Door Seal Pressure System; Standby Door Seal Pressure - Raytheon BEECH BARON 58P Maintenance Manual

BEECHCRAR
BARON 58P AND BARON 58TC
MAINTENANCE MANUAL
GENERAL
DESCRIPTION
AND OPERATION
FOflWARD CAB/N DOOR SEAL PRESSUR/ZAT/ON
I
SYSTEM (TJ-3 and after)
I
PRESSURltL\TION SYSTEM
(TJ-3
and
after)
The forward cabin door
on
the airplane is equipped with
an
Pressurized air
for the cabin is taken
from the
turbocharger
inflatable door seal. The door seal pressure
system
compressor of each engine and reduced
to
a
controlled now
provides air pressure
to
inflate the forward cabin door seal
by
a
restrictor in
the line called
a
sonic noule. The air then
and is controlled by
the DOOR SEAL-INFL-DEFL switch
on
passes
through
a
firewall shutoff
valve, through
an
the pressurization
console. When the DOOR SEAL switch
is
intercooler,
and into the cabin
through
one
way check
placed in the INFL position,
an
electrical signal is
relayed
to
valves located
beneath the pilot
and
copilot
floorboards. The the door seal pump to
provide
air
to
pressurize
the door seal
intercooler reduces the heat acquired by
the air during
pressure tank. When the pressure in the tank reaches the
pressurization
with
a
flow of
ram
air
from
a scoop
at the top required pressure, the pressure
tank solenoid closes and
of each engine
nacelle. After the air enters the
pressure
seals off the pump allowing the pressure tank to
provide the
vessel it is drawn into
the conditioning plenums
where it is
pressure needed to pressurize
the door seal. With the pump
heated
or
cooled
according
to
the selected
system.
air sealed off,
the pressure tank solenoid sends
an
electrical
signal
to
the control unit which
removes
the electrical power
A
safety valve/dump solenoid and
an
outflow valve
are
to
the pressure pump causing it to stop.
located
on
the aft pressure bulkhead. The pressurization
controller
on
the pedestal pneumatically regulates the The inflatable door seal is deflated
automatically when the
outflow valve
to
maintain the selected cabin altitude. The door is opened. When the door is opened,
the automatic
safety
valveldump
solenoid is connected to the pressure deflate switch
in the door frame is actuated (oveniding the
dump switch, and to
the landing
gear
safety switch. If either
DOOR SEAL switch in the INFL
position)
which
causes
the
of these switches
is
closed, the safety valve/dump solenoid door seal solenoid valve to
release the pressure from the
will open and the cabin will
depressurize.
door seal.
The pressurization system
controls consist of
a
cabin climb
The emergency door deflate valve is located in the door
indicator,
door seal inflate-deflate switch,
the
cabin altitude
adjacent to
the hook assembly. When the door handle is in
controller,
a
PRESS-TO-TEST
switch,
a
PRES- the EMERGENCY DOOR SEAL DEFLATE position, the
SURIZATIONIDUMP switch
and the cabin differential
hook assembly
actuates the
cam
follower of the emergency
pressure gage. Pressurization from the engines may be door deflate valve which dumps
the air pressure in the door
shut off by pulling the pressurization air controls (push-pull seal.
controls)
located
on
the pilot's subpanel placarded
CABIN
PRESS AIR
SHUTOFF-PULL CLOSED. This closes the
firewall shutoff valve and
dumps
the pressurized air into the
engine
compartment.
and
a f t e ~ - ) S TANDBY
DOOR SEAL PRESSURE SYSTEM (TJ-3
The cabin altitude controller is located
on
the pedestal
above the cabin climb indicator and the cabin differential
The standby door seal pressure
system operates
off of the
pressure gage. The
cabin altitude is maintained with the
DOOR SEAL STANDBY switch located
on
the left
subpanel.
control anywhere
from
zero pressure
to
the maximum Air is
supplied by
an
engine-driven
pressure pump mounted
I
differential pressure of 3.75 psi
on
TJ-3 thru TJ-168, except
on
the
accessory drive
pad
on each
engine.
The
air is
TJ-153
or
3.9 psi
on
TJ-153 and TJ-169 and after,
drawn through
an
air filter, located
on
top
of the engine,
to
the pressure pump and then routed to the pressure manifold
The controller is rotated until
the desired cabin altitude for
through
a
dual pressure relief valve and air filter. The air is
flight
is obtained.
Any selected cabin altitude will be
then routed
to
the forward cabin door seal standby
pressure
maintained during the flight provided
the cabin pressure is
regulator and door seal. The
system
is controlled by
the
at
or
below the maximum differential pressure. The
rate
DOOR SEAL STANDBY switch,
located
on
the
control
control
knob, located adjacent to the cabin altitude
console adjacent
to
the pressurization controls. The
controller, will regulate
the rate at which cabin
pressure
inflatable door seal is deflated automatically when the door
ascends
or
descends to
the selected altitude. If the cabin is opened. When the door is open, the automatic deflate
I
reaches the maximum differential of 3.75 psi
on
TJ-3 thru
switch in the door frame is
actuated (oveniding
the DOOR
TJ-168, except TJ-153,
or
3.9 psi
on
TJ-153 and TJ-169 SEAL-INFL-DEFL switch in the INR position) which
causes
and after, and the
airplane is still climbing,
the cabin altitude the door seal solenoid valve
to
release the pressure from
will climb with the airplane,
the door seal.
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