Aerodynamics and Systems Flashcards
1
Q
When the bank angle increases to 60 degrees, what happens to G force and stall speed?
A
G force approx 2 G
Stall up about 40%
2
Q
Where does weight act through?
A
Centre of gravity
3
Q
Where does lift act through?
A
Centre of lift
4
Q
What happens if centre of lift is ahead of centre of gravity?
A
Aircraft suffer nose up pitch
5
Q
What happens if centre of lift is behind centre of gravity?
A
Aircraft suffer nose down pitch
6
Q
Longitudinal stability is about what plane?
A
Pitching plane
7
Q
Lateral stability is about what plane?
A
Roll plane
8
Q
What will increase lateral stability?
A
Dihedral
Swept back wings
9
Q
What is dihedral?
A
Wing tips higher than wing root
10
Q
What does dihedral do to stability?
A
Increases lateral stability
11
Q
What is anhedral?
A
Wing tips lower than the root
12
Q
What does anhedral do to stability?
A
Reduce lateral stability and increase turning stability
13
Q
What is the chord?
A
Longitudinal distance between leading and trailing edge
14
Q
What is the mean chord?
A
Average length of chord
15
Q
What is the wing span?
A
Distance from wing tip to wing tip
16
Q
What is aspect ratio?
A
Relationship of span to average chord.
17
Q
What would a wing look like if it had high aspect ratio?
A
Long and thin
18
Q
What would a wing look like if it had low aspect ratio?
A
Short and thick
19
Q
What does a high aspect ratio wing do to drag?
A
Produces less induced drag
20
Q
What is maximum thickness for aerofoil?
A
Point on wing where it is thickest.
21
Q
What is camber?
A
Relationship between chord and thickness.
22
Q
What a high camber wing section look like?
A
Thick wing and short chord
23
Q
What is mean camber?
A
Average thickness compared to average chord
24
Q
What is MAC?
A
Mean aerodynamic chord.
Position of centre of gravity within an imaginary rectangular wing chord.
25
What is angle of incidence?
Angle between chord line of aerofoil and fore/aft datum line of aircraft
26
What is angle of attack?
Angle between chord line and relative airflow
27
What is upwash?
Motion of relative airflow as approaches leading edge
28
What is downwash?
Motion of relative airflow as it leaves trailing edge
29
What is the separation point?
Point in front of the wing at which approaching air is separated by approaching wing
30
What is the boundary layer?
Thin area above surface of wing that is stationary
31
What does a thick boundary layer do to drag?
Increases drag
32
What is the transition point?
Flow instability develops.
Turbulent flow starts
Drag increases
33
What is centre of pressure?
Point through which lift pressure foces act
34
When is induced drag highest?
Just before the stall.
| Also at minimum steady flight
35
How would we get CAS?
IAS corrected for pressure and instrument errors
36
How would we get EAS?
CAS less compressibility error
37
How would we get TAS?
EAS corrected for air density error
38
What is the biggest influence in the speed of sound?
Temperature
39
When is speed of sound faster, warm or cold air?
Warm
40
When at high altitudes and cold temps, what is the speed of sound, faster or slower?
Slower
41
What is the approx speed of sound?
662 knots
42
The Mach number defines the relationship between what?
TAS to speed of sound
43
Mach numbers values are written as a percentage of seed of sound, true or false?
True
44
If you were flying at the speed of sound, what would the Mach number be?
M1
45
What happens to TAS if climbing at fixed Mach number?
TAS will reduce
46
What is Vmo/Mmo?
IAS for max normal operating speed and Maximum Mach normal operations speed
47
Where would you find figure for Vmo/Mmo?
Flight manual
| Vmo/Mmo needle on ASI (known as Barbers Pole)
48
If you are climbing at IAS just below Vmo, what will eventually happen to Mmo?
Will be eventually exceeded
49
What is the True OAT always equal to with relation to Total Air Temperature?
Equal to or colder than TAT
50
What is does Vmcg stand for and what is it?
Minimum control indicated airspeed on ground.
Minimum speed pilot can maintain direction control of aircraft with one engine becoming inoperative during take off roll using aerodynamic controls only.
51
What aircraft config is found with Vmcg?
Flaps and trim in takeoff config
Critical engine failed
Take off power on available engine
CoG rear
52
When using Vmcg, what is assumed with the wheels?
Nose wheel no longer on ground.
| Main wheels are still on ground
53
What will forward CoG do to Vmcg?
Lower it
54
What does a low Vmcg speed do?
Gives us greater asymetric control
55
What factors will reduce Vmcg?
```
High density
Reduced take off thrust
Large tail fin area
Large rudder area
Forward CoG
Short distance from engine to fuselage
```
56
What does Vmca stand for?
Minimum control indicated airspeed in air.
57
What does Vmca assume the aircraft is doing?
```
Completely clear of ground.
Sudden loss of critical engine
CoG rear
Max available take off thrust remaining engine
AoB no more 5 degrees
Trim in take off position
Out of ground effect
Landing gear retracted
Windmilling prop
Max sea level take off weight
```
58
If one engine were to fail, what is the pitching and yawing tendency?
Pitch down
| Yaw towards dead engine
59
What will moving the CoG forward do to controls with one engine out?
Assist with control
60
What is the critical engine?
Engine that if failed will produce most adverse yaw couple
| Down going blade closest to fuselage
61
To reduce performance loss during critical engine failure, wha should be done?
Slight bank towards live engine
62
What factors reduce Vmca?
```
Fuselage mounted engines
Reduced thrust
Large tail fin area
Large rudder area
Forward CoG
Short distance from engine to fuselage
Banking towards live engine
High altitude
High density altitude
Dihedral and fuselage blanket of wing
```
63
What is the risk of loss on engine at high altitude?
Aircraft likely to be close to stall speed.
64
What actions should be taken at high altitude following engine failure
Descent to more suitable engine one level
65
The area on the aerofoil where smooth streamline airflow beginning to break up and become turbulent is know as what?
The transition point
66
With increased curvature (camber) of surface what happens to speed and pressure above the surface?
Speed increases
Pressure decreases
(This is Bernoullis theory
67
What happens to lift as angle of attack increase?
Lift increases until stall AoA then decreases
68
What does a laminar flow wing do?
Reduces drag, has laminar flow over entire wing (no turbulent flow at all
69
What are the characteristics of a super critical wing section?
Section thickness and camber further aft
More gradual camber
Reflex curve on underside near trailing edge
70
What is the primary purpose of super critical wing?
To increase Mach number at which shockwaves form which delays shockwave drag rise
71
Will aircraft that fly at high Mach numbers be more efficient with swept back wings or straight wings?
Swept back
72
Where do swept back wings tend to stall first and why?
At the tips.
| Air approaching leading edge of wing deflected upwards (upwash)
73
In swept back wings what happens to the transition point as approaching stall?
Transition point moves forwards and inwards
74
What is the tendency of the nose during a swept back wing stall?
Nose pitch up
75
What is generally done to ensure a pitch down at stall?
```
Washout (twist of wing so incidence angle at tips less than root)
Leading edge slat deployment
Wing fences
Saw/dog tooth
Vortex generators
Shark teeth
```
76
What do leading edge slat devices do?
Extend when within certain AoA/speeds.
Energises the flow over the top surface
Delay break up of streamline flow
Improves aileron effectiveness near stall
77
What do wing fences do?
Prevent span wise flow.
| Rotates opposite direction to usual wing tip trailing vortex
78
What do leading edge slots do?
Re-energise airflow above wing by injecting high pressure air from below into leading upper surface.
This delays airflow separating into turbulent flow.
Creates greater lift at higher angle of attack
79
What do leading edge slats do?
Device that moves forward from leading edge to create a slot.
Directs high energy air onto upper wing leading edge to re-energise boundary layer.
Increases camber of wing
Increases stall angle
80
What does deployment of leading edge slats do to pitch?
Causes a pitch up moment
81
When are leading edge slats most effective?
High angles of attack
82
What do leading edge flaps do?
Helps air flow at leading edge overcome early stall
83
What do Krueger leading edge flaps do?
Increase camber of aerofoil (but dont incorporate a slot)
Increase drag at all speeds
Produces nose pitch up
Increase lift
84
What do Droop Snoot leading edge flaps do?
Leading edge of wing pivots forward and down to increase camber and wing area which increases lift.
85
All leading edge devices contribute to lift best at what angle of attack?
High angle of attack
86
What happens to AoA and approach speed if leading edge devices are not deployed?
Lower AoA
| Higher approach speed
87
What do leading edge flaps do to camber, wing area and stall speed?
Increase camber
Increase wing area
Decrease stall speed
88
Do leading edge flaps feature slots or re-energise boundary layer?
No
89
What are the main effect of deploying trailing edge flaps?
```
Increase camber of wing
Increase drag
Increase in lift at all AoA
Stall AoA reduced
Stall speed reduced
Nose down pitch
```
90
On the wing, what do speed brakes (spoilers) do?
Reduce lift
Creating drag
Providing roll control
Increase descent gradient
91
What do tail mounted speed breaks do to drag and lift?
Increase drag
| Don't spoil lift
92
What can be done with spoilers if requiring a roll to the right?
Spoilers on right wing deflect upwards, spoilers on left wing remain down
93
What happens when the spoilers are set to armed?
Spoilers will raise all spoiler panels automatically when aircraft touches down
94
Apart from the lift and drag benefits, why use spoilers and inboard ailerons
Helps reduce fatigue on wings/outboard ailerons at high speeds
95
What is the Critical Mach Number (Mcrit)?
Free stream Mach number at which first shock waves forms
Any part of ac reaches Mach 1 (supersonic)
Marks beginning of transonic range
96
What happens to drag if you fly faster than Mcrit?
Increase in drag
97
What is Mfs?
Freestream Mach number
| Mach number of aircraft through the air
98
When do shockwaves form?
After reaching a value greater than mach 1, it reduces back to mach 1, that is when shock wave forms
99
Where do shock waves tend to form first, thick or thin parts of aerofoil?
Thick
100
What is the pitch tendency with shockwave?
Nose pitch down
101
What is the Mach trimmer for?
To counter the nose pitch down tendency after shockwave
102
What happens to centre of lift with shockwave as speed increases?
Centre of lift moves rearward (pitch down)
103
What happens to lift and drag after upper shockwave forms?
Lift reduces
| Drag increases
104
What is Mdet?
Detachment Mach number.
| When bow shockwaves attach to leading edge
105
What is all flow above Mdet?
Supersonic
106
What angles does a normal shockwave form and where?
At right angles to the wing surface
107
What angles does oblique shock form and where?
Bends backwards on bow wave and tail wave
108
Why is flying at the aerodynamic ceiling not recommended?
High drag created and significant increase in fuel flow required to maintain speed (reducing range)
Tailplane becomes less effective if stalled
109
What is Mcdr?
Critical drag rise
| Mach number where drag increases significantly due to shockwave formation
110
Which is higher, Mcdr or Mcrit?
Mcdr
111
What three things can be done to increase Mcrit and Mcdr values?
Wing sweep
Low thickness/chord ratio
Supercritical wing sections
112
What speed and altitude is wing sweep most effective at?
High speed
| High altitude
113
Compared to a swept back which, what angle of attack does maximum lift occur on a straight wing?
Less angle of attack
114
A swept wing has less lift at all AoA than a straight wing, true or false?
True
115
What does increased sweep do to dutch roll tendency?
Increases it
116
What does increased sweep do to flap effectiveness?
Decreases it
117
As Mcrit is reached, what happens to lift?
Peaks just as Mcrit is reached and drops thereafter to M1
118
What do thin wings do to Mcrit and Mcdr? What about to lift?
Increase Mcrit and Mcdr
| Reduce lift
119
Where is the point of max camber on a supercritical wing?
About 40-45% along
120
What does supercritical wing do to acceleration of airflow over upper surface?
Reduces it
121
What do vortex generators do to shockwaves?
Weaken the shockwave that develops and inhibit the thickening of boundary layer behind shockwave.
Increases the Mcdr
122
What happens in the intake cycle?
Piston moves down
| Sucks in mixture of air and fuel
123
What happens in compression cycle?
Piston moves up
| As piston reaches top, spark is supplied which causes ignition of mixture
124
What happens in the power cycle?
Piston goes down
| Explosion/expansion of mixture forces piston down
125
What happens in the exhaust cycle?
```
Piston moves up.
Expels burnt(spent) fuel through exhaust valve
```
126
Describe the BGT and the basic steps of BGT
- At intake end of engine is compressor which is attached to turbine at exhaust end. These are rotating parts of engine
- When rotated, the compressor squeezes air and passes compressed air to combustion chamber
- At combustion chamber, fuel is added and mixture ignited by spark plug
- Explosion causes gases to expand inside combustion chamber
- Expansion converted into velocity through Convergent duct
127
How much of the energy is required by the compressor to rotate the turbine? How much is used for remaining thrust?
75% rotate
| 25% thrust
128
What are some advantages of turbine engines to piston?
```
Can develop more power and thrust
Lighter (better power to weight ratio)
More compact
Less drag
More reliable
Cheaper fuel
Greater time between overhauls
```
129
What is the pure jet type?
Allow all residual gas stream velocity to exit the exhaust
130
What is the turboprop?
Additional turbines which extract more residual energy and feed it to a prop through connecting shaft
131
What is the turbofan?
Additional turbines which extract more residual energy and feed it to a multibladed fan through connecting shroud
132
What is turboshaft type?
Using horsepower from rotating shaft and drive a pump or electric generator to pump fluids or create electricity
133
What is convergent duct?
Distance across duct narrows
134
Where is speed greatest in convergent duct?
At narrowest point
135
At the convergent duct, what is the velocity, pressure and temp?
Velocity increases
Pressure decreases
Temp decreases
136
At the divergent duct, what is the velocity, pressure and temp?
Velocity decreases
Pressure increases
Temp increases
137
What is the policy for engine intake anti ice?
Turn on if OAT is +10C or below when operating in presence of visible moisture
138
What are the advantages of centrifugal compressors?
More robust than axial
Resist damage from foreign objects
Less complex
139
What are the disadvantages of the centrifugal compressor?
Lower compression ratio
Prone to gas leaks
Prone to compressor surges
140
What sort of engines are centrifugal type engines suited to, large or small?
Small
141
What are the advantages of axial flow compressors?
```
Greater thrust
Greater fuel economy
Less chance of surging
Reduced engine diameter
Less drag
```
142
What are stators?
Mounted additional blades between each row of the compressor blade that don't rotate
143
What do stators do?
Convert increased velocity into increased pressure
| Guide gas stream so it's angle of attack is optimum
144
When is surging most likely?
```
Low RPM
Thrust opened/ closed too quickly
AoA at intake too great
Turbulence
High altitude
Compressor blades damaged
Heavy rail or hail
Reverse thrust ops
Aircraft side slipping
```
145
What are compressor stall indications?
Rising EGT
Steadying or reducing fuel flow
Steadying or reducing engine RPM
Engine popping, vibration and banging
146
How can you cure compressor stall?
Reduce throttle
Lower nose
Increase forward airspeed
147
What are the advantages of twin spool types?
Develop high compression ratios while reducing compressor stall
Faster spool up times then single
Greater operator flexibility
148
What are the advantages of 3 spool types?
Shorter in length
Suffer less flexing
Less prone to surging
Spool up fast
149
What are the advantages of turbofans over pure jet?
Better fuel economy
Reduced noise
Greater thrust
Lighter core components
150
What are the disadvantages of turbo fans over a pure jet?
Increase drag due to increased frontal area
| Increased diameter may affect design of undercarriage
151
When is lean flame out likely to occur?
Low fuel pressure
Low engine speed
High airspeed
High altitude
152
When is rich flame out likely to occur?
Over rich mixture
| Rapid engine acceleration
153
How many separate primary control actuation systems must there be and why?
3
| In case of failure
154
As speed increases, what do aileron lockout devices do?
Restrict the movement of outboard ailerons, leaving inbound ailerons and spoilers to effect roll at high speed
155
Where do the speed signal inputs come from for the aileron lockout device?
CADC (Central Air Data Computer)
156
What is the aileron powered by and how many?
2 hydraulic systems
157
What would an aileron lockout failure at low speeds indicate?
One or both of the lockouts have failed to unlock the outboard ailerons
158
What are the implications if aileron lockout failure occurs during approach?
Decrease ability of low speed roll characteristics
| Reduce crosswind landing capability
159
How many hydraulic systems power the rudder acutator?
3
160
What are yaw dampers for?
Reduce dutch roll
| Assist in turn co-ordination
161
Where does the yaw damper get info for speed?
From the CADC (central air data computer) which is blended from Ring laser gyro that is part of Inertial reference unit (IRU)
162
What happens if one yaw damper is lost?
Flight crew need to restrict forward speed and altitude to within published yaw damper inoperative limits
163
How many spoiler panels are there on each wing? How many hydraulic actuators are allocated for the spoiler panels?
12 spoiler panels in total, 6 per wing (4 outter, 2 inner)
| Each spoiler panel has its own hydraulic actuator
164
What are the spoiler panels used for in the air?
Slow aircraft in flight
Steepen descent gradient
Reduce lift
Increase drag
165
What are the spoiler panels used for on the ground?
Spoil any lift
166
What controls the spoilers?
Speed brake lever
167
What are the different positions of the speed brake?
Down (spoilers stay down, even after landing)
Armed (spoilers automatically deploy to full up once landing gear bogie has levelled on touch down)
Up (allows spoiler panel to be used as speed brakes in flight)
168
If the speedbrake lever is NOT in the armed position, but all three conditions are met and reverse thrust is applied, what happens to spoilers and speedbrake lever?
Spoilers will automatically extend and speedbrake lever will move to up position
169
How many elevator panels are there and how many hydraulic systems power them?
Two elevator panels
| 3 hydraulic systems
170
What is the mach trimmer?
Nose up trim application when operating around transonic speeds
171
Where does the mach trimmer get its speed info from?
CADC (central air data computer)
172
What does the flap/slat asymmetry monitoring system do?
Stops flaps being extended further should one wing high lift devices extend at different rate than the other
173
What does the flap load relief system do?
Prevent exceedance of flap limit speed when flaps are set to 25 by retracting flaps to previous stage.
COCKPIT FLAP LEVER WILL NOT MOVE WHEN THIS HAPPENS.
When speed is reduced to below the speed limit, the flap will automatically extend to previous settings
174
Which is always greater, CAS or EAS?
CAS
175
Can you intentionally fly above Vmo/Mmo?
No
176
What will flying above Mmo do?
Creation of shockwaves
| Pilot will feel buffet through elevator (stalling)
177
What is Vdf? Is it IAS or TAS?
Max demonstrated dive flight speed
| IAS
178
What is Vs?
Stall speed
| Minimum control speed for level flight with 2 engines
179
What are the most adverse conditions for Vs?
```
Power off
Forward CoG
1G
Out of ground effect
Max take off weight
```
180
As the speed of sound decreases, what happens to coefficient of lift?
Decreases
181
If you lose one engine, how much performance is lost?
80%
182
What power and speed is the asymmetric condition worsened>
High power
| Low speed
183
Do aircraft with counter rotating props have a critical engine?
No
184
The speed of sound varies according to what?
Environment temperature
185
As airflow moves from supersonic to subsonic, what happens to temp, pressure, velocity, mach number, density and flow direction?
```
Temp rise
Pressure rise
Velocity drop
Mach number drop
Density rise
Flow direction NO CHANGE
```
186
What will the difference be in Mcrit value for low thickness/chord ratio compared to high?
Low will have a higher Mcrit
187
The overall drag for thin wings is less that for straight wings at all speeds, true or false?
True
188
What is static stability?
Initial tendency for an object to return to equilibrium after a disturbance
189
What is positive static stability?
Tendency to return to equilibrium
190
What is negative static stability?
If object tends to continue in direction of distrubance
191
What is neutral stability?
When object is displaced from equilibrium it stays in new position
192
What is dynamic stability?
Resulting motion with time after disturbance
193
What is positive dynamic stability?
If the amplitude of motion decreases with time after disturbance
194
What is negative dynamic stability?
If the amplitude of motion increases with time after distrubance
195
What is neutral dynamic stability?
If amplitude of motion remain unchanged after initial disturbance
196
What happens to controllability with increased stability?
Lower the controlability
197
What is positive longitudinal stability?
Aircraft will return to trimmed position after being displaced in pitch
198
What position of centre of gravity will positive longitudinal stability occur?
When centre of gravity is ahead of centre of lift
199
Where would centre of gravity be if there was negative longitudinal stability?
Centre of gravity behind centre of lift
200
What will engines below the wing do to static longitudinal stability when power is increased?
Reduce longitudinal stability
201
Which axis is directional stability about?
Normal axis
202
What factors affect the longitudinal stability?
```
CoG
Wing
Engine nacelle and fuselage
Thrust line
Power
```
203
What does a large fin surface area that is displaced aft of CoG do to directional stability?
Increases it
204
What do aft body strakes do to directional stability at high and low speeds?
Increase directional stability at both high and low speeds and
205
What happens to directional stability at high airspeed and high altitude?
Direction stability is lower
206
What is the effect of dorsal fin extension on directional stability?
Preserves directional stability at large side slip angles
207
What contributes for to direction stability, swept or straight wing?
Swept
208
If the prop or jet inlet is ahead of the centre of gravity, what does an increase in power do to directional stability?
Decreases it
209
When are the destabilising affects of power most noticeable?
High power at low speed
210
If the nose yawed to the right what would the positive lateral stability do?
Sideslip to the right
| Cause greater lift on down going (right) wing, rolling aircraft to the left
211
What does a large dihedral wing do to lateral stability?
Increases it
212
What does high velocity slipstream behind the props do to lateral stability?
Decreases it
213
What does deployment of flaps do to lateral stability?
Reduces effective dihedral and therefore reduces lateral stability
214
When does dutch roll occur?
High lateral stability and low directional stability
215
What happens to stability as altitude increase?
Spiral stability increases
| All other stability decreases
216
At what height and speed is dutch roll tendency the highest?
Highest at high altitude and high speeds
217
What is the formula for calculating rate one turns?
(TAS / 10) + 7 = xx bank angle degrees
218
Does aircraft weight affect the turn radius?
No
219
What does the mach trimmer do?
Automatically trims nose up during transonic speed range
220
What is the airflow velocity, static pressure, density, total pressure and temp with normal and oblique shockwave?
```
Reduction in velocity to subsonic
Rise in static
Rise in Temp
Less total pressure
Rise in density
```
221
What is the airflow velocity, static pressure, total pressure and temp with expansion wave?
Increase in velocity
Increase in static pressure
increase in temp
No change in total pressure
222
What happens to Pressure, density and velocity in divergent ducts with sub sonic flow?
Pressure and density increase
| Velocity decrease
223
What happens to Pressure, density and velocity in divergent ducts with supersonic flow?
Pressure and density decrease
| Velocity increase
224
What happens to Pressure, density and velocity in convergent ducts with sub sonic flow?
Pressure and density decrease
| Velocity increase
225
What happens to Pressure, density and velocity in convergent ducts with supersonic flow?
Pressure and density increase
| Velocity increase
226
What happens to shockwave, COP, nose position, controls, Clift and Cdrag when passing Mcrit?
```
Shockwave forms
COP moves aft
Nose down
Control buffet
Clift decreases
Cdrag increases
```
227
What speeds would aileron reversal occur in?
Transonic range
228
What is spiral stability?
Ability to recover from spiral dive after yaw input
229
What is spiral instability?
Tendency to enter spiral dive
230
What does increase spiral stability lead to?
Dutch roll
231
What does spiral stability increase with?
Increase in altitude
232
What does dutch roll tendency increase with?
Increase in altitude
233
What happens to lateral, longitudinal and spiral stability as altitude increases?
Lateral decreases
Longitudinal decreases
Spiral increases
234
Where do aileron lock out warning messages illuminate?
EICAS
235
When are inboard ailerons active?
ALWAYS
236
What are yaw dampers used for?
Used to reduce dutch roll
237
What is ram effect?
Air compressed (higher density -greater mass airflow) at the engine intake due to high forward velocity
238
What happens to ram effect as airspeed increase?
Ram effect will increase
239
What happens to thrust with increase in speed?
Decreases
240
Does ram effect recover all thrust lost with increase in speed>
No, only partial
241
What happens in the intake cycle for BGT?
Direct turbulent free airflow to compressor
| Increase potential energy of air
242
What happens to static pressure and velocity (dynamic pressure in compressor)?
```
Increasing static pressure
Decrease velocity (dynamic pressure)
```
243
What happens to pressure in combustion?
Pressure slightly decreases as temp increases
244
What happens in exhaust stage of BGT?
Energy converted to kinetic energy to rotate shaft connecting to compressor
Remaining energy used to thrust ac
245
What does EPR measure?
Thrust indicating system, to adjust thrust output of engine
246
What shape is the intake duct?
Divergent
247
What is intake duct divergent?
Decreases airflow velocity
| Increases static pressure
248
What is the primary purpose of the compressor?
To increase total pressure
249
When is compressor surge likely?
```
92-98% RPM
Thrust levers opened too quickly
AoA of intake too high
Turbulence
Altitude
Heavy rain or hail
Reverse thrust
Side slipping
Compressor blades damaged
```
250
How can you prevent compressor stall?
Variable inlet guide vanes
Variable stator vanes
Bleed valves
Multi spool compressors
251
What do bleed valves do?
Compressed air tapped from compressor to increase air flow over rotor blades maintaining optimum angle of attack
252
When is fuel added in BGT?
Combustion cycle
253
What is the entrance to the combustion cycle?
Divergent
254
How much % of air goes through snout and flare?
20% (12 to snout for swirl and 8 to flare to mix fuel and air)
255
How much % of air is not directed to snout?
80%
256
Of the air not directed to snout, what % goes to later part of primary combustion zone?
20% of 80%
257
What % of air the dilution zone?
20% of 80%
258
What % of air not directed to snout is for cooling?
40%
259
Where is the hottest section of combustion chamber?
1st 1/3rd (primary zone)
260
What are the main causes of flameout?
Turbulent weather (turbulent inlet air)
High altitude
Slow acceleration during manoeuvres
High speed manoeuvres
261
What is lean flame out?
Low engine speed and low fuel pressure. Generally low powered descent
262
What is rich flame out?
High powered climb where over rich mixture increase pressure in combustion chamber
263
What are the advantages of the annular chamber?
Weight and space saver
Better combustion propagation
Reduced pressure reductions
264
What are the disadvantages of the annular chamber?
Entire system has to be removed for maintainance
265
What are the advantages of the multiple chamber?
Simple to construct and maintain
266
What are the disadvantages of the multiple chamber?
Takes up a lot of space
| Uneven delivery of air loads to turbine
267
What is the primary function of turbines?
Transform heat into kinetic energy
268
What do nozzle guide vanes do? (NGV)
Direct flow onto moving turbine blades in correct direction
269
What do nozzle guide vanes do to pressure and velocity?
Decrease pressure
| Increase velocity
270
What is fitted to nozzle guide vanes to avoid tip leakage?
Shrouds
271
What are shrouds and where are they located?
Caps on tips of turbine blades to reduce leakage, vibration and increase strength
272
What is blade creep?
Length of the blade increases due to centrifugal forces acting on blade and the temp at which it operates
273
What are the different blade creep types?
Primary, secondary and tertiary
274
What is primary creep?
Process of manufacture
| Considerable change in materials shape
275
What is secondary creep?
Occurs over lift of blade
276
What is tertiary creep?
Deterioration of blade rapidly until failure. Shouldn't be fitted to engine
277
What is primary function of exhaust?
Develop thrust
| Discharge gas to atmosphere
278
What direction is exhaust duct?
Convergent
279
What are exhaust struts??
Straighten out airflow from exhaust
280
How do high bypass engines reduce noise?
Mixing of coo and hot air prior to exhaust
281
How do blocker doors assist with reverse thrust? Are they internal or external?
Divert coldstream airflow
| Internal
282
How do clampshell doors assist with reverse thrust? Are they internal or external?
Change direction of all air
External
Pneumatically operated
283
Can reverse thrust be used in the air?
No
284
Why don't we use thrust reverse at low speed?
Less effective and prone to foreign object damage
285
What frequency noise travels great distances and creates large noise foot print?
Low frequency
286
What do negative torque systems do?
Sense negative torque (when prop begins to rotate faster than reduction gear and drives the engine)
287
What does negative torque system do to blade angle
Coarsens blade angle to reduce stress
288
How long does negative torque system alter the blade angle?
Coarsens blade until negative torque no longer sensed or until full coarse stop
289
What happens to NTS when reaches full coarse stop?
Disengage reduction gear from engine and then reconnect automatically once negative torque no longer sensed
290
What is the prop brake used for?
Prevent prop windmilling in flight when feathered
| Holds blade during shutdown (engine still be running while blade is stationary)
291
What is TSS and what does it do?
Thrust sensitive signal or autofeather
| Automatically feathers prop if required after takeoff
292
When does TSS work?
System must be armed prior to take off.
| Once prop develops more than 500lbs of thrust, system will feather prop if output drops below this mark
293
What is primary purpose of APU?
Provide bleed air for pneumatics
| aircon, engine start without GPU, anti ice
294
Where is APU located?
In the tail
295
What are some conditions that lead to APU automatic shutdown?
```
Low oil pressure
High oil temp
High EGT
Over speed
Duct overheat
```
296
Where in engine is fire detection located?
Engine cowl
297
How many fire extinguishing bottles are installed in the engine nacelle
Two
298
What is the basic sequence for undercarriage retraction?
```
Sequence valve ensure doors open first
Undercarriage downlocks removed
Indicators go from green to red
Wheels come up
Uplocks come in
Doors close and lock
Transit light goes out
```
299
What is the ground lock?
Prevents inadvertent retraction of gear on ground
300
How does the gear lock work?
Safety switch is opened in gear circuit if aircraft is on ground and allows spring loaded pin in solenoid to block gear selector movement
301
In the 767, how are uplocks operated?
Electrically operated solenoids
302
What is the most common tyre tread and why?
Ribbed tyre
| Offers low rolling resistance, good directional stability and water displacement
303
What are advantages of tubeless tyres over tubed tyres?
Lighter
Less chance of puncture
Cooler (less friction)
Fusible plugs (protects from blowing out)
304
What is the power source for the brake system?
Hydraulic system pressure of 3000psi
305
What does Brake control valve do?
(BCV)
Reduces hydraulic pressure to operating range (1500psi)
Regulates flow of return fluid
306
Which system does anti skid system work in conjunction with?
Auto brake system
307
What does anti skid provide?
Touch down protection
Skid protection
Locked wheel protection
Hydroplane protection
308
If a skidding wheel is detected, what happens to pressure on the brake for that wheel?
Pressure is reduced (NOT REMOVED)
309
What is the formula for hydro plane speed for static wheel
7.7 square root (Tyre pressure psi)
310
What is the formula for hydro plane speed for rotating wheel?
9 square root (tyre pressure psi)
311
Which tyres are more prone to hydroplaning?
Forward tyres
312
What will cause auto brakes of 767 to disarm?
```
Pilot hits brakes hard enough (>750psi)
Retraction of speed brake lever to down
Selector switch to disarm or off
Advancing throttle
INS u/s
Anti skid u/s
```
313
What are the degrees of steering for rudder pedals and tiller wheel?
Rudder +/- 7 degrees
| Tiller +/-65 degrees
314
Can different hydraulic fluids be mixed?
NO
315
What does the hydraulic reservoir do?
```
Allows for variations in fluid level
Provides reserve for leaks
Provides space for returning fluid
Allows for changing temp and volume
Provides positive pressure to pumps to avoid cavitation
```
316
What pressure does hydraulic pump provide up to?
3000psi
317
What is EDP and what does it do?
Engine driven pump
| Primary source of pressure for hydraulic system
318
How does EDP provide pressure for hydraulic system?
Constant or variable displacement pumps
319
What do hydraulic pressure relief values do?
Ensure pressure in system isn't exceeded
320
How do hydraulic pressure relief valuves work?
Spring loaded valve being forced by high pressure fluid which allows excess to pass back into a return line to reservoir.
321
What do check valves do?
Allows fluid to flow in one direction only
322
Where are check valves located?
Downstream of the pump
323
What are shuttle valves?
Enable services to be provided with hydraulic pressure from one of two sources. Whichever line has greater pressure allows that line to provide fluid
324
What are selector valves and how are they operated?
Controlling valve which opens to allow high pressure oil into actuating hydraulic actuator.
Electrically operated
325
In the 767, what hydraulic systems are there?
Left, centre right
326
What power sources are used by LEFT hydraulic system?
EDP (engine driven pump)
| ACMP (alternating current motor pump)
327
What power sources are used by CENTRE hydraulic system?
2ACMP (alternating current motor pump)
ADP (air driven pump)
RAT (ram air turbine-emergency)
328
What power sources are used by RIGHT hydraulic system?
EDP (engine driven pump)
| ACMP (alternating current motor pump)
329
What is RAT?
Ram air turbine
330
What does RAT do?
Provides emergency hydraulic power using ram air
331
How can RAT be deployer?
Automatically or manually
332
When can RAT be retracted?
Only on ground
333
Where is hydraulic pressure displayed?
Centre of EICAS panel
334
What are advantages of pneumatics?
```
Lighter
Cheaper
Low fire risk
Once used, air can be dumped over board
Easily compressed
```
335
What are disadvantages of pneumatics?
Air must be dried
Components must have separate lubrication system
More prone to leaks
336
What are the advantages of hydraulics system?
```
Uses incompressible hydraulic fluid
Self lubricating
Fewer problems with water or water contamination
Easy to find leaks
Faster response times
```
337
What are the disadvantages of hydraulic systems?
High fire risk
Requires coolers
Hydraulic oil can destroy electrical insulation surfaces, finishes and seals
Hydraulic oils cant be mixed
338
In 767, how do we control leading edge slats and double slotted fowler flaps?
Flap lever which sends signal to three power drive units (PDU)
339
What happens to the flap and flap lever if airspeed exceeds set limitation?
Flaps automatically retract
| FLAP LEVER DOES NOT MOVE
340
What type of pressure is kept in the cabin compared to outside?
Higher pressure
341
Should the pressure in the cabin be less than the atmospheric pressure?
No
342
Where is the outflow valve located and why?
Rear of cabin to draw pollutants away from the flight crew
343
What are the three functions of the outflow valve?
Isobaric control (maintaining cabin altitude)
Differential pressure protection (ensuring max pressure not exceeded)
Negative pressure differential (prevents negative pressure being exceeded)
344
What pressure is maintained by the pressure controller sensors during climbs and descent?
500fpm for climb
| 300fpm for descent
345
What do safety valves do?
Provide positive and negative over pressure protection
Automatically dump remaining cabin pressure on landing
Allow emergency dump during rapid decompression
346
Where is the negative pressure relief valve located?
Cargo doors
347
When will negative pressure relief valve open?
Any time when outside pressure exceeds cabin pressure
348
What is the source of pressurisation?
Engine or APU bleed air and atmospheric air mix
349
What must pilot enter in the system for automatic pressurisation of system?
Destination elevation
350
When will pressurisation system warnings be displayed on EICAS?
If cabin altitude exceeds 10000
| O2 masks drop if cabin altitude exceeds 14000
351
What systems typically use electrical anti ice?
```
Pitot static probes
Angle of attack vanes
Total air temp probes
Engine probes
Mach probes
Windscreens
Inner sections of prop
Engine intakes
```
352
Can rain repellent be used on a dry windscreen?
No
353
What will the use of thermal protection do to engine performance? When is it most noticeable?
Reduce engine performance as air sourced from output of engine (engine bleed air).
During high power settings at take off and climb
354
How are the de-icing boots used?
Pneumatically
355
What are the de-icing boots?
Slightly raises black areas on leading edge of wings, comprised of rubber material that inflate cracking any ice
356
What fuel is typically used in Australia for jets?
JETA1
357
What type of additives can be found in turbine fuel?
```
Anti static (required if refuelling with pax on board)
Anti oxidants
Anti fungal
Anti freeze
Lubricating additive
```
358
What could be an indicator of icing detected in the fuel system? And what should be done to rectify?
Low filter pressure.
| Pilot select bypass generally for short periods (1min)
359
What is incorporated in the fuel tank to prevent CoG changes when turning?
Baffles
360
What is the purpose of the LP pump?
To provide uninterrupted flow of fuel to high pressure pumps
361
How many booster pumps are used during takeoff? Landing? Cruise? Descent?
Take off 2
Landing 2
Cruise 1
Descent 1
362
What does HP pump do?
Supplies pressure to fuel manifold
363
What is the most common HP pump type?
Variable displacement
364
Where does FCU (fuel control unit) receive its inputs from?
Altitude
Throttle position
Inlet air temp
Speed of N2
365
What is the function of the circuit breakers?
Provide circuit protection and isolation from excessive amps
366
What power do batteries supply?
Power for start and emergency power
367
What does IRS use?
3 gyros and 3 accelerometers
368
Outside of what latitudes will RDMII display true heading? In this case what happens to VOR flag?
73N 60S
| VOR flag inoperative
369
Where is input for RDMI from?
IRS (inertia reference system)
370
Where do inputs for VSI come from?
ADC and IRS
371
What level do radar altimeters operate?
0-2500 ft AGL
372
The FMS systems managers which flight path?
LNAV and VNAV (lateral and vertical flight paths)
373
How should entries be made in the CDU?
One CDU used to enter data, one used to cross check
374
What do the boxes represent on CDU?
Must have info
375
What do the dashes represent on CDU?
Requested info
376
What is done on the IDENT page?
Preflight, first page to have data entered.
377
Which page allows present position of plane to be supplied to IRS and can consist of LAST POS, REF AIRPORT or GATE?
Position initialisation page
378
What is the RTE page?
Route page.
| Enables crew to enter route into FMC
379
How would pilots display possible departure routes?
Go to SID entry and then select DEP/APR button
380
Where would gross weight, ZFW, fuel reserves, cost index and cruise altitude be entered?
Performance initialisation page
381
Where would the crew enter the V1, VR and V2 speeds?
Take off reference page
382
Where can the crew monitor the flight plan of the aircraft through the CDU? What else can be monitored on this page?
Progress page.
| Last waypoint, next waypoint, destination, speed, TOPD, wind
383
What does the Electronic flight instrumentation system (EFIS) consist of?
```
EADI
EHSI
Symbol generator
Control pannel
FMS
```
384
The captains RDMI and VSI are supplied by what ?
RDMI by R - IRS
| VSI by L - IRS
385
The first officers RDMI and VSI are supplied by what ?
RDMI by L - IRS
| VSI by R - IRS
386
What display modes are the on the EDSI?
MAP, PLAN, ILS and VOR
387
What are the different colour indications for MAP mode?
```
Green = engaged flight mode
White = present status situation
Cyan = non active and background info
Red = warning
Amber = cautionary info
Black = blank areas OFF condition
```
388
What does expanded VOR mode show?
VOR nav info
Weather radar
TCAS available
389
What does expanded ILS mode show?
ILS info
Weather radar
TCAS available
390
What does PLAN mode show?
Static true north orientated map of flight planned route.
| No weather radar
391
Which of the modes use track? Which use heading?
MAP and PLAN use track
| VOR and ILS use HDG
392
Is the flight director manual or automatic?
Can be both
393
Will manual position of lever disengage autothrottle?
No
394
How many autopilots are required for Approach mode?
2
395
Which modes will autopilot are with approach mode?
Glide Slope and LOC
396
How many autopilots does 767 use?
3
397
How many autopilots does AFDS require?
1
398
When can you use more than one autopilot?
During precision approach
399
How many autopilots are required for autoland?
2
400
What does fail operational mean?
Means system has adequate redundancy to allow approach to continue if one of three autopilots fails
401
What does fail passive mean?
If a fault is detected in one of the autopilots.
Landing is being done with 2 autopilots
A/C unable to conduct auto landing in extreme low visibility
402
What happens as altitude decrease to 1500 ft during landing?
LOC and GS have been capture and APP modes will be armed
403
When is FLARE mode active?
45 ft
404
When is ROLLOUT mode activated?
5 ft
405
At what height does pilot assume command of rudder?
1500 feet
406
What happens at 500 feet during landing?
Runway align submode becomes active. (reduces crab with cross wind)
407
Between what heights will aircraft automatically introduce increment of nose up trim in preparation for flare?
330-100ft
408
What happens at 15ft during landing?
SPD mode on auto throttle becomes IDLE
409
How long will rollout mode continue?
Until aircraft comes to fullstop OR autopilots are disengaged
410
What are the three types of message displayed on EICAS?
Warning (red)
Caution (yellow)
Advisory (yellow)
411
What does the CANCEL switch do?
Removes displayed cautions and advisories (warnings not affected)
Shows next page of messages
412
What does RECALL switch do?
Recalls cancelled cautions and advisories
| Goes to page 1 of messages
413
Which direction does GPWS mode operate in?
Vertically only
414
What are the soft warnings for mode 1 excessive descent rate?
Aural: Sink rate sink rate
Visual: GND prox light
415
What are the hard warnings for mode 1 excessive descent rate?
Aural: Whoop whoop pull up
Visual: Pull up light
416
What are the soft warnings for mode 2 excessive terrain closure rate?
Aural: Terrain, terrain
| VisualL GND Prox light
417
What are the hard warnings for mode 2 excessive terrain closure rate?
Aural: Whoop whoop, pull up
Visual: Pull up light
418
What does extension of flaps do if the hard warning for mode two is being heard?
Replaced with terrain terrain
419
What are the soft warnings for mode 3 altitude loss after take off/go around?
Aural: Don't sink
Visual: GND prox light
420
What are the hard warnings for mode 3 altitude loss after take off/go around?
Aural: Too low terrain
421
What are the soft warnings and when do they occur for Mode 4 unsafe terrain clearance in config?
Below 190 kts at 500ft
Aural Too low gear
Visual: GND prox light
422
What are the hard warnings and when do they occur for mode 4 unsafe terrain clearance in config?
Above 190 kts below 1000
| Aural: Too low terrain
423
What does the TCAS rely on?
Interrogation of other a/c SSR transponder
424
Does TCAS use ground SSR?
No, totally independent of any ground based SSR
425
How long after TCAS messages does pilot have before impact?
20-35s
426
What colour are TA and how long do you have?
Amber circle
| 20-48 s
427
What colour are RA and how long do you have?
Red square
| less than 25s
428
What is proximate traffic?
Cyan diamond, is neither TA or RA but within 6nm and has 1200ft separation
429
What is other traffic for TCAS?
Hollow cyan diamond.
| Above and separated by more than 2700ft
430
What does +## symbol mean in TCAS?
Indicated traffic is above you (i.e +05 is 500 ft above)
431
What does - signal mean in TCAS?
Indicated traffic is below you
432
What does up arrow indicate in TCAS?
Traffic is climbing
433
What does down arrow indicate in TCAS?
Traffic is descending
434
What does TA 6.8-1.1 Up arrow mean?
No bearing info. Intrudering aircraft is 6.8 nm away 1100 ft below and climbing
435
What conditions will cause TCAS to fail?
Mode S transponder fail
Barometric altitude sources fails (TCAS OFF)
Radio altimeter fails
436
What time do you have to action preventative TCAS advice? What about Corrective?
5s for preventative
| 2.5 for corrective
437
What warnings override the TCAS?
GPWS and Stall
438
How many parameters and for how long does DFDR record?
300 parameters
| 25 hours
439
Where is the DFDR located?
Tail
