Aircraft exam Flashcards
1
Q
What is Bernoulli’s principle?
A
Rise (fall) in pressure within a flowing fluid must always be accompanied by a decrease (increase) in the speed, and conversely, an increase (decrease) in the speed of the fluid results in a decrease (increase) in the pressure within the fluid.
Why the air going over the wing has a lower pressure
2
Q
What are the four forces acting upon an aircraft in flight?
A
Lift
Weight
Thrust
Drag
3
Q
What would be condsidered stable flight?
A
If an aircraft in flight will tend to return to level flight of its own accord without pilot interference it is stable.
4
Q
What is lift?
A
Lift: To overcome weight, aeroplanes generate an opposing force called Lift, which is generated by the motion of the aircraft through the air and is an aerodynamic force. Argument between Bernoulli principle and Newtons Laws of Motion. Works through the centre of pressure of the wing.
5
Q
What is weight?
A
Weight: Force generated by the gravitational attraction of the earth on the aircraft. Acts downwards towards the earth irrespective of the aircrafts attitude. Works through the centre of gravity of the aircraft.
6
Q
What is thrust?
A
Thrust: Mechanical force provided by the aircrafts system of propulsion. Used to overcome drag. Works through the thrust line.
7
Q
What is drag?
A
Drag: Aerodynamic force that opposes an aircrafts motion through the air, generated by every part of the aircraft: Profile drag- consequence of shape, increases as speed increases. Induced drag- consequence of lift, decreases as speed increases. Profile + Induced= Total Drag. Works through the drag line which is the exact opposite of the thrust line.
8
Q
What is laminar flow?
A
Laminar Flow is the smooth, uninterrupted flow of air over the contour of the wings of an aircraft in flight.
It is most often found at the front of a streamlined body and is an important factor in flight.
If the smooth flow of air is interrupted, turbulence is created which results in a loss of lift and increased drag.
An Aerofoil designed for minimum drag and a smooth flow of the boundary layer is called a laminar aerofoil.
If the angle of attack of a wing is too high the laminar flow of air will separate from the wing, becoming turbulent, this is called the critical angle of attack and is the point where the wing will begin to stall.
9
Q
How does an aircraft’s wing work?
A
Bernoullis principle
The curvature of the wing forces the air going over the top to speed up and therefore decrease in pressure whilst the opposite happens underneath the wing. The pressure underneath the wing then pushes the aircraft into the air.
10
Q
What is an aerofoil?
A
A part of an aircraft designed to produce lift.
11
Q
What is the chord line of a wing?
A
A line that dissects a wing from the leading edge through to the trailing edge.
12
Q
What is the angle of incidence of a wing?
A
the angle at which the wing is attached to the fuselage.
13
Q
What is a stall?
A
An aircraft is considered to be stalled when the critical angle of attack is reached and the laminar flow over the top of the wing seperates leading to a drop in the amount of lift generated.
14
Q
What is the Angle of Attack of a wing?
A
The angle between the chord line and the flow of air. Has a large affect on amount of lift generated by a wing- greater angle= more lift (up to stall point where lift decreases because of flow separation).
15
Q
How does a Piston Engine work, and what are its advantages and disadvantages?
A
Based on internal combustion engine using four stroke cycle: Intake- air and vaporised fuel drawn in Compression- fuel vapour and air compressed and ignited Combustion- fuel combusts and piston driven downwards Exhaust- exhaust gasses expelled.
16
Q
How does a Jet Engine work?
A
Discharges a fast moving jet of hot expanded gases to generate thrust in accordance with Newtons Third Law (every action…). Uses the intake, compression, combustion and exhaust process. Turbojet- Generic term for simple turbine engines (100% air in/out) Turboshaft- similar to turbojet, gas turbine optimised to produce shaft power.
17
Q
How does a Turboprop Engine work?
A
Type of gas turbine engine where the power produced is used to drive a propeller attached to the turbine shaft.
Variable pitch propellers- angle of attack of propeller blade can be altered to change thrust and drag profile in flight.
18
Q
What are the three differences between aircraft and car engines?
A
- Aircraft engines are air cooled- saves weight and is safer
- Dual ignition systems- independent magnetos and spark plugs
- Fuel/Air mix- manually controlled.
19
Q
How many operations is there in a four stroke engine?
A
5
- Induction
- Compression
- Ignition
- Power stroke
- Exhaust
20
Q
What is a carburetor?
A
A device that provides a suitable mixture of air and fuel to the cylinder for ignition.
21
Q
What happens to air as it enters a carburetor?
A
- It accelerates
- There is a drop in air pressure?
- This causes the fuel to be drawn through the main jet where is mixes with air in the venturi
22
Q
How does carburetor icing occur?
A
Due to the venturi effect and bernoulli’s principle;
- The pressure decrease of the air accompanying the deceleration also causes an instant air temperture drop
- Latent heat is absorbed by the fuel as it vaporises into vapour, further cooling the air.
Can cause temp drops of 20°C
23
Q
What should pilots do to prevent carburetor icing?
A
- If possible avoid areas where such icing is likely to occur
- Turn on the carburetor heating system
- During descents with engine at idle power, apply engine power frequently, so as to keep the engine warm
24
Q
How does a propoller work?
A
Propeller: Means of converting engine power into a propulsive force, rotating blade accelerates a mass of air rearwards, aircraft moves forward in reaction. Aerofoil shape (like a wing). Outer edge of disc travelling faster, therefor blade is twisted in order to alter the angle of attack and give constant lift along whole blade. More blades= solidity increasing= less radius necessary.
25
What is the pitch of a propeller blade?
The angle made by the chord of the blade and its plane of rotation.
Much like the angle of attack of a wing, the higher the pitch the higher the propellers angle of attack and the more air it pushes back with each revolution.
26
What pitch is better for taking off and climbing?
A fine pitch
27
Which pitch is better for cruising?
Coarse
28
What is the term for a pitch that is a compromise between a fine and coarse pitch for a fixed propeller blade?
Standard
29
What is a variable pitch propeller?
A propeller that can vary its pitch dependent on need. They can even use a reverse pitch.
30
What are the advantages of piston engines and propellers?
Advantages:
- More protected and easier to access and maintain
- Lower temperatures and pressures
- RPM increases and decreases more rapidly than jet
- Cheaper to manufacture
- Shorter take off and landing runs
31
What are the disadvantages of a piston engine and propeller?
Disadvantages:
- Less economical on fuel= more fuel carried
- Vertical rather than linear movement of engine components, inefficient transfer of power and more wear and tear due to vibration
- Relatively expensive fuel
- Lower ceiling (10-12000ft) due to air density
- Noise, both onboard and ambient
32
What are the stages of a jet engine?
1. Air intake
2. Compressors
3. Combustion chambers- mixed with fuel and ignited
4. Turbine stages- extracts energy from the air leaving to drive the compressors
5. Exhaust stage
33
Name the different types of jet engine
Low bypass Turbofan
High bypass Turbofan
Turboprop
Ramjet
Scramjet
Turboshaft (turboprop for a helicopter)
34
What are the two types of compressors found in a jet engine?
Axial
Centrifugal
35
How does a centrifugal compressor work?
Uses an impeller to accelerate air and a diffuser to produce the required pressure rise.
36
How does an axial flow compressor work?
Employs alternate rows of rotating blades to accelerate the air and stationary vanes to diffuse the air until the required pressure rise is reached.
37
What advantage does a centrifugal compressor have over an axial one?
Favoured for small engines due to its simplicity, ruggedness and ease of manufacture outweighing any disadvantages.
38
What advantages does an axial compressor have over centrifugal?
Can have long thin engine shapes
Extra pressure rises can be achieved with addition of other compressor stages.
39
What is a turbo fan engine?
An engine with a turbojet core which also uses the fans to acclerate air around this engine, the purpose of the turbines is mainly to turn the fans.
This helps to reduce engine noise and increase efficiency.
Bypass ratios can equal 26:1
40
What are the advantages of a turbofan engine?
* More efficient- thrust generated by core **and** the air being pushed around it
* Can use afterburner to reignite gases to increase thrust
* Can travel further for less fuel
41
What are the disadvantages of a turbofan engine?
High cost
Longer to accelerate than piston engines
42
What are the advantages of a turboprop engine?
Advantages:
- More efficient at lower levels
- Can operate on shorter runways
- Propeller can be feathered to minimize drag in event of engine failure
- More mechanically reliable, due to lower moving parts.
43
What are the disadvantages of a turboprop engine?
Disadvantages:
* Propellers lose efficiency at higher altitudes
* Vibration levels can cause slight passenger discomfort
* en-route weather can cause problems
* additional passenger discomfort due to operating altitudes
* older generation turboprops are slow.
44
What shape of propeller blades are used for higher flight speeds?
Scimitar shaped
45
What are the two types of drag?
1. **Parasite Drag
a. Form Drag**
-Form Drag
-Skin Friction
**b. Interference Drage**
2. **Induced Drag**
46
What is form drag?
A type of parasite drag
Results when airflow seperates from the surface and the streamlined flow becomes disturbed and increases drag.
Point at which streamline flow seperates from the surface is known as the seperation point.
Can be postponed by streamlining the aircraft.
47
What is skin friction drag?
Type of parasite drag
Results from friction between the aircraft and the air.
Is dependent on;
* Surface area of aircraft
* Whether the boundary layer airflow near the surface is laminar or turbulent
* Roughness of surface
* Airspeed
* Aerofoil thickness.
48
What is interference drag?
Type of parasite drag
Drag created at the junction of aircraft surfaces caused airflow interference. This creates additional drag
Fairings and streamlining can reduce this.
49
What is induced drag?
Drag caused by the generation of lift.
Some of the high pressure air will 'spill' over the edge of the wings (at the edges and the wing tips) causing a flow of air towards and away from the fuselage producing wingtip vortices.
This is most pronounced during phases of flight where lift generation is at its highest, eg. take-off and landing.
50
What wing shape is most efficient at combating induced drag?
Long narrow wings.
51
Does an aircraft in a clean configuration have more or less induced drag?
More as the vortices are undisturbed.
52
What aircraft configuration has the greatest effect on dispersing wake vortices and induced drag?
Landing configuration with wheels and flaps down
This is due to these interrupting the smooth airflow over the wing which upsets the generation of the wake vortices.
53
What can be attached to an aircraft wingtip to resuce wing tip vortices?
Winglets.
54
What are the types of devices that can be used to modify lift and drag?
Trailing edge devices
Leading edge devices
Spoilers/Airbrakes
55
What is a FLAP?
A type of trailing edge device that modifies drag and lift.
It works by increasing the camber (or curvature) of the wing which increases the amount of lift generated by that wing.
They also produce extra drag but this can be useful when an aircraft is landing as it would reduce the landing roll.
56
What happens to an a/c's take off or landing roll when it has deployed its Flaps?
It decreases, so less runway is needed for a take off and the landing roll is much shorter.
57
What is a slot?
A fixed leading edge device that works like a fixed SLAT.
It increases the maximum angle of attack a wing by around 20° allowing it to generate more lift by using a higher angle of attack
58
What is a SLAT?
A retractable leading edge device
It increases the maximum angle of attack a wing by around 20° allowing it to generate more lift by using a higher angle of attack
59
What unfortunate side effect do flaps and slats produce?
The cause the a/c to pitch up causing an unstable condition and higher drag.
60
What are spoilers/airbrakes?
Small hinged plates on the top portion of wings.
When deployed they disturb the airflow over the wing reducing lift and increasing drag.
They are used to slow down aircraft on landing roll and ensure it remains on the runway and does not lift off again.
61
What problems are associated with landing during the failure of high lift devices?
* Landing approach will have to be made at a shallower angle
* Land at higher speed leading to;
- Possible brake fires
- Possible tire bursts
- Runway overrun
- Overheating of brakes
62
What problems are associated with take off during the failure of high lift devices?
* Shallow take of angle, leading to less obstacle clearance
* Slow rate of climb
* Premature retraction (failure to climb or loss of height)
* Full stall close to ground- usuall fatal.
63
What behaviour will an a/c exhibit when stable?
Aircraft tends to return to its original condition after being disturbed
64
What behaviour will an a/c exhibit when neutrally stable?
Aircraft will assume a new position
65
What behaviour will an a/c exhibit when unstable?
Aircraft will continue to diverge from its original position.
66
What are the three axes and how is an aircraft controlled through them?
Vertical- Yaw
Longitudinal- Roll
Lateral- Pitch
67
What are most aircraft designed to have with regards to stability?
A natural inbuild stability.
68
What is directional stability?
The surface area of the vertical stabiliser in relation to the side of the area of the fuselage and centre of gravity and the sweep angle of wings.
69
What is longitudinal stability?
The area of the horizontal stabiliser in relation to the length of the aircraft and its centre of gravity.
70
What effect can the wing shape have on the stability of an aircraft?
Swept wings help to increase lateral stability
Dihedral Wings also increase lateral stability
Anhedral Wings decrease stability (good for fighter planes)
71
What are the horizontal stabilizer?
A fixed wing section which assists in longitudinal stability. It prevents up and down, or pitching motion of the a/c nose.
72
What is the elevator and how does it work?
A moveable surface attached to the horizontal stabilizer that gives pitch control in the lateral axis, determing the a/c's attitude.
It works by changing the angle of deflection which when deflected downwards increases the lift on the rear of the aircraft pitching it down.
When deflected upwards it decreases the amount of lift generated at the rear and the aircraft pitches up.
73
What is an aileron?
A small hinged section on the outer part of the wing that provides roll control in the longitudinal axis.
The ailerons on either side move opposite to one another. When one is deflected downwards it increases the lift on that side and the other aileron will deflect upwards reducing lift causing the aircraft to roll.
For example when rolling to the left, the right aileron will be deflected downwards creating more lift and lifting the right side of the aircraft up.
74
What is the vertical stabiliser?
A fixed aerofoil section which provides directional stability for the aircraft.
75
What is the rudder?
A small moveable section at the rear of the vertical stabilizer
It varies the aerofoil section of the vertical stabilizer, this varies the amount of horizontal 'lift' force generated by the vertical stabilizer. This controls the side-to-side or yawing motion of the aircraft.
76
What is rudder input used for?
To ensure that the aircraft is properly aligned to the flight path,
not used to turn the a/c
77
What are trim tabs?
Small moveable control surfaces located at the trailing edge of the rudder, ailerons and elevator.
They are used to assist the movement of the main control surface.
By means of small control wheels or electric trim buttons, the pilot is able to move the trim tabs, so as to relieve the load from the main control surface.
This reduces pilot fatigue.
78
What does the Airspeed Indicator show and how is it measured?
The Airspeed Indicator provides the pilot with airspeed information in knots- called Indicated Airspeed.
The Pitot tube protrudes from the aircraft in the direction of airflow to sense Static and Dynamic Pressure. Static Pressure is removed from Pitot Pressure by means of a Static Vent, and Dynamic Pressure is displayed on the A.S.I. The Pitot tube can become blocked by detritus or ice, especially at high altitudes, so they are often heated. On larger aircraft multiple redundancy will be achieved by utilising 2 Pitot tubes- one on each side of the aircraft.
Different colour bands draw the pilots attention to various airframe limitations, for example a band might show the range at which the aircrafts flaps can be used.
79
What does an Altimeter measure and how does it work?
An Altimeter provides the pilot with 'level' information which is measured in feet (in the Europe). Altimeters are a sealed unit with only one input- a Static Vent. As Static Pressure reduces the sealed capsule expands. The opposite is also true. The smallest of expansions and contractions are measured, geared and then displayed on the Altimeter. The datum pressure of the sealed capsule is adjusted on the altimeter by rotating a nob (set for QNH, QFE, SAS).
Altimeters are calibrated to the ISA.
80
What is a Vertical Speed Indicator (V.S.I.) and how does it work?
A Vertical Speed Indicator displays the rate at which an aircraft climbs or descends and is measured in feet per minute. Inside the V.S.I. a sealed capsule expands and contracts as Static Pressure changes. The capsule has one small calibrated hole or vent, which allows air pressure to EVENTUALLY equalise inside and outside the capsule. (Hence the measurement is of the pressure in relation to what it was recently- rate of change).
81
What is the Turn and Slip Indicator and how does it work?
A skid and slip ball indicate the rate of turn of an aircraft and whether there is any slip.
Slip is indicated by a ball in an arc, when it is no longer centred the aircraft is unbalanced and is slipping or skidding.
The turn indicator uses a gyro and its property of **precession** to react to the turn, ie when you turn it tilts.
82
What are the main Flight Instruments used in an aircraft?
Attitude Indicator Airspeed Indicator Altimeter Vertical Speed Indicator Turn and Slip Indicator Compass Direction Indicator
83
What error does a VSI suffer from?
A lag of a few seconds.
84
What errors do Airspeed indicators suffer from?
* Instrument Error
* Position errors
* Density errors- due to air decreasing with altitude, this is what causes a TAS to be higher than IAS above MSL
* Compression errors- speeds above 300kt, air is compressed before entering pitot tube creating wrong errors.
85
What is a MACH meter?
Shows the a/c's speed as a MACH no.
This is used to overcome the problem of the difference between IAS and TAS at higher levels.
86
What happens to the speed of sound as you climb?
It decreases due to reduced density and temperature/
87
What errors does a Mach Meter suffer from?
It is a combination of an altimeter and ASI so suffers from the errors of both.
88
What errors does an altimeter suffer from?
Pressure errors caused by temperature and pressure changes not always following the ISA assumptions
89
What is a gyro and what properties does it have?
A gyroscope
Its most important properties are;
* Inertia- The tendancy of the gyro to keep a fixed position relative to space
* Precession- When subjected to a force, the gyro acts as though the force has been applied at 90° to the rotor at a position 90° forward in the direction of rotation of the rotor.
90
What does one division of the turn indicator indicate?
A rate one turn
Two divisions equals rate two turn etc
Rate 1 =3°/second
91
What is an artificial horizon?
A device that displays an artifical horizon allowing the pilot to gain his situational awareness in IMC w/o visual reference to the actual horizon.
It uses a gyro and its property of **inertia** tied to the centre of the earth to maintain a fixed reference point for the indicator.
92
What errors is the aritificial horizon subject to?
* Acceleration- when accelerating on take-off the AH may give a small nose up indication
* Turn- similar to acceleration error when in a tight turn.
93
Why do pilots still sometimes use magnetic compasses for navigation?
They are reliable, small, and self contained, requiring no power source. For these reasons they make excellent back-up systems.
94
What errors is a magnetic compass subject to?
* Deviation-caused by local magnetic currents
* Dip error-Causes needle to point towards the ground more as you head towards the magnetic poles.
* Acceleration Error
95
Briefly describe deviation error with a magnetic compass
Caused by local magnetic fields pushing the compass of a true reading of magnetic north.
Must be checked periodically by a procedure called a compass swing. This checks the deviation at 30°intervals of the compass headings, the difference between magnetic heading and compass heading is shown on a compass correction card.
96
Briefly describe dip error with a magnetic compass
The magnetic fields of the earth point towards the earth the closer you get to the magnetic poles, therefore a compass will experience slight dipping towards the surface of the earth the further north you go.
When turning in a banked attitude the vertical component of the earths magnetic field causes the compass to dip to the low side of the turn.
97
Briefly describe acceleration error with a magnetic compass
Occurs during airspeed changes and is most apparent on headings east and west.
It is caused by a combination of inertia and magnetic dip, when the a/c accelerates either westerly or easterly the compass card temporarily indicates a turn to the north. When you decelerate the card will point south
ANDS- Accelerate North, Decelerate South.
Compass is only accurate whil the aircraft is flying wings level in steady flight.
98
What is a gyrosyn compass?
A combination of a gyro and a magnetic compass
The gyro is continously aligned with magnetic north by a magnetic flux detector. Thus, a steady reading of compass heading is shown, eliminating the turning and acceleration erros found in magnetic compass'
99
How is VOR information displayed in the cockpit?
On an OBS (Omni-Bearing Selector)
This will display either a radial from or a QDM to fly for the station, the TO or FROM flag indicates whether the aircraft has passed over the station or not.
Each dot will indicate 2° of deviation from the desired course.
100
How would a pilot know if a VOR has failed?
A flag on the OBS will indicate as such.
101
What are the advantages of a VOR?
* VOR transmitter is not affected by weather, coastal or day/night refraction
* It gives very accurate radials. Radials from two suitable sited VOR's will give a fix
* Can be used to make accurate instrument approaches to airfields.
102
What is the disadvantage of a VOR?
Range is limited by LOS
103
What is a TACAN?
A military version of a VOR/DME that operates on UHF frequency.
These are more accurate than VOR's becuase they use two different frequencies.
104
What are VORTAC's?
Co-located VOR and TACAN, the TACAN will provide the DME element of a normal VOR/DME
105
106
What is a DME?
Distance measuring equipment. A transponder on the ground that is interrogated by the aircraft transponder before being transmitted back. The time the signal takes to return is used to calculate the **slant range** of the aircraft from the DME. Gives range in NM. Can be interrogated by up to 100 aircraft at once. Operates UHF. Slant range error can make the reading inaccurate the closer the aircraft is and the higher it is.
Information is displayed on the DME receiver in the cockpit.
107
What is the accuracy of an DME?
* Accurate to within 1nm
* Can accept up to 100 aircraft interrogations simultaneously
* Subject to slant error - the closer to the beacon, the less accurate the readings become
108
How are DME's used?
* Co-located VOR/DME stations provide range and bearing
* Provides positive ranges for aircraft flying same track and interrogating same DME ATC separation
* Co-location with precision approach aid accurate range from touchdown eg ILS
* Enhances the accuracy of holding patterns
* Suitable computer + DME accurate area navigation
* Military use for air to air refueling
109
How does an aircraft use a DME?
The aircraft will send out a digital or analogue pulse train on one frequency which is received by the DME, the DME will then send back the same pulse train but on a different frequency back to the aircraft. Two frequencies are used so the aircraft don't interrogate each other and the pulse train is randomly generated so each aircraft will know when its own signal is being returned.
The time calculated between transmission of the first signal and receipt of the reply is used to work out the range of the DME. This will then be displayed in the cockpit for the pilot.
110
What is an ILS?
Instrument Landing System
## Footnote
The Instrument Landing System (ILS) is a highly accurate and dependable means of navigating to the runway in IFR conditions. When using the ILS, the pilot determines aircraft position primarily by reference to instruments. The ILS consists of:
A. The localizer transmitter;
B. The glide path transmitter;
C. The outer marker (or an NDB or other fix); and
D. In association with a suitable runway, the approach lighting system.
Has different categories
The localizer provides lateral guidance. The localizer is a VHF radio transmitter and antenna system using the frequency band as VOR transmitters (between 108MHz and 112MHz). Located at the upwind end of the runway.
The glide path transmitter provides vertical guidance to the pilot during the approach. The ILS glide slope is produced by a ground-based UHF radio transmitter and antenna system, operating in the 329.30 MHz to 335.00 MHz frequency band. Normally 300m from the threshold, also offset by 100-200m.
**It is a precision approach.**
111
What is a CAT 1 ILS?
**Category I** ILS provides guidance information down to a decision height (DH) of not less than 200 ft. Vis not less than 800m or RVR of less than 550m.
*The RVR can be reduced to 400m for a non standard CAT I approach.*
112
What is a CAT II ILS?
**Category II**
ILS approaches and a DH lower than 200ft but not less than 100 ft. RVR not less than 350m.
*You can have non standard CAT II approaches that are missing some or all of the elements of a standard CAT II precision approach but still use these figures above.*
113
What is a CAT III A ILS?
**Category III**
A- Decision height lower than 100ft or no decision height, RVR of no less than 200m.
114
What are the figures for a CAT III B ILS?
B- Decision height lower than 50ft or no decision height
RVR not less than 200m but not less than 75m.
115
What are the figures for a CAT III C ILS?
C-A precision instrument approach and landing with no decision height, and no runway visual range limitations.
116
What four things does an ILS consist of?
1. The localizer transmitter
2. The glidepath transmitter
3. The outer marker
4. The approach lighting system
117
What are the advantages of ILS?
* Pilot interpreted and simple to use
* Precision approach
* Can be coupled to auto-pilot for automatic approach and landing
118
What are the disadvantages of ILS?
* Subject to interference from commercial VHF stations
* Reflections from other ground facilities can create false glidepaths
* Shortage of frequencies.
119
What is MLS?
Microwave landing system
Uses passive arrays to send scanning beams towards aircraft
The aircraft then calculates its position by measuring the arrival times between the beams
Gives a much wider azimuth and elevation range
120
What are VLF nav aids?
Very Low Frequency Aids
A group of long range nav aids operating VLF. They are navigation systems and provide position information globally to an accuracy of better than 1nm.
Introduction of GPS has caused most of these to be phased out.
121
What is Fuel in flight management?
The pilots responsibilities for the verification, utilisation, monitoring, recording and reconciliation of the fuel loaded on the aircraft.
This includes ground ops with intent to fly so by definition is included as a facet of in flight fuel management.
122
What are the threats to in flight fuel management?
1. Complacency
2. Failure to comply with company policy
3. intentional deviation from the planned flight profile
These are divided into categories operational, legal and financial.
123
When must pilots check their fuel levels and why?
At regular intervals to ensure the fuel is not leaking.
124
What are Hydraulic systems?
A fluid system that powers the movement of various systems on the aircraft. This includes the control surfaces, doors, and landing gear.
On most commercial airliners run at 3000psi due to space and lightweight factors as they can generate higher torque forces and power from a smaller unit.
125
What might fail if hydraulics failure occurs?
Wheel brakes
Nose wheels
Control surfaces
Doors
126
What is GPWS?
Ground Proximity Warning System
Uses a/c's radar altimeter to determine the a/c's height above terrain immediately below the a/c. If it is too close or the closure rate is too high the system will produce an audible warning to flight crew.
127
What is EGPWS?
Ehanced Ground Proximity Warning System
GPWS only sees downwards so doesn't help when the terrain rises steeply.
To combat this the GPWS is combined with a nav terrain database which provides the system with information of the terrain ahead of the a/c as well.
Also known as TAWS (Terrain Awareness and Warning System)
128
What are the types of TAWS warnings?
Alerts- These are **soft** warnings and indicate a situation which is unusual but not yet critical to flight
eg "Terrain, Terrain"
"Caution Terrain"
Warnings- These are **hard** warnings that indicate a critical situation which the crew must react to immediately.
eg "whoop whoop, pull up, pull up"
129
What should controllers be aware of in the event of an aircraft initiating a go-around due to TAWS? What else should the controller do?
Be aware that the a/c may not conform to published missed approach preocedures
Immediately confirm altimeter setting with the a/c
130
What is weather radar?
A radar mounted on the aircraft which displays areas of bad weather allowing the aircraft to divert around them and inform ATC of weather patterns.
131
What is an Autopilot and what can pilots control with it?
A system which automatically pilots the aircraft reducing pilot workload from continous hand flying.
Pilots may select;
* Cruise mode
* Speed/Mach
* height
* climb and descent rates
* auto landings
132
What are the advantages of Auto-Pilot?
* Reduces pilot workload
* Ensures accuracy
* Many factors can be considered
* Reduces input errors
133
What is an FMS?
Flight Management System
A data base which integrates route planning and airport data with engine management and auto-pilot
It can plan, navigate, and fly a selected route from just after take-off to an auto-landing at destination.
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What is an EFIS?
Electronic Flight Instrumentation Systems
Combines data from different sources within the a/c and provides pilot with a unified electronic display.
Pilots can select an individual EFIS to show info in various modes eg, Primary Flight Display (PFD) combines Attitude Director Indicator and Horizontal situation indicator.
Pilots can also select NAV mode.
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What is provided as a backup to EFIS?
A full set of vital mechanical flight instruments.
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What factors affect aircraft during take-off?
1. Take off mass
2. Power
3. Elevation of airfield
4. Runway
5. Air temp
6. Wind
7. Noise abatement and ATC
8. Company instructions
9. Servicability
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What factors affect an aircraft during the Climb?
1. Mass
2. Speed
3. Wind
4. Cabin pressuration
5. Air temp
6. Air density
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What factors affect an aircraft during cruise?
1. Mass
2. Cruising Speed
3. Wind
4. Cabin pressurisation
5. Level
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What factors affect aircraft during final descent and landing?
1. Landing mass
2. Elevation of airfield
3. Runway
4. Air temp
5. Wind
6. ATC
7. Company instructions
8. Pilot references
9. Aircraft configuration
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How is a fixed wing aircraft controlled?
Rudder- used for directional control, causes aircraft to manoeuvre in yawning plane, about vertical axis. NB not used to turn aircraft!
Elevators- used for longitudinal control, aircraft manoeuvres in the pitching plane. Used for climb/descent.
Ailerons- used for lateral control, causes aircraft to manoeuvre in the rolling plane. Enables pilot to roll about the longitudinal axis. Does this by altering the camber of both wings, increasing the lift on one and decreasing it on the other.
Trim tabs- auxiliary flight control surfaces, enable pilot to make adjustments in flight to correct an unbalanced condition. Flaps and Slats- used during take off and landing to keep lift high at lower speeds. Extending flaps increases camber to increase lift, pivoting flap downwards increases drag which slows aircraft for landing. Slats keep airflow laminar for longer, permitting an increase in attitude of aircraft (angle of flare). Power- application of power increases aircraft speed and has secondary effect of climb. (And vice versa).
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How are Rotary Wing aircraft (helicopters) controlled?
Cyclical control- changes pitch of rotor blades cyclically (pitch of a given blade different depending on position of rotation). Tilts rotor, causing movement in that direction.
Collective- changes pitch of all rotors at same time, results in helicopter climbing or descending.
Anti- torque pedals- control direction in which nose of helicopter faces, by changing pitch of tail rotor blades to increase or decrease thrust. Nose yaws in direction of applied pedal.
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What is the Flight Envelope of an aircraft?
Refers to the capabilities of a design in terms of speed and altitude. Affected by a number of critical factors: maximum speeds, stall speeds, ceiling, airflow- streamline (laminar) or turbulent flow, angle of attack.
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What is V1?
The speed beyond which the take-off can no longer be safely aborted
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What is VR?
Rotate speed
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What is VLO?
Maximum landing gear operation speed
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What is V2?
Take- off safety speed, the speed at which the a/c may safely become airborne with one engine inoperative
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What is VNE?
Velocity Never Exceed
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What is VREF?
Landing reference speed
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How are engines numbered on an a/c?
From left to right from the captains side
150
When is wake turbulence produced most by an a/c?
When flying slow in a clean configuration at a high angle of attack.
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What are the ICAO wake turbulence categories?
Super- A380
Heavy- 136,000kg or greater
Medium- More than 7000kg but less than 136,000kg
Light- 7000kg or less
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What is the approach category of an aircraft?
A speed which is used to create a standardised basis for aircraft manoeuvrability when conducting instrument approaches.
This is defined as 1.3x the stall speed of the aircraft in the landing configuration at maximum certificated landing mass.
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What are the approach categories?
A= Less than 91kts IAS
B=91-120kts IAS
C=121-140kts IAS
D=141-165kts IAS
E= 166-210kts IAS
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Why do we try to provide aircraft with continous descent approaches?
* Airline operators are in favour of them
* There are considerable environmental benefits.
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What is a CDA?
Continous Descent Approach
Instead of approaching an airport in a stair step fashion leveling off at intervals a CDA allows a smooth constant angle descent to landing.
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How do controllers aid pilots in achieving CDA's?
Providing them with Distance to touchdown so the pilot can configure and plan his descent accordingly.
STARS
A combination of both
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What is the transition point?
The point at which laminar air flow becomes turbulent.
158
What is geometric pitch?
The distance the screw travels per turn depends on the number of threads per mm or depends on the pitch/
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What stroke in a four stroke engine has two elements?
Power stroke
(question may ask for two so put intake as the other one in that case)
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How does the venturi work?
Draws fuel out by decreasing the pressure of the incoming air by speeding it up (venturi effect)
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What is the primary role of a the bypass in a turbo fan engine?
It is more noise efficient.
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What is induced drag aka?
Wake vortex
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What direction do wake vortices spin?
Out to in.
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What does the increase of a wings aspect ratio achieve?
An improvement in laminar flow of wing.
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What effect does lowering the flaps have on induced drag?
it reduces it, (remember the clean/dirty configuration effects on aircraft)
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What part of the aircraft do all three axis of movement cut through?
The centre of gravity.
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What are the three axis of aircraft control?
