Everything Flashcards
Purpose of aircraft pressurisation
To allow comfortable and safe flying at high altitudes
3 pressurisation modes
Rate mode - pressurises aircraft upto 8000ft
Isobaric mode - holds cabing pressure at 8000ft while aircraft can continue to change altitudes
Constant differential mode - maintains a set pressure differential during flight
Aircraft pressurisation achieved by what 3 methods
Compressor bleed air from engine
Engine driven compressor
ground supply
2 ways pressurisation control systems are operated
Pneumatically
Electrically
3 cockpit indicator instruments
Cabin altitude
Cabin rate of climb
Pressure differential
What controls cabin outflow valve
Pressure regulator
What is the purpose of a an aux vent valve?
Bonus what else can do this
When weight on wheels the valve opens to atmosphere to equalize pressure.
Bonus: most electronic outflow valves do the same
Purpose of safety valve
To stop over pressurisation of the aircraft. Doesn’t allow max PD to be reached
Temperature and pressure at sea level
59F or 15C
14.69 PSI
Sealing of axial and radial control tubes
Axial use felt or leather glands packed with grease
Radial use a rubber seal attached to control tube
6 SAFETY WITH CABIN PRESSURE TESTING
- Safety man outside AC
- Audio/visual contact between safetyman and crew
- AC to be fully depressurised before opening of windows, doors, hatches
- Person carrying external Leak check exercise care when around hatches, windows, doors
- Person suffering cold/sinus symptoms not allowed in pressurized cabin
- Decompress sickness, personal are to wait 12hrs before flying and diving
Explain de ice
De ice is the removal of built up ice. Can be done through heat (pneumatic or electric) or pneumatic boots
Explain Anti ice
The prevention of ice build up. Use electric thermal, hot oil, hot pneumatic air, chemical means of prevention
3 methods of rain removal/prevention
Wipers
Pneumatic
Chemical
How are de ice boots held to LE when not in use
Vacuum
Material of ducting for Aircon system
Stainless steel, anconel
3 elements aircon system control
Temperature
Humidity
Ventilation
Components of a air cycle system
Primary heat exchanger Compressor Secondary heat exchanger Turbine Water seperator Shut of valve Temperature control valve Refrigeration bypass valve
Purpose of refrigeration bypass valve
Keep air exiting ACM from freezing. Keeps air at 35F or 2C.
Passes warm bleed air around ACM and mixes at output of ACM.
Primary purpose is to prevent water from freezing in water seperator
Function of temperature control valve
Controls amount of bypassed air from ACM.
Secondary can direct air into entry point of water seperator to prevent freezing
Types of ice detection
Visual
Electronic
Optical
2 types of leakage
Controlled
Uncontrolled
What is controlled leakage
The allowance of air to leave the aircraft via the outflow valve or safety valve
Passenger airline pressurisation rate of climb and decent
Rate of climb at 500fpm
Decent at 300fpm
