A/C system Recit Flashcards
Hydraulic system
it uses a pressurized fluid to transmit power and create force, motion, or control through a network of interconnected components
Pascal’s Law
Pressure applied to a liquid spreads equally in all directions.
Users of Hydraulic System in Airbus
Flight controls
Landing gear
Brakes
Nose wheel steering
Cargo doors
Thrust reverser
Ram Air Turbine (RAT)
Advantages of using Hydraulic System
- Lightweight
- Easy to install
- Easy to Inspect
- Low Maintenance requirements
- Incompressible, nagtratravel liquid without loss of time and motion
- They provide good lubrication of components.
- Low viscosity
- They prevent internal corrosion in the system.
- They have a wide operating-temperature range.
Hydraulic Fluid
used primarily to transmit and distribute forces to various units to be actuated
Viscosity
a liquids ability to resist flow
as temperature decrease, viscosity increases
Chemical Stability
the liquid’s ability to resist oxidation and
deterioration for long periods.
Viscosimeter
measure the viscosity of a liquid
Sludge
Dirt or thick build-up that forms if the fluid breaks down.
Flash Point
the temperature at which a liquid
gives off vapor in sufficient quantity to ignite momentarily or flash when a flame is applied
The lowest temperature where the fluid can catch fire briefly.
Fire Point
the temperature at which a
substance gives off vapor in sufficient quantity to ignite and continue to burn when exposed to a spark or flame
The temperature where the fluid keeps burning once it starts.
Mineral-based hydraulic fluid (MIL–H-5606)
Red color
Good in cold weather
Flammable
MIL-H-6083 is a version with rust protection
MIL-H-6083
is a version with rust protection of mineral based hydraulic fluid
POLYALPHAOLEFIN-BASED
FLUID
Fire-resistant
Can self-extinguish
Works in very high temperatures
Good against rust
Phosphate Ester-Based Fluid
used in most commercial aircraft
not fireproof
Sensitive to water contamination
GIVE 2 BRANDS OF PHOSPHATE ESTER-BASED HYD. FLUID AND THEIR COLORS
Skydrol - Purple
Hyjet - Purple Blue
CHARACTERISTICS OF A PHOSPHATE ESTER BASED HYDRAULIC FLUID
Good fire safety
Protects against rust
Works well in heat and cold
Lightweight
HYDRAULIC RESERVOIR
is a tank in which supply of hydraulic fluid for
the system is stored.
HYDRAULIC PUMP
is responsible in
delivering hydraulic power into
the users of hydraulic system.
Hydraulic power output 3000 psi.
input psi is 40-47
output pressure of hydraulic system
3000 psi
input pressure of hydraulic system
40-47 psi
Check Valve
Fluid can only flow one way
Stops backflow
HYDRAULIC FILTERS
is a screening or straining device used to clean the hydraulic fluid, preventing foreign particles and contaminating substances from remaining in the system.
micron element
is designed to prevent the passage
of solids greater than 10 microns
Shutoff Valve
are used to shut off the flow of fluid to a
particular system or component
Stops fluid flow during problems or emergencies
PRESSURE RELIEF VALVE
Releases extra pressure if it gets too high
also called Safety Valve
can not be used as pressure regulator
Pressure Regulator
Controls system pressure
Keeps the pump running safely without wasting energy
is to manage the output of
the pump to maintain system operating.
SELECTOR VALVE
allows the changing of
direction of the flow of pressurized
hydraulic fluid
HYDRAULIC ACTUATOR
converts hydraulic power to
mechanical action
ACCUMULATOR
is a steel sphere divided into
two chambers by a synthetic rubber
diaphragm.
The upper chamber contains fluid at
system pressure
the lower chamber is
charged with nitrogen or air.
STORES HYDRAULIC PRESSURE
FUNCTIONS OF ACCUMULATOR
Absorbs sudden pressure changes (to prevent damage)
Provides extra power when many parts work at the same time
Stores power for emergency use if the pump stops
Maintains pressure to cover small leaks and prevent the system from turning on and off repeatedly
Hydraulic System Safety Procedures
Wear coveralls
Use nitrile or polymer gloves
Use safety goggles
Fluids like Skydrol can dry or irritate your skin
Prevent leaks and handle with care
Pneumatic system
utilized the use of compressed air for the operation and use of the air conditioning and pressurization system,
anti- icing, engine starting, hydraulic reservoir and potable water
tank pressurization.
Location of the controls of the hydraulic system
cockpit
Uses of pneumatic system
AIR CONDITIONING AND PRESSURIZATION
ANTI- ICING
HYDRAULIC RESERVOIR PRESSURIZATION AND
POTABLE W ATER PRESSURIZATION
Air Bleed
Compressed air taken from the engine or APU (auxilliary power unit)
compressed air
pneumatics, bleed air, or air bleed
Fokker F-27 Turboprop Aircraft
first aircraft to use full pneumatics on
* Brakes
* Opening and closing doors
* Driving hydraulic pumps, alternators, starters, water
injection pumps.
* Operating emergency devices
Disadvantages of pneumatic system
*Loss of precision due to the high
compressibility of gas compared to liquid.
*Bleed Air does not respond immediately to
pressure differentials.
Short:
Not precise
Slow reaction compared to hydraulics
Compressible (hard to control accurately)
Sources of pneumatics in wide bodied
Engines (8th and 13th compressor stage)
Auxiliary Power Unit (APU)
Pneumatic Cart / Ground Power Unit
Auxiliary Power Unit
acts as a standby source of bleed air in case during flight
OPERATING PRESSURE AND
TEMPERATURE OF PNEUMATICS
200-250 °C and 40 psi
PRECOOLER
air-to-air heat exchanger located in the
pylons that cools and regulates the bleed air before it enters the distribution manifold
Pressure Regulating Valve / Bleed Valve
Controls air pressure and temperature of bleed air prior to entering the system
Shuts off air during emergencies
CROSSBLEED VALVE
Allows the connection of the
two sides of the Pneumatic system.
When both engines cannot supply bleed air during operation, this valve allows the APU to supply bleed air to the users of Pneumatic System.
Check Valve
prevents the reverse
flow of bleed air
BLEED AIR SUPPLY DUCT
Acts as supply line where the bleed air
travels to the distribution manifold
HEPA Filter
HIGH EFFICIENCY PARTICULATE
ARRESTANCE FILTER
bleed monitoring computer
control all the valves that
comprises the Pneumatic System and monitors the system as a
whole.
shuts off the valves when encountering emergencies.
ECAM (Electronic Centralized Aircraft Monitor)
Monitors aircraft systems (like pneumatic and hydraulic)
CFDIU (Centralized Fault Display Interface Unit)
Displays system faults or problems for the pilot
LEAK DETECTOR CAMERA
quick leak detections in a safe environment
The camera uses 124 microphones to form a very precise acoustic image in
the desired direction.
location of the controls of pneumatics
The controls of the pneumatic system are located in the cockpit.
The pilots control and monitor the system using buttons, switches, and screens.
It is part of the ECAM or monitoring system inside the cockpit.
X bleed Valve
Same as cross-bleed valve, allows air sharing between engines or from APU
OVER PRESSURE VALVE
Protects the pneumatic system by releasing extra pressure if it’s too high (same function as pressure relief valve in hydraulics)
Users of pneumatic system
air conditioning
pressurization system
anti- icing
engine starting
hydraulic reservoir
potable water tank pressurization
Sources of pneumatic in wide bodies
APU and bleed air
Where to locate controls of pneumatic
Overhead control panel
Important Properties of a hydraulic fluid that is use in aviation
viscosity
chemical stability
fire point
flash point
