when pressed) - Replace receiver-R-T FAILURE (indicated by failure of TEST/STATUS switch/
OK
System No. 3 is operative.
EFFECTIVITY
CONFIG 1
AZ ALL
799 Page 104
IB 406-499
Apr 25/88
34-33-00
PROCEDURE 1
EFFECTIVITY
CONFIG 1
AZ ALL
799 Page 105
IB 406-499
34-33-00
Apr 25/88
LRRA SYSTEM - TROUBLE SHOOTING
______________________________
1. General
_______
A. The following trouble shooting procedures are based on performance of the system operational test and are presented in tree-type format. The test steps (heavy-line boxes) are connected by shaded arrows to show the OK condition path. When all steps in the OK condition path check out, the system is operable.
B. When a test step does not check out, follow the NOT OK line to the box containing the trouble symptom. Turn to the procedure indicated and continue to follow a single line by analyzing the results of each test step until the required corrective action is determined. Perform the specified corrective action, then repeat the step at which the failure was encountered.
C. All trouble shooting procedures are based on the assumption that wiring is OK and that electrical power is available. If the corrective action in the procedure does not correct the problem, check wiring using the wiring diagram.
D. The trouble shooting procedures are for LRRA system No. 1 or LRRA system No. 2. Use the captain's instruments to check system No. 1 and the first officer's instruments to check system No. 2.
2. Prepare for Trouble Shooting
____________________________
A. Check that ALTM LOW R1 and R2 circuit breakers on overhead circuit breaker panel P7 are closed.
B. On SN 351-399,
check ALTM LOW R3 circuit breaker is closed.
C. Provide electrical power (Ref 24-22-00, Maintenance Practices [Apply Power]).
D. Operate equipment cooling system (Ref 21-58-00, Adjustment/Test
[Operational Test]).
E. On all LRRA height indicators except AF 121, 122 and 155-199, turn on LRRA-1 and LRRA-2 systems by rotating DH index control clockwise until release from off detent is ascertained. DH index should be at zero foot (or lower) position on dial.
EFFECTIVITY
AF ALL; SN 351-399; CONFIG 2 MD ALL; GN ALL; 09 Page 101 AT ALL: VM ALL Sep 25/94
34-33-00
Prepare system for trouble shooting as described in par. 2. Observe that height indicator pointer indicates between -3 and -11 feet and that warning flag is out of view. IF -
Press and hold TEST button on height indicator. Observe that height indicator altitude pointer indicates 100 |10 feet and height indicator warning flag appears. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航2(73)
