25-11-00
 ALL  ú ú 08 Page 4 ú Feb 15/99 
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details. 
A 
747-400 
MAINTENANCE MANUAL
F 
THERMALPROTECTION
D 
DM536 THERMAL
DF 
PROTECTION
115V AC
1 
A 
A BUS 224-51-02 
2 
B B 
3 
C 
C C878CAPTAINSSEAT (P414) 
5 E E 
YM3SO4 UPYM3RO3 POWER RLY 
LIMIT SW
YM3SO1 FWD 
YM3MO1 HORIZ  YM3MO2 VERT
YM3RO2 AFT RLY YM3RO5 DWN RLY
LIMIT SW ACTR MOTOR ACTR MOTOR UP 
AFT 
YM3SO6 DWNDWN 
FWD LIMIT SW YM3SO2 FWD/AFT CONT SW 
YM3SO3 AFT
LIMIT SW
YM3SO5 UP/DWNCONTROL SW 
YM3RO1 FWD RLY  YM3RO4 UP RLY M536 (YM3) SEAT - CAPTAINS POWER (STA 308, WL 313, LBL 37) 
F THERMAL 
D 
PROTECTIONDM537 THERMAL
DF 
PROTECTION
1
A A 
115V AC
BUS 2
2 
B B 
24-51-03 3 
C 
C C877FIRST OFFICERS
SEAT (P415) 
5 E E 
YM4SO1 FWDYM4SO4 UPYM4RO3 POWER RLY LIMIT SW
LIMIT SW YM4RO2 AFT RLY 
YM4MO1 HORIZ  YM4MO2 VERT
YM4RO5 DWN RLYACTR MOTOR ACTR MOTOR UP 
AFT 
YM4SO8 AFT
YM4SO9 20` YM4SO6 DWN
FWD LIMIT 20`RECLINE SW DWN LIMIT SW
RECLINE SW 
____ YM4SO2 FWD/AFT CONT SW
NOTE:
THE CAPTAIN'S AND FIRSTYM4SO5 UP/DWN
OFFICER'S SEAT MAY RUN 
CONTROL SWUP OR DOWN BY OPERATIONOF THE VERTICAL POWER 
YM4SO7 MIN
SWITCH AND FORWARD OR 
YM4RO1 FWD RLYAFT BY OPERATION OF THE
HORIZONTAL POWER SWITCH. 
YM4SO3 AFT LIMIT SW RECLINE SW  YM4RO4 UP RLY 
M537 (YM4) SEAT - FIRST OFFICERS POWER (STA 308, WL 313, RBL 37)
Pilots' Power Seats Simplified Schematic
Figure 3
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
 25-11-00
 ALL  ú ú 08 Page 5 ú Feb 18/02 
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details. 
D18464
A 
747-400 
MAINTENANCE MANUAL
 (7)  
Manual Seat Back Lumbar Support Up/Down Adjustment
(a) Operation of the manual seat back lumbar support up/down adjustment control handwheel, located on left side of seat, allows the seat back lumbar support pad to be manually raised or lowered incrementally.
 (8)  
Manual Seat Back Lumbar Support In/Out Adjustment
(a) Operation of the manual seat back lumbar support in/out adjustment control handwheel, located on right side of seat, allows the seat back lumbar support pad to be manually adjusted fore and aft incrementally.
 (9)  
Manual Armrest Adjustment
 (a)  Operation of the manual armrest adjustment control knob, located at forward end of armrest, allows the armrest to be manually raised or lowered incrementally. The armrests can be folded to a stowed position behind the seat back to reduce overall width of seat for pilot ingress and egress.
 C. Observers' Seat Adjustment Controls
 (1)  
Manual Horizontal Adjustment (First Observer Seat Only)
(a) Operation of the manual horizontal adjustment control handle, located on inboard side of seat, allows the seat to be manually adjusted fore and aft incrementally only when seat is adjusted to its fully inboard position.
 (2)  
Manual Lateral Adjustment (First Observer Seat Only)
(a) Operation of the manual lateral adjustment control handle, located on inboard side of seat, allows the seat to be manually adjusted laterally in incremental positions only when seat is adjusted to its fully aft position.
 (3)  
Manual Vertical Adjustment (First Observer Seat Only)
(a) Operation of the manual vertical adjustment control handle, located on outboard side of seat, allows the seat to be manually raised or lowered incrementally.
 (4)  
Manual Seat Back Recline Adjustment
(a) Operation of the manual seat back recline adjustment control handle, located on inboard side of seat, allows the seat back to be manually adjusted fore and aft incrementally.
 (5)  
Manual Seat Back Lumbar Support Up/Down Adjustment
(a) Operation of the manual seat back lumbar support up/down adjustment control handwheel, located on inboard side of first observer seat and on outboard side of second observer seat, allows the seat back lumbar support pad to be manually raised or lowered incrementally. 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 EQUIPMENT/FURNISHINGS 1(27)