A
RETURN
PRESSURE
SUCTION
B
ASf08047
Figure 8-47.--Basic open-center system.
Q8-18. What type of hydraulic system has fluid flow
hydraulic systems. Identify procedures for
but no pressure in the system whenever the
decontamination of hydraulic systems.
actuating mechanisms are idle?
1.
A full-flow system
Contamination is the direct or indirect cause of
2.
A free-flow system
more hydraulic system failures than any other single
3.
A open-center system
source. For this reason, contamination prevention is a
4.
A closed-center system
major concern for all who operate and maintain
hydraulic systems. Contamination in hydraulic
Q8-19. Which of the following systems has multiple
systems of support equipment not only causes
directional valves arranged in parallel rather
malfunctions in the equipment but in aircraft as well. A
than in series?
small mistake that leads to contamination can result in
1.
A full-flow system
enormous damages. For example, consider the case of
2.
A free-flow system
a hydraulic check and fill stand or a portable hydraulic
3.
A open-center system
power supply that has contaminated fluid. If these are
4.
A closed-center system
used to service aircraft, the result can be damage to
expensive equipment, loss of an aircraft costing
HYDRAULIC SYSTEM
millions of dollars, or even injury to or loss of life of
CONTAMINATION
personnel.
The Aviation Hydraulics Manual, NAVAIR
LEARNING OBJECTIVES: Identify classes
01-1A-17, and the Aviation Hose and Tube Manual,
of contamination in hydraulic systems. Identify
NAVAIR 01-1A-20, are excellent publications on the
tests for detection of contamination in
subject of contamination. These manuals are required
8-38