time, rather than the number of cycles, is the only
method. For example a leakage rate of five drops per
minute from a rod seal would produce a leakage of
0.915 cu in (15 cm
exposed to leakage, it is not particularly detrimental to
the operation of the hydraulic system or the aircraft.
Up to this degree, it is more convenient to wipe up the
excess oil and to check the reservoir level than to
replace the seals in the control actuators. The most
important indication must be immediate evidence of
an increase in the quantity of leakage.
and in any system to determine what amount of
leakage can be tolerated, and what amount might be
a hazard to the safe and effective operation of the
aircraft. It is important that piston rods are cleaned
and lubricated periodically in order to keep wipers and
seals wet with fluid. This procedure will aid in cutting
down leakage and will reduce the number of seal
failures.