be formed when cylinders containing residual
combustible gases such as hydrogen, propane, or
acetylene are charged with air or oxygen. The
reverse of this procedure is equally hazardous.
Cylinders used for aviators breathing oxygen,
dry nitrogen, dry argon, dry helium, or dry air
that are found to have open valves and/or a
positive internal pressure of less than 25 psi
(gauge) should be tagged Dry Before Refilling.
When operating the compressed air servicing
trailers, (gaseous oxygen or nitrogen) the
following precautions should be observed:
1. Only qualified operators should operate the
trailers while charging. Complete familiarity with
the trailer is a basic prerequisite for safe operation.
2. The servicing hose end and installation
connection fitting should be thoroughly inspected
prior to servicing and any foreign matter removed.
3. Never charge an installation without the
proper fusible safety plug and blowout disc in the
trailer charging system.
4. Always know the pressure existing in the
system to be filled and the pressure in all cylinders
to be used in the cascading process before starting
5. A malfunctioning pressure regulator should
be disconnected from the line by closing its
associated shut-off valve. The trailer can then be
operated with the remaining pressure regulator.
6. The charging hose should never be
stretched tightly to reach a connection. Position
the trailer so that the servicing hose is not under
tension while charging.
7. Always open all valves slowly. The dangers
of rapid cascade charging must be avoided.
Compressed air should never be blown towards
anyone, used for cleaning of personal clothing,
or as a means of cooling off a person.
SAFETY PRECAUTIONS FOR
EJECTION SEATS AND EXPLOSIVE
Learning Objective: Identify the
importance of the ejection seat check-out
Ejection seats have several inherently
dangerous features that are a definite hazard to
uninformed and/or careless personnel. Con-
sequently, whenever the aircraft is on the ground,
all safety pins must be installed and not removed
until the aircraft is ready for flight. Caution must
be observed at all times during maintenance of
and around the seats to avoid injury and equip-
ment damage by explosive devices of the seat.
Safety precautions and correct procedures cannot
Keep all cartridges away from live circuits.
Under no circumstances should any person reach
within or enter an enclosure for the purpose of
servicing or adjusting equipment without the
immediate presence or assistance of another
person capable of rendering aid.
When removing cartridges for inspections or
for safety reasons, they must be marked for
identification so they can be reinstalled in the same
device from which they were removed. Under no
circumstances should an unmarked or
unidentified cartridge be installed in any cartridge-
Cartridges should be handled as little as
practicable to minimize risk of fire, explosion, and
damage from accidental causes. All safety devices
must be kept in good order and used only as
Cartridges must be stored where they will not
be exposed to direct rays of the sun, and they must
be protected from extremely high temperatures.
When in containers, they must be stored in a cool,
dry place where they can be readily inspected.
The seat must always be disarmed before
removal from the aircraft because firing of the
seat may occur. While handling percussion-fired
cartridges, you must exercise extreme caution not
to drop cartridges because they can fire upon
The following general precautions should
always be kept in mind.
1. Ejection seats must be treated with the
same respect as a loaded gun.
2. Always consider an ejection seat system as
loaded and armed.
3. Before you enter a cockpit, know where the
ejection seat safety pins are located, and make
certain of their installation.
4. Only authorized personnel may work on,
remove, or install ejection seats and components,
and only in authorized areas.
EJECTION SEAT CHECK-OUTS
The modern, high-performance aircraft used
by todays Navy place extreme demands on
emergency escape systems. These systems contain
highly explosive devices that are designed for one-
time use only. Actuation of these devices could