Saab 340B, Руководство по эксплуатации

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EMERGENCY EQUIPMENT
Oxygen
Aircraft Operations Manual
6/2.1
PAGE 9
Apr 01/15
5. FIXED OXYGEN SYSTEM DISPATCH
PRESSURE
Oxygen dispatch pressure varies with the number
of oxygen masks (passenger and crew), number of
fixed bottles, oxygen temperature, descent profile
and national operating regulations. To simplify the
presentation 3 different system configurations are
covered in this section, additionally oxygen con-
sumption per individual crew and passenger mask
are given for the individual operator to develop his
unique dispatch pressure.
It is important to understand that the oxygen pres-
sures presented are based on the Crew Oxygen
mask selector in NORMAL position (supplemental
oxygen supply). Keeping the selector in 100% posi-
tion (Smoke Protection supply) will result in a much
faster depletion of oxygen. Oxygen for smoke
protection is, according to the regulations, required
to be available for 15 min. to the cockpit crew. With
3 cockpit masks and descent profiles to below ei-
ther FAR Part 121 or 135 profile this requirement is
met with 800 psi indicated oxygen pressure. This
requirement is always covered in the following pre-
sentation and needs not to be considered.
Oxygen masks
Crew: Data are given for 2 and 3
masks.
Passengers: Data are given for 3 different
configurations:
− Configuration denoted FAR 121
operation includes 4 passenger
oxygen masks.
− Configuration denoted FAR 135
operation includes 30 passenger
oxygen masks.
− Configuration denoted 34 oxy-
gen masks includes accordingly
34 passenger oxygen masks.
Oxygen bottles
Two different system configurations are covered,
the basic 1 and the optional 3 fixed bottles installa-
tion.
Oxygen temperature
OXYGEN SUPPLY DURATION charts are pres-
ented for
− 20

C ( − 4

F), 0

C (32

F), +20

C (+70

F) and +40

C (+105

F) oxygen temperature and
the MINIMUM DISPATCH PRESSURE tables are
presented for
− 50

C ( − 60

F) to +50

C (+120

F)
oxygen temperature in steps of 10

C. The oxygen
consumption given per individual crew and passen-
ger mask is based on a oxygen temperature of +20

C (+70

F). It is however expected that the oxygen
temperature will remain below about +20

C (+70

F) during normal ground and flight operations. If the
aircraft is hot
− soaked on the ground for an ex-
tended period (longer than normal turnarounds), the
oxygen temperature might 20

C (+70

F).
Descent profiles
Two different descent profiles have been used in
the calculations, one is made up to meet FAR Part
121 regulations while the other is made up to meet
FAR Part 135 regulations. Both meet their respec-
tive minimum requirements. If unable to descent to
or below the descent profiles, because of terrain
restrictions special calculations have to be per-
formed.
Operating regulations
Crew: Some operating regulations re-
quire a 2 hour − oxygen supply to
each cockpit crew regardless of
flying time while other regulations
require less oxygen supply. The
OXYGEN SUPPLY DURATION
charts are made for those opera-
tors who can make a trade off in
oxygen pressure based on actual
flying time. The MINIMUM DIS-
PATCH PRESSURE tables are
made for those operators who are
required to carry a 2 hour oxygen
supply regardless of flying time
and therefore only can make a
trade off in oxygen pressure based
on number of passenger on −
board.
Passenger: The supply duration given is al-
ways for a 30 minute − supply to
each passenger mask.