Use an external hydraulic test unit or
the aircraft hydraulic system with
Check operation of down-limit switch
by unwinding winch to Its limit to assure that winch will
stop when cable If fully unwound
Check operation of up-limit switch by
running cable until up-limit switch is actuated
Electrical Hoist System. Maintenance and testing
procedures for electric hoist systems are explained in the
Maintenance of the electric hoist system consists
primarily of replacement of defective parts using the
Replace hoist cable when kinked or
when cable has been broken strands.
Replace monorail attaching parts
when found to be defective.
Lubricate hoist as prescribed in the
applicable aircraft maintenance manual.
Testing of electric hoist system Perform a
functional check, to test the electric hoist system for
operation periodically, and when a unit or electrical wiring
is replaced in the system.
9-17. Oxygen Systems. Oxygen system types,
maintenance, and servicing is explained in the following
Oxygen System Types. The design of the various
oxygen system types used in aircraft depends largely on
the type of aircraft, Its operational requirements, and,
where applicable, the pressurization system. In some
aircraft a continuous-flow oxygen system is installed for
both passengers and crew. The pressure demand system
is widely used as a crew system, especially on the larger
transport aircraft. Many aircraft have a combination of
both systems which may be augmented by portable
Continuous-flow system. The continuous
flow oxygen system is shown in figure 9-35. The oxygen
flows from the charged cylinder through the high-pressure
line to the pressure-reducing valve, which reduces the
pressure to that required at the mask outlets. A calibrated
orifice in the outlets will control the amount of oxygen
delivered to mask.
pressure-demand oxygen system is shown in figure 9-36.
Note that there Is a pressure-demand regulator for each
crewmember, who can adjust the regulator according to
Maintenance of Oxygen Systems. Maintenance
of oxygen systems Is described in the following
Oxygen leaks. Use soap test to
locate leaks unless individual leaks are large enough for
personnel to hear or feel. Apply soap solution, using mild
soap, A-A-50, to suspected part using a soft brush and
watch carefully for frothing, bubbling, or growing bubbles
Do not allow petroleum base products
to come in contact with components
of the oxygen system, as explosion or
fire may result.
Drain tubing of all solutions and blow
out with oxygen prior to installation in
aircraft. Contamination may otherwise
(2) Tubing and fittings. Maintenance,
repair, replacement, and Installation of oxygen system
tubing is given in TM 1-1500-204-23-2.
cylinders. No maintenance is authorized on installed low
or high pressure cylinders.
All low pressure oxygen cylinders
which carry a maximum charge of 450
psi will be painted yellow. High
pressure oxygen cylinders which carry
a maximum of 2000 psi will be painted