-
the MLG door uplock (2521GM).

 (2) NLG
 In the NLG bay, the mechanical linkage connects to:
 -
the vent valve (2532GM)

 -
the NLG uplock (2530GM)

 -
the NLG door uplock (2534GM).

 (3) Uplocks
 Refer to (Ref. 32-31-00) for the description and operation of these components:
 -
the MLG uplock 2509GM (2510GM)

 -
the MLG door uplock 2521GM (2520GM)

 -
the NLG uplock 2530GM

 -
the NLG door uplock 2534GM.

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 B. Hydraulic Components
 The hydraulic components in the free-fall extension system are:
 -
a cut-out valve 2515GM

 -
a MLG vent valve 2516GM

 -
a NLG vent valve 2532GM.

 (1)
 Cut-out Valve

 The cut-out valve isolates the L/G hydraulic system from the Green hydraulic system supply and connects the L/G selector manifold to the hydraulic reservoir return.

 (2)
 Vent Valve

 Two ports on the vent valve connect to these components (Ref.
 32-31-00):
 -
the L/G downlocks

 -
the L/G actuating cylinders

 -
the L/G door actuators

 -
the L/G uplocks.

 The vent valve lets the hydraulic fluid move between the extension and retraction lines on some components, to prevent cavitation. It also lets any unwanted fluid go back to the reservoir through the third port on the vent valve.
 The third port on the vent valve connects to the Green hydraulic system return.
 4. Power Supply____________
 A. Hydraulic Power Supply
 The operation of the free-fall extension system isolates the Green hydraulic power system from the extension and retraction system.
 B. Electrical Power Supply
 The only electrical power used is for indication functions.
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 5. Interface_________
 (Ref. Fig. 003)
 6. Component Description_____________________
 A. Handle Assy - Free-Fall Control
 (Ref. Fig. 004)
 (1)
 Description

 The L/G free-fall extension-handle assembly is at the rear of the cockpit center-pedestal. During the normal extension and retraction operations, the free-fall extension-handle is folded for storage.

 (2)
 Operation

 When the free-fall extension-handle is rotated for three revolutions in a clockwise direction, it:
 -stops the high-pressure hydraulic supply and connects the L/G system to the reservoir return
 -connects the L/G hydraulic-actuator 'retraction' chamber and the L/G door hydraulic-actuator 'close' chamber to the reservoir return
 -
releases the L/G door uplocks

 -
releases the L/G uplocks.

 B. L/G Free-Fall Cut-out Valve (2515GM)
 (Ref. Fig. 005, 006)
 (1) Description
 The mechanically operated cut-out valve is in the RH MLG bay, immediately upstream of the electro-hydraulic selector manifold.
 There is a rigging hole for locking the input handle, to permit system rigging.
 The valve has three hydraulic-port connections identified A, B and C:
 -
port A is the hydraulic-pressure supply inlet

 -
port B is the hydraulic-pressure supply to the L/G selector manifold

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 Free-Fall Extension - Interface
 Figure 003
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 Handle Assembly Free-Fall Control
 Figure 004
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 Landing Gear Free-fall Cut-out Valve (2515GM)
 Figure 005
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 Landing Gear Free-fall Cut-out Valve - Schematic
 Figure 006
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 -port C is the hydraulic-reservoir return connection.
 (2) Operation
 During a L/G normal extension and retraction operation, the cut-out valve port A is open to port B so that hydraulic power is supplied to the L/G selector manifold.
　
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