Aircraft Systems 2 Flashcards
1
Q
Hydraulics are typically used on what aircraft components?
A
Flying Controls, Flaps, Undercarriage, Wheel brakes
2
Q
Hydraulics are used to transmit ___ forces with rapid, _____ response to control demands.
A
HIGH forces, ACCURATE response
3
Q
List some advantages of using hydraulics (5)
A
Capable of transmitting very high forces, Rapid and precise response to input signals, Good power to weight ratio, Simple and reliable, Not affected by EM interference
4
Q
Hydraulic fluid is what is known as an ________ fluid
A
INCOMPRESSIBLE
5
Q
List some limitations and hazards of hydraulic fluid
A
Temperature and Aeration, Contamination, Flammability, Hazardous Liquids
6
Q
List the key components of the hydraulic system
A
Reservoir, Filters, Pump, Accumulator, Valves (Pressure Control and Directional), Actuator
7
Q
What is the name of the engine or motor driven positive displacement pump that the majority of hydraulic systems use?
A
Rotary Swash Plate pump
8
Q
What does PFCU stand for? (Hydraulics)
A
Powered Flying Control Unit
9
Q
What are PFCUs (Powered Flying Control Units) predominantly used for?
A
Assist in controlled movement of larger surfaces to counter aerodynamic forces at higher speeds.
10
Q
What does 3 REDS on the landing gear lights designate?
A
Unit is unlocked. Moving between up and down position
11
Q
What does 3 GREENS on the landing gear lights designate?
A
Unit is locked down.
12
Q
When the landing gear is LOCKED UP. What coloured lights will be shown?
A
NIL, No lights will be shown when the landing gear is locked up.
13
Q
What can be used to provide an alternative power source in the hydraulics, in the event of an emergency?
A
Ram Air Turbine (RAT)
14
Q
List some advantages of using hydraulics (5)
A
Capable of transmitting very high forces, Rapid and precise response to input signals, Good power to weight ratio, Simple and reliable, Not affected by EM interference
15
Q
Cabin pressure is typically controlled at _____ to _____ ft
A
6000-8000 ft
16
Q
List some symptoms of Hypoxia at altitude
A
Marked impairment to perform even simple tasks., Loss of critical judgement and willpower., General lack of awareness that impairment exists., Thinking is slowed, Reduced muscle co-ordination, Emotional changes. Garrulous, Euphoric or even violent., Possible blueness of lips, tongue, face and finger tips.
17
Q
List some causes of Hyperventilation
A
Anxiety, apprehension or fear, Rise in body temp, Whole body vibration 4-8 Hz, Hypoxia
18
Q
List some symptoms of Hyperventilation
A
Tingling hands, feet and lips, Vague feeling of unreality, Light-headedness/dizziness, Faintness, Spasms of muscles in hands/feet, Impaired performance, Unconsciousness
19
Q
What might give you ‘the bends’?
A
Decompression sickness
20
Q
List some symptoms of Decompression Sickness
A
Bends, Effects on the skin, Chokes, Neurological affect, Collapse
21
Q
List some symptoms of Barotrauma
A
Pain in ears, teeth and/or sinuses, Deafness, Ruptured eardrum
22
Q
Why do we need pressurisation?
A
To fly over high obstacles, To climb above inclement weather, To improve efficiency of turbo-fan engines, To increase cruise speed
23
Q
Cabin pressure is maintained around ___ to ___ ft
A
6000 to 8000 ft
24
Q
Maximum climb rate of change of cabin altitude is ___ ft/min.
A
500 ft/min
25
Maximum descent rate of change of cabin altitude is ___ ft/min.
300 ft/min
26
Name an op focussed circumstance whereby normal cruise alt may not be possible
Aeromedical evacuation flights if patient has severe head injuries
27
List the components of the CONTROL MODULE in the pressurisation system
Cabin Pressure, Rate Capsule, Metered Orifice, Static Vent/Pressure, Altitude Capsule
28
List the components of the DISCHARGE VALVE UNIT in the pressurisation system
Control Pressure line from control module, Calibrated Spring, Diaphragm, Valve Outlet
29
Other than CONTROL MODULE and DISCHARGE VALVE UNIT, what other main part is in the pressurisation system?
SAFETY RELIEF VALVE
30
List the main components of the AirCon system
Engine, Primary HX, Cold Air Unit, Secondary HX, Mixing Chamber, Water Extractor
31
List the 3 types of O2 systems
Gaseous O2, Liquid O2, Molecular Sieve
32
List adv and disadv of Gaseous O2 system
Adv: Relatively simple, O2 is not lost to venting, Can be used immediately after filling; Disadv: Cylinders are bulky and heavy, No suitable as primary O2 source when weight and space at premium
33
List adv and disadv of Liquid O2 system
Adv: Reduced bulk and weight, Will not explode if damaged; Disadv: Loss by evaporation and venting, Must be stabilised, Prone to contamination
34
List adv and disadv of Molecular Sieve O2 system
Adv: Efficient removal of contaminants; Disadv: Separate gas supply still needed for crew ejection, Not all MSOCs are able to be removed to provide enough O2 in rapid decompression.
35
Emergency O2 supply can be done in 2 principal forms, these are ….
Continuous Flow, On Demand
36
Emergency O2 typically lasts for about ____
10 mins
37
CWS (Central Warning System) gives _____ and ____ indications in response to certain failures and events in a/c systems.
VISUAL and AUDIO
38
The CWS (Central Warning System) Master Control Unit will have feeds from what other systems? (6)
Fire, Engine, Electrical, Hydraulics, Pressurisation, Avionics
39
What does CWP stand for?
Central Warning Panel
40
Momentarily pushing the ____ _____ button or an ______ _____ will stop them flashing, and cancel audio tones and voice messages.
MASTER CAUTION, ATTENTION GETTER
41
In the event of multiple alerts, the ______ _____ will be alerted to first.
HIGHEST PRIORITY
42
Pressing the attention-getter cancels ALL, SOME or ONE of the Warnings or Cautions in progress?
ONE
43
Aural warnings ______ cancel when their cause is removed, or when they are reset manually by the pilot.
AUTOMATICALLY cancel
44
A ______ warning normally demands IMMEDIATE attention.
PRIMARY
45
A ______ warning indicates a malfunction that needs to attention but does not necessarily require immediate attention.
SECONDARY
46
Define a PRIMARY warning
One that require immediate attention
47
Define a SECONDARY warning
One that does not require immediate attention but should be dealt with when appropriate.
48
Name the 3 types of CWS (Central Warning System) Warnings?
PRIMARY, SECONDARY, ADVISORY
49
What colours are the 3 types of CWS warnings?
Primary - RED, Secondary - AMBER, Advisory - WHITE or BLUE
50
“CWP TEST” tests the integrity of the ____ of the CWS and NOT the associated systems.
PARTS, i.e. lights buttons, switches
51
The undercarriage should be as _____ as needs be while as _____ as possible.
STRONG as needs be while as LIGHT as possible
52
Nose and Tail undercarriages are required to ______ to allow the aircraft to be steered.
SWIVEL
53
List the simple basic features of a retractable undercarriage
Doors and Fairings, Sequencing, Jacks and Linkages
54
______ _____ restrain the fully retracting undercarriage against ‘g’ forces in flight and when fully extended, absorb landing loads.
MECHANICAL LOCKS
55
There are 2 types of MECHANICAL LOCKS. These are ….
UP locks, DOWN locks
56
What does 3 GREENS on the landing gear lights designate?
Unit is locked down.
57
What does 3 REDS on the landing gear lights designate?
Unit is unlocked. Moving between up and down position
58
The emergency landing gear lowering mechanism MUST be ___________ of the normal operating mechanism.
INDEPENDENT, Typically a one use system and will require resetting following safe completion of incident.
59
List some design criteria for an aircrafts wheel and tyre assembly
Light weight, Minimum size, Good fatigue resistance, Accommodation of brake unit with sufficient heat dissipating ability., Easy tyre replacement.
60
Aircraft tyres are re-_____ as a matter of course to extend their life.
RE-TREADED
61
Brakes convert _____ energy to _____ energy. Thus reducing the speed of the aircraft.
convert KINETIC energy to THERMAL/HEAT energy
62
Brakes tend to be used as the final means of dissipating kinetic energy. List other ways of reducing kinetic energy
Use of flaps and spoilers, Reverse thrusters or propeller reverse pitch, Arrestor wires or parachutes (tend to be last resorts)
63
Disc brakes are made out of _____ _______ materials in order to operate at the necessary temperatures.
CARBON COMPOSITES
64
The maximum braking force should be used to minimise landing run but we must not allow the wheels to ____
SKID
65
Water on the ground may cause the wheels and the aircraft to _________
AQUAPLANE
66
What system can be used to apply maximum brake force whilst avoiding the wheels from skidding.
Anti-skid system
67
Name the 3 main categories of power sources
Primary, Auxiliary, Emergency
68
List the main PRIMARY power sources
Generators, AC - 200V, 3 Phase, 400Hz, DC - 28V, Batteries - 24V
69
List the main AUXILIARY power sources
Ground Power Unit (GPU), Auxiliary Power Unit (APU)
70
What is the DC standard used on aircraft?
28V
71
What is the AC standard used on aircraft?
200V, 3 phase, 400Hz
72
List some of the EMERGENCY power sources
Batteries, Ram Air Turbine (RAT), Emergency Power Unit (EPU), Airborne Auxiliary Power Unit (AAPU)
73
Name the 2 types of batteries
PRIMARY (Non-rechargeable), SECONDARY (Rechargeable)
74
The generator will convert mechanical energy into electrical energy by E_______ I_______
Electromagnetic Induction
75
What is the purpose of the CSDU (Constant Speed Drive Unit)?
To maintain a constant generator RPM and therefore a constant voltage output.
76
List the 3 different pieces of power conversion equipment
Inverter - DC to AC, Converter - Change the frequency of primary AC supply to a different secondary frequency, Transformer/Rectifier Unit (RTU) - AC to DC
77
Whenever batteries are fitted they will power the V___ DC b____
Vital DC busbar
78
Aircraft electrical systems divide consumer services into 3 categories. These are…
Vital - Needed for emergencies., Essential - Ensure safe flight during in-flight emergencies., Non-essential - not essential to maintain flight.
79
What kind of current flows at a constant voltage in one direction?
DC
80
What kind of current flows at varying voltage and cycles it’s direction?
AC
81
Aircraft system voltage must be maintained within a set tolerance over a wide range of
Engine Speeds, Electrical Loads
82
What does LSCU stand for? (electrics)
Load sharing control unit
83
What is the purpose of the LSCU (Load sharing control unit)?
Balance the loading between generators if multiple are present.
84
What does CSDU stand for? (electrics)
Constant Speed Drive Unit
85
The frequency control unit varies the speed of the generator by being connected to the ____
CSDU (Constant Speed Drive Unit)
86
Protection devices are essential in electrical circuits to guard against fault conditions such as:
Over/Under volt, Over current, Reverse current
87
What pieces of equipment protect against electrical circuit faults?
Circuit breakers, Reverse Circuit Cut-Out (RCCOs), Fuses
88
The output of the generator is i_____ p_______ to the input to the exciter field.
INVERSELY PROPORTIONAL
89
The output of the generator increases. Therefore, the input to the EXCITER FIELD will _______
DECREASE
90
What are the advantages of a bottle type O2 system?
Relatively Simple, O2 is not lost by venting when not in use, Can be used immediately after filling
91
2 key advantages of LOX
Less bulk and weight, Wont explode if damaged
92
Mixing chamber, secondary HX and water extractor form components from which system?
Air-Conditioning
93
What H describes an absence of an adequate supply of O2
Hypoxia
94
What is a Molecular Sieve?
A molecular sieve is the 3rd type of oxygen system. It will require a separate O2 supply to cater for rapid cabin depressurisation.
95
What B is caused by an imbalance of the pressure on the eardrum when contraction and expansion of gas on the middle ear cavities and fail to balance through the nose.
Barotrauma
96
What CO occupies haemoglobin seats and does not give them up?
Carbon Monoxide
97
List the 4 key reasons why we need pressurisation
Fly over high obstacles, Climb over inclement weather, Improve turbo-fan efficiency, Increase cruise speed
98
Decompression sickness has 4 key symptoms. These are
Itchy tingly skin, Chokes, Bends, Collapse
99
Continuous flow Emergency O2 systems usually last for how long?
10 mins
100
Cabin pressurization is usually maintained at what altitude?
6000-8000 ft
101
What is the PHE in the Air Con system?
Primary Heat Exchanger
102
In pressurisation operation what does SRV stand for?
Safety relief valve
103
What does PSID stand for?
Pressure differential
104
In pressurisation operation what does DV stand for?
Discharge valve
105
Hypoxia is likely to develop at what Altitude?
8000 ft
106
What are the 3 annunciations relating to the warnings?
Warnings (RED), Cautions (ORANGE/AMBER), Advisories (BLUE/WHITE)
107
If a WARNING appears, what do you do?
Deal with immediately
108
If a CAUTION appears, what do you do?
Deal with when safe to do so
109
How can you cancel Warnings, Cautions and Advisories?
Pressing the MASTER CAUTIONS
110
What are the 3 key requirements of undercarriage design?
Absorb shock from landing, taxying and movement of uneven surfaces, Ability to manoeuvre/control the a/c, No of components (should be minimal)
111
Name the component that ensures equipment in the undercarriage is operated in the correct order.
Sequencing valve
112
Name 3 undercarriage components that use the incompressibility of oil
Shock Absorbers, Actuators, Brake Callipers
113
Where are fusible plugs fitted and what is their purpose?
Fitted to the main wheels., The inner core is designed to melt before the wheel gets too hot.
114
3 GREENS means…
Gear is down and locked
115
What is the name of the component that must be disengage to release the undercarriage prior to extending
Up-lock actuator
116
What is the name of the undercarriage component that utilises N2 in an emergency
Accumulator
117
What does WOW stand for and give 2 examples of its function?
Weight on Wheels, Enable components in the air - pressurization/ weapons, Disable components in the air - Brakes, Reverse Thrust, Parachute, Prop reverse thrust
118
What system do we use to prevent wheel locking?
Anti-skid system, which releases pressure at the brake unit to prevent skidding
119
What does re-tread mean?
Replace the tyres tread after it has worn down., This is done to extend the effective life of the tyre.
120
What system is fitted in a brake system to prevent wheel locking?
Anti-skid system, which releases pressure at the brake unit to prevent skidding.
121
How do micro-switches operate, where are they fitted what is their purpose?
Micro-switch plunger only moves a very small distance, moving from on to off or vice-versa., Located in all wheel bays, Switch on or switch off red and green landing gear warning lights
122
What type of brakes are fitted to aircraft and what material are the brake pads made from?
Disk brakes., Carbon composite pads
123
What typical warnings are associated with the hydraulic system
Low pressure, High Temp
124
What does the term ‘differential braking’ mean?
Allows for independent activation of wheels brakes
125
What typical warnings are associated with the hydraulic system
Low pressure, High Temp
126
Describe ‘creep marks’ and explain why they are important
Creep marks are painted on the tyre and wheel rim., Under high impact loads experienced during landing, tyres tend to creep by small distances around the wheels., If tubed tyres creep, the valve stem of the inner tube which is firmly attached to the wheel is stretched and will eventually fracture.
127
What typical warnings are associated with the hydraulic system
Low pressure, High Temp
128
What would a confined column of hydraulic fluid want to do if force is applied to one end?
Expand in every direction
129
Which components remove debris and therefore prevents damage to system components?
Filter
130
How are hydraulic brakes ‘locked on’ in the parking mode?
Moving the parking brake from off to set, changes a two-way valve to a one-way valve and locks the hydraulic fluid in the brake unit.
131
What is the term used to describe the increase in strength in hydraulics?
Force Multiplication
132
What is the term used to describe the increase in strength in hydraulics?
Force Multiplication
133
List advantages of hydraulics
Capable of transmitting very high forces, Rapid and precise response to input signals, Good power to weight ratio, Simple and reliable, Not affected by EM interference
134
Know the Hydraulic System schematic
LOOK AT DIAGRAM
135
List the key components of the hydraulic system
Reservoir, Filters, Pump, Accumulator, Valves (Pressure Control and Directional, Actuator
136
What is the name of the engine or motor driven positive displacement pump that the majority of hydraulic systems use?
Rotary Swash Plate pump
137
What is the effect on hydraulic oil if it is allowed to boil?
Presence of gas introduces an unacceptable level of compressibility in the oil.
138
List some systems that use hydraulics and which is the most common?
Control surfaces, Flaps, Undercarriage, Wheel brakes, Cargo ramps, Speed brakes, Weapon release linkages, Undercarriage is most common
139
What are the 2 types off accumulator in the hydraulic system?
Damping, Emergency
140
What quality of liquid does hydraulic fluid utilise?
Incompressibility
141
What is the name of the component used to overcome larger control surfaces and thereby counter high speed aerodynamic forces and how does it differ from a normal actuator?
Powered Flying Control Unit (PFCU), Piston is fixed to the airframe and the PFCU body is connected to the control surface.
142
What is the name of the component that stores oil and what can be its secondary functions?
Reservoir, De-aeration, Cooling
143
What must be incorporated into aircraft system design if an aircraft has hydraulically operated PRIMARY flying controls?
Back-up system, Endurance should be indefinite
144
Name the 3 emergency electrical systems
Ram Air Turbine (RAT), Emergency Power Unit (EPU, Batteries
145
How quickly must an EPU be capable of developing full power and why?
Within 2 seconds, Fitted to aircraft with unstable controls
146
What voltage do most batteries provide?
24V
147
What voltage does a DC generator provide and why?
28V, Needs to have sufficient potential difference in order to charge batteries.
148
What are the 2 types of AUXILIARY power systems?
GPU - Ground Power Unit, APU - Auxiliary Power Unit
149
What is a CSDU?
Constant Speed Drive Unit
150
A CSDU maintains a constant generator ___ and therefore a constant voltage.
constant RPM
151
What is the name of a generator with an integrated CSDU (Constant Speed Drive Unit)?
IDG - Integrated Drive Generator
152
List the 3 different pieces of power conversion equipment
Inverter - DC to AC, Converter - Change the frequency of primary AC supply to a different secondary frequency, Transformer/Rectifier Unit (RTU) - AC to DC
153
Describe difference between normal relays and emergency relays
Normal - When the switch is turned ON this completes the circuit, powering the electromagnet and completing the contact., Emergency - When the switch is OFF, the emergency completes the circuit, powering the electromagnet and completing the contact. (FAILSAFE)
154
Std military and civilian aircraft AC systems are configured to ….
200 V, 3 phase, 400 Hz
155
Managing two generators in parallel must therefore sense …
Voltage, Frequency, Phase Angle
156
Voltage must be maintained within a ___ range of Engine speeds and Electrical loads.
WIDE range of Engine speeds and Electrical loads
157
What is the purpose of the Load Sharing Control Unit?
Ensure that there is an equal output from each generator
