Raytheon Beechraft Starship 2000, Руководство по обслуживанию

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STARSHIP 1 MAINTENANCE MANUAL
Page 1
B10 Oct 31/06
21-30-00
000
PRESSURIZATION CONTROL - DESCRIPTION AND OPERATION
WARNING: Anytime the airplane is on the ground (whether on jacks or on the wheels), the nose and main
landing gear MUST be pinned in the down and locked position. The only exceptions to this
would be during landing gear operational checks, during the removal or installation of the
landing gear components, and during taxiing operations prior to takeoff or after landing. When
any work is being performed in the nose gear wheel well, the nose gear doors MUST be pinned
in the open position. Refer to Chapters 32-10-00 and 32-20-00 for the proper lock pin installation
procedures.
The pressurization control system is designed to control cabin altitude and cabin rate of change. The system utilizes
two outflow valves, two altitude limit regulators, a jet pump ejector, manual shutoff valve, manual rate control valve,
auxiliary volume tank, air filters, the cabin pressurization controller and the cabin pressurization control module
assembly. The cabin pressurization control module assembly is mounted on the aft side of the forward pressure
bulkhead behind the rudder pedals on the pilot’s side. It consists of a pneumatic relay, vacuum regulator, the "B"
and "C" solenoid valves and the associated plumbing and test ports. The pressurization control system continuous
flow air filter and auxiliary volume tank are mounted on top of the cabin pressurization control module assembly.
The cabin altitude/differential pressure indicator and cabin climb indicator are located on the copilot’s inboard
subpanel. The actual cabin altitude pressure differential is continuously indicated by the cabin altitude/differential
pressure indicator. Rate of cabin pressure change is continuously indicated by the cabin climb indicator.
The cabin pressurization controller and manual rate control valve are located on the pressurization control panel in
the lower center of the instrument panel. The manual rate control valve provides manual control of the pressurization
system. It is connected to the regulated vacuum source with the pneumatic relay and cabin pressurization controller,
and to the outflow valves reference pressure line. When the manual rate control valve is in the NORM position, the
pressurization system is automatically controlled according to crew selected settings. Full rotation of the manual rate
control valve clockwise selects the DUMP position, and will depressurize the cabin.
The cabin pressurization controller controls modulation of the outflow valves through a compensated type
pneumatic relay, and is capable of controlling rate-of-change from a minimum of approximately 50 feet per minute
up to 3000 feet per minute. The cabin pressurization controller is connected to the regulated vacuum source, the
pneumatic relay (control pressure), and to actual cabin pressure. The control pressure referenced by the
pressurization controller and pneumatic relay is stabilized by the auxiliary volume tank to prevent momentary
fluctuations from affecting the system and to allow for smooth operation.
When the cabin altitude select knob on the cabin pressurization controller is rotated, an interconnecting actuator
actuates the bellows inside the controller. The cabin rate control select knob is connected to the rate control valve
position actuator. When rotated, the rate control valve position actuator controls the position of the rate control valve
in the rate pressure chamber. The rate pressure chamber contains a rate spring, rate control valve and check valve.
When cabin pressure decreases below the rated pressure, the check valve opens to allow air flow to the cabin
pressure chamber from the rate pressure chamber. A reference chamber in the cabin pressurization controller
contains the pressure metering valve, metering follower spring and the necessary pneumatic connections to
influence the pneumatic relay. The "A" solenoid is connected to the reference chamber, and when energized
(closed), renders the cabin climb change rate function inoperative.
Vacuum is generated by engine bleed air passing through the jet pump ejector. The vacuum is plumbed through a
check valve and manual shutoff valve to the vacuum regulator, where it is regulated to 4.75 inches Hg less than
cabin pressure. The regulated vacuum is then plumbed to the VACUUM ports on the cabin pressurization controller
and pneumatic relay. Raw cabin air is filtered by the pressurization system continuous flow air filter before entering
the FILTER port on the pneumatic relay. The filtered air flows through an orifice in the pneumatic relay and
contaminates the regulated vacuum. Once contaminated, the regulated vacuum creates a reference pressure. This
reference pressure is plumbed from the pneumatic relay to each outflow valve diaphragm to unseat the poppet in