Preflight Preparation Flashcards
1
Q
Why is having good systems knowledge essential for pilots?
A
In order to troubleshoot effectively in the event of a system malfunction or failure. The stakes are high when things break in airplanes. In a car you can just pull over to the side of the road - you can’t pull over to the side of the sky, though.
2
Q
What are your aircraft’s primary and secondary flight controls?
A
Primary: ailerons, rudder, elevator. Secondary: flaps, trim.
3
Q
How are the yoke and rudder pedals linked to their associated flight control surfaces?
A
Mechanical linkage using a control wheel for the ailerons and elevator, and rudder/break pedals for the rudder.
4
Q
When you turn the yoke to the left, which direction does each aileron move?
A
Left aileron up, right down.
5
Q
When you turn the yoke to the left, aerodynamically, how does this cause the plane to roll left?
A
The right aileron that drops has the effect of increasing its wing’s camber, thus increasing the speed of the airflow over the top of its wing and increasing lift. The left wing’s aileron goes up, decreasing camber, decreasing lift.
6
Q
Around what axis does the airplane roll?
A
Longitudinal.
7
Q
What type of ailerons does your plane have?
A
Differential, frise.
8
Q
Describe the purpose and function of each of those features.
A
Differentia l ailerons counteract adverse yaw. During a turn to the left, the right wing creates more lift and rises, but it also creates more induced drag, causing the nose of the airplane to yaw away from the direction of the turn toward the raised wing. To negate this, the left wing’s aileron sticks up high (higher than the right wing aileron’s downward deflection) in order to create additional parasite drag and help the plane yaw properly in the direction of the turn. Further helping to counteract this adverse yaw is the frise feature of the ailerons. Sticking with the left-turn scenario, when the trailing edge of the left wing’s aileron goes up, the leading edge of that aileron deflects downward below the wing in order to create additional drag and prevent the plane from yawing in the opposite direction. The frise feature also allows airflow beneath the wing to join and re-energize the airflow on the top surface of the aileron in order to increase its effectiveness (same idea behind slotted flaps).
9
Q
What type of horizontal tail surface does your plane have?
A
Elevator (attached to the back of the fixed horizontal stabilizer).
10
Q
How is this different from a stabilator?
A
With a stabilator, the entire horizontal tail surface moves as one slab, pivoting from a central hinge point (like on the PA44).
11
Q
When you pull the yoke back/pitch up, which direction does the trailing edge of the elevator deflect?
A
up
12
Q
Aerodynamically, how does pulling the yoke up cause the plane to pitch up?
A
When the trailing edge deflects upward, it sticks up into the relative wind, pushing the tail of the airplane down, raising the nose into a pitch-up attitude. Also, when the trailing edge deflects upward, more camber is created on the bottom of the horizontal tail surface, generating more negative lift to push the tail down and the nose up.
13
Q
Around what axis does the airplane pitch?
A
Lateral.
14
Q
When you step on the left rudder pedal, which direction does the trailing edge of the rudder surface deflect, and what effect does this have on the plane’s orientation? Why?
A
The rudder surface deflects to the left and the plane yaws to the left. The rudder is like a wing
on its side - when it deflects to the left, the camber on the right side is increased, accelerating air faster over that side, increasing the rightward horizontal lift produced by the rudder, causing the tail to swing right and the nose left. In addition, when the rudder deflects to the left, the relative wind strikes it, pushing the tail to the right and the nose left.
15
Q
What function(s) does the rudder serve?
A
Primarily the rudder exists to counteract adverse yaw (slips), as well as to counter any unwanted yaw tendencies, such as the left-turning tendencies. The rudder is also used to intentionally create more parasite drag during forward slips to land, to maintain longitudinal alignment during crosswind landings, and to help maintain directional control after engine failures in multi-engine airplanes. Lastly, the rudder can be used to turn the airplane in the event that the ailerons malfunction.
16
Q
Around what axis does the rudder cause the plane to yaw?
A
Vertical.
17
Q
All the primary flight controls utilize balance weights (aka counterweights) located toward the front of the control surfaces. What is the purpose of these weights?
A
Primarily to decrease control surface flutter at higher airspeeds. The weights also have the effect of reducing pilot control forces.
18
Q
At slow airspeeds, would you expect your flight controls to be more or less effective? Why?
A
Less, due to the reduced airflow over the control surfaces.
19
Q
Let’s say I trim the plane nose down, i.e. roll the trim wheel from bottom to top. What effect will this have on the trim tab?
A
The trailing edge of the trim tab will deflect upward.
20
Q
And how does this cause the airplane to maintain its nose-down pitch attitude?
A
With the trim tab up and into the airstream, the airflow over the horizontal tail surface tends to force the trailing edge of the elevator down. This causes the tail of the aircraft to move up and the nose to move down.
21
Q
What is the primary purpose of trim?
A
To relieve control pressure.
22
Q
Does the 172 have a servo or anti-servo trim tab? What’s the difference?
A
Servo, which means the tab deflects in the opposite direction as the elevator’s movement in order to increase control sensitivity, i.e. make the elevator more controllable. Anti-servo tabs are typically found on planes with stabiliators; because the whole control surface moves and therefore deflects a relatively large amount of air, stabilators are generally outfitted with anti-servo tabs in order to decrease control sensitivity, thereby preventing over-controlling the airplane and overstressing the airframe.
23
Q
Does your rudder have trim? If so, what kind?
A
Yes, it has a ground-adjustable trim tab - basically a piece of metal that can be bent manually on the ground.
24
Q
Can pilots adjust the ground adjustable rudder trim tab, or just certified mechanics?
A
Yes pilots can adjust the rudder trim, although ATP wants maintenance to handle rudder trim adjustments.
25
What kind of flaps does your aircraft have?
Electrically operated, single-slot type flaps, with detents at 0, 10, 20, and 30 degree positions.
26
Where is the flaps motor located? In
the right wing, a couple feet outboard of the cabin.
27
What are some of the purposes of flaps?
1) Flaps produce more lift for any given angle of attack, permitting a lower landing speed,
2) flaps produce greater drag, permitting a steeper descent angle without airspeed increase, and
3) flaps reduce the length of the
landing roll.
28
Which flap settings increase lift, and which increase drag?
The AFH says that, generally, the first 15 degrees of flaps primarily produces lift, whereas any flap deflection beyond 15 degrees generates large increases in drag.
29
How does the slot in the slaps aid in producing lift?
When the slotted flap is lowered, high energy air from the lower surface of the wing is ducted to the flap’s upper surface. The high energy air from the slot
1) accelerates the upper surface boundary layer and
2) delays airflow separation.
30
The metal skin of all the control surfaces - primary and secondary - is bent. What’s this bent metal called, and why is it designed this way?
It’s called “corrugation.” It increases the structural strength of the metal.
31
What are some of the various functions of the engine?
Provides the power to turn the prop, generates electrical power, provides a vacuum source, provides a source of heat for the cabin.
32
Reciprocating engines operate on what basic principle?
They convert chemical energy (fuel) into mechanical energy.
33
How is this done? How do we go from fuel inside the cylinders, to a spinning prop creating thrust?
The sparks generated from the spark plugs ignite the fuel, causing controlled explosions that push the pistons inside the cylinders down. These pistons are connected to the crankshaft, causing the crankshaft to rotate. The rotating crankshaft is directly connected to the propeller, causing the prop to rotate at the same speed as the crankshaft. As the prop spins it throws back air, and the equal/opposite reaction to this air being thrown back is called thrust.
34
Tell me about your aircraft’s engine.
```
Lycoming
Horizontally opposed
Air-cooled
Normally-aspirated
Carbureted
Overhead Valve
4-cylinder
0-320-D2J,-D2G, D1A
```
35
What is its horsepower rating, and at what RPM?
160 horsepower at 2700 RPM.
36
What do the “O,” “320,” and “D2J” represent?
“O” stands for Opposed, as in the cylinders are positioned such that they horizontally oppose each other. It also means its carbureted
“320” means 320 cubic inches of air displacement, meaning that the total space inside the engine’s 4 cylinders adds up to 320 cubic inches - the more space, the more fuel/air can be burned so the more power the engine can produce.
The “L2A” is the engine model.
37
What does horizontally opposed mean, and what makes horizontally-opposed engines so popular?
This refers to the layout of the cylinders - they horizontally oppose one another with 2 cylinders on one side of the crankshaft, and 2 on the other. These engines are popular because they tend to be lighter as well as more compact/streamlined, minimizing drag.
38
What does direct drive mean?
This means that the propeller is directly connected to the crankshaft - if the engine (the crankshaft) is spinning at 1,000 RPM, the prop is spinning at 1,000 RPM. Some aircraft with more powerful engines and/or longer props use gear reduction boxes to keep their props spinning at lower RPM than the engine in order to prevent the prop tips from achieving supersonic speeds.
39
Take me through what is going on internally during the ignition process for your aircraft, from battery master on to the engine running on its own. Feel free to reference your checklist.
- [ ] Battery master switch
- [ ] Prime engine
- [ ] Starter
- [ ] Flywheel
- [ ] Crankshaft
- [ ] Magnetos
- [ ] Spark plugs
- [ ] Cylinders
- [ ] Combustion
40
What happens if you turn off the master switch after ignition, why?
Nothing, the engine would continue to run because the engine drives the engine-driven magnetos, which generate the electricity to produce sparks, causing the fuel in the cylinders to burn, causing the engine to keep running, causing the magnetos to keep running…it’s a self-sustaining process.
41
Explain how a magneto works.
Inside a magneto there is a magnet, geared to the engine, spinning rapidly in close proximity to a coil of copper wires. This generates and harnesses electricity for the spark plugs.
42
Where are the magnetos located?
On the accessory case - the back of the engine.
43
What’s the function of the Impulse Coupler?
When the starter is engaged, the engine RPM are too low for the mags to generate sufficient electrical current for the spark plugs. So to generate that high amount of initial electrical current despite low RPM, one of the mags has something called an impulse coupler attached to it. The impulse coupler is a coiled spring that winds up real tight at first, then snaps, causing the magnet inside to spin really fast and generate a lot of electricity for its spark plugs.
44
How many magnetos does your plane have, and why?
2, for redundancy, as well as for more even burning of the fuel (better performance).
45
How many spark plugs are connected to each magneto, and where do those plugs go?
Two spark plugs in each cylinder 8 total. 4 from each mag
46
During the run-up, you check the left mag and the engine quits. What’s the problem?
Mag failure.
47
During the run-up, the engine feels rough and there’s a 200RPM drop. What’s the problem?
Fouled spark plug(s).
48
What causes fouled spark plugs?
Usually running the engine with the mixture full rich at low RPM, i.e. running the engine too cold. If the engine runs too cold, lead and carbon don’t burn off completely and end up in the form of deposits of the plug heads.
49
What’s the remedy for fouled spark plugs?
Follow the checklist to run the engine hot and burn off the lead and/or carbon deposits, then do the mag check again to verify smooth operation.
50
Say during the right mag check the RPM drop is normal, but there is no drop when you check the left mag? What is likely the issue?
The right mag isn’t grounding.
51
How do you verify if the right mag isn't grouding?
Turn the mags to OFF. If the engine continues to run then the right mag is clearly still operating, meaning it isn’t grounding.
52
Take me through each step of your aircraft’s air induction system.
The engine air induction system receives ram air through an intake
in the lower front portion of the engine cowling. The intake is covered
by an air filter which removes dust and other foreign matter from the
induction air. Airflow passing through the filter enters an air box.
After passing through the airbox, induction air enters the inlet in the
carburetor which is under the engine, and is then ducted to the engine
cylinders through intake manifold tubes. In the event carburetor ice is
encountered or the intake filter becomes blocked, alternate heated air
can be obtained from a shroud around an exhaust riser through a duct
to a valve, in the airbox, operated by the carburetor heat control on the
instrument panel. Heated air from the shroud is obtained from an
unfiltered outside source.
53
Approximately how much power loss should be expected when the engine operates off of
unfiltered alternate air?
Use of full carburetor heat at full throttle
| will result in a loss of approximately 100 to 225 RPM.
54
What does “normally (or naturally ) aspirated” mean? As opposed to what?
It means that the engine’s air intake does not utilize a forced induction system such as a turbo or supercharger - rather it depends solely on ambient atmospheric pressure.
55
What does “air cooled” mean? As opposed to what?
This means that the relative wind flowing over the engine is primarily what cools it - as opposed to using some other cooling system like a radiator or heat exchanger or water cooling system.
56
How can the relative wind adequately cool the cylinders when they are largely confined within the cowling and therefore not exposed to the outside air?
This is where the cooling fins and baffles come in. The heat from the cylinders transfers to the cooling fins, which are exposed to the relative airflow, allowing the heat to dissipate. The baffles are positioned to guide the airflow to where engine cooling is needed, namely over the cooling fins/cylinders.
57
What else cools your engine besides air?
Oil.
58
What are the 3 ways to cool an engine in flight?
Decrease throttle, increase airspeed, enrichen the mixture
59
How many strokes does your plane’s engine use? Describe each stroke.
It’s a 4-stroke engine.
1) The intake stroke begins as the piston starts its downward travel. When this happens, the intake valve opens and the fuel-air mixture is drawn into the cylinder.
2) The compression stroke begins when the intake valve closes, and the piston starts moving back to the top of the cylinder. This phase of the cycle is used to obtain a much greater power output from the fuel-air mixture once it is ignited.
3) The power stroke begins when the fuel-air mixture is ignited. This causes a tremendous pressure increase in the cylinder and forces the piston downward away from the cylinder head, creating the power that turns the crankshaft.
4) The exhaust stroke is used to purge the cylinder of burned gases. It begins when the exhaust valve opens, and the piston starts to move toward the cylinder head once again.
60
What do the throttle and mixture lever control in a carbureted?
The flow of the fuel to air mixture to the combustion chambers is regulated by the throttle butterfly valve which is controlled by the throttle in the flight deck
Fuel to air proportion is controlled by the mixture control in the instrument panel
61
List off the specs for your plane’s propeller.
The airplane is equipped with a two-bladed, fixed-pitch, one piece forged aluminum alloy propeller which is anodized to retard corrosion. The propeller is 75 inches in diameter. MFG by Mc Cauley
62
Say there’s a half-inch knick at the top of the propeller blade. Would maintenance be able to shave that down?
Yes, as long as the blade’s diameter doesn’t dip below 75 inches, which is the minimum permitted by section 2 of the POH/AFM.
63
Explain how the blade is twisted, and why?
The outside of the blade spins significantly faster than the inside due to the fact that the tip is traveling a longer distance in the same amount of time as the hub. If the blade had the same angle of incidence (aka pitch) throughout its length, the blade tip would produce more thrust than the blade hub. To prevent this, the blade is designed such that the tip takes a relatively small bite of air (has a low pitch), whereas the hub takes a large bite (high pitch). This allows the blade to produce uniform lift - or rather, thrust, because it’s directed forward - throughout its length.
64
What does “fixed-pitch” mean?
This means that the blade angle (or pitch) is set by the manufacturer and cannot be changed.
65
What are the two types of fixed-pitch propellers? Describe each.
Climb and cruise . A climb prop utilizes a low pitch, meaning that the blade spins through the air like a knife (from the perspective of the blade’s plane of rotation), rotating rapidly but taking small bites of air. A cruise prop uses a high pitch, meaning the blade spins through the air more like a paddle, rotating slowly but taking large bites of air.
66
What are the benefits and drawbacks to each type of fixed pitch propeller?
The climb prop’s low, knife-like pitch translates to less drag as the blade slices easily through the air, allowing it to spin at higher RPM and produce more horsepower. This increases performance during takeoffs and climbs, but decreases efficiency during cruising flight because the high RPM means more fuel burn. The cruise prop’s higher pitch/low RPM prop configuration doesn’t provide good climb performance, but it is more efficient for cruise flight due to the reduced RPM and therefore lower fuel burn.
67
Which type of fixed pitch propeller does your aircraft use?
The 172 uses a compromise of the two, a middle pitch.
68
What kind of landing gear does your plane have?
Tricycle type, with a steerable nose wheel and two main wheels. Shock absorption is provided by the tubular spring steel main landing gear struts and the air/oil nose gear shock (oleo) strut.
69
How do the tubular spring main gear struts work to absorb shock in our landing gear?
They ration the shock of the touchdown throughout the plane’s airframe.
70
How does the oleo strut work in our landing gear?
The exposed portion of the strut that we check for proper extension during preflight is a piston that has oil or some sort of hydraulic fluid inside it. During landing, when the tire hits the ground, the piston gets pushed up into the cylinder (upper chamber) above it, which contains compressed air or nitrogen. When the hydraulic fluid pushes against the air, it cushions the blow on the nose gear.
71
What is the purpose of the torque link, aka scissor?
The bottom section of the torque link is attached to the piston, while the upper torque link is attached to the cylinder (aka upper chamber). By locking firmly onto both the piston and the cylinder, the torque link prevents the piston from rotating inside the cylinder.
72
What landing gear feature prevents the nose wheel from vibrating excessively during higher speed ground operations?
Shimmy damper.
73
How does the Shimmy damper work?
There is hydraulic fluid inside the tiny horizontal cylinder. When you turn the nose wheel wheel at slower speeds, the fluid can easily get pushed around from side to side, so the turning is easy. At faster speeds, though, like on takeoff or landing roll-out, if the nose wheel starts turning too rapidly, the fluid can’t get through as fast, causing the damper to resist movement/vibration.
74
How is the nose wheel linked to the rudder pedals?
Through a spring-loaded steering bungee.
75
While on the ground, up to how many degrees each side of center does your plane turn, with the rudder pedals as well as with differential braking? 10
degrees with the rudder pedals alone, 30 degrees with differential braking.
76
Describe your aircraft’s brake system.
The airplane has a single-disc, hydraulically-actuated brake on each main landing gear wheel. Each brake is connected by a hydraulic line (looks like a hose) to a master cylinder attached to each of the pilot's rudder pedals.
77
So how many master cylinders for the brakes are there in total on the plane
2
78
How is the co-pilot able to brake if there are no cylinders behind the right-seat pedals?
The right seat’s brake pedals are mechanically linked to the left seat’s pedals, which press down on the master cylinders.
79
Take me through what happens internally in the brake system after the pilot presses on the brake pedals.
Pressing on a brake pedal has the effect of pushing down on the piston in the master cylinder located just behind the brake pedal. The piston pushes the hydraulic fluid in the master cylinder through the hydraulic line into the brake assembly. Here, the fluid pushes against another piston which causes the brake pads to clamp down against the steel wheel disc that spins with the wheel. This creates friction and slows the plane.
80
What color is hydraulic fluid, and why is this important to know?
It’s a light reddish color. Knowing the color of the plane’s operating fluids makes troubleshooting leaks easier.
81
Where is the hydraulic fluid reservoir for the brake system located?
As mentioned earlier, the hydraulic fluid for the brake system is located in the master cylinders themselves, the ones behind the pilot-side rudder pedals.
82
What are some of the symptoms of an impending brake failure?
Gradual decrease in braking action after brake application, noisy or dragging brakes, soft or spongy pedals, and excessive travel and weak braking action.
83
If the brakes feel spongy and unresponsive on your landing roll-out, what are you going to do to get the plane stopped?
Pump the pedals in order to build up pressure in the brake lines.
84
What is the procedure for applying the parking brake ?
Hold the brakes firmly, then pull the barking brake lever out and rotate the handle 90 degrees down in order to lock in the hydraulic pressure.
85
Why do engines have oil systems?
1) Lubrication of the engine’s moving parts,
2) cooling of the engine by reducing friction,
3) removing heat from the cylinders,
4) providing a seal between the cylinder walls and pistons, and
5) carrying away contaminants.
86
What type of oil is approved for your aircraft?
Aviation Grade with Ashless Dispersant SAE 50
87
Say you need to add oil to an unfamiliar aircraft, how would you go about verifying the required oil type and quantity?
Check the POH/AFM.
88
What are your aircraft's oil quantity limitations?
5 - 8 quarts.
89
What type of oil sump does your engine use?
Wet.
90
How is a wet sump different from a dry sump oil system?
A wet sump system has a pan attached to the bottom of the engine that collects oil as gravity pulls it down through the system. A dry sump oil system, on the other hand, instead of having a pan that is an integral part of the engine, uses an oil tank that is seperate from the engine and uses a series of pumps to keep the oil circulating throughout the engine. Dry sump systems are more complex and costly, but are necessary in aerobatic aircraft to prevent oil starvation during extremely high/low g-loads.
91
Describe the path that oil takes through your engine’s oil system
Sump -> oil suction strainer screen-> Engine driven oil pump -> bypass valve.
If oil is cold, the bypass valve allows the oil to bypass the oil cooler and go directly to the full flow oil filter;
If the oil is hot, the bypass valve will route the oil to the oil cooler on the right rear engine baffle -> oil from the oil cooler goes to the full flow oil filter ->oil pressure relief valve, which regulates oil pressure by sending excessive oil back to the sump while the rest of the oil is circulated through various engine parts. Residual oil returns to the sump by gravity flow.
92
What is ashless dispersant oil?
This type of oil contains an additive that helps to scavenge contaminants and carry them to the oil filter.
93
Adding oil isn’t listed under Part 43 Appendix A Preventative maintenance. Why are pilots allowed to do this?
Adding oil is just basic upkeep, like washing the windscreen or adding air to the tires.
94
For longer flights, what oil level does Cessna recommend?
8 quarts.
95
what is the minimum qty of oil we can operate at?
The engine must not be operated with less than 5 quarts in the sump.
96
Describe your aircraft’s fuel system.
Fuel is housed inside the wings in integral-type tanks, aka wet wings.
Total fuel capacity is 54, 50 of which is usable. There are 3 fuel sumps: 1 under each wing and 1 under the engine cowling.
There are 3 fuel vents: 1 under the left wing and 1 in each fuel cap. 100LL Grade Aviation Fuel (Blue) or 100 Grade Aviation Fuel (Green, although ATP does not allow this type) are the approved types of fuel.
97
What are “integral” fuel tanks?
These are tanks that are just part of the aircraft structure - in our case, the wing - that have been sealed to allow fuel storage.
98
Is the fuel stored throughout the length of the entire wing? Where along the wings do the tanks end?
Fuel is stored within the inboard portion of the wing, out to approximately where the flaps end.
99
Looking at the plane, there doesn’t seem to be a viable path for fuel to take from the wings to the engine . . . Where are the fuel lines located that transport the fuel from the wings to the engine?
The fuel lines connecting the tanks in the wings to the engine descend through the slivers of airframe that separate the pilot/copilot windows from the windscreen.
100
Why design the plane so that 4 gallons are unusable?
4 gallons remain unusable because fuel is drawn from slightly above the bottom of the tanks, to avoid drawing contaminants into the engine.
101
How many fuel vents does your plane have?
3.
102
Where are the fuel vents located, and what is their purpose? Each
The right fuel filler cap is vented. Also, there is an outboard fuel vent located under the left wing behind the strut. This vent is connected to the right wing internally through a vent line between the fuel tanks.
All together, the vents allow air to enter the tanks as fuel gets burned, replacing the space previously occupied by fuel, in order to prevent vacuums from forming that disrupt fuel flow.
103
Does the outboard vent serve any other purpose?
Yes, it also acts as a fuel drain when heat causes the fuel inside the tanks to expand.
104
Why is the outboard vent positioned directly behind the strut?
This prevents ice from forming on the vent. Also, it prevents ram air from pressurizing the tank, which could cause variations in fuel flow.
105
Walk me step-by-step through the path that fuel takes as it travels from the tanks into the cylinders.
- [ ] Wing tanks
- [ ] Fuel selector
- [ ] Strainer
- [ ] Carburetor
- [ ] Intake manifold
- [ ] Cylinders
106
Explain your airplane’s recommended cruise leaning procedure.
the mixture should be leaned until engine RPM peaks and drops 25-50 RPM. At lower powers it may be necessary to enrichen the mixture slightly to obtain smooth operation. Should it be necessary to cruise at higher than 75% power, the mixture should not be leaned more than is required to provide peak RPM.
107
How must the plane be operated when using either the LEFT or RIGHT fuel selector?
Level flight only. Takeoff and landing with the fuel selector valve handle not in the BOTH position is strictly prohibited. (Note: ATP conducts all normal flight operations with the fuel selector in the BOTH position.)
108
When you sump the fuel, what are you checking for?
Water and contaminants. I’m also verifying that the fuel iis the correct color/type of fuel.
109
What colors do you NOT want to see?
Red or clear. Green/100 octane is permitted per Cessna, but it is no longer produced
110
How can you tell that your fuel has water in it?
Water is heavier than fuel, so it will sink to the bottom of the drain jar. Smaller amounts of water will show up as bubbles at the bottom of the jar.
111
Other than water, what else might be indicated by a clear fluid at the bottom of your drain jar?
Possibly Jet-A.
112
Why is 100LL blue?
A blue dye is added in order to make it easily identifiable.
113
What does the “100” represent?
This is the octane rating. The higher the number, the more energy it takes for the fuel to combust.
114
What annunciator indication(s) is associated with the fuel system? What sets it off
An empty tank is indicated by a red line and the letter E on the fuel gauge. When an indicator shows an empty tank, approx 2 gallons remain.
115
What is vapor lock?
This is when the fuel becomes so hot it vaporizes in the fuel lines, not allowing fuel to reach the cylinders. Our carbureted engine has simplified fuel passages to prevent vapor locking
116
How do carbureted systems prevent vapor lock?
simplified fuel passages prevent vapor locking
117
How is a fuel injected system different from a carbureted system?
In a carbureted system, the fuel and air mix inside the carburetor. In a fuel injected system, the fuel/air control unit measures the air going through the induction system, then nozzles spray the appropriately ratioed amount of fuel directly into the intake ports of each cylinder.
118
What are the advantages of fuel injection over a carbureted system?
Minimal-to-no chance of engine icing; better fuel flow; faster throttle response; precise control of the mixture; better fuel distribution to the cylinders; easier cold weather starts.
119
How about disadvantages to fuel injection?
Difficult hot engine starts; vapor lock during ground operations on hot days; problems associated with restarting an engine that quits because of fuel starvation.
120
Describe your carburetor system
The engine is equipped with an up-draft, float-type, fixed jet carburetor mounted on the bottom of the engine.
121
How does the carburetor work?
```
Outside air
Filter
Intake
Carburetor
Venturi - Low Pressrue area
Discharge nozzle
Intake Manifold
Cylinder
```
the outside air first flows through an air filter, usually located at an air intake in the front part of the engine cowling. This filtered air flows into the carburetor and through a venturi, a narrow throat in the carburetor. When the air flows through the venturi, a low-pressure area is created that forces the fuel to flow through a main fuel jet located at the throat. The fuel then flows into the airstream where it is mixed with the flowing air The fuel-air mixture is then drawn through the intake manifold and into the combustion chambers where it is ignited.
122
What temps cause carb ice?
Carburetor ice is most likely to occur when temperatures are below 70 degrees Fahrenheit (°F) or 21 degrees Celsius (°C) and the relative humidity is above 80 percent.
But because of the sudden cooling that takes place in the carburetor, icing can occur even in outside air temperatures as high as 100 °F (38 °C) and humidity as low as 50 percent
123
Why is the carburetor called “float type”
The float-type carburetor acquires its name from a float that rests on fuel within the float chamber. A needle attached to the float opens and closes an opening at the bottom of the carburetor bowl. This meters the amount of fuel entering into the carburetor, depending
When the level of the fuel forces the float to rise, the needle valve closes the fuel opening and shuts off the fuel flow to the carburetor. The needle valve opens again when the engine requires additional fuel.
124
Why is our fuel system considered to be gravity-fed
Because gravity plays a major part in moving the fuel from the tanks into the engine (along with engine and electric pumps). High wing aircraft often use gravity fed systems, whereas low wing aircraft have to rely on pumps.
125
How do you get carb ice?
Carburetor icing is caused by the temperature drop in the carburetor, as an effect of fuel vaporization, and low pressure in the venturi. If the temperature drops below freezing the metal walls get cold, water vapor will freeze onto the throttle valve, and other internal surfaces of the carburetor.
126
When draining from the 1 drain located under the nose, from where in the fuel system is that fuel being sampled?
fuel strainer.
127
Where are the alternator and battery located?
The alternator is located just behind the nose cone on the right side; it is connected to the belt and is visible during preflight. The battery is in the back of the nose compartment, attached to the left side of the firewall.
128
How many amp-hours and volts does your aircraft’s battery produce?
12 volt and 25 AMP hour
129
How many amps and volts does your aircraft’s alternator produce?
14 volt 60 amp
130
Why does the alternator produce more volts than the battery?
The extra 2 volts are directed toward recharging the battery.
131
What does 25 amp hours mean?
This means that the battery, when it’s new, can support a 25 amp system for an hour before it’s drained. In other words, it can produce 25 amps constantly for one hour.
132
What is the difference between amps and volts?
Volts represent the pressure applied to the electrical current (aka amps). Amps represent the amount of electrical current.
133
What type of battery does your plane have?
Lead acid (same type of battery cars use).
134
How is it possible that your plane has a DC system, yet still uses an alternator which produces alternating (AC) current?
The system uses a rectifier to convert the AC current produced by the alternator into DC.
135
How does an alternator work?
In simple terms, the engine spins the alternator belt which spins a magnet inside the alternator. This magnet spins inside a circular winding of wires, generating electricity through the concept of electromagnetic induction.
136
If the engine drives the alternator, what prevents system voltage from varying rapidly with RPM changes?
The voltage regulator.
137
What does the voltage regulator do?
The regulator minimizes voltage fluctuations in the electrical system, that way close to 16 volts is always being produced despite low or high RPM.
138
Our aircraft has an ACU, what is that?
An Alternator Control Unit combines a voltage regulator with overvoltage protection?
139
Does your electrical system have any protection against voltage spikes?
Yes, the ACU contains an overvoltage sensor circuit behind the instrument panel and a red warning light labeled high voltage, adjacent to the ammeter
The overvoltage sensor automatically removes alternator field current and shuts don the alternator. A red warning light turns on indicating that the battery is supplying all electrical power
We can reset by turning the master switch off and on
140
What does the ammeter measure?
It measures current going to/from the battery. In other words, the ammeter measures the battery’s rate of charge (positive indication) or discharge (negative indication, meaning the alternator has either failed or isn’t doing its job properly).
141
How do we know we have an insufficient rate of charge?
The ammeter indicates a continuous discharge rete in flight. The alternator is not supplying power to the system and should be shut down. All non-essential equip should be turned off and the flight terminated asap
142
How’s an excessive rate of overcharge indicated
The ammeter should be indication less than two needle widths of charging current unless i just started the engine in which case it can be higher.
Over voltage sensor will shut down the alternator and an over-voltage light will appear
143
What is a bus bar, and what is its purpose?
A bus bar like a power strip. It is used as a terminal in the electrical system to connect the electrical system to the equipment using electricity as a source of power. This simplifies the electrical system by reducing wiring, and also makes it easier for the pilot to take electrical equipment off-line by pulling a circuit breaker.
144
What busses exist on our plane?
Split bus bar, one side containing electronic system circuits and the other having general electrical system circuits. Both sides of the bus are on at all times except when an external power source is connected.
145
What are circuit breakers, and how do they work?
Circuit breakers protect automatically against excess current, which could create fire hazards. When an electrical overload or a short circuit exists, the excess current/heat causes the small metal conductor inside the circuit breaker to expand and ultimately pop, breaking the circuit.
146
What do the numbers on the faces of the circuit breakers represent?
They are the amp ratings for the circuit breakers - they tell you how many amps cause the breaker to pop.
147
What is the general policy for resetting circuit breakers?
If the failed equipment is essential, the breaker can be reset once after allowing it to cool off.
148
From where is the air that goes through the vacuum system originally drawn?
The air gets sucked in from the cabin.
149
And where is that vacuum air that is drawn from the cabin air ultimately discharged?
After passing through the vacuum pump, the vacuumed air gets discharged into the engine compartment.
150
Where is the vacuum pump located?
On the back of the engine - on the accessory case.
151
How does the compass work?
Inside the compass there are two small magnets that align with Earth’s magnetic field. These magnets are attached to a metal float, allowing the magnets to float freely in a fluid similar to kerosene. A compass card marked with letters and numbers representing magnetic headings is wrapped around the magnet-float assembly. When we turn, we are just turning around this stationary compass card that remains aligned with the magnetic field.
152
What mounting mechanism allows the magnet-float assembly the freedom to rotate and tilt when the aircraft is banked?
Jewel-and-pivot type mounting.
153
What is the name of the vertical line on the face of the compass that shows your present heading?
Lubber line.
154
What is the purpose of having kerosene inside the compass?
1) It dampens oscillations of the float and card, and 2) it takes the weight of the float/magnets off of its pivot so that magnets are free to align with the magnetic field.
155
What errors are associated with the compass?
```
DVMONA:
Deviation
Variation
Magnetic dip
Oscillation,
Northerly/southerly turning errors (UNOS),
Acceleration errors (ANDS).
```
156
Describe each compass error
● Variation refers to the difference between true north and magnetic north. True north/south are the geographical top/bottom of the globe, i.e. the north and south poles. Magnetic north/south are located over 1,000 miles away. These are the north/south to which compasses are oriented.
● Deviation. The aircraft’s avionics and various magnetized parts produce their own magnetic fields that can cause the compass to misalign with the Earth’s magnetic field. This misalignment is referred to as magnetic deviation . The compass correction card provides the appropriate corrections.
● Magnetic Dip is what leads to the northerly/southerly-turning and acceleration errors. Lines of magnetic flux emerge vertically from the magnetic north pole, then bend over the earth such that they are parallel to the Earth at the equator, then descend vertically downward into the magnetic south pole. When flying anywhere other than over the equator, the magnets in the compass will try to dip in order to align with the slightly vertical nature of the lines of magnetic flux. To prevent this, compasses are designed to resist this dip by lowering the CG below the pivot point and by increasing the weight of the float assembly. This works great during straight-and-level unaccelerated flight, but otherwise this extra weight and low CG can lead to inertial issues.
● Oscillation refers to the way that the float assembly bounces around in turbulence causing the compass readings to be erratic.
● Northerly Turning Errors. Magnetic dip leads to errors when turning to north and south headings. When turning to a north heading, stop the turn prior to arrival at the desired heading on the compass card. When turning to a south heading, allow the compass card to pass the desired heading prior to stopping the turn. The mnemonic here is UNOS: Undershoot North, Overshoot South. (Specific examples of this are provided below.)
● Acceleration Errors refer to the way that the compass points northbound while accelerating on an east or west heading. Accelerating on a south of north heading has no effect. The mnemonic here is ANDS: Accelerate North, Decelerate South.
157
While heading 360 you accelerate. What will the compass heading indicate?
It will continue indicating north. The acceleration/deceleration errors only apply to east and west headings.
158
You’re southbound and you make a left turn with the goal of rolling out on a compass heading of 360. What heading will the compass indicate when you should roll wings level in order to roll out on the 360 heading?
030. Undershoot north by 30 degrees.
159
What if you want to roll out on a heading of 060 instead?
Undershoot by 10 degrees. (Ultimately goes down to 0 under/overshoot when rolling out due east or west.)
160
Is the wet compass required equipment per 91.205?
No, provided the plane is equipped with some other type of “magnetic direction indicator,” such as an HSI.
161
Which instrument(s) is powered by both the pitot and static systems?
Airspeed indicator.
162
How does the airspeed indicator (ASI) work?
The ASI is an instrument that indicates dynamic pressure
there's a wafer that compresses or expands due to pressure forces from the pitot tube and the casing is receiving pressure from the static port
The difference is registered by the airspeed pointer through gears that move the pointers of the ASI
163
What are the errors of the ASI?
Position error: erroneous static pressure causing plus or minus value
Density error: changes in altitude and temperature aren't compensated by the instrument
Compressibility error: packed air in pitot tube resulting in higher indications
164
If just the ram air hole on the pitot tube is blocked, but the drain and the static port are both unobstructed, what indication(s) can you expect on your flight instruments during the flight?
The air inside the pitot lines and diaphragm will bleed out through the drain hole, causing the indicated airspeed to drop to zero kts. No other instruments will be affected.
165
What if the pitot tube’s ram air hole and drain are both blocked, but the static port is unobstructed?
The ASI will act like an altimeter: as the plane climbs the indicated airspeed will read faster (despite airspeed not actually increasing), whereas descents will translate to a decreasing airspeed. In addition, acceleration and deceleration will no longer affect indicated airspeed. No other instruments will be affected.
166
What if the static port is blocked, but the holes on the pitot tube are unobstructed?
In this case, the ASI will indicate erratically, generally like a reverse altimeter: climbs will indicate slower airspeeds, descents will indicate faster. That said, because the ram air hole remains open, the ASI will still show acceleration and deceleration. A static blockage will also affect the altimeter and VSI: the altimeter will indicate the altitude at which the blockage occurs (the air pressure at the blockage altitude is now stuck inside the static casing), whereas the VSI’s needle will gradually return to 0 rate-of-climb (once all the pressure leaks out of the calibrated leak, there is no longer a pressure difference between the air in the diaphragm and the air inside the casing).
167
What makes a static blockage especially dangerous? As
airspeed continues to climb (falsely) during a descent, the pilot could be inclined to keep reducing power in a misguided attempt at slowing the already slow aircraft. This could lead to a stall.
168
Which instruments run solely off of the static system?
Altimeter and Vertical Speed Indicator (VSI).
169
How does the altimeter work?
This instrument measures absolute pressure
The wafer inside the casing is reacting to the atmospheric pressure received by the static port.
When we climb the pressure is low and the wafer expands, when we descend the pressure is higher and the wafer contracts
Because the pressure at any given point does not stay the same the pilot can set the current atmospheric pressure by setting the current pressure reading in the kolsman window. This realigns the gears inside the instrument allowing the pointers to indicate the altitude
170
When you adjust the altimeter setting in the Kohllsman window, are you adjusting the pressure inside the aneroid wafers? If not, what exactly is being adjusted?
Adjusting the altimeter setting merely changes the position of the needles, i.e. it recalibrates what altitudes correspond to the various pressures the instrument senses.
171
How can you tell whether the altimeter is indicating below or above 10,000ft MSL
The presence of the crosshatch flag signals that the indicated altitude is below 10,000ft.
172
Describe the limitations/errors associated with the altimeter?
On a warm day, the pressure level is higher than standard and the instrument indicates lower
On a cold day, the pressure level is lower than standard and the instrument indicates higher
When the pressure level is higher than standard, the altimeter indicates lower
When the pressure level is lower than standard the altimeter indicates higher
173
How does the VSI work?
The VSI is an instrument which indicates deviation from a constant pressure level
The wafer and the casing are vented to the static system but the case is vented through a calibrated orifice that causes the pressure to change slower than the pressure in the diaphragm (not wafer) allowing it to indicate a rate of climb or rate of descent
When we climb the diaphragm expands. When we descend the diaphragm is compressed. This is registered through gears that move the pointer of the VSI
174
What 2 types of information does the VSI provide?
At first it shows TREND information, i.e. an immediate indication of an increase or decrease in the aircraft’s rate of climb or descent. After 6-9 seconds of holding a constant climb rate, the VSI will indicate the actual rate of climb/descent.
175
Does the VSI have a diaphragm or an aneroid wafer?
Diaphragm.
176
What’s the difference between a diaphragm and a wafer?
Aneroid wafers are sealed at a fixed pressure - the pressure inside doesn’t change. A diaphragm has air constantly being fed into it.
177
Is the calibrated leak connected to the diaphragm or to the static casing that surrounds the diaphragm?
Static casing.
178
Take me through the limitations associated with the VSI?
The instrument lags
turbulence may cause airflow fluctuations and erroneous readings
179
What do you do if the VSI needle shows +100ft while on the ground?
+100 becomes the new 0ft/min - continue with the flight.
180
How many vacuum pumps are on your aircraft?
1
181
What drives the vacuum pump?
The engine (the pumps are geared to the crankshaft).
182
From where is the air that gets sucked through the vacuum system originally drawn?
The air gets sucked in from the cabin.
183
And where is that vacuum air ultimately discharged?
After passing through the vacuum pumps, the vacuumed air discharges into the engine compartment
184
Where is the vacuum pump located?
On the back of the engine - on the accessory case.
185
When vacuum pressure falls below limits, what indication will you get
The directional indicator and attitude indicator will be disabled
186
Which instrument(s) are vacuum-powered?
The Attitude Indicator (AI) and Heading Indicator (HI)
187
What are the two fundamental properties of gyroscopic action? Explain them
“Rigidity in space” and “precession.” Rigidity in space refers to the principle that a gyroscope remains in a fixed position in the plane in which it is spinning. Precession refers to the principle that when a force is applied to a spinning object, that force is felt 90 degrees later in the direction of the object’s rotation.
188
How does the AI work?
It is a gyroscopic instrument operating on the principle of rigidity in space.
An engine driven vacuum pump provides suction pulling air from the case which spins the gyro at a high speed.
The horizontal mounted gyro remains fixed on a set of gimbals as the airplane moves around it. The horizon bar is fixed to the gyro and it indicates the attitude of the airplane
189
The AI’s gyro spins on a _____ plane around a _____ axis.
Horizontal and vertical, respectively.
190
What is the AI’s principle of operation?
Rigidity in space.
191
Name all the limitations/errors associated with the AI?
If we exceed the banking and pitching limits the instrument will tumble and spill and give incorrect indications
192
On the AI, is the gyro attached to the artificial horizon/ground-sky card or to the miniature airplane?
The artificial horizon. Just like the actual horizon, the artificial horizon doesn’t move and the plane rotates around it.
193
What design feature keeps the AI’s gyro upright and prevents it from precessing?
Pendulous veins.
194
How does the heading indicator (HI) work?
It is a gyroscopic instrument operating on the principle of rigidity in space.
An engine driven vacuum pump provides suction pulling air from the case which spins the gyro at a high speed.
The vertical mounted gyro remains fixed on a set of gimbals as the airplane moves around it. The compass card is fixed to the gyro and it indicates accurate heading information
195
Describe all of the HI’s limitations.
if we exceed the banking and pitching limits the instrument will tumble and spill and give incorrect indications. we may reset the instrument with a knob
196
What is the difference between a Turn Coordinator (TC) and a Turn and Slip Indicator (TSI)?
TC shows rate-of-roll then rate-of-turn; TSI shows only rate-of-turn.
197
What design feature enables the TC to show the rate-of-roll?
30 degree canted gyro.
198
How does the TC work?
The turn part of the instrument uses precession to indicate direction and approximate rate of turn.
A gyro reacts by trying to move in reaction to the force applied thus moving the miniature aircraft in proportion to the rate of turn
The slip skid indicator or inclinometer is a liquid filled tube with a ball that reacts to centrifugal force and gravity.
199
How do you know if your TC is inoperative?
It will display a red OFF flag after engine start, meaning the instrument is not receiving electricity. Also, when the plane turns during taxi, the wing won’t dip properly.
200
If your vacuum pump(s) fail, will the TC continue to operate? Why or why not
Yes, electricity spins the gyro, not vacuum pressure.
201
Will the TC tumble with excessive pitch or bank? Why or why not?
No it won’t tumble - the gyro has stoppers that prevent this.
202
Let’s say you’ve lost your AI. You’re in a standard rate turn to the left per the airplane on your TC. You start leveling the wings. What will your rate-of-turn indicator (the miniature airplane) show you when the aircraft is wings level, and why?
The miniature airplane will show a standard rate turn to the right. This is because the rate-of-turn indicator initially shows rate-of-roll, and as I roll out of the left bank toward the right, this rightward roll trend will show up on the rate-of-turn indicator as a roll to the right, i.e. the right wing will drop. When approximately a standard rate turn to the right is shown, stop banking. The plane should be approximately wings level.
203
While establishing a fwd slip to land on final, what will the needle and ball on a TSI show?
The needle will continue to point straight up and down. The ball will show a slip, i.e. fall to the inside of the bank.
204
You’re turning to the left and the ball falls to the inside, is this a slip or a skid?
Slip.
205
What are the definitions and causes of a slip and a skid?
A slip is when you have too much bank for your rate-of-turn, causing the ball on the inclinometer and the tail of the aircraft to slip inward (in the direction of the bank). A slip is generally caused by adverse yaw and insufficient rudder in the direction of the turn. A skid occurs when your rate-of-turn is too great for the angle of bank, causing the ball (and the tail of the airplane) to swing to the outside. This is caused by too much rudder in the direction of the turn.
206
Your engine fails, which flight instruments do you expect to lose (remember, conventional instrumentation)?
The vacuum-powered instruments, so the AI and HI.
207
Your electrical system fails, which flight instruments do you expect to lose (again, conventional)?
The rate-of-turn indicator part of the TC. Environmental
208
How do you get fresh air into the cabin?
Pull the cabin air knob and open up all the overhead vents. The windows can be opened as well, up to 163kts.
209
Where does this cabin air come from?
Pulling the cabin air knob opens up the ventilating air door on the right side of the airplane’s nose, allowing it to scoop outside air and direct it through the cabin floor air outlets. Opening the overhead cabin air outlets allows ram air passing through the fresh air inlets on the leading edges of the wings to duct into the cabin.
210
How does the cabin heat work?
Hot exhaust gas gets expelled through the exhaust pipe, causing the pipe itself to become hot. Wrapped around the pipe is an exhaust muffler shroud that traps the heated air between the pipe and the shroud. This heated air gets ducted into the cabin through floor outlets when the cabin heat knob is pulled.
211
Say you apply the cabin heat, then a few minutes later you start feeling nauseous. What’s your concern here?
Carbon monoxide (CO) poisoning.
212
Where is the CO coming from?
A crack in the exhaust pipe allows CO to leak into the exhaust muffler shroud. When cabin heat is applied, this CO gets ducted into the cabin.
213
What de-icing and anti-icing features are on your aircraft?
Carb heat, pitot heat and the defroster. The automatic alternate induction air door and the wing strut blocking the external fuel vent on the left wing also have anti-icing features.
214
What is the difference between de-icing and anti-icing equipment?
De- icing equipment is intended to remove ice that has already formed, whereas anti -icing equipment is intended to prevent ice from forming.
215
How does the pitot heat work?
There is an electrical heating element built into the body of the pitot head that heats the metal casing around it when the PITOT HEAT control switch is selected in the cabin.
216
When should pitot heat be used?
At least a few minutes prior to flying into IMC when the ambient air temperature is such that structural icing is even remotely possible (ATP requires pitot heat to be activated when operating in IMC within 10 degrees C of freezing).
217
What is an accelerator pump
a “plunger” that shoots extra fuel into the air stream when the throttle is advanced rapidly.
When the throttle is opened rapidly, the airflow increases suddenly and there is a slight delay in the suction nozzle increasing the fuel flow to meet the increase in air flow
