Airframes, Engines and Systems Flashcards
(119 cards)
1
Q
Airspeed Indicator
A
Instruments tells the pilot at wich speed the aircraft is flying through the air
2
Q
Attitude Indicator
A
Also called the Artificial Horizon, this
gyroscopic instrument tells the pilot if the
aircraft is in a nose high or nose low attitude, and or if the aircraft is banked to the left or to the right.
3
Q
Altimeter
A
The Altimeter indicates at what height the
aircraft is compared to sea level.
4
Q
Vertical Speed Indicator
A
his instrument tells the pilot if the aircraft is
climbing or descending, and if so, at what
speed in feet per minute.
5
Q
Heading Indicator
A
This gyroscopic instrument is used like a
compass, but it is more precise and more
stable during climbs, descents and turns.
6
Q
Turn Coordinator
A
In a turn this gyroscopic instrument gives the
pilot an indication of the rate of turn, how
long it will take to turn 180°.
It also includes the ball, that shows whether
or not the flight is coordinated (symmetrical).
7
Q
Tachometer
A
This instrument allows the pilot to precisely
set the engine RPM.
8
Q
VOR
A
The VHF Omnidirectional Range is a radio
navigation instrument.
● Its Course Deviation Indicator (CDI) gives
the pilot an indication on the position of the
aircraft in relation to a ground station.
● The VOR is the primary system used to
define airways.
9
Q
ILS
A
The Instrument Landing System is a very
sensitive VOR that also includes vertical, glide
slope information.
● It is used for precision approaches when
landing in poor weather conditions.
10
Q
ADF
A
● The needle of the Automatic Direction Finder always points towards the ground station on which frequency the receiver is operating, acting like an “artificial North pole”.
● This radio-navigation instrument is also
called a radio-compass.
11
Q
GPS / GNSS
A
● Global Positioning System / Global Navigation Satellite System
● Uses a satellite constellation and a database to pinpoint the
airplane’s position anywhere in the world.
12
Q
Transponder
A
● Whenever it is interrogated by a RADAR the Transponder
sends back a 4 digit code, along with altitude information if operating in Mode C.
● This allows Air Traffic Controllers to identify the aircraft displayed as echoes on their RADAR screens.
13
Q
Three types of airframes?
A
- Truss
- Semi-Monocoque or Stressed Skin
- Composite
14
Q
What is a Truss?
A
● A fuselage that is usually made up of
steel or aluminum tubes, which are
welded or bolted together in the shape
of a truss design.
● The strength of this design comes from
the steel truss tubes.
● The truss may be covered with metal,
fabric or composite materials for
aerodynamic purposes.
15
Q
What is a Semi-Monocoque?
A
● This airframe consists of a series of formers (or bulkheads) held together by stringers running lengthwise.
● The frame is wrapped tightly with a skin that is called Stressed Skin.
● It is called stressed skin because the airframe loads pass through
the aircraft skin, unlike in a truss design, where the loads travel through the internal frame of the aircraft.
● The majority of aircraft manufactured today are of this type of airframe.
16
Q
What is a Monocoque?
A
● If the stringers are eliminated, then we would have a Monocoque type of airframe.
● Like Semi-Monocoque, it also employs Stressed Skin.
17
Q
What is Composite pros?
A
● This is one of the newer types of construction and is frequently used in homebuilt aircraft and some new designs such as Cirrus, and Diamond Aircraft.
● Allows for smooth, compounded curved
construction.
● It makes use of materials such as Fiberglass, Carbon Fiber, or Kevlar.
● Composites are stronger and somewhat lighter than metal and do not have fatiguing problems like metal.
18
Q
What is Composite cons?
A
● Cons
➢ Composites have their own set of problems such as heat deterioration and internal damage from impact that does not show externally.
➢ More expensive than aluminum.
➢ Also, metal structures will permanently deform before they break, giving warning of overstress, whereas composite structures generally will not give warning of overstress and will break suddenly.
19
Q
What are the two main types of landing gear configuration?
A
➢ Tricycle － These aircraft have a nose wheel.
➢ Conventional － These aircraft have a tail wheel and are often called taildraggers.
● Either one of these configurations can be fixed or retractable.
20
Q
Advantages of the Tricycle Gear?
A
● Advantages over Conventional gear:
➢ Does not nose over as easily.
➢ Better directional stability on the ground.
➢ Visibility over the nose while taxiing is better.
➢ Overall ground handling is easier.
21
Q
Advantages of the Conventional Gear?
A
● Advantages over tricycle:
➢ Propeller clearance is increased.
➢ Landing gear experiences less parasite drag.
➢ Better suited for rough and unimproved runways as the main gear takes most of the load.
➢ Less damage to the plane if the wheel gives out!
22
Q
Retractable Gear
A
● Gear that either folds or tucks away into the wings or fuselage.
● Retractable gear results in a huge reduction in parasite drag and noise by making the aircraft more streamlined.
● Several methods are used to retract the gear: electric motor, hydraulic pump, or manually operated.
➢ If an electric motor or hydraulic pump is used a manual backup for gear extension is also available for in an emergency.
● Disadvantages
➢ More complicated to maintain
➢ You can forget that it is up!
23
Q
3 types of Main Gear?
A
● Split axle
● Spring steel cantilever
● Single Strut
24
Q
What type of brakes do we have?
A
● Most aircraft are fitted with hydraulic disc brakes similar to those found on automobiles, however, unlike an automobile there is a right and left brake system.
➢ This is known as differential braking.
25
Pros of the Differential braking?
● Having brakes that operate in this manner allows the pilot
greater control and a much tighter turning radius on the ground.
26
What are flaps?
● Flaps are devices installed on the wing to increase the lift and drag of the wing by increasing the camber of the wing and some types wing area.
27
5 types of flaps?
➢ Plain flap
➢ Split flap
➢ Slotted flap
➢ Fowler flap
➢ Combo flaps
28
Particularity of soft or rough airstrips for the tire?
low pressure tires
29
What are flaperons?
● A flaperon is a type of aircraft control surface that combines aspects of both flaps and ailerons.
● In addition to controlling the roll or bank of an aircraft, as do conventional ailerons, both flaperons can be lowered together to
function similarly to a dedicated set of flaps.
30
What are cowl flaps?
● On high performance piston engine
powered aeroplanes adjustable openings
called cowl flaps are incorporated into the
cowling to control the amount of cooling
air circulating around the engine.
● During high power settings, such as
during takeoff and climb, the forward
airspeed of the aeroplane is low and
engine power is high.
31
Horizontally Opposed Engine
● These are the most common type of reciprocating, air-cooled four-stroke, piston engines used in general aviation aircraft.
● Use even number of cylinders and has a small frontal area giving low parasite drag.
32
What are the keys part of the piston engine?
- Cylinder
- Intake valve
- Exhaust valve
- Piston
- Spark plug
- Crankcase
- Connecting rod
- Crankshaft
33
Radial Engines
● These are round shaped,
air-cooled, reciprocating piston
engines that have an odd number
of cylinders in each row.
● Large frontal area giving lots of
parasite drag.
● Expensive to maintain.
34
Two-Stroke or Four-Stroke
Engines?
● There are two basic types of piston engines:
➢ Two-stroke
➢ Four-stroke
● Most certified aviation and automotive engines are four-stroke engines.
● Many Ultralights use two-stroke engines.
35
Four-Stroke Cycle
➢ Intake
➢ Compression
➢ Power
➢ Exhaust
36
Intake Stroke
● The first stroke of the piston.
● The intake valve is open, and the exhaust valve is closed, while the piston moves downward.
● This develops a vacuum in the cylinder.
● This vacuum then pulls the fuel and air mixture into the cylinder through the open intake valve.
37
Compression Stroke
● The second stroke of the piston.
● The intake and exhaust valves are closed as the piston moves upward.
● This will compress the mixture of fuel and air, increasing its total density.
● The compression allows this mixture to reach its maximum potency.
38
Power Stroke
● The third stroke of the piston.
● Both valves are still closed, initially.
● Prior to the piston reaching top dead centre, the spark plug fires, and this ignites the compressed fuel and air mixture.
● The mixture burns and expands, forcing the piston downward.
● Prior to bottom dead centre the exhaust valve opens, leads.
● The linear (up and down) motion of the piston is then converted to rotational motion by the crankshaft, through the connecting rod.
39
Exhaust Stroke
● The fourth stroke of the piston.
● The exhaust valve opens as the intake valve remains closed.
● The piston moves upward, forcing the burned gasses out of the cylinder through the exhaust valve.
● The intake valve will then open just prior to the piston reaching top dead centre, leading; and the exhaust valve will remain open, lagging, to help improve engine performance.
40
2 Methods of Cooling?
● Most certified piston-powered aircraft are air cooled by multiple fins on the crankcase and cylinders.
● Some piston engines are liquid cooled... WarBirds like the P51 Mustang, and some trainers like the Katana.
● This allows better control of the engine temperature, but is heavier and more complex, with the water jacket, radiator, pumps, and coolant.
41
What is a Magneto?
● An aircraft magneto is an engine driven electrical generator (independent of the aircraft’s alternator/battery) that uses
permanent magnets and coils to produce high voltage to fire the spark plugs.
● Aircraft magnetos are used in piston aircraft engines and are known for their simplicity and reliability.
42
Why do we have 2 Magnetos?
● Aircraft piston engines are designed with two independent ignition systems, made up of two spark plugs per cylinder.
➢ The left magneto fires one plug per cylinder, while the right magneto fires the other.
● This arrangement produces a smoother and more complete combustion of the fuel/air mixture while also providing ignition redundancy in the event one magneto should fail.
● Turning the mag switch OFF causes a short circuit (called grounding) of the magneto coil that prevents it from working.
➢ The wire that does the grounding is called a P-lead.
● By selecting the RIGHT magneto the left magneto is grounded and when selecting the LEFT magneto the right is grounded.
➢ The run-up check proves that each ignition system operates without help from the other one.
● The BOTH position of the mag switch removes the ground from both magnetos, and the engine uses the full dual system.
43
What is the reason for no RPM drop during the run-up?
● No drop in RPM during run-up could be an indication of a broken P-lead.
➢ You check this yourself by bringing the engine to idle RPM and placing the ignition switch to OFF momentarily.
● If the P-lead is broken the engine will continue to run. (mags are still “LIVE” not grounded when shut down.) MUST KNOW
● If the P-leads are good, the engine will begin to quit, placing the mag switch back to BOTH before the prop stops turning the
engine will restart and continue to run.
● Another cause for little or no RPM drop could be improper magneto timing.
44
Purpose of the Exhaust System?
● Used to reduce noise and take pollution away from the cabin area.
● By placing a shroud around the muffler it can be used to provide cabin heat. Caution!
➢ Due to the possibility of leaks in the exhaust system, careful inspections are required.
➢ Carbon monoxide poisoning is possible!!!
➢ If you smell exhaust, turn off the cabin heat.
45
What are the Ancillary Controls?
● These controls are also known as the auxiliary controls.
➢ Mixture Control
➢ Carburetor Heat Control
46
Basics on Mixture Control
● A rich mixture is lots of fuel and a lean mixture is reduced fuel.
● The fuel/air ratio is regulated with the mixture control.
➢ This adjusts the proportion of fuel/air by weight and is approximately 1:15 for a chemically correct mixture.
➢ 1:14 is the best power mixture
47
Why leaning the mixture?
➢ Save fuel
➢ Increase the efficiency of the engine
➢ Decrease the chance of spark plug fouling
➢ Keeps the combustion chamber clean which decreases the possibility of pre-ignition
48
Too lean of mixture can cause...
➢ Rough engine operation
➢ Backfiring
➢ Overheating
➢ Sudden engine stoppage
49
Too rich of mixture results in...
➢ Fuel wastage
➢ Spark plug fouling
➢ Combustion chamber deposits
➢ Rough engine running
➢ Loss of power or even outright engine failure
50
When to turn ON and OFF Carburetor Heat?
● An aircraft without a Carburetor Temperature Gauge should use
carb heat as full ON or OFF.
➢ Turn it ON before reducing power
➢ Turn it OFF after applying power
51
Goal of the Turbocharger and Supercharger?
● A Turbocharger or Supercharger can be used to compress and increase the density of the air.
➢ The engine will then ‘think’ that it is at a lower altitude.
● Turbocharger/Supercharger increases the altitude at which full power can be maintained.
52
What is a turbocharger?
● Powered by the engine exhaust which turns the power turbine of the turbocharger.
● Advantage
➢ Lightweight and does not take power directly from the engine.
● Disadvantage
➢ Very hot operating, expensive, and maintenance intensive.
● This system compresses the air prior to entering the carburetor or fuel injection.
53
What is the Wastegate?
● The wastegate regulates the amount of exhaust gas directed to the turbine.
➢ In doing this it regulates the speed of the turbocharger.
● When the wastegate is open the engine is not turbocharged.
➢ The exhaust gas is ported overboard.
● When the wastegate is closed the engine is turbocharged.
➢ The exhaust is directed through the turbine before being
ported overboard.
54
What is a Supercharger?
● Is an internally driven compressor powered directly by the engine.
➢ Typically this will come off of the crankshaft via a gear reduction system.
● Advantages
➢ Reliable and less expensive.
● Disadvantages
➢ Takes power, up to 16%, away from the engine.
● This system compresses the fuel/air mixture downstream of the carburetor.
55
What is the density altitude?
● Density Altitude is the Pressure Altitude corrected for temperature.
➢ Is the altitude that the aircraft ‘thinks’ it is operating at.
56
Effect of the Density altitude and Humidity?
➢ In airplanes It changes the power output of the engine, the performance of the propeller, and the lift created by the wings.
➢ In helicopters it also changes the rotor performance.
57
High(er) Density altitude
High temperature (hot), High humidity (moist air), High altitude, Low air density (thin air)
58
Low(er) Density altitude
Low temperature (cold), Low humidity (dry air), Low altitude, High air density (thick air)
59
How to take care or your engine?
● Always follow the manufacturer’s recommendations.
➢ Read the POH (pilot operating handbook) or AFM (aircraft flight manual)
● Avoid long climbs at low airspeeds.
➢ The high power setting produces a lot of heat with low amounts of cooling air which can stress the engine.
● Avoid descents with large or quick power reductions and high airspeeds.
➢ This can cause sudden cooling (called shock cooling) of the engine.
➢ Cracked cylinders and an expensive repair bill may result!
60
Engine instruments that we must have for VFR?
➢ Oil Pressure Gauge
➢ Oil Temperature Gauge
61
Engine instruments not mandatory for VFR?
● The aircraft might include (optional, but nice to have):
➢ Cylinder Head Temperature (CHT) gauge (for setting mixture)
➢ Exhaust Gas Temperature (EGT) gauge (for setting mixture)
➢ Carburetor Temperature gauge
➢ Fuel Flow/Pressure gauge
● If the engine is liquid cooled, there will be a Coolant Temperature gauge
62
Cylinder Head Temperature instrument?
● This measures the temperature of one or all of the cylinders in Fahrenheit or Celsius.
● Too high of temperature is an immediate indicator of overheating. Lower the nose, reduce power, open cowl flaps if you have.
● This can lower the resistance of metals and risk pre-ignition.
● Too low of temperature may not vaporize the fuel properly.
63
Oil Pressure instrument?
● Indicates the oil pressure in the engine. It is measured in pounds per square inch (PSI).
● Oil pressure should register within 30 seconds of a start, 60 seconds if cold.
● If it does not then shut down and investigate.
● Low oil pressure － engine damage may take place.
● High oil pressure － may result in damaged seals, resulting in oil loss.
64
Oil temperature instrument?
● This indicates the oil temperature in Celsius or Fahrenheit.
● If oil temperature is rising fast, check the oil pressure.
➢ This may indicate there is not enough oil in the system by showing very high temperatures.
➢ When oil is cold it is thick, high viscosity, and when the oil is hot it is thin, low viscosity.
➢ High oil temperatures may be caused by too low of oil level.
➢ Low oil pressure may be caused by too low of oil level.
65
Exhaust Gas Temperature instrument?
● The EGT gauge measures the temperature of the gases at the exhaust manifold. Can indicate on one cylinder or all cylinders.
● This temperature varies with the ratio of fuel to air entering the cylinders and can be used as a basis for regulating the fuel-air mixture.
● The EGT gauge is highly accurate in indicating the correct fuel-air mixture setting.
● When using the EGT to aid in leaning the fuel-air mixture, fuel consumption can be reduced.
66
What is a Vacuum pump?
● Vacuum pumps are used to power attitude indicators, heading indicators, and inflate device boots.
● They are mounted onto the back of and driven off the engine.
➢ If the engine fails the vacuum pump fails.
67
What is BHP?
● Friction in the engine (moving parts and imperfect lubrication) causes a loss of available power.
● Brake horsepower is what is available after friction and other losses have been accounted for.
68
Use of a Carburetor?
● The carburetor provides two principal functions:
➢ Mixing the fuel and air.
○ This is accomplished by vaporizing the fuel into the air in the proper ratio.
➢ Regulating the amount of fuel/air ratio by weight that enters the engine.
○ This is accomplished with the help of the throttle setting.
69
General info on Carburator?
● Most aircraft engines with carburetors use an updraft float carburetor.
● This type of carburetor is mounted on the bottom of the engine.
● The outside air is routed from the intake through ducts into the carburetor.
● The fuel/air mixture is then sucked up and into the engine.
● The carburetor is equipped with a small chamber containing fuel and a float valve.
● The valve maintains a constant amount of fuel in the chamber.
● This provides a constant and sufficient source of fuel to satisfy the fuel demands of the engine.
70
Venturi?
● The main air duct of the carburetor is a tubular structure which decreases in diameter near the middle of the duct and then increases in diameter near the intake manifold of the engine.
● This is called the Venturi. This decreased diameter creates a vacuum in accordance with the Bernoulli Principle.
● Difference in pressure between the venturi throat and the air inlet is how it operates.
● The fuel intake port is located in this section.
71
What is Vaporized Fuel?
● A metered amount of fuel is sucked into the carburetor.
● The fuel vaporizes into fine particles in the intake airflow.
● This vaporized fuel and air mixture is of the correct ratio to cause correct burning in the engine.
72
What is an accelerator pump?
● The carburetor has an accelerator pump which will provide an additional amount of fuel for sudden engine acceleration.
➢ This prevents stumbling when the throttle is opened to develop maximum horsepower.
73
What is an Economizer
Valve?
● An economizer valve is a small needle that will allow more fuel to flow through at high power settings.
74
What is the Idle Jet?
● The idle jet allows the engine to idle when the throttle is closed.
75
What is the Effect of Air Density Changes
On Fuel/Air Ratio?
● As the aircraft climbs the air density decreases and the fuel/air ratio gets richer.
● As the aircraft descends the air density increases and the fuel/air ratio gets leaner.
● If mixture adjustments are not made during high altitude operation, performance will be affected because of a decrease in the weight of air while the same amount of fuel enters the carburetor. Making for a richer mixture
76
Funtion of Mixture Control?
● The purpose of the mixture control is to regulate the fuel flow into the carburetor to adjust the fuel/air ratio.
● Operating the engine over a range of altitudes and air densities will affect the fuel/air ratio.
● The pilot can adjust the manual mixture control according to the correct mixture adjustment procedure that is covered in the Pilot Operating Handbook (POH) for a given aircraft.
➢ Enriching the mixture will lower the engine temperature.
➢ Leaning the mixture will increase the engine temperature.
77
Goal of adjusting the mixture during cruise?
● Adjusting the mixture control during cruise
will allow the engine to operate at the
proper temperature, keep the engine
cylinders clean, prevent spark plug fouling,
engine roughness, and reduce fuel
wastage.
78
Goal of adjusting the mixture during cruise?
● Adjusting the mixture control during cruise
will allow the engine to operate at the
proper temperature, keep the engine
cylinders clean, prevent spark plug fouling,
engine roughness, and reduce fuel
wastage.
79
EGT Gauge?
● Different fuel/air mixtures will produce a
given exhaust gas temperature.
● As the mixture is pulled towards lean from
full rich at altitude, the EGT will rise until it
peaks, then the EGT will fall if the mixture
is leaned further.
80
What is Induction Icing?
● Induction icing is the buildup of ice in the fuel induction system and can affect all types of piston engined aeroplanes, helicopters, and gyroplanes.
81
Risk of Induction Icing?
● The air induction port at the front of the cowling can become partially or totally blocked with ice when air temperature is at 0°C (32°F) or less when visible moisture is in the air.
● This is known as impact ice and it is most prevalent when the Outside Air Temperature (OAT) is around -4°C or 25°F in snow, sleet, or supercooled liquid.
● This type of icing can affect fuel injection systems as well as carburettor systems and is also the main type of icing hazard for turbocharged engines.
82
Use and functionnig of Carburetor Heat?
● This air comes from an unfiltered section inside the cowling, passes through a heat box which warms the intake air.
➢ Its use on the ground is not recommended.
● Carburetor heat can be selected when atmospheric conditions are conducive to carburetor icing.
➢ Note Carb Icing Chart on slide 26
● When the normal intake duct becomes blocked by impact ice at the induction port or air filter the carburetor heat can
be used as an alternate air source.
83
Effect of the Venturi on temperature in the Carburetor?
➢ As air passes through the venturi it speeds up experiencing a decrease in air pressure causing a decrease in the air temperature.
➢ Added to that, when fuel is passing through the venturi it is vaporized, which also takes heat from the air.
● These two actions combine to cause a temperature drop of 20 to 30 o C relative to the original outside air temperature.
● The most severe carburetor ice is likely in conditions with high relative humidity and temperatures between -5°C and +15°C.
84
Relation between Carburetor and Throttle Ice?
● Throttle ice occurs most often when the throttle is partially closed and at low power settings because as the throttle closes it has the effect of a sort of venturi;
as the air passes around the edges of the throttle plate it has to speed up and this again reduces the temperature in this area.
● Some manufacturers recommend carb heat be used anytime the power setting is below a certain RPM, even if a high atmospheric moisture content is not
present due to increased susceptibility to throttle ice at lower power settings.
● For fixed pitch propeller configurations most aircraft should use carburetor heat below 2 100 RPM.
85
How to detect and recover from Carburetor Ice?
● Carburetor ice is usually first detected by a gradual drop in the RPM of a fixed-pitch propeller aeroplane or in manifold pressure decrease in a constant-speed propeller aeroplane.
● Application of carburetor heat will cause an additional decrease in power and the engine will start running rough as the ice melts.
● Once the ice is gone the original drop in RPM or manifold pressure will be gradually restored, and no engine roughness, and then turning OFF the carburetor heat will restore proper power.
86
Effect of the Carburetor Heat on the mixture
● If the icing is persistent it may be necessary to continuously operate with carburetor heat ON.
● This will require the mixture to be leaned, the less dense air results in a richer mixture.
● When carburetor heat is applied hotter air enters the engine causing a decrease in power (reduced RPM for fixed-pitch and
manifold pressure for constant-speed prop aircraft) and an increase in engine temperature.
● This hotter air is less dense than colder
air and therefore the mixture will get
richer.
➢ If there is an increase in RPM or
manifold pressure after applying carb
heat then too lean of a mixture may
have been set.
87
How does the throttle work?
● The throttle regulates the amount of fuel/air mixture that enters the engine and thereby controlling the power that the engine develops.
● On aircraft with a fixed pitch propeller the throttle directly controls the engine RPM.
➢ The tachometer gives the indication of engine power output.
88
Mixture and long climb?
● Running an engine slightly rich can help cool the engine as the extra fuel acts like a coolant.
➢ The vaporization of the extra fuel cools the hot air.
● Typically when climbing you want to run the engine a bit rich because the aircraft is flying at a slower airspeed and this means less air is available to cool the engine.
89
What is the Fuel Ice?
● Another name used for carburetor ice--technically it is the process that happens as the fuel is vaporised.
● This forms at, and downstream from, the point that fuel is introduced into the carburettor when the moisture content of the air freezes as a result of the cooling caused by fuel vaporization.
● It generally occurs between +4°C to +27°C but may occur at even higher temperatures.
● It can occur whenever the relative humidity is more than 50%.
90
How a Fuel injection is working?
● In a fuel injected system the fuel is atomized by nozzles.
○ This atomized fuel is discharged into the air stream entering the intake manifold.
○ In some engines it will be discharged into the intake of each cylinder.
● The throttle is connected to the fuel metering valve.
○ This is automatically calibrated to send the correct fuel/air mixture to the engine.
91
What are the advantage of the fuel injection?
○ More uniform distribution of fuel to all the cylinders. The fuel is separately metered to each cylinder.
○ More power since the need to heat carburettor air is eliminated.
○ Better cooling, through the elimination of lean/hot mixtures to some of the more distant cylinders.
○ Less susceptibility to icing, only impact and throttle icing. Carburetor icing is eliminated.
○ Savings on fuel through more regulated fuel flow.
○ A faster, more accurate throttle response due to the fuel being directly injected into the cylinder.
○ Easier starting in cold weather.
92
What are the disadvantage of the fuel injection?
○ Starting a hot engine can be more difficult.
○ During ground operations on a hot day vapour lock may occur.
■ To determine if you have a vapour lock, set the power to a high power setting and turn on the electric fuel pump.
■ If there is no fuel flow, there is a vapour lock.
○ Engine restart may be difficult if the engine quits due to
fuel starvation.
93
What type of Icing the fuel injection can have?
● Impact and throttle ice are still possible with fuel injection.
● Carburetor ice is eliminated along with the need
for carburetor heat.
94
What's the role of the battery?
● The battery supplies power for the
starter motor and acts as a backup
should the generator or alternator fail.
● It can be thought of as a "reservoir"
that stores energy, but it has a limited
amount stored energy!
● Aircraft operate with either a 12 or 24
volt system.
95
During flight the generator or alternator provides components
like...
lights, flaps, gear, avionics, de-icing equipment with
electrical power and recharges the battery.
96
Difference between Alternator and Generator?
● Alternators produce electrical power/current even at low RPM
settings.
● Generators require a high RPM to effectively create electrical
power.
● Piston engines generally use alternators because of their large
RPM changes.
● Since Turbine/Turbofan and Turbojet engines run at much
higher RPM, they use generators.
97
What are the 4 position an Ammeter can show?
○ A deflection of zero means there is no charge in the system.
○ A deflection on the positive side indicates that the alternator
is providing power.
○ A deflection on the negative indicates that the battery is
providing power, and the load exceeds the alternator
capacity.
○ A full-scale positive deflection indicates a malfunction of the
voltage regulator.
98
What are the different position the Master Switch can have?
● The electrical system in an aircraft contains
a linked master switch for the battery and
alternator.
● The battery can be turned on independent
of the alternator!
● The alternator side can only be turned on
with the battery side but can be turned off
independently.
● Turning off the battery turns off both sides.
99
What's the role of a Load meter?
● A load meter shows the load imposed on the electrical system
by all of the components that are running.
● This is handy, because you can test if a subsystem is working
by watching the "draw" on the load meter as you turn on the
system.
● If the alternator failed, then the load meter would indicate zero.
100
What's the role of the Voltage Regulator?
● A voltage regulator controls the rate of
charge to the battery by stabilizing the
generator or alternator electrical output.
● The generator/alternator voltage output
should be higher than the battery voltage.
● For example, a 12-volt battery would be fed
by a generator/alternator system of
approximately 14 volts.
● The difference in voltage keeps the battery
charged.
101
How many times can you reset a Circuit Breaker?
● A circuit breaker can be reset, once, to its normal position by
pushing it back in.
● If the breaker pops out again, a malfunction exists somewhere
within the circuit that the breaker is a part of. Do not reset it
again!
● The circuit should be checked and repairs made prior to the
next flight.
102
How do Fuses work?
● Fuses do not trip.
● Instead, a thin wire that is contained within them breaks or
burns out, stopping the flow of electricity.
● Fuses need to be visually checked and replaced.
● If after replacement, the fuse continues to burn out, then the
circuit itself is faulty.
○ If this is the case, then have it checked and repaired.
103
What is a Bus Bar?
● The Bus Bar takes the current that is
generated by the alternator (or
generator) and then branches it out to
the various electrical components that
are located in the aircraft.
104
What are the different types of Battery?
● Almost every piston powered aircraft has a lead-acid type
battery.
● These come in two further subtypes:
○ Flooded cell, and
○ Sealed cell. (Sometimes called Active Glass Matt or AGM).
● Transport aircraft tend to use a Nickel Cadmium (NiCd) battery,
and those who fly other turbine aircraft are likely to find a
mixture of NiCd and lead acid.
105
What are the 4 roles of Engine Oil?
➢ Lubricating
➢ Cooling
➢ Sealing
➢ Cleaning
106
3 Differents types of Oil?
● Viscosity is the resistance to flow.
➢ High viscosity equals high resistance and low viscosity
equals low resistance to flow.
● During the winter, oil is very cold and does not flow very well.
➢ A low viscosity oil should be used.
● In the summer, oil is warmer and it flows more readily.
➢ A high viscosity oil should be used.
● To eliminate the need for changing the type of oil
a multi-grade oil can be used.
107
What is a Detergent Oil?
● This is the normal everyday use type of oil.
● Detergent oil contains additives that help keep the engine clean
and sludge from forming.
108
What is a Detergent Oil?
● This is the normal everyday use type of oil.
● Detergent oil contains additives that help keep the engine clean
and sludge from forming.
109
What is a non-detergent Oil?
● Normally used to break in a new engine.
● These are also known as Mineral Oils.
● Often used only during the first 50 hours of an engine’s life.
110
What are the two main ways of moving the oil around inside an
engine?
➢ Splash
➢ Force Feed
111
What is the Splash method for lubricating an engine?
● The oil is contained at the bottom of the crankcase and is
splashed throughout the engine via the turning crankshaft.
● Splash lubrication is not used in new aircraft.
112
What is the Force Feed method for lubricating an engine?
● In a force fed system, the oil is forced under pressure to the
various engine parts.
● There are two types of force feed systems:
➢ Dry Sump Lubrication uses a separate tank of oil that is
forced into and through the crankcase and back by a pump.
➢ Wet Sump Lubrication uses oil contained in the bottom of
the crankcase where it is fed through the engine by a pump.
113
What is the purpose of the Vent in the motor?
● The oil system is fitted with a vent to allow blow by gasses to
escape the crankcase without damaging seals or gaskets.
● If the oil is overfilled or if it expands too much when heated then
it will spill out through the vent.
● This will likely result in a small amount of oil along the belly in a
pattern like a spray gun.
● Unusual streams or puddles should be investigated thoroughly.
114
What's the goal of the Oil Filter?
● These can be fitted to force feed systems the filter is used to
clean the oil and engine.
● Filters can extend the life of
the engine considerably.
● The oil filter is typically
located downstream of the oil
pump.
● Mechanics will thoroughly check the filter at each oil change for
metallic particles.
● The colour and state of the oil can also give hints as to the
engine's condition.
115
What's a Pressure Relief Valve?
● In a force feed dry sump system a pressure relief valve is
provided as a means of regulating oil pressure to the engine.
● Pressure relief valves are used in wet sump systems also, to
regulate oil pressure.
116
What's an Oil Cooler?
● Used to cool the oil.
● In extremely cold
temperatures the oil in the oil
cooler could become so
viscous (resist flow) that it may
plug up the cooler resulting in
an overheated engine.
● The use of a non-congealing oil cooler will prevent
overheating with a bypass that allows the viscous oil to flow and
warm up, then warm up the remaining oil.
117
Why is it important to have the good Oil Viscosity in your engine?
● Having too low a viscosity is more likely to result in premature
engine wear due to greater difficulty in maintaining the oil film
between moving parts, but it is not as likely to cause
overheating.
● Having too high a viscosity could actually cause overheating due
to slowing the flow through the oil cooler and causing the oil
cooler to be bypassed.
● Too low viscosity oil would give lower oil pressure and the
opposite with high viscosity oil giving higher pressure.
118
What is the sign of an Oil leak?
● An increasing oil temperature when combined with a decreasing
pressure usually indicates a leak.
119
Why should you verify the Oil Temperature Gauge before taking off in cold weather?
● The oil temperature gauge is also used in colder climates to
ensure that it has warmed up enough for operations.
➢ Oil is more viscous at colder temperatures and may not
provide the required lubrication until it has warmed up.
➢ Engine damage may occur if you operated with cold oil.
