Pressurisation Flashcards
How is pressurization achieved?
By supplying constant inflow of air and by regulating amount of air leaving aircraft through Thrust Recovery Outflow Valve(TROV)
How is control of the Cabin Pressure Selector page on the SMC affected by the pressurization system mode of operation?
With pressurization system in AUTO mode, the cabin pressure selector page provides a means to view the input data provided by FMS and ADS, and the RNG/SET knob is disabled. With pressurization system in SEMI mode, data is input via the RNG/SET knob for aircraft cruise/cabin altitude, barometric correction, landing field elevation, and cabin rate of climb/descent.
Automatic pressurization is available down to what source of power?
Main batteries through static inverter
What’s the meaning of the amber FAULT light on the CABIN PRESSURE CONTROL panel?
It indicates a failure of both channels of the dual channel controller: you’d have to select MANUAL
When does the pressurization system automatically switch to FLIGHT and begin to pre-pressurize the cabin prior to takeoff?
It’s initiated if the doors are closed and any of the following occur: switch is in FLIGHT position, airplane begins to move >9 knots or throttles are advanced
What happens in-flight when LANDING is selected on FLIGHT-LANDING switch?
Cabin pressure control system automatically switches to descent pressurization schedule (i.e. 300 fpm).
When does the FLIGHT-LANDING switch automatically switch to LANDING?
When the aircraft descends from cruise at least 1,000 feet
When would you use the semi-automatic (SEMI) mode?
Whenever FMS data is not available or is invalid, when directed by a checklist, or at discretion of the flight crew (e.g. flying in a QFE environment or to high altitude airport).
What’s one of the benefits of flying in the SEMI mode?
You have more control over the system
What’s the purpose of the MANUAL mode?
Used to manually control TROV and may be used as backup method in event of failure of both channels of cabin pressure controller.
What controls the TROV in the manual mode?
You do using a DC motor
In the manual mode, how would you determine the rate of TROV movement?
By observing the motor power indicator: frequency of flashes is proportional to valve opening or closing speed.
What’s the purpose of the pressure relief valve?
It provides a rate-limiting function to prevent damage to aircraft fuselage from excessive positive or negative pressures.
What type of action does the system perform after landing to ensure minimal differential pressure exists within the cabin?
During ground operations when TROV is full open, the pressure relief valve is forced open with bleed air (unless you’re in the manual mode)
When would the pressure relief valve start to relieve pressure?
There are two (2) pneumatic chambers: one relieves at 10.80 differential pressure and the other relieves at 11.00
