Operation of Systems Flashcards
What are the four main control surfaces and what are their functions?
Elevators - Control the movement of the airplane about its lateral axis. This motion is called pitch.
Ailerons - Control the airplane’s movement about its longitudinal axis. This motion is called roll.
Rudder - Controls movement of the airplane about its vertical axis. This motion is called yaw.
Trim Tabs - Small, adjustable hinged-surfaces on the aileron, rudder, or elevator control surfaces. They are labor-saving devices that enable the pilot to release manual pressure on the primary control.
How are the various flight controls operated?
The flight control surfaces are manually actuated through use of either a rod or cable system. A control wheel actuates the ailerons and elevator, and the rudder/break pedals actuate the rudder.
What are flaps and what is their function?
The wing flaps are moveable panels on the inboard trailing edges of the wings. They are hinged so that they may be extended downward into the flow of air beneath the wings to increase both lift and drag. Their purpose is to permit a slower airspeed and a steeper angle of descent during a landing approach. In some cases, they may also be used to shorten takeoff distance.
Describe the landing gear system on the airplane.
The landing gear consists of a tricycle-type system using two main wheels and a steerable nosewheel. Tubular spring steel main gear struts provide main gear shock absorption, while nose gear shock absorption is provided by a combination air/oil shock strut.
Describe the braking system on the aircraft.
Hydraulically actuated disc-type brakes are utilized on each main gear wheel. A hydraulic line connects each brake to a master cylinder located on each pilot’s rudder pedals. By applying pressure to the top of either the pilot’s or copilot’s set of rudder pedals, the brakes are applied.
What type of hydraulic fluid does your aircraft use and what color is it?
How is steering accomplished on the ground?
With nosewheel steering capabilities through a simple system of mechanical linkage connected to the rudder pedals. When a rudder pedal is depressed, a spring-loaded bungee (push-pull rod) connected to the pivotal portion of a nosewheel strut will turn the nosewheel.
What four strokes must occur in each cylinder of a typical four stroke engine in order for it to produce full power?
Intake - Begins as the piston starts its downward travel causing the intake valve to open and the fuel-air mixture to be drawn into the cylinder.
Compression - 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’s ignited.
Power - Begins when the fuel-air mixture is ignited which 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.
Exhaust - Is used to purge the cylinder of burned gases and begins when the exhaust valve opens, and the piston starts to move toward the cylinder head once again.
Suck, squeeze, bang, blow
What does the carburetor do?
Carburetion may be defined as the process of mixing fuel and air in the correct proportions so as to form a combustible mixture. The carburetor vaporizes liquid fuel into small particles and then mixes it with air. It measures the airflow and meters fuel accordingly.
Step before being drawn into the cylinders and ignited.
How does the carburetor heat system work?
A carb heat valve, controlled by the pilot, allows unfiltered, heated air from a shroud located around an exhaust riser or muffler to be directed to the induction air manifold prior to the carburetor. Carb heat should be used anytime suspected or known carburetor icing conditions exist.
What change occurs to the fuel/air mixture when applying carb heat?
The introduction of heated air into the carburetor will result in a richer mixture. Warm air is less dense, resulting in less air for the same amount of fuel. Use of carburetor heat can cause a decrease in engine power of up to 15%.
What does the throttle do?
Allows the pilot to manually control the amount of fuel/air charge entering the cylinders. This in turn regulates the engine speed and power.
What does the mixture control do?
It regulates the fuel-to-air ratio. All airplane engines incorporate a device called a mixture control, by which the fuel/air ratio can be controlled by the pilot during flight. The purpose of a mixture control is to prevent the mixture from becoming too rich at high altitudes, due to decreasing air density. It is also used to lean the mixture during cross-country flights to conserve fuel and provide optimum power.
What type of ignition system does the 172 have?
Engine ignition is provided by two engine-driven magnetos and two spark plugs per cylinder. The ignition system is completely independent of the aircraft electrical system. The magnetos are engine-driven self-contained units supplying electrical current without using an external source of current. However, before they can produce current, the magnetos must be actuated, as the engine crankshaft is rotated by some other means. To accomplish this, the aircraft battery furnishes electrical power to operate a starter which, through a series of gears, rotates the engine crankshaft. This in turn actuates the armature of the magneto to produce the sparks for ignition of the fuel in each cylinder. After the engine starts, the starter system is disengaged, and the battery no longer contributes to the actual operation of the engine.
What are the two main advantages of a duel ignition system?
1) Increased safety - if one system fails, the engine may be operated on the other until a landing is safely made.
2) More complete and even combustion of the mixture and improved engine performance.
What type of fuel system does the 172 have?
The fuel system is a gravity feed system. Using gravity, the fuel flows from two wing fuel tanks to a fuel shutoff valve which, in the “on” position, allows fuel to flow through a strainer and then to the carburetor. From there, the fuel is mixed with air and then flows into the cylinders through the intake manifold tubes.
What purpose do the fuel tank vents have?
As the fuel level in an aircraft fuel tank decreases, a vacuum would be created within the tank which would eventually result in a decreasing fuel flow and finally engine stoppage. Fuel system venting provides a way of replacing fuel with outside air, preventing formation of a vacuum.
Does your aircraft use a fuel pump?
No, the fuel is transferred from the wing tanks to the carburetor by the gravity feed system. The gravity system does not require a fuel pump because the fuel is always under positive pressure to the carburetor.
What type of fuel does the 172 need and what color is it?
100LL. Blue.
Can other types of fuel be used if the specified grade is not available?
It is possible, but not desirable, to use the next higher grade fuel as a substitute, but the plane’s POH should be referenced first.
What color dye is added to 80, 100, 100LL, and Turbine fuel?
80 - Red
100 - Green
100LL - Blue
Jet A - Colorless/Straw
If a non-turbine piston engine powered airplane is fueled with Jet-A fuel, will it start?
Yes. Reciprocating engines may run briefly on jet fuel, but detonation and overheating will soon cause power failure. When an aircraft that requires Avgas is fueled with Jet A, there is usually a small amount of Avgas remaining in the aircraft’s fuel system. This remaining fuel can enable an aircraft to taxi, perform an engine run-up, and possibly take off before experiencing engine failure.
What is the function of the manual primer and how does it operate?
The manual primer’s main function is to provide assistance in starting the engine. The primer draws fuel from the fuel strainer and injects it directly into the cylinder intake ports. This usually results in a quicker, more efficient engine start.
Describe the electrical system of the 172.
Electrical energy is provided by a …
How are the circuits for the various electrical accessories within the aircraft protected?
Most of the electrical circuits in an airplane are protected from an overload condition by either circuit breakers or fuses or both. Circuit breakers perform the same function as fuses except that when an overload occurs, a circuit breaker can be reset.
The electrical system provides power for what equipment in an airplane?
1) Radio equipment
2) Turn coordinator
3) Fuel gauges
4) Pitot heat
5) Landing light
6) Taxi light
7) Strobe lights
8) Interior lights
9) Instrument lights
10) Position lights
11) Flaps
12) Oil temperature gauge
What does the ammeter indicate?
The ammeter indicates the flow of current, in amperes, from the alternator to the battery or from the battery to the electrical system. With the engine running and master switch on, the ammeter will indicate the charging rate to the battery. If the alternator has gone off-line and is no longer functioning, or the electrical load exceeds the output of the alternator, the ammeter indicates the discharge rate of the battery.
What function does the voltage regulator have?
The voltage regulator is a device which monitors system voltage, detects changes, and makes the required adjustments in the output of the alternator to maintain a constant regulated system voltage. It must do this at a low RPM, such as during taxi, as well as at high RPM in flight.
Why is the generator/alternator voltage output slightly higher than the battery voltage?
The difference in voltage keeps the battery charged.
How does the aircraft cabin heat work?
Fresh air, heated by an exhaust shroud, is directed to the cabin through a series of ducts.
How does a pilot control temperature in the cabin?
NOTE: check to see if this is accurate
Temperature is controlled by mixing outside air (cabin air control) with heated air (cabin heat control) in a manifold near the cabin firewall. This air is then ducted to vents located on the cabin floor.
What are the five basic functions of aircraft engine oil?
1) Lubricates the engine’s moving parts
2) Cools the engine by reducing friction
3) Removes heat from the cylinders
4) Seals - provides a seal between the cylinder walls and pistons
5) Cleans by carrying off metal and carbon particles and other oil contaminants
What causes carburetor icing and what are the first signs of its presence?
Venturi effect.
The carburetor narrows in the middle where the butterfly valve controlled by the throttle is. The narrow opening causes the air moving through the carburetor to move faster - then Bernoulli Principle kicks in. The air moves faster, which causes the air to cool down, and then the moisture in the air freezes and ice forms (especially when the throttle is idle or close to idle, because the valve narrows the passage even more).
The first indication of carburetor icing is a loss of RPM.
What method is used to determine that carburetor ice has been eliminated?
When heat is first applied, there will be a drop in RPM. If ice is present, there will be a rise in RPM after the initial drop (often accompanied by intermittent engine roughness). And then, when the carburetor heat is turned off, the RPM will rise to a setting greater than that before application of heat. The engine should run more smoothly after the ice has been removed.
What conditions are favorable for carburetor icing?
Carb ice is most likely to occur when temperatures are below 70 degrees F (21 degrees C) and the relative humidity is above 80%. However, due to the sudden cooling that takes place in the carburetor, icing can occur even with temperatures as high as 100 degrees F (38 degrees C) and humidity as low as 50%. This temperature drop can be as much as 60 to 70 degrees F.
Define the terms anti-icing equipment and deicing equipment and give several examples of both.
Anti-icing equipment prevents ice from forming on certain protected surfaces. Examples are heated pitot tubes and static ports, carb heat, heated fuel vents, propeller blades with electro-thermal boots, and heated windshields. It is normally actuated prior to flight into suspected icing conditions.
Deicing equipment removes ice that has already formed on protected surfaces. It is generally limited to pneumatic boots on the wing and tail leading edges.
Describe how an aircraft deicing system works.
Upon pilot actuation, boots attached to the wing leading edges inflate with air from a pneumatic pump(s) to break off accumulated ice. After a few seconds of inflation, they are deflated back to their normal position with vacuum assistance. The pilot monitors the buildup of ice and cycles the boots as directed in the POH.
If an airplane has anti-icing and/or deicing equipment installed, can it be flown into icing conditions?
The presence of anti-icing and deicing equipment does not mean that an airplane is approved for flight in icing conditions. The POH, placards, and even the manufacturer should be consulted for specific determination of approvals and limitations.
What is detonation?
Detonation is an uncontrolled, explosive ignition of the fuel/air mixture within the cylinder’s combustion chamber. It causes excessive temperature and pressure which, if not corrected, can quickly lead to failure of the piston, cylinder, or valves. In less severe cases, detonation causes engine overheating, roughness, or loss of power. Detonation is characterized by high cylinder head temperatures, and is most likely to occur when operating at high power settings.
What are some of the most common operational causes of detonation?
1) Using a lower fuel grade than that specified by the aircraft manufacturer.
2) Operating with extremely high manifold pressures in conjunction with low RPM.
3) Operating the engine at high power settings with an excessively lean mixture.
4) Extended ground operations or steep climbs where cylinder cooling is reduced.
What action should be taken if detonation is suspected?
1) Ensure the proper grade of fuel is used.
2) Keep the cowl flaps (if available) in the full-open position while on the ground to provide the maximum airflow through the cowling.
3) Use an enriched fuel mixture, as well as a shallow climb angle, to increase cylinder cooling during takeoff and initial climb.
4) Avoid extended, high power, steep climbs.
5) Develop the habit of monitoring the engine instruments to verify proper operation according to procedures established by the manufacturer.
What is preignition?
Preignition occurs when the fuel/air mixture ignites prior to the engine’s normal ignition event, resulting in reduced engine power and high operating temperatures. Premature burning is usually caused by a residual hot spot in the combustion chamber, often created by a small carbon deposit on a spark plug, a cracked spark plug insulator, or other damage in the cylinder that causes a part to heat sufficiently to ignite the fuel/air charge. As with detonation, preignition may also cause severe engine damage, because the expanding gases exert excessive pressure on the piston while still on its compression stroke.
