Eagle ICA-D212-725, Instructions Manual

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ICA-D212-725 (63)
Page 94 of 144
CHAPTER 63 – MAIN ROTOR DRIVE SYSTEM (63-00-00)

COPYRIGHT

2007 BY DART AEROSPACE LTD.

THIS DOCUMENT IS PRIVATE AND CONFIDENTIAL AND IS SUPPLIED ON THE EXPRESS CONDITION THAT IT IS NOT TO BE USED FOR ANY PURPOSE OR COPIED OR COMMUNICATED TO ANY
OTHER PERSON WITHOUT WRITTEN PERMISSION FROM DART AEROSPACE LTD.
Revision:
6
Date: 13.08.26
end fitting engages the coupling body seldom
occurs. In the event it does occur, the end fitting
seal is the most probable cause.
63.6.3.1.3 Leakage
that occurs at the
coupling end fitting and hose or tube connection
point may be attributed to such causes as follows:
63.6.3.1.3.1
Insufficient coupling nut torque.
63.6.3.1.3.2 Over-torque which may have
damaged the sealing surfaces of component parts.
63.6.3.1.3.3
Dirt or other foreign material on
the sealing surfaces, when leakage occurs at a
flared end connection.
63.6.3.1.4
Leakage that occurs at the valve
end of either the nipple or socket half when
coupling is disconnected can be attributed to worn
or damaged valve seal or to the metal-to-metal
sealing surfaces if coupling does not employ a
valve seal.
63.6.3.1.5
Signs of impending failure are:
63.6.3.1.5.1
Major thread damage on either
coupling half end fitting.
63.6.3.1.5.2
Major damage to the quick lead
acme threaded portion of either coupling half.
63.6.3.1.5.3 Damage to the spring loaded
valve stems of either coupling half.
63.6.3.1.5.4
Loss of spring tension on the
socket outer shell.
63.6.3.2 Inspection – Quick Threading
Couplings
NOTE
Installation side load and vibration will impose
wear upon the internal lock ring and flank of the
acme thread of this type coupling, that can disrupt
the flow characteristics and adversely affect
system operation. As wear occurs in the coupling
assembly, an internal spring forces the poppet
guides apart, allowing movement of the poppet
valves. As the wear progresses, movement of the
poppets increase, reducing volume of the flow
cavity or allowing fluid to push the valves
downstream to restrict the flow by closing the
poppet in the upstream coupling half.
63.6.3.2.1
Inspect installed quick threading
couplings, for excessive wear, as follows:
63.6.3.2.1.1
With system pressure at zero and
the coupling connected, compress the coupling
lengthwise and measure from the back of the
nipple half adapter hex to the back of the socket
half adapter hex.
63.6.3.2.1.2 Record
the measurement as value
A.
63.6.3.2.1.3
Extend the coupling by pulling
lengthwise and repeat the measurement.
63.6.3.2.1.4 Record
this measurement as
value B.
63.6.3.2.1.5 Compare values A and B to
determine amount of length variation.
63.6.3.2.2
If length variation exceeds the
given value in Table 63-2, for the particular dash
size, early failure is indicated. Replace the
coupling assembly.