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LATCH OPEN SWITCH ú ú 06 Page 8 ú Feb 10/92
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MAINTENANCE MANUAL
C814 FWD CARGO DOOR (P14) FORWARD CARGO DOOR SCHEMATIC
Cargo Door Schematics
Figure 2 (Sheet 3)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. FORWARD CARGO DOORS ú
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MAINTENANCE MANUAL
C815 AFT CARGO DOOR (P59) AFT CARGO DOOR SCHEMATIC Cargo Door Schematics Figure 2 (Sheet 4)
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LATCH OPEN SWITCH ú ú 06 Page 10 ú Feb 10/92
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CAUTION:_______ IN CASE THE DOOR DOES NOT OPEN, STOP IMMEDIATELY. DO NOT
OPERATE THE DOOR CONTROL SWITCH. HOLDING THE DOOR CONTROL
SWITCH MAY DAMAGE THE ACTUATOR. WAIT AT LEAST 1 MINUTE BEFORE
SECOND ATTEMPT. IF THE DOOR STILL DOES NOT OPEN, WAIT AT LEAST
10 MINUTES BEFORE THIRD ATTEMPT.
(1)
Open door electrically.
(a)
When the master latch lock handle handle on the exterior of the door is released and allowed to rotate down, it rotates the master latch lock torque tube which retracts the eight latch lock sectors to free the latches for rotation. Rotation of the master latch lock torque tube causes the pressure relief door torque tube to rotate by way of bellcranks and pushrods. Both pressure relief doors are pulled inward, as the pressure relief door torque tube rotates. When the forward pressure relief door moves away from the fully closed position, the cargo door caution message appears on the upper EICAS display. When the lock sectors reach fully retracted position, the master latch lock switch is actuated to complete the circuit to the door control switch to permit electrical operation. (See Fig. 1 for switch location and Fig. 2 for electrical schematic).
(b)
At the same time, the switch on the master latch lock handle makes the green LATCHES CLOSED light on the door control panel go on. This shows that the door is latched but not locked.
(c)
When either (inside or outside) door control switch is placed in the open position, electrical sequencing of all three electrically powered mechanisms begins to drive the door fully open.
(d)
When you put the door control switch in the OPEN position, it energizes the door restraint solenoid. This frees the hook torque tube so it can turn. The door control switch also supplies 28-volt dc control power to the latch actuator.
(e)
The 28-volt dc power for the latch actuator goes through the hook position relay and the latches open switch.
(f)
When the latch actuator moves the latch mechanism away from the closed position the latch closed switch moves. The latch closed switch moves to the not closed position. This supplies power to the closed side of the inside and outside control switches. Because of this, you can reverse the operation of the door, if necessary.
(g)
The latch closed switch also removes power from the green LATCHES CLOSED light on the operators control panel. This shows that the door is not locked and not latched.
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(h)
The latch actuator moves the latch mechanism to the full open position. This moves the latch open switch and the midspan latch open switches to the open position. When the latch open switch moves to the open position it removes electrical power from the latch actuator. The latch open switch and the midspan latch open switches connect in series to supply power to the hook actuator. The power goes through the contacts of the door restraint solenoid which is energized.
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