(b)
Make sure that these values show on the ECS area of the main EICAS:
~................................................ | CAB ALT | (present field elevation |500 ft) | .................................................. | LDG ALT | (any value) | .................................................. | RATE | 0 |200 ft/min | .................................................. | .P | 0 |0.4 psid | 2...........…....................................1
(c)
Apply vacuum at a rate of 2000 ft/min. 1) Make sure that the CAB ALT values increase. 2) Make sure that RATE is approximately 2000 ft/min. 3) Make sure that the .P values are negative and that they
increase.
(d)
Decrease the vacuum rate to 500 ft/min when the CAB ALT value becomes approximately 8000 ft. 1) Make sure that the CAB ALT value changes from white to
amber color at approximately 8500 ft.
2) Make sure that these occur when the CAB ALT value becomes 10,000 |300 ft: a) The aural warning siren starts. b) The master warning lights come on. c) The EICAS warning message CABIN ALTITUDE shows. d) The CAB ALT value changes from amber to red color.
3) Push either MASTER WARNING light to stop the siren.
(e) Stop the vacuum increase and then start the rate at -500 ft/min. 1) Make sure that these occur when CAB ALT becomes
approximately 9500 ft:
a) The EICAS warning message CABIN ALTITUDE does not show.
b) The CAB ALT value changes from red to amber color.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
21-31-00
ALL ú ú 01 Page 511 ú Oct 10/96
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
2) Make sure that the CAB ALT display changes from amber to white color when the CAB ALT value becomes approximately 8000 ft.
(f) Stop the vacuum decrease when CAB ALT reaches approximately 7000 ft.
J. Do the Cabin Altitude Sensors Disagreement Test
S 715-078
(1) Make sure that there is backup sensor failure indication:
(a)
Turn the valve on the vacuum harness to the closed position. This will make a seal of the vacuum to one of the cabin pressure controllers.
(b)
Apply vacuum at a rate of 500 ft/min until the CAB ALT value is 8100 ft, and hold the vacuum for 60 seconds. 1) Make sure that the EICAS status message CPCS BACKUP SENS
shows.
(c)
Decrease the vacuum at -500 ft/min until the CAB ALT value is approximately 7000 ft.
(d)
Turn the valve on the vacuum harness to return the vacuum to both controllers.
(e)
Decrease the vacuum at a rate of 4000 ft/min until it is at ambient pressure.
(f)
Push the MAN L and MAN R switches on the CPCS selector panel to the off position.
K. Do the Landing Altitude Display Test
S 715-035
(1) Monitor the lower elevation limit of the manual landing altitude selection:
(a)
Set the AUTO SELECT switch on the CPCS selector panel to the A position.
(b)
Turn the LDG ALT knob on the CPCS selector panel fully counterclockwise.
(c)
Push the LDG ALT button. 1) Check that LDG ALT reads -2000 |50 MAN on the main EICAS.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
21-31-00
ALL ú ú 05 Page 512 ú Oct 10/95
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
(d) Set the AUTO SELECT switch on the CPCS selector panel to the B position. 1) Check that LDG ALT reads -2000 |50 MAN on the main EICAS.
S 715-036
(2) Monitor the upper elevation limit of the manual landing altitude selection:
(a)
Turn the LDG ALT knob on the CPCS selector panel fully clockwise. 1) Make sure that the LDG ALT value is 14000 |50 MAN on the
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：747-400 AMM 飞机维护手册 空调 AIR CONDITIONING 1(107)
