(10)
The monitor also provides a flag output signal. The flag signal is a stimulus for the flag alarm circuit which results in a shutter (flag) blocking the miles-to-go indicator.
(11)
The system also has an automatic standby feature which places it in the standby mode when a ground station is not available or when the ground station signal is too weak to be usable. When this occurs, the search operation stops, the transmitter is turned off, the dashed lines appear, and the system is in all respects in standby. When a usable ground station signal reappears, the system automatically starts operating.
(12)
With the function selector in VOR/ILS or DME, power is applied to the interrogator and normal search and measurement is performed to a maximum range of 390 nautical miles.
(13)
With the function selector in DME and the TEST switch depressed, a ground is applied to the BCD frequency converter which in turn appropriately programs the distance circuits.
(14)
The distance circuits measure the time between the interrogation and self-test reply pulse and apply appropriate distance information to the control circuits. The control circuits then develop the serial BCD word which is applied to the DME indicator.
(15)
When the test is activated, the DME indicator will display the following test sequences:
EFFECTIVITY LH 011-099;
AF 121-122, 152-199; AZ 221-299; IB 406-499; CONFIG 3 SN 351-399; AT, GN, MD, 01 Page 20 AND VM ALL Apr 25/95
34-55-00
(a)
On airplanes with 860E-3 interrogators installed; 1) The DME readout will show a flag for 1 second, then 2) The DME readouts will display dashes for 1 second, and then 3) The DME will lock on and the DME readouts will display
between 000.0 and 000.5 miles.
(b)
On airplanes with 860E-5 interrogators installed; 1) The DME readouts will show a flag for 2 seconds, then 2) The DME readouts will show dashes for 3 seconds, and then 3) The DME will lock on and the DME readouts will show between
000.0 and 000.5 miles.
D. Control
(1)
System power is applied by closing DME 1 or DME 2 circuit breakers on P7 panel.
(2)
The system then is tuned (using the VOR/DME frequency tuning controls) to a DME channel. The Mode switch is not connected to the DME system.
EFFECTIVITY
LH 011-099;
AF 121-122, 152-199; AZ 221-299; IB 406-499; CONFIG 3 SN 351-399; AT, GN, MD, 01 Page 21 AND VM ALL Apr 25/95
34-55-00
DME 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 to aid in rapid fault isolation. The test steps (heavy-line box) 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 and complete the test to check out the system.
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 either for DME system No. 1
(captain's) or DME system No. 2 (first officer's).
2. Prepare for Trouble Shooting
____________________________
A. Verify that all DME system circuit breakers on P7 panel are closed.
B. Place VHF NAV control panel switches as follows: Function Select - DME (ON XA ALL EXCEPT LH 011-030, 051-070, 082-099) Frequency Controls - 108-00 MHz
C. Apply electrical power. Refer to 24-22-00, Manual Control - Maintenance Practices (Apply Power).
NOTE: Allow 2-minute warmup.
____
EFFECTIVITY
ALL 12 Page 101 Aug 25/8134-55-00
On SN airplanes,
check for 094.5 |0.5 readout on captain's and first officer's
DME indicators.
On SN airplanes,
check for 094 readout on DME R/T unit range indicator.
T35312
EFFECTIVITY
LH 001-010, 031-050, 071-080; 799 Page 102
AF 101-171; AZ 201-220; IB 405;
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本文链接地址：747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航4(98)
