Presurization Flashcards
How is pressurization achieved?
By supplying constant inflow of air and by regulating the amount of air leaving aircraft through the Thrust Recovery Outflow Valve (TROV)
Automatic pressurization is available down to what source of power?
Main batteries through static inverter
What’s the meaning of amber FAULT light on CABIN PRESSURE CONTROL panel?
It indicates failure of both channels of dual channel controller: you’d have to select MANUAL
When does pressurization system automatically switch to FLIGHT and begin to pre-pressurize cabin prior to takeoff?
It’s initiated if 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 FLIGHTLANDING switch?
Cabin pressure control system automatically switches to descent pressurization schedule (i.e., 300 fpm).
When does FLIGHT-LANDING switch automatically switch to LANDING?
When aircraft descends from cruise at least 1,000 feet
When would you use semi-automatic (SEMI) mode?
Whenever FMS data is not available or is invalid, when directed by checklist, or at discretion of flight crew (e.g., flying in QFE environment or to high altitude airport)
What’s one of the benefits of flying in SEMI mode?
in SEMI mode?
You have more control over the system
What’s the purpose of 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 moves the TROV in manual mode?
A DC motor controlled by the pilot with the knob on the CPCS
In manual mode, how would you determine rate of TROV movement?
By observing motor power indicator: frequency of flashes is proportional to valve opening or closing speed.
What’s the purpose of pressure relief valve?
It provides rate-limiting function to prevent damage to aircraft fuselage from excessive positive or negative pressures.
What type of action does the pressurization system perform after landing to ensure minimal differential pressure exists within the cabin?
During ground operations when TROV is full open, pressure relief valve is forced open with bleed air (unless you’re in manual mode)
When would 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
What are cabin pressure low warning trip points based on?
Landing field elevation
What are the prerequisites for Emergency Descent Mode (EDM)?
Cabin Pressure Low CAS message Aircraft altitude ≥ FL400 Autopilot engaged
Describe aircraft operation in EDM
Aircraft automatically enters HDG hold mode, turns 90° left and enters FLCH mode with 340 kt manual speed (MAN SPD) target. Altitude preselector is set to 15,000 ft. If not already engaged, AT engages, and throttles pull back to facilitate rapid descent. The aircraft performs an ASEL capture at 15,000 ft and SPD target changes from 340 kts to 250 kts. The target SPD is maintained as long as AT is engaged.
How can EDM be cancelled?
By disengaging AP
With rapid loss of cabin pressure or altitude, what’s the first thing the crew should accomplish?
Don personal oxygen mask and ensure mask is set to 100% oxygen
What is the air conditioner temperature range in NORMAL?
60 - 90
What is the air conditioner temperature range in MANUAL?
35 - 230
What do blue wing anti-ice lines indicate on ECS/PRESS synoptic page?
Wing anti-ice temperature is <=100 F within two minutes of activation.
What do green wing anti-ice lines indicate on ECS/PRESS synoptic page?
Normal temperature (100 - 180 degrees F)
What do amber wing anti-ice lines indicate on ECS/PRESS synoptic page?
Wing temp is <100 AFTER two minutes from the time it’s commanded to ON or > 180 F.
What is the BAC minimum manifold set point range for operations at low power settings?
14 to 24 PSI
Why are there set points for the BAC?
Set points exist to ensure adequate pneumatic temp and press at the various power settings and bleed air requirements.
Can a BAC maintain 35 PSI without opening the high stage (8th) valve?
Yes.
If engine power is such that mid-stage air is enough to maintain 14, 24 or 35 PSI, then nothing happens. If not, the BAC opens the high stage valves.
