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TROUBLE  PROBABLE  ISOLATION PROCEDURES  REMEDY 
CAUSE 
Airstair fails to  5. Faulty retract or  5. Check for continuity on connector  5. Replace retract 
retract when Control  extend relay  D4846J between pin No. 1 and pin No.  relay and/or extend 
switch on internal  9. If continuity is not present, replace  relay 
control panel is  retract relay and repeat continuity 
operated (Cont)  check. If continuity is still not present, 
replace extend relay. If continuity is 
present, reconnect D4846P to D4846J 
and proceed to step 6. 
6. Faulty retract  6. Disconnect connector D502 from ac  6. Replace retract 
relay or ac power  power unit. Attempt operation of system  relay or ac power 
unit  with control switch and check for 115  unit 
volts ac between pins No. 1, 2, 3, and 
ground on pin No. 4. If voltage is not 
available, retract relay is faulty. If 
voltage is available, ac power unit is 
faulty 

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4. Auto Lighting Aft Entry Door and Airstair Trouble Shooting Chart TROUBLE PROBABLE CAUSE ISOLATION PROCEDURES REMEDY Treadway lights fail to illuminate when airstair is extended. Switch in AUTO position 1. Faulty aft airstair tread light switch 1. Disconnect electrical connector D455OP from mating connector D425OJ on aft attendant’s panel. Check for continuity on D425OJ between pin No. 16 and pin No. 17. If continuity is not present, tread light switch is faulty. If continuity is present, reconnect D425OP to D425OJ and proceed to step 2.  1. Replace aft airstair tread light switch 2. Faulty light control relay or extend limit switch 2. Disconnect electrical connector D4846P from mating connector D4846J on aft airstair control panel. On connector D4846J, ground pin No. 11 to pull in light control relay and check for 28 volts dc on pin No. 4. If voltage is not available, relay is faulty. If voltage is available, extend limit switch is fault 2. Replace light control relay. Replace or adjust extend limit switch (refer to 52-14-81) 

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AFT ENTRY DOOR AND AIRSTAIR - MAINTENANCE PRACTICES
EFFECTIVITY
Airplanes with Aft Airstair
1.  General
A.  The maintenance practices included in this section (201-299 page block) are general maintenance instructions that do not definitely fall within a specific category. Other maintenance practices such as Servicing, Removal/Installation, Adjustment/Test, etc. are provided in the applicable page blocks.
B.  The airplane can be flown under certain conditions with the aft airstair deactivated. The aft entry door and airstair must be deactivated when the airstair is removed or when the lower and/or middle segments of the airstair have been removed. If a segment has been removed, the airstair cannot be used as an emergency escape exit. Also, the airstair will exceed the rotation limits causing damage to the airplane. If the airplane is to be flown with a segment removed, retract the airstair, check that the door is closed and latched, and placard all airstair controls as being deactivated. If the airstair has been removed, deactivate the system as follows.
2.  Aft Entry Door and Airstair Deactivation
A.  Remove radius rod from control console. (See figure 201.)
B.  Remove free motion flanges from hinge support fittings.
C.  Manually install door in opening and engage door cams with frame-mounted rollers.
D.  Move door inward and down until cams and rollers are fully engaged and door stop pins are centered on frame stops.
E.  Engage latch pin by rotating control console handle to the latched position.
F.  Pry back interior acoustical seal to visually check latch pin and door stops.
G.  Safety wire control handle in latched position and placard all airstair controls as being deactivated.
Aug 15/71 52-14-0 Page 201
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Aft Entry Door and Airstair Deactivation  500 
52-14-0  Figure 201  May 15/68 
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AFT ENTRY DOOR AND AIRSTAIR - REMOVAL/INSTALLATION
　
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