TM 1–1520–238–T–3
Change 5
23–1
CHAPTER 23
RADAR ALTIMETER (RADALT) MULTIPLEX READ CODES
FAILURE SYMPTOM INDEX
Symptom
Refer to paragraph
OFF FLAG IS VISIBLE AND RHI DOES NOT INDICATE 0 (–5/ +5) FEET . . .
23–1
VDU DISPLAY ALTITUDE LO WARNING IS NOT DISPLAYED . . . . . . . . . . . . .
23–3
VDU DOES NOT DISPLAY 1000 (–100/ +100) FEET . . . . . . . . . . . . . . . . . . . . .
23–5
VDU DISPLAY ALTITUDE HI WARNING IS NOT DISPLAYED . . . . . . . . . . . . .
23–7
Personnel Required:
(2)
References:
TM 9–1230–476–20–1
TM 11–1520–238–23–2
TM 11–1520–238–23–1
Equipment Conditions:
Ref
Condition
TM 11–1520–238–23–2
RADAR ALTIMETER –
MAINTENANCE
OPERATIONAL CHECK in
progress
NOTE
All multiplex read code responses are read from right to
left.
Multiplex read codes must be used in conjunction with
applicable Maintenance Operational Check (MOC) in
progress.
Multiplex read codes are observed on the HOD (ADC) or
CDU (ADD).
MULTIPLEX READ CODE INTERPRETATIONS
23–1 SIGNAL NAME:
PILOT RADALT CONT
MEMORY LOCATION: 000677
MEMORY DATA BIT(S):
19
(BINARY)
CONDITION:
(None)
SIGNAL FUNCTION:
Monitors radar altimeter (RADALT) ON/OFF status.
REMARKS: From FCC to receiver–transmitter.
PASS:
If first digit displayed on the HOD is 0, 2, 4, or 6, go to paragraph 23–2.
FAIL: Location of fault: remote height indicator (RHI), wiring from remote height indicator to
receiver–transmitter, receiver–transmitter. Troubleshoot wiring to isolate fault
(TM 11–1520–238–23–2).
