Emergency Extension Torsion Bar Installation 500
52-14-31 Figure 401 May 15/68
Page 402
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
AFT ENTRY DOOR AND AIRSTAIR TRANSMISSION UNITS - REMOVAL/INSTALLATION
EFFECTIVITY
Airplanes With Aft Airstair
1. General
A. The airstair forward and aft transmission unit installations are similar. Therefore, only one procedure is given. Differences in removal and installation between the forward and aft units are given in the procedure.
2. Equipment and Materials
A. Grease - MIL-G-23827A
3. Prepare for Removal
A. Extend airstair using emergency mode.
CAUTION: IF AIRSTAIR IS EXTENDED MORE THAN 132 INCHES DURING EMERGENCY OPERATION, SECONDARY STRUCTURE MAY BE DAMAGED.
B. Open aft airstair circuit breakers (2 places) on P6 panel.
C. If aft transmission unit is being replaced, remove control console shroud.
D. Remove cover over transmission unit.
4. Remove Transmission Unit
A. Remove retract and/or extend limit switch from forward and/or aft transmission units respectively. Refer to 52-14-81 and/or 52-14-91 for removal and installation procedures.
B. Remove bolts attaching gearbox to transmission unit and move gearbox from splined shaft of transmission unit and transfer shaft (Fig. 401).
C. Block airstair hinge to prevent movement while unscrewed from free motion flange. Remove hinge screws and flange and remove wedges between transmission shaft and free motion flange. This step not required for those airplanes without wedges.
D. Remove bolts attaching transmission unit to airstair hinge support fitting and withdraw transmission unit from support fitting shaft.
Feb 15/79 52-14-41 Page 401
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
Aft Airstair Transmission Unit Installation 500
52-14-41Page 402 Figure 401 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Feb 15/68
5. Install Transmission Unit
A. Position transmission unit on shaft of hinge support fitting and install mounting bolts. (See figure 401.)
B. Butter lubricate gearbox transfer shaft spline with grease.
NOTE: Do not lubricate splined shaft which mates with transmission unit.
C. Position gearbox on splined shaft of transmission unit and transfer shaft. Install mounting bolts.
D. Install wedges between transmission shaft and free motion flange on those airplanes requiring wedges. Install airstair hinge with screws and flange.
E. Install limit switch in transmission unit. Refer to 52-14-81 and/or 52-14-91 for retract and/or extend limit switch removal and installation procedures.
6. Restore Airplane to Normal
A. Install cover over transmission unit.
B. If aft transmission unit is being replaced, install control console shroud.
C. Close aft airstair circuit breakers (2 places) on P6 panel.
D. Cycle airstair and check for smooth operation with no evidence of binding in the transmission unit.
E. Rearm emergency extension system. Refer to Emergency Extension Mechanism, 52-14-21.
500
May 15/68 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 52-14-41 Page 403
AFT ENTRY DOOR AND AIRSTAIR AC POWER UNIT - REMOVAL/INSTALLATION
1. Prepare for Removal
A. Open aft airstair circuit breakers (2 places) on P6 panel.
B. To gain access to power unit, enter lower cargo compartment and remove fasteners at aft end of upper left access panel and roll back panel. It is not necessary to remove entire panel.
2. Remove AC Power Unit
A. Disconnect electrical connector from power unit. (See figure 401.)
B. Remove bolts attaching power unit to gearbox and remove power unit.
3. Install AC Power Unit
A. Engage spline of power unit with gearbox and install mounting bolts. (See figure 401.)
B. Connect electrical connector to power unit.
C. Close aft airstair circuit breakers (2 places) on P6 panel.
D. Operate airstair using normal mode of operation. Check that 35 to 45 seconds are required for full extension and full retraction.
CAUTION: A 2-1/2 MINUTE COOLING PERIOD SHOULD BE ALLOWED AFTER TWO CONSECUTIVE POWERED OPERATIONS. (A POWERED OPERATION CONSISTS OF EITHER A RETRACTION OR AN EXTENSION.)
E. Fasten side access panel in aft end of lower cargo compartment.
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