in each half closes the valve, preventing the loss of fluid
Q8-22.
Considering maintenance man-hours and
and entrance of air.
material requirements, what is the most
effective decontamination method?
The union nut has a quick-lead thread that permits
connecting or disconnecting the coupling by turning
AIRCRAFT HYDRAULIC HARDWARE
the nut. The amount the nut must be turned varies with
AND SEALS
different styles of couplings. For one style, a quarter
turn of the union nut locks or unlocks the coupling. For
LEARNING OBJECTIVE: Identify the
another style, a full turn is required. Some couplings
various hydraulic hardware and seals used in
require wrench tightening; others are connected and
naval aircraft.
disconnected by hand. Some installations require that
Hardware, such as the quick-disconnect coupling,
the coupling be safetied with safety wire; others do not
and seals and packings are used throughout the aircraft.
require any form of safetying. Because of these
They are essential for safe and proper operation of
individual differences, all quick disconnects should be
aircraft systems. You must be familiar with the various
installed in accordance with the instructions in the
types used on naval aircraft.
applicable MIM.
The series 145 and 155 (Aeroquip) couplings make
QUICK-DISCONNECT COUPLINGS
up one type of quick-disconnect coupling found on
naval aircraft. These couplings may be identified by the
Quick-disconnect couplings provide a means of
part number (145 or 155) stamped on the face of the
quickly disconnecting a line without the loss of
union nut.
hydraulic fluid or entrance of air into the system. Each
coupling assembly consists of two halves, held together
Each quick-disconnect coupling consists of two
by a union nut. Each half contains a valve, which is held
halves, referred to as S1 half and S4 half. See figure 8-8.
open when the coupling is connected. This action
When disconnected, the union nut remains with the S1
allows fluid to flow in either direction through the
half. The S4 half has a mounting flange for attaching to
coupling. When the coupling is disconnected, a spring
a bulkhead or other structural member of the aircraft.
Figure 8-8.--Series 145 and 155 quick-disconnect couplings.
8-20
