Systems Flashcards
1
Q
How likely is a minor failure
A
Probable
2
Q
How likely is a major failure
A
Remote
3
Q
How likely is a hazardous failure
A
Extremely remote
4
Q
How likely is a catastrophic failure
A
Extremely improbable
5
Q
What is “safe life”
A
Life given to a aircraft in which it will not suffer a catastrophic failure
6
Q
What is fail safe
A
A failure of a particular part is compensated by an alternative part for a limited time
Limited time is until next periodic inspection
Disadvantage is it’s heavy
7
Q
What is a damage tolerant structure
A
Spreading load over a large area
Damage can be detected during normal inspection cycles before failure occurs
8
Q
What is a stress
A
Internal force per unit area inside a structural component as a result of external loads
9
Q
What is strain
A
Deformation caused by stress on a material
% dimension of original
10
Q
What are the 4 types of stress
A
Tension (traction)
Compression
Torsion
Shear
11
Q
What strain is placed on a component during bending
A
Compression inside of bend
Tension outside of bend
Shear in middle (@spar)
It is a combined load
12
Q
What is torsion
A
Twisting
Tension is at outer edge
Compression in the centre
Shear cross structure
13
Q
What is elasticity
A
A material can elongate then return to original shape
14
Q
What is plasticity
A
Material permanently reform
15
Q
What is a stringer used for
A
To prevent compression load on outside of skin buckling
16
Q
What is buckling
A
Occurs to thin sheet materials when subject to compressive forces
17
Q
What are dynamic loads
A
Built up quickly due to changes in flight conditions
18
Q
What are static loads
A
Usually Constant and build up slowly
I.e loading up with fuel
19
Q
Where experiences the largest bending moment
A
Wing root
On ground = static force is main gear on wings
In air = upward forces by lift
Max on empty wings
20
Q
How to reduce wing loading / stress
A
Outboard ailerons locked it at same time as flap retraction
Aileron upwards = pushes wing down at High speeds
Fuel in winds
Engines on wings
21
Q
What is a cyclic load
A
Repetitive load placed on and off
Causes structure to fail quicker than static load
22
Q
What determine the number of cycles to failure
A
Amplitude of the load
23
Q
What is design load limit
A
Max load designer expects the aircraft to experience in service
Based on 2.5g for transport aircraft
24
Q
Design ultimate load
A
Safety factor applied to design load limit
Must withstand design ultimate load without collapse
Safety factor of 1.5 added to design load limit
25
If aircraft is at ultimate load what is the impact
Should remain largely intact for at least 3 seconds
26
What is failure
Fail of a structure which is subjected to continual reversals of load
27
What does the S-N diagram / wohler curve represent
The relationship between fatigue and amplitude
28
What type of load is failure more likely under
Tensile (tension / traction)
29
What is a alloy
2 or more metals together that give properties not had before
Good weight to strength ratio
30
What qualities but a material contain
Elasticity
Plasticity
Stiffness
Strength
31
What are common materials used in aircraft
```
Aluminium
Titanium
Magnesium
Alloys
Steel
```
32
What is the most common aluminium alloy used
Daralumin
33
What is daralumin
Copper based aluminium alloy
Magnanese, silicon, magnesium
Very god thermal / electrical conductivity
Excellent strength to weight ration
Susceptible to corrosion
34
What is Alclad
Sheets of duralumin with pure aluminium coating on its surfaces
```
Duralumin = strength
Aluminium = protects the duralumin
```
35
What is a composite material
2 or more elements to produce w material with different properties to those of the original
36
What does a composite material consist of
Matrix usually a thermosetting polymers or eproxy resins
Fibres = carbon / Kevlar / glass
37
What is a radar dome made out of and why
Fibre glass and it is radar transparent
38
What is carbon fibre good for
Strength to weight ratio
But doesn’t like big impacts
39
What is Kevlar (aramid) good for
Impact resistance
40
What is a matrix used for
Spread the load to each fibre
Also protect the fibres
41
What is a honeycomb / sandwich construction
Typically used for flight control surfaces, flooring, fuselage panels
Has good strength to weight ratio + really strong in direction of honeycomb openings
42
What is corrosion
Disintegration of a engineered material
Oxidisation = when metal is exposed to air
Electrolytic = am electric current between two metals
Degree of corrosion is proportional to level of moisture
43
What is stress corrosion
Integration between fatigue and corrosion
Combination of corrosive conditions and tensile loads
Causes quick, unpredictable failure
44
What is stress corrosion (cracking) (SCC)
Unexpected failure due to stress fatigue
45
What is hard time maintenance
Definite time limit for individual components and structures
Item is removed from service before scheduled maintenance period for inspection of repair
46
what is on condition maintenance
Inspection or check that can be done without disassembly or overhaul, to assess the performance and then if required will be removed for maintenance
47
What is the fuselage
Pressure hull between forward and rear bulk heads
48
What is the main structural member of framework / truss
Longeron
Frame take all the loads
49
What is a monocoque construction
Formers just give the shame
Skin takes all the loads
Extra strength (Doublers) needed to be built around holes (window etc)
Heavier
Only suitable for small aircraft
50
What is a semi- monocoque construction (stressed skin)
Main structural member = longeron = goes nose to tail
Stringer = prevents buckling = gives fuselage shape
Skin takes majority of the load but is supported and assisted by frames, longeron, stringers
Good weight / strength ratio
51
What are stiffeners
Additional lengths of metal between frames riveted to the skin to provide additional support
52
What are different attachment methods
```
Riveting
Welding
Bolting
Bonding
Pinning
```
53
What is a firewall made out of
Stainless steel/ titanium alloy
54
What is a rectangular fuselage
Many non pressurised
High weight / strength ratio
Cheaper to build
55
What is a circular fuselage
Ideal shape for pressurised
Stress spread evenly
Relatively easy built
Sometimes space is wasted when pax and cargo has to be accommodated
56
What is a double bubble fuselage
Figure of eight
Can carry more pax
Will save fuel
Will be slightly slower
57
What is designed to oppose hoop stresses
Frames
58
What are hoop stresses
Outward stress in shape of s hoop round fuselage
59
What is the max difference of pressure between inside and outside
9 psi
60
What is the main spar of a wing
Front spar
61
What gives the shape of a wing
Ribs = front to back
62
What goes spanwise of a wing
Stringers
63
What structure is on the leading edge of s wing
Honeycomb structure
64
What is a externally braced wing
Usually older aircraft
Like a biplane
65
What is a semi cantilever wing structure
Mostly light / high wing aircraft
Like Cessna
66
What is a cantilever wing
Fully self supporting
No external bracing
67
What is the middle of a main spar called
web
68
What is the torsion box
2 spars with skin on upper and lower side
With rilo inside
69
What is the empennage
Tail section
Provides longitudinal / directional stability
Horizontal and vertical stabiliser
Rudder
Elevator
Supporting structure underneath
70
What load does a wing NOT want
Twisting
Can cause flutter
71
Where is the max bending moment of s wing
At the root
Reduces by fuel in wings
Engines as mass balance (forward of cg)
72
What is floor venting
Blow out panels = open automatically to equalise pressure across floor structure
Prevent distortion during rapid decompression
73
Aircraft doors are what type
Plug type
74
What is a cargo door operated by
Hydraulic power pack
Not s plug type door
75
What do windows need to withstand
```
Airflow
Precipitation
Birds
Insects
Pressurisation
```
76
What is the typical window construction
Glass
Heating element
Vinyl (polycarbonate)
Glass
= like a sandwich
77
What is a DV window
Direction vision window
= can open
= pilot must have a window that can open when cabin not pressured
78
What is a eye reference position
To set seat at correct position
79
What is the difference between a heavy landing and a overweight landing
Heavy = too much vertical descent rate
Overweight = too heavy
80
What is the primary damage of overweight / heavy landing
Landing gear
Support structure in wings / fuselage
Wing / tailplane attachments
81
What is secondary damage of a heavy and overweight landing
Fuselage structure
Fuselage upper and lower skin
Wing structure
Wing upper / lower skin
82
What is the damage of s nosewheel landing
Front pressure bulkhead
Nose wheel drag / shock struts
Possibility of nose wheel collapse
83
What is the damage / risk or tail strike
Higher risk on flapless landing
Over rotation
Damage to:
Empennage structure
Rear pressure bulkhead
84
What is sea level pressure
14.7 psi
1 bar = 14.5psi
85
What is hydrostatic pressure
Pressure generated by height
86
What is pascals law
Pressure will be felt the same everywhere 90° to surfaces
87
What is bramah press
Force = pressure x area
Small piston = small force
Large piston = large force
For the same pressure
88
What is a passive hydraulic system
No pump
If air in brakes = feel spongy
Solution = bleed breaks normally
89
What is a active hydraulic system
Pump is used to ensure pressure
Typically 3000psi
= size of actuators can be reduced = needs less fluid = pipes can be smaller = easier to fit
Reduces weight
90
What is a O-ring seal
With high pressure = night leak
Acts both directions
91
What is a chevron seal (v seal)
Only seals one direction
Better for very high pressure
92
What is the purpose of a backing ring
Prevents extrusion
93
What is mineral oil
DTD 585 = Def Stan 91-48 super clean
Red
Seal material = synthetic rubber
Flammable
94
What is synthetic oil
Skydrol
Green or purple
Butyl rubber seal
Irritant to both skin and eyes = fire resistance = less prone to cavitation
95
What happens if wrong oil is used
Eats away at seals
96
What is a single acting actuator
Hydraulic pressure moves piston in one direction
Spring returns pressure when released
= undercarriage door locks
97
What is a double acting balance
Hydraulic pressure moves piston in both directions
Equal pressure on both sides
Nose wheel steering
98
What is double acting unbalanced actuator
Pressure either side
One side has a ram shaft = less pressure that side
= more force going one way
= Landing gear / flaps
99
What are the 2 types of selector valve
Linear or spool
100
What is hydraulic lock
Nothing in / nothing out
101
What hydraulic system do some small planes use
Self contained package system
Or
Basic open centre system
When nothing selected = oil goes round and round
Simplest
Only one service can be operated at a time
102
What is a constant delivery pump
Gives same flow of hydraulic fluid
Requires automatic cut out valve to stop exploding pipes = senses pressure downstream
103
What happens if there isn’t enough pressure in accumulator
Hydraulic pressure will fluctuate
Can get chattering
104
What does a content delivery pump require
ACOV
| accumulator
105
What is a constant pressure pump
Makes sure sufficient pressure to maintain 3000psi
Can simultaneously operate multiple services
106
Why is a hydraulic reservoir sometimes pressurised
Prevents cavitation
Or
Prevents boiling
107
How should a hydraulic reservoir be checked for level
When all system components are at correct setting
Accumulators are fully charged
108
What is a stack pipe
Stops fluid becoming too low so can be used for emergency system
109
Where is a hydraulic fluid temperature sensor found
In reservoir
110
Where does the air for a hydraulic system come from
Compressor stage of turbine
111
What are baffles for
Stop hydraulic fluid moving round too much
112
What are accumulators
Filled with nitrogen
Should be at half system pressure
But when main hydraulic system is fully charged should be 3000psi
Acts as a store of hydraulic fluid under pressure
damps our pressure fluctuations
113
What is a brake accumulator for
For operation of brakes if hydraulic pressure lost
Gives a limited number of applications
114
What happens to the ACOV if there is a leak
Cut in and out frequently
115
What happens to the swash plate in a constant pressure (variable volume) pump when at low pressure
Swash plate = acute angle = max deflection
116
What is a quill drive
Drive shaft necked so that if pump stops the drive shaft snaps to stop damage to engine
117
What is a drain case for
Small amount of fluid is let through holes in a hydraulic pump for lubrication
Collected in drain case
118
Purpose of a drain case filter
Monitor condition of pumps
119
If 2 pumps that deliver 3000psi @ 10 gals/ min each
What is the combined output
3000psi @ 20gals/ min
If one pump fails = services work slower / operating times extended
Not half speed!!
120
What are the 2 types of hydraulic filter element
Paper (replaceable)
Metal ( washable)
121
What is a full pressure full flow relief valve
Excess pressure acts against a spring causing the ball to unseat at cracking pressure
Dumps flow of pressure
122
What is a thermal relief valve
Relieves excess pressure caused by expansion of trapped fluid as ambient temperature increases
Senses pressure not temperature!!!
123
What does a mechanical overload protection do
Fitted in flap circuits and some spoiler circuits
Prevents damage caused by aerodynamic forces
Eg flaps at High speed
124
What is a restrictor valve
Used for undercarriage down
Flaps up
Restricts fluid flow to slow speed of operation
Found in up lines
125
What is a pressure maintaining valve (priority valve)
In event of system supply reducing
Ensures pressure is provided to essential services
126
What is a pressure reducing valve
Reduces pressure for use on some systems
127
What is a modulator
Specific to brake system = helps anti skid
Basically a flow control valve
128
What is a shuttle valve
Provides a method of having both emergency and normal supplies of pressure to a single source
129
What is a hydraulic fuse
If massive leak downstream = stops you leaking all your fluid
System upstream still operates normally
130
If there is a slow external hydraulic leak what happens to contents pressure and temperature
Contents slowly decrease
Pressure no change
Temperature no change
131
What happens to a fast external hydraulic leak in terms of contents pressure and temperature
Contents rapid loss
Pressure nil
Temperature n/a
132
What happens for a internal hydraulic leak in terms of contents pressure and temperature
Contents no change
Pressure no change
Temperature increases
133
What is a hand pump
Hydraulic pump
Double acting
134
What are sequence valves
Males systems work in right sequence
Can be mechanical or hydraulic
135
What prevents landing gear being selected up
Patched pin on leaver
136
What is the steps of landing gear retraction
Doors fully open
Inflight braking to stop wheels spinning usually around 400psi ish
Break the down lock
Main retraction jack starts to rotate
Doors shut
Cockpit indicator lights off
137
What are the steps of landing gear extension
Doors fully open
Undercarriage down
Over centre geometric device locks
Doors shut
Green cockpit indicators
138
What happens if landing gear doors are in incorrect position
Orange light
139
What are the characteristics of spring steel cantilever leg and rubber chord / bungee
Nothing to stop recoil / bounce
Typically used on small aircraft
140
What prevents the sliding / plunger or a oleo pneumatic strut from rotating in the leg
Torsion torque
141
What is a bogey
4 or more wheels would
142
In a shock absorber what acts as a damper
Oil
143
In a shock absorber what acts as the spring
Gas
144
In a shock absorber what happens when flutter plate is open
Oleo can compress easily
145
In a shock absorber what happens if flutter plate is closed
Oleo has slow extension (stops bounce)
146
Whats the most common cause of having insufficient extension of oleo (fescalised portion being to small)
Not enough gas (leak)
Could cause bottoming out on landing
147
What happens if oleo oil levels are too low
Rebound is not properly damped
148
What are brake bars
Torque limiting
Won’t let you brake too much
149
What does a fuselage mounted screw jack landing gear require
Means of locking up and down
Creep = unwanted movement of screw jack
= to prevent = mechanical locks
150
What force does the nose wheel feel when being towed
Shear
151
What does part of the landing gear door need to be made out of
A frangible portion to break on landing during emergency landing gear extension
152
What prevents the up selection of gear on the ground
Ground locks = pins which are in undercarriage to stop collapsing
Gear selector leaver have latches in to prevent being moved
153
What is a landing gear configuration warning
When flaps and slats in landing configuration and throttles pulled back to a pre defined position with gear still up
= continuous tone
154
What is castoring
Ability of a nose wheel to turn either side in response to differential braking or rudder
(Like a shopping trolley wheel)
155
What is the normal angular movement of the nose wheel limited to for large aircraft
75° left or right
To prevent scrubbing
156
What is a nose wheel steering centring mechanism used for
Automatically centres wheel for retraction
157
What is nosewheel shimmy
Rapid sinusoidal oscillation of nose wheel of a divergent nature
158
What causes nosewheel shimmy
Uneven tyre pressure
Unevenly work tyres
Unbalanced wheels
Worn shimmy damper / wheel bearings
159
How can you reduce shimmy
Provisions of hydraulic locks across the steering jack piston
Fitting a hydraulic damper
Heavy self centring springs
Double nose wheels
Twin contact tyres (maarsyrad)
160
What is a well based tyre
Light aircraft with tubed tyre
161
What is a loose or detachable flange
Designed to facilitate tyre replacement
162
What is divider or split wheel
2 half’s mounted together
Designed for tubeless tyre
Seal incorporated at joint to provide air tightness
163
What is a knurled flange
Inner face is milled
Locks tyre onto wheel flange
164
What are wheels usually made from
Aluminium alloy
| Magnesium alloy
165
What are fusible plugs for
Melt when internal tyre pressure gets too high
Prevents blowout
166
What do pneumatic tyres tend to be filled with
Nitrogen
167
What does the flexible casing of a tyre tend to be made from
Rubber coated rayon, cotton, or nylon ply chords
Wrapped round beads at each edge of the tyre
168
What is the crown of a tyre
Area of tyre that holds the tread pattern
Makes contact with the surface
169
What is the shoulder of a tyre
Thins out from crown to sidewall
170
What is the sidewall of a tyre
Weakest part of a tyre
Least able to cope with damage
171
What is the bead of a tyre
Strong rim of tyre which engages with rims of the wheel to form a air tight seal
172
What is a ply rating
Index of strength
Does NOT relate to number of plies
173
What does a tubeless tyre have
A layer of non permeable vulcanised rubber
174
What is the advantages of a tubeless tyre
Gas pressure maintained over longer period
No rapid loss of pressure = more resistant to blow outs and rough handling
Approx 7.5% weight saving
No inflation valve damage from creep
Cooler than tubed = no friction between tube and tyre
175
What is bias / cross ply
Plies are laid in pairs with chords paced @ 90° to one another
176
What is radial ply
Plies are laid from bead to bead
Approx perpendicular to centreline of tyre
177
What is a retread tyre
New tread heat bonded onto old carcass
Tyre repaired over again unless main body damaged
178
What is an inflation valve
Tube inflated through a schrader valve
| Basically a non return valve
179
What is acceptable creep limit for <24” tyre
1” of creep
180
What is acceptable creep limit for a tyre of greater than or equal to 24” diameter
1.5” of creep
181
What is a chined tyre
Fitted on nosewheels of aircraft with fuselage mounted engines to prevent water ingestion from wet runways
182
What is a maarstrad tyre
Anti shimmy
183
What speed is taxi usually limited to to prevent tyre wear
25mph
184
When is aqua/ hydroplaning a risk
When water depth exceeds tread depth
Speed = 9(*squareroot*tyre pressure)
185
How to reduce risk of aquaplaning
Correct tyre pressure / tyre wear
Using anti-skid
Avoid large standing water
186
What aircraft usually used single disc brakes
Light aircraft
187
What aircraft usually uses multi disc brakes
Heavier aircraft
188
What is brake fade
Results from brakes overheating
Not able to absorb any further energy and retardation is reduced
Overheated brakes may judder
189
What is brake drag
Wrongly adjusted or faulty brakes
Prevents brakes from releasing correctly
May contribute to fade
190
What are multi plate brakes
Consists of interleaved stators and rotors
191
What are friction pads / plates made from
Heavy steel with a special case of hardened surface carbon
If steel brakes on fire = used dry powder not water
192
How to check for brake wear
Have brakes applied / on
Check the retraction pin (if can feel it then they are good)
193
Benefits of carbon brakes
Lighter
Absorb 2x as much heat as steel
Less prone to brake fade
More durability (last longer)
More expensive but fit for longer time
194
Can you take off from a contaminated runway with anti skid inoperative
No
195
Benefits of s electronic anti skid system
Can be checked prior to use
Quicker response rates
196
Anti- skid functions
Skid prevention
Touch down protection
Locked wheel protection
Hydroplane protection
197
When is antiskid deactivated
Either manually or automatically when aircraft slowed to approx 20mph
198
What is touch down protection
Prevents brakes being applied before touch down
Controllers monitor wheel speed and air ground logic
Looks for signal from 2 separate wheels
199
What is locked wheel protection
If wheel locks = releases pressure until it spins up fully again
200
What is hydroplane protection system
Looks for all wheels on a bogey to be locked
Will release a number of brakes
201
What is torque limiting in terms of brakes
Stops you braking too hard and damaging landing gear
Problem on carbon brakes
202
When can you use auto brakes
Only with a silly working antiskid and braking system
203
What happens when auto brakes fail
Selector switch automatically turns to disarm
Alarm sounds
204
What are the conditions for rejected take off autobrakes to work
Speed of 85/90 knots approx
Throttles retarded to pre determined point
“Positive attempt to take off has been made”
205
How to set parking brake
Put feet on pedals
Set parking brake handle
Maintains constant pressure
206
How to disarm autobrakes
Foot brakes
Advance thrust leavers
Moving speed brake leaver down
Normally disarmed by non handling pilot as aircraft slows to approx 20 knots (not set speed)
207
What are primary stops (manual controls)
Controls range of movement of control surfaces
208
What are secondary stops (manual controls)
Controls range of movement of control stick / pedals
209
What is a turnbuckle
Adjust tension on cable
210
Is a artificial feel system (q-feel) in series or parallel with control runs
Parallel
211
How is excessive rudder deflection prevented in both Boeing and airbus
Rudder ratio changing = Boeing
| Variable stop system = airbus
212
What is a rudder ratio changer
Pedals move through their full range at all speeds but rudder deflection reduces with increasing IAS
213
What is a variable stop system (rudder)
Movement or rudder is directly proportional to pedal travel
Movement of both pedals and rudder is reduces with increasing IAS
214
What are manual primary flight controls
Reversible
Natural feel
No artificial feel
215
What are power assisted primary flight controls
Reversible
If loads large enough would give feedback
No artificial feel
216
What are fully power operated primary flight controls
Irreversible
No natural feel
Requires feedback
217
If primary stops are at the edge / full range of moment what is the condition of the secondary stops
Has slight gap
218
What is backlash
Moving of control stick = delay in movement of control surfaces
May indicate worn or faulty components
219
What happens to cable tension with increase in ambient temperature
Aluminium frame will expand more than the steel cables
Increases cable tension
220
What are hinge moments
Force multiplied by distance from the hinge to control surface centre of pressure
Fxd
221
What is a set back hinge
Hinge is moved back into control surface
The arm and hinge moment will be reduced
Does not reduce the effectiveness of the control
Only reduces the moment
222
What is a horn balance
Surface forward of hinge line = gives hinge moment in opposite direction
Reduces moment NOT effectiveness
223
What is a balance tab
Moves in opposite direction to control surface
Makes it easier
Does have a slight reduction in control effectiveness
224
What is a servo tab
No direct movement of the control surface
Move tab not control surface
Makes it easier
May accidentally leave control locks in
225
What is spring tap
Greater assistance the faster you go
Easier at high speeds
226
What is a anti balance tab
Moves same direction as control surface
Increase control effectiveness
Will increase hinge moment / heavier stick forces
227
What are power operated controls
Use hydraulic actuators / powered flying control units
Actuator operated by hydraulic servo valve
Each control surface is oppressive by two or three actuators
228
What are power assisted controls
Direct link between you and control surface
2 inputs
= 1 to control surface
= 1 to control unit
Once aerodynamic force overcomes hydraulic assistance = feedback
229
What are fully powered flying controls
1 input in = goes to servo valve
No direct connection between you and control surface
No feedback
Control is lost if hydraulic pressure is lost
230
What is he downside of spring feel artificial feel system
Doesn’t cater for change in speed
231
What is a blow back system
Allows control surface to ‘blow back’ into a less deflected position
Relieving any excessive loss
Prevents damage
232
Benefits of fly by wire system
Saves weight (natural stability of aircraft can be reduced = smaller stabilising surfaces)
Pilot workload reduced
Flight envelope protection
233
When does the take off configuration warning sound
Armed when aircraft is on ground and thrust levers advanced for take off
Sounds if:
Stabiliser trim outside sage range
Trailing edge flaps not in take off position
Leading edge devices not in take off position
Speedbrake leaver not in down position
Doors not fully locked
Control locks not fully unlocked
234
What are secondary flight controls
Flaps
Trimming devices
Slats
Spoilers
235
What shape is a flap lever
Flap shape
Tactile dissimilar
236
Kreuger flaps
Leading edge close to wing root
2 positions
- retracted
- extended
237
Variable camper flaps
2 positions
Retracted
Extended
238
Slats
Have an intermediate position
When fully extended = has a slot
239
Move flap lever to intermediate position what happens
Trailing edge flaps in intermediate position
Krueger flaps put
Variable camber leading edge flaps out
Slats intermediate position
240
Move flap level to fully extended position
Slats all the way out to create slot
All high lift devices fully out
241
What is a flap load relief system (LRS) or load limited
Retracts the flaps to the mid position if airspeed exceeds a pre determined speed
242
What are auto stats
As approaching stall angle = will fully extend flaps automatically
243
What is the ideal speed brake
Produce increase in drag with no loss or lift or change in pitching moment
Fuselage mounted speed brakes best suited
244
Why won’t ground spoilers operate in flight
Ground spoiler shut off valve
Looks for weight on wheels and wheel spin up
245
What happens to spoilers if throttles advanced
All spoilers retracted
246
What are the properties of duralumin
Aluminium / copper base
Hard to weld
Good thermal / electrical conductivity
(Not poor resistance to corrosion it’s just more susceptible)
247
What is a pressure controller for pneumatic systems
Senses pressure outside and inside = adjusts accordingly
248
When does a pneumatic system safety valve operate
When 0.25 PSI above max differential pressure
249
Where does bleed air come from at low engine speeds
Low and high pressure stages of the high pressure compressor
250
Where does bleed air come from at high engine speeds
Low pressure stages or the high pressure compressor
251
How is moisture removed from the air in the pneumatic system
Moisture separator = takes out most of the moisture
Dissident = removes all remaining moisture
252
What is a spill valve
Dumps air overboard if too much
Controlled by mass flow controller
253
What is a engine driver compressions (pneumatics)
Rotates blower = cabin compression
254
What is the purpose of a choke heat valve
Raise temperature of air if required
255
What does a choke valve do
Provides back pressure to blower
256
What is the high pressure shut off valve for (HPSOV)
Open relatively slowly on engine start to prevent surge of air pressure
Also close quickly to prevent ingress of fumes or fire into cabin
257
What do light aircraft use for air conditioning
Ram air
258
What do medium sized aircraft use for cabin conditioning
Takes ram air through combustion heater = burns fuel to heat air
259
What is the purpose of air conditioning
To supply a constant delivery of clean air to cockpit and cabin within a set temp range
260
What is conditioned air
Air which has been treated for pressure and temperature
261
What is the minimum mass of air per person per minute (normal system)
1 pound / person / min
262
What is the minimum mass of air per person per minute (after system failure)
0.5 pounds / person / minute
263
Maximum carbon monoxide that a pax can be exposed to
1 part per 20,000
264
Cabin temp range must be within
18-24°c
265
What is a mass flow controller
Ensures constant mass flow regardless of engine rpm
266
Where will you find the water separator in a bootstrap system
Downstream of cold air unit / turbine
267
Where is the biggest drop in temp for a bootstrap system
Secondary heat exchange /intercooler
268
If on ground and not a lot of ram air (low speed) what do you use
Ground cooling fan
269
What is a centrifugal water separator
Air driver fan throws water outwards
270
What is a impingement water separator
Air hits collector tubes
Runs down tubes
271
Where can air not be recirculated from
Toilets and galleys
272
What is trim air
Hot air taken from before conditioning air pack = introduced to conditioned air to control temp
273
What is a Punkah louvres
The nozzle above your head u can control your air with
274
What is the max differential pressure of a jet aircraft
9 psi
275
What is max cabin altitude for a emergency
15,000ft
276
Altitude where cabin oxygen system automatically drops
14,000ft
277
Altitude where cabin altitude warning system operates
10,000ft
278
Max cabin altitude for normal operation
8,000ft
279
cabin climb rate for comfort
500fpm
280
Cabin descent rate for passenger comfort
300fpm
281
Max cabin altitude rate of change
1800fpm
282
Max negative differential pressure
0.5 psi
283
Max positive differential pressure
9 psi
284
What is the ditching control
Close outflow valves in event of water landing
285
Why can’t you pressurise on the ground
Weight on wheels
Automatically opens outflow valves
286
What is ground flight switch for cabin pressurisation
Stops nasty fumes from
Other aircraft while on ground
Puts in 0.1=psi
287
On landing what happens to aircraft pressure
Weight on wheels = dumps all pressure except 0.1 psi
Set “ground” = dumps final 0.1psi
288
What is the pressure around 30,000
4 psi
289
What is the pressure at 8000’
11 psi
290
What happens in terms of pressurisation at 10,000ft
Aural / visual cabin altitude warning
291
When does the auto fail light on pressure control panel illuminate
13,850ft
292
When do the passenger oxygen masks automatically drop
14,000ft
293
3 types of ice
Hoar frost
Most likely in clouds;
Rime ice
Clear / glaze ice
294
5 techniques of de / anti icing
Hot bleed air
Hot engine oil
Electrically heated mats
Pneumatically operated mats
Fluid de icing
295
5 types of ice detection devices in common use
```
Hot rod
Vibrating
Pressure
Rotary
Inferential
```
296
What is a hot rod ice detector
Aerofoil shape protruding from fuselage but visible from cockpit
No ice on detector = no ice on wings
297
What is a vibrating rod ice detection system
Vibrates at roughly 40khz
When ice = vibrates slower = ice sensed
298
What is a pressure ice detector
Probe sticks out of aircraft with holes in the front and back
If holes ice up = no pressure
Therefor ice
299
What is a rotary ice detector
Rotor spins, if ice builds up = blade tries to cut it off = slows rotation = ice sensed
300
What is a inferential ice detector
Detects conditions necessary for ice to build up
301
How much ice needs to build up for pneumatic boots to be operated
1.5cm
302
What is the state of the pneumatic icing boots when the system is turned off
Vacuum to suck tubes to leading edge
303
What is a fluid based ice protection system
Uses alcoholic / anti freeze fluid thingy to melt ice / stop it forming
Fluid come out of distribution panels
Sometimes called a weeping wing
Can run out of fluid mid air
304
What is a head compensation valve
Fluid de icing system
Ensures fluid goes to all parts of the system
305
What are panel distributors
Fluid de icing system
On leading edge of wing
More economical and efficient than strip distributors
Can not be used on surfaces with double curvature
306
What is thermal ice protection
Used hot air
Leading edges warmed by hot air ducts
Can heat slats
Not leading edge flaps
Only some tail sections
Once air is used = exhausted to atmosphere
307
What is the main anti-icing for turbo props
Thermal = hot air
308
Turbo prop de icing is most likely
Pneumatic boots
309
How is thermal anti icing for a turbo prop produced
Take ram air and pass it through thermal heat exchange
310
How are turboprop engine intake normally protected against ice
Tend to be electronic heating elements
311
How are propellers normally protected against ice
Anti icing =fluid system
De icing = electrical thermal
Only inner 3rd or propeller
312
How is the spinner (hub) anti iced
Alway electrically
313
How is jet engine fan / nose cone anti iced
Hot engine oil / air
Crew has no control over this
314
How is the electrical power delivered to the heating elements for a propeller ice depletion heating system
Carbon brushes
And
Slip rings
315
How does a propeller fluid system deliver the fluid for ice depletion
Uses a slinger ring
316
How are windscreens ice protected
Dc controlled
Ac powered
Temperature control from a control unit keeping it in a reasonable band
317
What are windscreen wipers
Has Independent 2 speeds
May be electrically or hydraulically powered
Should not be used on a dry windscreen
318
Purpose of a fuel system
Supply main aircraft engines with sufficient fuel at a given pressure under all operating conditions
319
Integral fuel tank
Interior structure of wing forms boundaries of tank
Saves weight
Maintenance may be difficult
320
Flexibility / bag fuel tank
Made from rubberised fabric
Attached to structure using chords and buttons
Used for awkward locations
Easier maintenance
Reasonable weight
Can be made self sealing
321
Drum fuel tanks
Rigid tank made from aluminium
322
What should be the characteristics of fuel
```
Low flash point
Good lubrication
Non corrosive
Usable across wide temp range
Anti knock properties
```
323
What colour is AVGAS 100LL
Blue
324
What colour is AVGAS 100
Green
325
What colour is AVGAS 80
Red
Used for low compression ratio engines
326
What is MOGAS
Used for some low powered engines
Not allowed for commercial operations
327
What is JET A1
Sg 0.8 at 15°c
Has FSII icing inhibitor which lowers the waxing point to -47°c
Jet A = no inhibitor
328
What is JET B
Wide cut- gasoline / kerosene mix of avgas and avtur
Low flash point
Waxing point -60°c
Usually military
329
Is avtur died a colour
No
330
If a fuel sample is cloudy and the cloud rises...
Air
331
If a fuel sample is cloudy and cold falls
Water
332
What additives may be added to jet fuel
FSII (fuel system icing inhibitor)
Contains an icing inhibitor and fungal suppressant
333
What is the fuel system in a light aircraft
Usually rigid tanks in wings
May be gravity fed or pressure pump
Measure volume
Collector tank ensures fuel available to engine at all times
334
Why might a fuel tank be pressurised
Stop fuel from boiling at high altitudes
335
What will you do if there is a fuel imbalance
Booster pump on from tank you want to take fuel from
Open crossfeed valve
Close booster pumps on fuel tank with lower fuel level
336
Where will you find a fuel tank temperature sensor
Tip
337
What are fuel booster pumps
Normally gotten in pairs
Low pressure centrifugal pump
Aircraft electrical motor 115/200v
400hz 3 phase
Switched on by dc
25-50 psi
High flow rate capability
338
What is a fuel venting system
Prevent pressure build up in tanks
Allows air in during fuel usage
Allows air to escape during refuelling
Vent surge tank collects droplets of fuel about to escape from vent = lowers fuel loss
339
How is a fuel tank usually pressurised
Ram air to give slight positive pressure to prevent boiling of fuel at high levels
340
In the event of a failure of the fuel gauging system what happens
Driven slowly towards zero
341
How can u check fuel level manually
Drip stick
Magnetic level indicator
342
How quickly must you be able to jettison fuel
Be able to reduce weight to MLM in 15 mins
343
What is optical and ionisation fire detection
Optical = light refracted by presence of smoke particles into a photo-electric cell
Ionisation = smoke stops current flow through ionised air
344
What does the fire suppression system shut off
Hydraulics
Bleed air
Isolated engine driven electrical generator
Arms extinguisher squibs
345
Where does fire detection / protection system must be fitted
Engines
Apu
Cargo compartments
Main wheel wells
346
What is a designated fire zone
Area where risk of fire following failure or leakage of any component or equipment
347
Examples of fire zones
Manufacturer designated areas:
Hydraulic bays
Baggage holds
Toilets
Galley areas
348
What is fire wire
Continuous detection
Continuous double loop = both loops having to detect a fire before initiating a warning
Usually have a negative coefficient of resistance
Or
Positive coefficient of capacitance
Needs to give a rapid warning within 5 seconds
349
What is a FFFD
Fault free fire detector
Positive coefficient of capacitance fire wire
Does not result in a false warning
350
What effect do CO2 / BCF / halon / methyl bromide engine fire extinguishers have
Non as long as engine turned over following use
351
What effect does foam or dry powder engine fire extinguishers have
Engine needs to be stripped and rebuild
352
Bimetallic overheat sensors
Principle of differential rate of expansion of dissimilar materials
Time delay Prevent false warnings due to vibration
353
Standard engine fire drill
```
Cancel fire bell
Close throttle
Shut the HP cock
Pull fire handle
Discharge fire extinguishers
```
If after 30 seconds still illuminated = use second extinguisher
354
When do you need fire extinguishers system in toilet
Pax seating of 20 or more
355
What colour are aviation oxygen bottles
Painted black with white neck = British
Green = European / American
356
When is a quick don mask required
Above 25,000ft
357
How many pax oxygen masks are required
110% of the passenger seats
2 in the toilet
358
How do chemical generators work
Sodium chlorate reacts with iron
359
Crew portable oxygen pressure and litre capacity
1800psi
120 litres
360
First aid oxygen requirements
120 litres
1800psi
2% of pax but never less than 1 when >8000ft
361
Smoke hood time requirements
Oxygen generator with 15 mins supply
