General / Misc Aircraft stuff (ACFT) Flashcards
1
Q
What are the thresholds of the 3 different weight turbulence categories, and what is the extra exception?
A
Light is anything up to 7000kg, medium is anything from 7000 to 136,000kg, and heavy is anything about 136,000kg. The exception is the Airbus A380, which is given the turbulence category “super”.
2
Q
What is “climb gradient”?
A
Climb gradient is the ratio of height gained to distance traveled, expressed as a %.
3
Q
What is a typical approach angle, and what has this led to in aircraft design.
A
A typical approach angle would be 3 degrees, and this has led to many aircraft manufacturers designing their aircraft to have glide points of 3 degrees, to make a normal landing possible in the case of engine failure.
4
Q
What is an ICAO standard turn, and what is it used for?
A
An ICAO standard turn is 3 degrees per second, at a bank of no more than 25 degrees. This is used for many maneuvers in instrument flight, including a holding pattern.
5
Q
Rule of thumb for feet/minute to meters/second.
A
200ft/minute = 1m/s.
6
Q
What are the 4 forces acting on an aircraft in flight, and how are they created?
A
Weight: created by the action of gravity on the mass of the plane.
Lift: created by the motion of air over lift surfaces (wings).
Thrust: created by the engines doing whatever it is that sort of engine does.
Drag: created by the air resistance of the air the plane is flying through.
7
Q
What is the empennage?
A
The tail part of an airplane, and all of the things attached to it.
8
Q
What is an aircraft’s auxiliary power unit?
A
A small secondary engine on board an aircraft intended to power the secondary systems, but which can also be used to generate lift in the event of engine failure.
9
Q
What is meant by the term “steady flight”?
A
A level flight in which speed and altitude remain constant, due to lift, gravity, thrust and drag all being balanced.
10
Q
What are the lift and drag formulae?
A
L = 1/2 X velocity squared X rho (air density) X surface area of wings X coefficient of lift. Drag is the same but with the word lift swapped for drag.
11
Q
What is the difference between static and dynamic pressure, and how are they related?
A
Static pressure is always present, and is the pressure created by the weight of air above the location, and energy of the air molecules from temperature.
Dynamic pressure is only present when an object is in motion relative to the air, and it acts in the direction of movement. It is proportional to the density and squared speed of the moving air.
The sum of static and dynamic pressure will always remain the same in a given system.
12
Q
If humidity decreases, what happens to air pressure and why?
A
It increases, because water vapour is less than air.
13
Q
What proportion of lift in generated from high pressure pushing up on wings vs. low pressure pulling up on wings.
A
1/3 to 2/3 respectively.
14
Q
What are the frontmost and rearmost parts of the wing called?
A
The leading edge and the trailing edge.
15
Q
What is a chord line?
A
A straight line directly connecting the frontmost part of the leading edge and the rearmost part of the trailing edge.
16
Q
What are the areas above and below the chord line called?
A
The upper and lower camber, respectively.
17
Q
What is the name for the position of the wing, relative to the movement of air, at which the wing is almost aerodynamically unstable.
A
The critical angle of attack.
18
Q
What is the flat part of the upper camber called?
A
The laminar wing, or the laminar surface.
19
Q
What are the 2 different types of drag?
A
Parasite drag and induced drag.
20
Q
What are the 3 different types of parasite drag?
A
Skin friction drag, form drag and interference drag.
21
Q
What causes induced drag?
A
Turbulent airflow created by the movement of the wings relative to the air.
22
Q
What is meant by the “aspect ratio” of a wing?
A
The ratio of wing length to wing depth.
23
Q
How can a wing’s aerodynamic properties be adjusted to compensate for a low aspect ratio?
A
By adding winglets (sticky-up bits at the ends of the wings).
24
Q
What’s a slat?
A
An extendable device on the leading edge of a wing which can be folded out when desired. It has a narrow slot which focuses the airflow approaching the wing, putting it under higher pressure, and generating lift by causing the air flow to remain stable and laminar for longer.
25
What are flaps?
Extendable surfaces at the backs of wings which can be deployed to change the wings' surface area, and therefore increase lift.
26
Which factors will limit a plane's highest possible speed? 3 answers.
The structural strength of the airframe, the plane's ability to generate enough thrust to overcome its weight and drag, and the critical Mach speed.
27
What factors will limit a plane's lowest possible speed? 2 answers.
Lift coefficient and weight.
28
Which factors will influence a plane's maximum load?
Size of fuselage, structural integrity, thrust generation capability and coefficient of lift.
29
What is an aircraft's "service ceiling"?
The height at which an aircraft is not able to climb by more than 100ft/minute.
30
How do indicated and true air speed vary with height.
Each 1000ft of elevation causes indicated air speed to read about 2% higher than true air speed.
31
What does the term "transonic" mean?
A speed between an aircraft's critical Mach number (up to 1, in theory), and Mach 1.3.
32
What is the difference between highest and lowest possible speed, and minimum and maximum speed?
Highest and lowest are physical limitations, minimum and maximum are legislative restrictions.
33
What is the maximum maneuvering speed?
The fastest an aircraft can go with all ailerons, spoilers, rudders and other control surfaces engaged, without breaking any of them.
34
Which factors decide maximum operating altitude? 2 answers.
Either your Mach number and stall speed approach one another as altitude goes up, in which case you can't rise without stalling or going supersonic, OR you don't have a pressurized cabin, in which case you can't fly so high you can't breathe, OR you have a pressurized cabin, in which case you can't fly so high that you wouldn't have time to get down to a safe breathing altitude in the event of a loss of cabin pressure before your onboard oxygen ran out,.
35
What are trims?
Aerodynamic control surfaces which can be manually set to lock into position, relieveing strain from the pilot.
36
What is the difference between autothrust and autothrottle?
Autothrust just changes what the engine is doing, autothrottle actually makes the throttle levels in the cockpit move around accordingly.
37
Which components of an aircraft help to ensure vertical rotational (yaw) stability?
The tail and dorsal fin always. Sometimes, aircraft will be fitted with a computer called a yaw damper system, in which case that.
38
Which component of an aircraft helps to ensure latitudinal rotational instability (pitching).
The tailplane.
39
What features of aircraft can counteract unintended longitudinal rotation (rolling), and how doe they work? 4 answers.
1: High wing position. This works because when a plane is rolling, it is physically like it is swinging on a pendulum, and by putting the wings higher, the centre of gravity is kept higher, which effectively shortens the string of the pendulum, reducing the duration of the roll.
2: Dihedral wings. This means slightly V-shaped wings, and this works because they are not quite horizontal normally. Therefore, when the plane rolls, the lowered wing actually becomes more horizontal than the other, meaning that it generates lift more efficiently, and therefore rolls back.
3: Swept back wings. These work because, if the aircraft rolls, it will also start to slide in the direction of roll. This puts more air flow over the lower wing, increasing its lift and undoing the roll.
4: High keel surface. This also works on the above-mentioned sliding effect: as the aircraft slides into its roll, air is directed at the keel surface, pushing it into a reverse roll.
40
What is a keel surface?
A surface facing perpendicular to the direction of the aircraft, above the centre of gravity.
41
How can an aircraft's speed self-correct if externally disturbed?
As the aircraft slows, airflow over the tailplane decreases, reducing the amount of downward "lift" it is creating, and causing the tailplane to rise. This causes the nose to drop, increasing the plane's speed, and subsequently levelling out the flight. The ivnerse happens if speed is accidentally gained.
42
What is the ICAO definition of a rotorcraft?
A power-driven, heavier-than-air craft supported in the air by the reaction of air on one or more rotors.
43
What are the four types or rotorcraft and how are they characterised?
Helicopters - the normal sort.
Autogyrocraft - the gliders of helicopters. The rotors are turned by motion of the craft through the air.
Gyrodyne - has lift rotors and wings for lift, and a forward propeller for thrust.
Convertiplane - Has wings and fully tiltable rotors which can act as propellers.
44
What is hovering and what are the risks?
Staying pretty much still in the air.
Risks:
Causes a big downforce, which creates pockets of turbulent air, which may disrupt flight stability.
Can also damage nearby things on the ground.
If your engine fails, you don't have enough forward motion to be saved by autorotation.
45
What's a flapping hinge, and why do rotorcraft have them?
It's a hinge which lets the rotor blades be individually angled, allowing thrust to be directed, and also the asymmetrical lift generated by the unequal force of the rotors when moving backwards and forwards.
46
What's the top speed of helicopters?
250 knots.
47
What are the 4 different anti-torque systems and how do they work?
1 - a tail rotor. Works by generating lift in the opposite direction to the rotation of the fuselage, exactly like the main rotor.
2 - a shrouded tail rotor. In a "fenestron" a tail rotor is protected from damage, and more blades can be fitted.
3 - having 2 main rotors. If one spins clockwise and the other spins counterclockwise, the overall force is balanced.
4 - a NOTAR. This is short for NO Tail Rotor, and it uses air from the turboprop engine, directed against a tail rudder, to control rotation.
48
What are the 3 main controls of a rotorcraft, and what do they do?
The Collective Contol. This controls climb and descent, and also has a thrust control on a twist grip.
The Cyclic Control. This individually varies the angle of attack of the rotor blades, via the flapping hinge, controlling the pitch and bank of the craft, and therefore forward and lateral movement.
The Rudder Pedals. Control whatever the anti-torque system is.
49
Which flight instruments are barometric?
The altimeter, the air speed indicator, the vertical speed indicator, and sometimes the artificial horizon, but sometimes not.
50
What is the Pitot-Static system, and how does it work?
It is a series of air inlets in the aircraft which allow the barometric instruments to work. There are multiple (redundant) static ports in places on the fuselage where they will not be disturbed by the turbulence of the plane which supply the static pressure to all of the instruments, and also a pitot tube somewhere near the front of most aircraft, which supplies the airspeed indicator with the dynamic pressure.
51
Which flight instruments are gyrometric, and what do they do?
Also, what errors are they prone to?
The Turn and Bank Indicator, which shows you your bank angle, and also comes with a curved spirit level to indicate centre of gravity, to show if you are slipping or skidding in turns.
If they gryo spins too fast, it will over-read turns, and if it is too slow, it will under-read.
The Artificial Horizon, which shows pitch and bank attitude.
Acceleration throws this one a bit, and the centre-crosshair will drift down and right, or up and left, depending on the direction of the gyro's rotation relative to the direction of the acceleration.
The Directional Gyro Indicator, or gyro-compass. This shows heading without relying on magnets, although it does take frequent re-calibrating.
This one gets out of calibration quickly due to friction, and also gets up to 15 degrees out of calibration per hour due to the rotation of the Earth.
52
What are the three traditional beacon direction indicating instruments? What are the differences between them?
Relative Bearing Indicator. Like a compass, but north is actually the aircraft's heading. The needle turns to point at the beacon, showing you your relative heading.
Moving Dial Indicator. Like the above, but you can rotate the dial, pointing the 0 at north, and finding out your true bearing to the beacon, if you want.
Radio-Magnetic Indicator. The clever new-fangled one. Automatically adjusts itself to north (so, is a compass), and can display two additional needles, one for an NDB and one for a VOR, at the same time.
53
Which instrument is used to display the information from the ILS?
The Course Direction Indicator, which looks like a floating crosshair on a background with notches for 2 degrees in the horizontal and vertical planes. The crosshair is a control instrument, i.e. it shows you where you need to point, not where you have deviated by.
54
What are INS/IRS, when it comes to navigation?
The inertial navigation system, or the inertial reference system. Basically, a bunch of super-finely calibrated, balanced gyroscopes which are read by lasers, and can keep track of every movement the aircraft makes.
55
What is an EFIS, and what sort of plane would you expect to find it in?
It is the Electronic Flight Instrument System. Basically, it is 3 computer screens (the primary display, the nav display and the multi-function display) which replace just about every traditional instrument readout in a more condensed and intuitive way. Mostly found in commercial jets.
56
What are ACAS and TCAS?
ACAS is the Aircraft Collision Avoidance System, which is a system developed by ICAO about how planes should avoid colliding.
The computers implementing this system are the TCAS, the Traffic (alert) Collision and Avoidance System, which shows, on the nav display of the EFIS, a vertical instruction for how to avoid any predicted collisions.
57
What possible failures can on board comms systems suffer, and how should these be dealt with?
Comms systems are usually duplicated, so failed radio can be switched for the other. If both fail, pilots should squawk 7600 and avoid entering controlled airspace unless necessary.
Mics can get stuck, in which case being quiet and not tying up the frequency is best.
Human error is common, and vigilance is the only defense.
58
What is ACARS, and what are its uses?
ACARS stands for Aircraft Communications Addressing and Reporting System, and it has 2 main groups of uses: ATC uses and company uses.
ATC uses of ACARS include Pre-departure clearances, departure clearance requests, CPDLC for re-clearing in flight, and relaying automatic dependent surveillance details to the ground.
Company-related uses of ACARS are passing maintenance reports, met reports and en-route wind updates, load sheets, operational flightplans and NOTOCs - notices to captain.
59
What are the four main components of the electrical systems on board aircraft?
The batteries, the generator, the inverter/s, and the buses.
60
TO DO: LIST ALL OF THE OUTCOMES OF FAILURES OF VARIOUS AIRCRAFT SYSTEMS, AND THE SOLUTIONS.
Find the info for this all in the handouts for aircraft 25 and 26.
61
What are the advantages and disadvantages of hydraulic systems in aircraft?
Disadvantages:
Danger of leaking
Requires a filtering system
Can be adversely affected by temperature changes
Advantages:
Simple way to generate force and torque
Easy to change direction of force
Continuous (as opposed to discreet) variation in force applies allows for fine responses.
62
Which parts of aircraft may be hydraulically controlled?
```
Landing gear deployment and retraction
Brakes
Nose wheel steering
Flaps and slats
Spoilers
Rudders
Ailerons and elevators
```
63
What are the potential consequences of hydraulics failures?
Loss of controls
Inability to deploy or retract landing gear
Higher sped during landing from loss of control surfaces
Loss of ability to perform a go-around due to loss of control surfaces
Need to dump/waste fuel in order to lighten aircraft in order to reduce stopping distance in the case of a high-speed landing
64
At or below which height can aircraft safely operate without a pressurised cabin?
12,000ft.
65
What 4 things need to happen to air taken from the outside before it is allowed in to a pressurised cabin?
It needs to have the ozone filtered out, some warmth and some pressure put in, and some humidity added.
66
How should a failure of the cabin pressure system be dealt with?
Basically, switching it off and descending to 12,000ft or below.
67
What are the 6 modes or systems available in the cabin pressure control panel?
The inward relief valve lets in air if you somehow manage to get the inside pressure lower than the outside pressure.
The outflow valve, confusingly, is the one you bring air in to the cabin through.
The safety valve uses an automatic, mechanical system to release pressure if it gets way too high or low.
The dump valve manually depressurises the cabin.
Ditching mode closes every possible port and valve, for water landings.
The emergency pressurisation system pumps bleed air into the cabin to try to keep pressure up if the seal is lost.
68
What is "the feathering position"?
When you rotate your variable-tilt propeller blades so that their leading edge as pointing directly into the direction of motion, in order to reduce drag in an engine failure situation.
69
What is the "pitch angle" of a propeller? How does it relate to thrust generation?
The pitch angle is the angle of attack of the rotor blades of a propeller. A greater pitch angle generates more thrust per rotation.
70
What are the advantages and disadvantages of variable vs. fixed pitch propellers?
Fixed pitch propellers are cheaper and easier to maintain, and also less prone to malfunction, whereas variable pitch propellers are more efficient, and give higher performance.
71
What are the advantages or propeller engines versus bypass or jet engines?
```
Advantages:
Power changes are rapid and responsive, and propeller engines are usually cheaper and more cost-effective for small aircraft.
Disadvantages:
High maintenance requirements
Inefficient at higher altitudes
Mostly cannot exceed 250kt
Power to weight ratio is low
Vibrations make ride uncomfortable
High drag
```
72
What are the two main types of aviation fuel?
AVgas and jet fuel. Basically the only AVgas you can buy is 100LL (low lead). Jet fuel comes in a few varieties, but the main one is A1.
73
How many spark plugs do the cylinders of piston engines have? Why?
2, for 2 reasons: redundancy, and when they are both working, they burn the fuel more evenly and efficiently.
74
What is the induction system on a piston engine, and how does it work?
It is the system which sucks in air through a carburettor, mixes it with fuel, and sends it to be burnt. It works by sucking in air from the outside, through a Venturi tube, which narrows dramatically in the middle. Forcing the air through this aperture lowers the pressure and temperature, causing it to mix readily with the fuel, which is added after this point. It then flows down manifolds and into the cylinders of the engine. The size of the Venturi tube's aperture can be altered using the throttle, thereby controlling the amount of fuel used, and therefore the thrust.
75
What are the four steps of the internal combustion engine's cycle?
Induction, compression, ignition and expulsion.
76
What is the primary danger of carburettor system? How is this overcome?
When the air passes through the Venturi tube, it is cooled so much that icing may develop, blocking the mechanism. This is overcome by directing air, warmed by the exhaust, into the carburettor's intake. This prevents or reverses icing, at the cost of slightly reduced thrust due to the warm air being less dense.
77
Under what air conditions may carburettor icing occur?
Air temperatures of 20 to -5 C, and relative humidity of 80%+.
78
What are the two sub-categories of jet engines?
Single-spool or twin-spool, also called traditional jet or fanjet/turbojet/bypass.
79
What are the three engine performance indicators available for jet engines?
Fan rotation speed (N1)
Engine Pressure Ratio (EPR, the ratio of air pressure entering the engine to leaving the engine)
Torque (for turboprops or turboshafts only)
80
What are the 4 engine monitoring metrics available for jet engines?
Exhaust gas temperature
Oil pressure/temperature/volume
Fuel flow rate
Vibration
81
How long can it take for a change to the thrust level made by a jet pilot to take effect?
6 seconds.
82
What is the difference between a contained and uncontained engine failure?
Uncontained is when a fan part breaks and flies into the fuselage or penetrates the engine cowling. Contained is if the part remains in the engine, or exits via the exhaust.
83
What do aircraft use to fight engine fires in flight?
Bottles of halogen gasses stored on the wings.
84
What are wet starts, hot starts and hung starts?
Wet Start
Engine feeds fuel, but no ignition. Unburned fuel comes out of the exhaust. Then engine is crsnked for a new minutes and then you try again.
Hot start
Engine pumps too much fuel, or ignition is late. Temperature may get too high, and flames mag come out of the engine.
Hung Start
Engine fails to accelerate to normal idle RPM. Temperature may be exceeded.
85
How are engines numbered?
Left to right, from the point of view of the pilot.
86
How is the take-off portion of a flight defined?
From when the aircraft starts moving until the point at which it is 35ft in the air.
87
What are V1, VR and V2, with reference to a take-off?
V1 - decision speed. This is the maximum speed at which a crew can decide to reject the take-off, and is sure they can stop the aircraft within the limits of the runway. If the pilots are aware of a failure after this point, they must continue the take-off as long as they will not exceed the take-off distance available.
VR - rotation speed. This is the speed at which the pilot pulls on the control column to set the take-off attitude.
V2 - take-off safety speed. This is the speed at which the aircraft can climb out safely with a critical engine failure. V2 must be reached by the time the aircraft is at least 35ft high.
88
What is the definition of the climb phase of a flight?
The time between the plane being 35ft off of the ground, and the point at which it levels off for cruise.
89
What are range and endurance?
Range is defined as the distance which can be travelled with the fuel available on board.
Endurance is the duration an aircraft can remain airbourne using the fuel on board.
90
What is the definition of the cruise phase?
The period between which the flight levels off for cruising, and the point at which the flight reaches the top of descent.
91
What is the optimum range for rate of descent for maintaining comfortable cabin pressure?
About 300-500ft/min.
92
How is the landing phase of a flight defined?
The time/distance between the point at which the aircraft is 50ft above the runway threshold, and the point at which it has come to a complete stop.
93
How should pilots consider headwind and tailwind when planning landings?
Multiply the headwind component by 0.5 and the tailwind component by 1.5.
94
What 7 features or attributes would an economic flight have?
Continuous taxi to the runway in use, without unnecessary delays on the ground.
Runway in use which will give the shortest routing after take-off.
Unrestricted climb to the aircraft's optimum cruise leve.
No speed restrictons.
Most direct routes.
Unrestricted continuous descent to the approach altitude.
No holding.
95
In which ICAO annex may details about noise restriction for aircraft be found?
Annex 16.
96
How far must aircraft be from the ground, and from other aircraft, in order to dump fuel?
For dumping fuel, you need 10NM in front of the dumping craft, and 50NM behind, 1000ft above, and 3000ft below. Fuel dumping should only be done above 6000ft, as this allows the fuel to evaporate on the way down before it hits the ground.
97
Advantages of jet engines, 5 answers.
High fuel efficiency at high altitudes.
High power, so can lift large aircraft.
High speed, not limited by propeller.
Only rotating parts, almost free of vibration.
High reliability, therefore cheap to maintain.
98
Disadvantages of jet engines, 3 answers.
Thrust depends on outside air temperatures and density.
Slow acceleration from low engine rotation speed.
Fuel efficiency low at low altitude.
99
Advantages of turboprop engines, 4 answers.
More efficient than a jet at lower altitudes.
Capable of using shorter runways.
Propellers can be feathered in case of engine failure.
Can achieve very high rates of descent by using braking mode of propellers.
100
Disadvantages of turboprop engines, 4 answers.
Propellers inefficient at high altitudes.
Vibrations are high.
Their most efficient altitudes tend to be full of clouds and weather.
Turboprop aircraft are slow.
