Pressurisation Flashcards
Components
- 2 computers: Cabin Pressure Control Unit (CPCU) 1 and 2
- Manual Motor Control Unit (MMCU) — Thrust Recovery Outflow Valve (TROV) – Pressure Relief Valve (PRV)
- Cabin Pressure Acquisition Module (CPAM)
- How is control of CPCS page of TSC affected by pressurization system mode of operation?
In Auto mode, Aircraft Altitude, Cabin Altitude, Baro Corr, Landing Elevation, and Rate Limit is viewed on CPCS page. In Semi mode, this data can be changed.
- What’s the meaning of amber FAULT light on the CABIN PRESSURE CONTROL panel?
It indicates failure of both CPCU 1 and 2: you’d have to select MANUAL.
- When does system automatically switch to Flight and begin to pre-pressurize cabin prior to takeoff?
Initiated if doors are closed and any of the following occur: switch is selected to Flight, airplane begins to move > 9 knots or throttles are advanced.
- What happens in-flight when Landing is selected on Pressure Profile switch?
Cabin pressure control system automatically switches to descent pressurization schedule (i.e., 300 fpm).
- When does the Pressure Profile switch automatically switch to Landing?
When 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 checklist, or at discretion of flight crew (e.g., flying to high altitude airport).
- What’s one benefit of flying 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 if CPCU 1 and 2 fail.
- 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 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.
- 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’s the trip point for red Cabin Pressure Low CAS message?
Landing field elevation
- What are the prerequisites for Emergency Descent Mode (EDM)?
Cabin Pressure Low CAS message
Aircraft altitude ≥ FL250
Autopilot engaged
- Describe aircraft operation in EDM.
Speed target on guidance panel changes to 340 KCAS in manual mode, altitude preselect is set to 15,000 feet, AP commands a left 90° heading change in heading hold mode, and A/T decreases engine throttles to idle. If not engaged, A/T automatically engages and decreases engine throttles to idle. Airplane descends to MMO/VMO to 15,000 feet and speed brakes automatically extend. At 15,000 feet, speed target changes to 250 KCAS. Override EDM by disconnecting AP.
