TM 55-1520-240-T 18-2.3 ALTITUDE VOICE WARNING SYSTEM OPERATIONAL CHECK 18-2.3 INITIAL SETUP Applicable Configurations: References: All TM 11-1520-240-23 TM 55-1520-240-23 Tools: Electrical Repairer's Tool Kit, Equipment Condition: NSN 5180-00-323-4915 TM 55-1520-240-23: Battery Connected Materials: Electrical Power Off None Hydraulic Power Off Altitude Voice Warning System Visual Check Personnel Required: Performed (Task 18-2.2) Aircraft Electrician (2) TASK RESULT CHECK CIRCUIT BREAKERS 1.  Check that the following circuit breaker on If circuit breaker is open (1), close it. No.  1 pdp are closed: INTPH LH (1) 2.  Check that the following circuit breakers on If any circuit breaker is open (2 and 3), close it. No.  2 pdp are closed: INTPH RH (2) RAD ALT (3) 3.  Start APU.  Refer to task 15-1.4 APU ON capsule shall come on. CHECK AVWS OPERATION NOTE • The following checks will only cover the Altitude Voice Warning portion of the Radar Altimeter operation. For indication discrepancies, refer to TM 11-1520-240-23. • Ensure that the pilot, copilot, and aft interphone stations are all operational. 4.  With the pilot's Radar Altimeter (4) turned ON The  warning  message "ALTITUDE  LOW,  TOO and the OFF Flag (5) not visible, and with a LOW" should NOT be heard.  If this message is headset connected to the pilot's headset jack, heard, go to task 18-2.6. rotate the LO SET knob (6) to position the LO SET Index (7.) just above the OFF detent. Adjust the HI SET knob (8) to position the HI SET Index (9) at 100 feet. TASK RESULT 5.  Adjust the LO SET Index (7) to approximately the The warning message "ALTITUDE LOW, TOO LOW" 10 foot position on the indicator. shall be heard at FULL volume.  If this message is NOT  heard or volume is NOT FULL, go to task 18-2.4. 6.  Momentarily depress the PUSH-TO-TEST knob The volume of the low altitude warning message (6) once. shall decrease by one-half (1/2).  If volume stays full, or NOT heard at all, go to task 18-2.5. 7.  Reset the LO SET Index (7) to a point just above The low altitude warning message shall be heard at the OFF detent, wait 11 seconds, and return LO FULL volume.  If message is NOT heard at all, or if SET index to the 10 feet mark. volume is NOT full, go to task 18-2.4. 8.  Press and hold the PRESS-TO-TEST knob (8) to The warning message "ALTITUDE HIGH, CHECK activate the self-test. ALTITUDE" shall be audible at FULL volume.  If message is NOT heard, or if volume is NOT full, go to task 18-2.4. 9.  Release the PUSH-TO-TEST knob. The warning message "ALTITUDE LOW, TOO LOW" shall be again heard, at FULL volume.  If message is NOT heard, or if volume is NOT full, go to task 18-2.4. 10. Repeat steps 4 thru 9 with a headset connected    Results shall be as specified in steps 4 thru 9.  If to the copilot's headset jack. altitude   warning   messages   are   not   audible,   even   after replacing Radar Altimeter (4), go to task 18-2.4. 11. Repeat steps 4 thru 9 with a headset connected    Results shall be as specified in steps 4 thru 9.  If to the hoist operator's headset jack. altitude   warning   messages   are   not   audible,   even   after replacing Radar Altimeter (4), go to task 18-2.4. FOLLOW-ON MAINTENANCE: TM 55-1520-240-23: Battery Disconnected Electrical Power Off 18-52 Change 18