Airbus Systems Flashcards
Air conditioning
Fully automatic.
3 zones, independently controlled.
Air supplied from the pneumatic system, via:
Two pack flow control valves,
Two packs,
The mixing unit (mixes air from cabin and packs)
In an emergency, a ram air unit can provide ambient air to the mixing unit.
Zone temperature selector range is from 18 degrees to 30 degrees.
Three trim air valves modulate hot air from the hot air pressure regulating valve.
Cabin pressurisation
The system consists of:
Two cabin pressure controllers
One outflow valve, with an actuator that incorporates 3 motors- two for automatic control, one for manual control
One control panel
Two safety valves
In automatic operation, the system receives signals from the FMGS based on the information input by the pilots when loading the FMGC (landing airfield elevation and QNH). When FMGS information not available in auto mode, the pilots have to manually select the airfield elevation.
In manual mode, flight crew controls the cabin altitude using the manual motor of the outflow valve.
Electrical system
In normal configurations, electrical system provides AC power via 2 engine generators and one APU generator. Each one can provide power to all electrical bus bars.
A part of this AC power is converted into DC power for certain applications.
If normal AC power is not available, an emergency generator can provide AC power using the RAT to drive the emergency generator using the blue hydraulic system. The emergency generator powers the AC ESS BUS, and DC ESS BUS via the ESS TR.
In the event that no AC power is available, DC power from the batteries can be inverted into AC power
AC BUS 1 normally supplies AC ESS BUS
TR 1 normally supplies DC BUS 1, DC BAT BUS and DC ESS BUS
Tr 2 normally supplies DC BUS 2
The two batteries are connected to the DC BAT BUS, in case they need charging. The battery charge limiter disconnects the batteries when they are fully charged.
After loss of all generators, the EMER GEN supplies the AC ESS BUS and the DC ESS BUS via the ESS TR.
Below 100 kts, the RAT stalls and power generation is transferred to the batteries and static inverter, and the system automatically sheds the AC SHED ESS and DC SHED ESS buses.
When on ground,
Below 100 kts the DC BAT BUS is automatically connected to the batteries,
Below 50 kts the AC ESS BUS is automatically shed, leading to the loss of all display units.
Hydraulic system
3 systems, blue green and yellow operating at 3000 psi (2500 psi when powered by the RAT)
Engine 1 pressurises the green system, an electric pump pressurises the blue system and engine 2 pressurises the yellow system, which can also be pressurised by an electric pump on the ground when the engines are stopped.
The PTU enables yellow system to pressurise the green system and vice versa, and comes into action automatically when the differential pressure is more than 500 psi. This allows the green system to be pressurised on the ground with the engines stopped.
Green system pressurises landing gear movement and normal braking.
Yellow system pressurises alternate braking and NWS.
G + Y failure:
Alternate law, slow slats, flaps jammed, cat 1, LG gravity extension, direct laws when gear down, no reversers, no NWS, braking only via accumulator (max 7 applications of max 1000psi available).
G + B failure:
Alternate law, slats jammed, flaps slow, cat 1, no ATHR, LG gravity extension, direct law with gear down, only 1 reverser, alternate braking.
Y + B failure:
Normal law, slats slow, flaps slow, cat 1, LG gravity extension, one reverser, normal braking, no NWS.
