Table 2-7. Recommended Fluid Dilution Chart
FREEZING POINT OF
FLUID BY VOLUME
+ 30 and above
1. Use anti-icing and deicing fluid (MIL-A-8243).
2. Heat mixture to a temperature of 180 to 200F (82 to 93C)
4. If tires are frozen to ground, use undiluted
2-93. Servicing Oxygen System.
defrosting fluid to melt ice around tire. Move aircraft as
soon as tires are free.
The oxygen system furnishes breathing oxygen to
the pilot, copilot and observer. Refer to Section VII for
2-92. Application of External Power.
location of oxygen cylinders.
a. Oxygen System Safety Precautions.
Before connecting the power cables
from the external power source to the
Keep fire and heat away from oxygen
aircraft, insure that the GPU is not
Do not smoke while
touching the aircraft at any point.
working with or near oxygen
Due to the voltage drop in the cables,
equipment, and take care not to
the two ground systems will be of
generate sparks with carelessly
handled tools when working on the
come in contact while the GPU is
operating, arcing could occur. Turn
1. Keep oxygen regulators, cylinders, gages,
connecting the power cable to, or
valves, fittings, masks, and all other components of the
removing it from the external power
oxygen system free of oil, grease, gasoline, and all other
supply receptacle. Be certain that
readily combustible substances. The utmost care must
the polarity of the external power
be exercised in servicing, handling, and inspecting the
source is the same as that of the
aircraft before it is connected. The
GPU shall not exceed 28 VDC.
2. Do not allow foreign matter to enter
An external power source is often needed to supply
the electric current required to properly ground service
3. Never allow electrical equipment to come
the aircraft electrical equipment and to facilitate starting
in contact with the oxygen cylinder.
the aircraft's engines. An external DC power receptacle
is installed on the outboard side of the right engine
4. Never use oxygen from a cylinder without
nacelle. A GPU capable of delivering a continuos load
first reducing its pressure through a regulator.
of 1000 amperes is required.
Change 7 2-79