T
RAINING
M
ANUAL
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L
ANCAIR
IV/IVP
(b) The density-reference waste gate system is controlled by compressor
discharge air. A density controller holds a given density of air by
automatically adjusting manifold pressure as airspeed, ambient
pressure, temperature, altitude, and other variables change.
Pressurized Magnetos
Thin air at high altitudes makes the unpressurized magneto susceptible to arcing
or crossfiring. The high-tension pressurized system is composed of sealed caps
and plugs that keep the electrodes contained within the body. A pressure line
extends directly from the upper deck to the magneto.
Pressurized magnetos perform better at high altitudes where low pressure and
cold atmosphere have a detrimental effect on electrical conductivity. Flight
above 14,000 feet with an unpressurized magneto should be avoided because of
its high susceptibility to arcing. Once arcing has occurred, magneto overhaul is
required to replace distributor blocks that have carbon traces.
Oxygen
Most high-altitude airplanes come equipped with some type of fixed oxygen
installation. If the airplane does not have a fixed installation, portable oxygen
equipment must be readily accessible during flight.
For flights in pressurized
aircraft above FL250 a 10 minute supply of supplemental O2 must be made
available to each occupant in the event is necessitated by loss of cabin
pressurization (14 CFR 91.211)
.The portable equipment usually consists of a
container, regulator, mask outlet, and pressure gauge. A typical 22 cubic-foot
portable container will allow four people enough oxygen to last approximately 1.5
hours at 1,800-2,200 pounds per square inch (PSI). The container should be
fastened securely in the aircraft before flight. When the ambient temperature
surrounding an oxygen cylinder decreases, pressure within that cylinder will
decrease because pressure varies directly with temperature f the volume of a
gas remains constant. Therefore, if a drop in indicated pressure on a
supplemental oxygen cylinder is noted, there is no reason to suspect depletion of
the oxygen supply, which has simply been compacted due to storage of the
containers in an unheated area of the aircraft. High-pressure oxygen containers
should be marked with the PSI tolerance (i.e. 1,800 PSI) before filling the
container to that pressure. To assure safety, oxygen system periodic inspection
and servicing should be done at FAA certified stations found at some fixed base
operations and terminal complexes.
Regulator and Masks
Regulators and masks work on continuous flow, diluter demand, or on pressure
demand systems. The continuous flow system supplies oxygen at a rate that
may either be controlled by the user or controlled automatically on some
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60
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©
Copyright
2007
LOBO
May
not
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copied
without
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