Airplane Systems

Question 1

What error is the heading indicator subject to?

Answer 1

• Because of precession, caused chiefly by friction , the heading indicator will creep or drift from a heading to which it is set.
• May indicate as much as 15 degrees of error per every hour of operation. (Depends on how old or dirty the gears)

Question 2

How does the turn coordinator operate?

Answer 2

• Uses precession to indicate direction and approximate rate of turn. A
• The slip/skid indicator is a liquid-filled tube with a ball that reacts to centrifugal force and gravity.

Question 3

What information does the turn coordinator provide?

Answer 3

• It shows the yaw and roll of the aircraft around the vertical and longitudinal axes.
• The miniature airplane indicates direction of the turn as well as rate of turn .
• When aligned with the turn index , it represents a standard rate of turn of 3° per second.
• The inclinometer of the turn coordinator indicates the coordination of aileron and rudder.
• The ball indicates whether the airplane is in coordinated flight or is in a slip or skid.

Question 4

What will the turn indicator indicate when the aircraft is in a skidding or a slipping turn?

Answer 4

• Skid - The ball in the tube will be to the outside of the turn; too much rate of turn for the amount of bank.
• Slip-The ball in the tube will be on the inside of the turn; not enough rate of turn for the amount of bank.

Question 5

How does the magnetic compass work?

Answer 5

• Magnetized needles fastened to a float assembly, around which is mounted a compass card , align themselves parallel to the earth’s lines of magnetic force.
• The float assembly is housed in a bowl filled with acid-free white kerosene.

Question 6

What limitations does the magnetic compass have?

Answer 6

• This jewel-and-pivot type mounting allows the float freedom to rotate and tilt up to approximately 18° angle of bank.
• At steeper bank angles, the compass indications are erratic and unpredictable.

Question 7

What are the various compass errors?

Answer 7

Oscillation error: Erratic movement of the compass card caused by turbulence or rough control technique.

Deviation error: Due to electrical and magnetic disturbances in the aircraft.

Variation error: Angular difference between true and magnetic north; reference isogonic lines of variation.

Dip errors:

a. Acceleration error - On east or west headings, while accelerating, the magnetic compass shows a turn to the north , and when decelerating, it shows a turn to the south.

Remember: ANDS Accelerate North Decelerate South

b. Northerly turning error - The compass leads in the south half of a turn , and lags in the north half of a turn .

Remember: UNOS Undershoot N orth 0 vershoot S outh

Question 8

What equipment would be considered hydraulic on this aircraft? Check you plane

Answer 8

a. The retractable landing gear
b. The emergency hand pump
c. The hydraulically-actuated brake on each main gear
d. The air/oil nose gear shock strut

Question 9

What provides hydraulic power to the landing gear system? (AFM/POH) Check you plane

Answer 9

An electrically-driven hydraulic power pack provides all hydraulic power to the landing gear system.

The power pack is located behind the firewall between the pilot’s and copilot’s rudder pedals.

Question 10

Describe hydraulic power pack operation. Check you plane

Answer 10

Hydraulic power pack operation is controlled by the landing gear lever. When the gear lever is selected in either the “Up” or “Down” position, a pressure switch will activate the power pack and a selector valve is mechanically rotated. Depending on the position of the landing gear lever (and corresponding valve position), hydraulic pressure will be applied in the direction selected. This hydraulic pressure is applied to actuator cylinders, which extend or retract the gear. When the landing gear has reached the desired position and the cycle is complete (a series of electrical switches have closed or opened), an indicator light will illuminate on the panel. In the “Gear Down” cycle only, the hydraulic power pack will continue to operate until system pressure is between 1,000 PSI to 1,500 PSI, at which time the pressure switch turns the power pack off. The hydraulic system normally maintains an operating pressure of 1,000 PSI to 1,500 PSI.

Question 11

Describe the landing gear system on this airplane. Check you plane

Answer 11

The landing gear consists of a tricycle-type system using two main wheels and a steerable nose wheel. 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.

Question 12

How is the landing gear extended and retracted? Check you plane

Answer 12

A hydraulic actuator powered by an electrically-driven hydraulic power pack enables the landing gear extension, retraction, and main gear down lock release operations to occur. A pressure switch starts and stops power pack operation and hydraulic pressure is directed by a landing gear lever.

Question 13

How is the gear locked in the down position? Check you plane

Answer 13

Mechanical down locks are incorporated into the nose and main gear assembly.

Question 14

How is the gear locked in the up position? (Check you plane

Answer 14

A positive “up” pressure is maintained on the landing gear by the hydraulic power pack. To accomplish this, the power pack automatically maintains an operating pressure of 1,000 PSI to 1,500 PSI in the landing gear system.

Question 15

How is accidental gear retraction prevented on the ground?Check you plane

Answer 15

Inadvertent gear retraction is prevented by a safety (squat) switch on the nose gear. Whenever the nose gear strut is compressed (weight of the airplane on the ground), this switch electrically prevents operation of the landing gear system.

Question 16

How is the landing gear position indicated in the cockpit? (AFM/POH)Check you plane

Answer 16

Amber (gear up) and green (gear down) position indicator lights are provided in the cockpit. They are located adjacent to the landing gear control lever and indicate that the gear is either up or down and locked. Both indicators incorporate a press-to-test feature and also provide dimming shutters for night operation. Note: If one of the indicator lights should burn out, the design allows for replacement inflight, with the bulb from the other indicator light

Question 17

What type of landing gear warning system is used? Check you plane

Answer 17

If the manifold pressure is reduced to less than approximately 12 inches at a low altitude with the master switch on, and the landing gear is not locked down, a switch on the throttle linkage will electrically actuate the gear warning circuit of the dual warning unit. An intermittent tone will be heard on the speaker. Also, if the wing flaps are extended beyond 20° while the landing gear is in the retracted position, an interconnect switch in the wing flap system will cause the horn to sound.

Question 18

What is the normal length of time necessary for landing gear retraction or extension?Check you plane

Answer 18

5 to 7 seconds for either extension or retraction of the landing gear.

Question 19

Can the landing gear be retracted with the hand-operated pump? (Check you plane

Answer 19

No, retraction of the landing gear cannot be accomplished with the emergency hand pump.

Question 20

Describe the braking system on this aircraft.Check you plane

Answer 20

Hydraulically-actuated disc-type brakes are used 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 may be applied.

Question 21

How is steering accomplished on the ground?

Answer 21

• nosewheel steering capabilities through a simple system of mechanical linkages connected to the rudder pedals.

Question 22

What are the landing gear tire pressures? (AFM/POH) Know your plane

Answer 22

Nosewheel Tire Pressure ……………. 40 - 50 PSI (5.00-5, 6-ply rated tires) Main Wheel Tire Pressure ………….. 60 - 68 PSI (l5x6.00-6, 6-ply rated tires)

Question 23

What type of engine does this aircraft have? Know your plane

Answer 23

The airplane is powered by an engine manufactured by Avco- Lycoming, rated at 180 horsepower at 2,700 RPM. It may be described as follows: a. Normally aspirated b. Direct-drive C. Air-cooled d. Horizontally-opposed e. Carburetor-equipped f. Four-cylinder g. 361-cubic-inch displacement

Question 24

Describe how each of the following engine gauges work. Know your plane.

Answer 24

Oil Temperature - Electrically powered from the aircraft electrical system.

Oil Pressure - A direct-pressure oil line from the engine delivers oil at engine operating pressure to the gauge.

Cylinder Head Temperature - Electrically powered from the aircraft electrical system. Tachometer - Engine-driven mechanically.

Manifold pressure - Direct reading of induction air mani fold pressure in inches of mercury.

Fuel pressure - Indicates fuel pressure to the carburetor

Question 25

What four strokes must occur in each cylinder of a typical four-stroke engine in order for it to produce full power?

Answer 25

Intake: fuel mixture is drawn into cylinder by downward stroke.

Compression: mixture is compressed by upward stroke.

Power: spark ignites mixture forcing piston downward and producing power.

Exhaust: burned gases pushed out of cylinder by upward stroke.

Question 26

Explain the operation of a carburetor

Answer 26

a. Outside air first flows through an air filter, usually located at an air intake in the front part of the engine cowling.
b. The filtered air flows into the carburetor and through a venturi, a narrow throat in the carburetor.
c. When the air flows through the venturi , a low-pressure area is created, which forces the fuel to flow through a main fuel jet located at the throat.
d. The fuel then flows into the airstream where it is mixed with the flowing air.
e. The fuel/air mixture is then drawn through the intake manifold and into the combustion chambers where it is ignited.

Question 27

Explain the function of the “float” in a “float-type” carburetor system. (FAA-H-8083-25)

Answer 27

• A float 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 correct amount of fuel into the carburetor depending upon the position of the float, which is controlled by the level of fuel in the float chamber.
• 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.
• The flow of the fuel /air mixture to the combustion chambers is regulated by the throttle valve, which is controlled by the throttle in the flight deck.

Question 28

How does the carburetor heat system work?

Answer 28

• A carburetor heat valve, controlled by the pilot
• allows unfiltered, heated air from muffler to be directed to the carburetor.
• Carburetor heat should be used anytime suspected or known carburetor icing conditions exist.

Question 29

What is fuel injection? (

Answer 29

• Fuel injectors have replaced carburetors in some airplanes.
• In a fuel injection system, the fuel is normally injected into the system either directly into the cylinders or just ahead of the intake valves;
• whereas in a carbureted system, the fuel enters the airstream at the throttle valve.

Question 30

What are some advantages of fuel injection?

Answer 30

a. Reduction in evaporative icing
b. Better fuel flow
c. Faster throttle response there
d. Precise control of mixture
e. Better fuel distribution
f. Easier cold weather starts