Airplane Systems Flashcards
How are the various flight controls operated? (AFM/POH)
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 rudder/brake pedals actuate the rudder.
What type of trim system is installed in this airplane? (AFM/POH)
Both rudder and elevator trim are provided. They are both manually actuated.
What are flaps, and what is their function? (FAA-H-8083-25)
The wing flaps are movable panels on the inboard trailing edges of the wings. They are hinged so 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 the takeoff distance.
Describe a typical wing flap system. (AFM/POH)
The wing flap system consists of “single-slot” type wing flaps. They are extended and retracted by a wing flap switch lever to flap settings of 10, 20, and 30 degrees. A 15-amp push-to-reset circuit breaker protects the wing flap system circuit.
State some examples of leading edge lift devices. (FAA-H-8083-31)
Slots—A slot in the leading edge of a wing directs high-energy air from under the wing to the airflow above the wing, accelerating upper airflow. By accelerating the airflow above the wing, airflow separation will be delayed to higher angles of attack. This allows the wing to continue to develop lift at substantially higher angles of attack.
Slats—A miniature airfoil mounted on the leading edge of a wing. They may be movable or fixed. At low angles of attack, movable slats are held flush against the leading edge by positive air pressure. At high angles of attack, the slats are moved forward either by the pilot or automatically by the low pressures present at the leading edge. Slats provide the same results as slots.
What are spoilers? (FAA-H-8083-31)
Spoilers are devices located on the upper surface of a wing which are designed to reduce lift by “spoiling” the airflow above the wing. They are typically used as speed brakes to slow an airplane down, both in flight as well as on the ground immediately after touchdown.
What instruments operate from the pitot/static system? (FAA-H-8083-15)
The pitot/static system operates the altimeter, vertical speed indicator, and airspeed indicator.
Does this aircraft have an alternate static air system? (AFM/POH)
Yes. In the event of external static port blockage, a static pressure alternate source valve is installed. The control is located beneath the throttle, and if used will supply static pressure from inside the cabin, instead of from the external static ports.
How does an altimeter work? (FAA-H-8083-15)
Aneroid wafers in the instrument expand and contract as atmospheric pressure changes, and through a shaft and gear linkage, rotate pointers on the dial of the instrument.
A pressure altimeter is subject to what limitations? (FAA-H-8083-15)
Non-standard pressure and temperature:
a. Temperature variations expand or contract the atmosphere and raise or lower pressure levels that the altimeter senses.
On a warm day—The pressure level is higher than on a standard day. The altimeter indicates lower than actual altitude.
On a cold day—The pressure level is lower than on a standard day. The altimeter indicates higher than actual altitude.
b. Changes in surface pressure also affect pressure levels at altitude.
Higher than standard pressure—The pressure level is higher than on a standard day. The altimeter indicates lower than actual altitude.
Lower than standard pressure—The pressure level is lower than on a standard day. The altimeter indicates higher than actual altitude.
Remember: High to low or hot to cold, look out below!
Define and state how you would determine the following altitudes. (FAA-H-8083-25)
Indicated altitude—the altitude read directly from the altimeter (uncorrected) after it is set to the current altimeter setting.
Pressure altitude—the height above the standard datum plane indicated when the altimeter setting window is adjusted to 29.92. It is used for computer solutions to determine density altitude, true altitude, true airspeed.
True altitude—the true vertical distance of the aircraft above sea level. Airport, terrain, and obstacle elevations found on aeronautical charts are true altitudes.
Density altitude—pressure altitude corrected for nonstandard temperature variations. Directly related to an aircraft’s takeoff, climb, and landing performance.
Absolute altitude—the vertical distance of an aircraft above the terrain.
How does the airspeed indicator operate? (FAA‑H‑8083‑25)
It measures the difference between the impact pressure from the pitot head and atmospheric pressure from the static source.
What are the limitations of the airspeed indicator? (FAA‑H‑8083‑25)
The airspeed indicator is subject to proper flow of air in the pitot/static system.
The airspeed indicator is subject to what errors?
Position error—Caused by the static ports sensing erroneous static pressure; slipstream flow causes disturbances at the static port, preventing actual atmospheric pressure measurement. It varies with airspeed, altitude, and configuration, and may be a plus or minus value.
Density error—Changes in altitude and temperature are not compensated for by the instrument.
Compressibility error—Caused by the packing of air into the pitot tube at high airspeeds, resulting in higher than normal indications. It is usually not a factor.
What are the different types of aircraft speeds? (FAA‑H‑8083‑25)
Indicated Airspeed (IAS)—the speed of the airplane as observed on the airspeed indicator. It is the airspeed without correction for indicator, position (or installation), or compressibility errors.
Calibrated Airspeed (CAS)—the airspeed indicator reading corrected for position (or installation), and instrument errors. CAS is equal to TAS at sea level in a standard atmosphere. The color-coding for various design speeds marked on airspeed indicators may be IAS or CAS.
Equivalent Airspeed (EAS)—the airspeed indicator reading corrected for position (or installation), or instrument error, and for adiabatic compressible flow for the particular altitude. EAS is equal to CAS at sea level in standard atmosphere.
True Airspeed (TAS)—CAS corrected for altitude and nonstandard temperature; the speed of the airplane in relation to the air mass in which it is flying.
What airspeed limitations apply to the color-coded marking system of the airspeed indicator? (FAA‑H‑8083‑25)
What are some examples of important airspeed limitations that are not marked on the face of the airspeed indicator, but are found on placards and in the AFM or POH? (FAA‑H‑8083‑25)
a. Design maneuvering speed (VA)
b. Landing gear operating speed (VLO)
c. Landing gear extended speed (VLE)
d. Best angle-of-climb speed (VX)
e. Best rate-of-climb speed (VY)
How does the vertical speed indicator work? (FAA‑H‑8083‑15)
The vertical speed indicator is a pressure differential instrument. Inside the instrument case is an aneroid very much like the one in an airspeed indicator. Both the inside of this aneroid and the inside of the instrument case are vented to the static system, but the case is vented through a calibrated orifice that causes the pressure inside the case to change more slowly than the pressure inside the aneroid. As the aircraft ascends, the static pressure becomes lower and the pressure inside the case compresses the aneroid, moving the pointer upward, showing a climb and indicating the number of feet per minute the aircraft is ascending.
What are the limitations of the vertical speed indicator? (FAA‑H‑8083‑25)
It is not accurate until the aircraft is stabilized. Sudden or abrupt changes in the aircraft attitude will cause erroneous instrument readings as airflow fluctuates over the static port. Both rough control technique and turbulent air result in unreliable needle indications.
Which instruments contain gyroscopes? (FAA‑H‑8083‑25)
The most common instruments containing gyroscopes are the turn coordinator, heading indicator, and attitude indicator.
What are the two fundamental properties of a gyroscope? (FAA‑H‑8083‑25)
Rigidity in space—A gyroscope remains in a fixed position in the plane in which it is spinning.
Precession—The tilting or turning of a gyro in response to a deflective force. The reaction to this force does not occur at the point where it was applied; it occurs at a point 90° later in the direction of rotation. The rate at which the gyro precesses is inversely proportional to the speed of the rotor and proportional to the deflective force.
What are the various sources that may be used to power the gyroscopic instruments in an airplane? (FAA‑H‑8083‑25)
In some airplanes, all the gyros are vacuum, pressure, or electrically operated; in others, vacuum or pressure systems provide the power for the heading and attitude indicators, while the electrical system provides the power for the turn coordinator. Most airplanes have at least two sources of power to ensure at least one source of bank information if one power source fails.
How does the vacuum system operate? (FAA-H-8083-25)
Air is drawn into the vacuum system by the engine-driven vacuum pump. It first goes through a filter, which prevents foreign matter from entering the vacuum or pressure system. The air then moves through the attitude and heading indicators, where it causes the gyros to spin. A relief valve prevents the vacuum pressure, or suction, from exceeding prescribed limits. After that, the air is expelled overboard or used in other systems, such as for inflating pneumatic deicing boots.
How does the attitude indicator work? (FAA-H-8083-25)
The attitude indicator’s gyro is mounted on a horizontal plane (a bar representing true horizon) and depends upon rigidity in space for its operation. The fixed gyro remains in a horizontal plane as the airplane is pitched or banked about its axis, indicating the attitude of the airplane relative to the true horizon.
Discuss the limits of an attitude indicator. (FAA‑H‑8083‑25)
Pitch and bank limits depend upon the make and model of the instrument. Limits in the banking plane are usually from 100°–110°, pitch limits are usually from 60°–70°. If either limit is exceeded, the instrument will tumble or spill giving incorrect indications until reset. Some modern attitude indicators will not tumble.
The attitude indicator is subject to what errors? (FAA-H-8083-15)
Attitude indicators are free from most errors, but depending on the speed with which the erection system functions, there may be a slight nose-up indication during a rapid acceleration and a nose-down indication during a rapid deceleration. There is also a possibility of a small bank angle and pitch error after a 180° turn. These inherent errors are small and correct themselves within a minute or so after returning to straight-and-level flight.
How does the heading indicator operate? (FAA‑H‑8083‑25)
It uses the principle of rigidity in space; the rotor turns in a vertical plane, and the compass card is fixed to the rotor. Since the rotor remains rigid in space, the points on the card hold the same position in space relative to the vertical plane. As the instrument case and the airplane revolve around the vertical axis, the card shows clear, accurate heading information.
What are the limitations of the heading indicator? (FAA‑H‑8083‑25)
The pitch and bank limits depend upon the make and model of the instrument. Limits in the banking plane are usually from 100 degrees to 110 degrees, and the pitch limits are usually from 60 to 70 degrees. If either limit is exceeded, the instrument will tumble or spill and will give incorrect indications until realigned. A number of modern attitude indicators do not tumble.
What error is the heading indicator subject to? (FAA‑H‑8083‑25, FAA-P-8740-16)
Because of precession, caused chiefly by friction, the heading indicator will creep or drift from a heading to which it is set. Among other factors, the amount of drift depends upon the condition of the instrument. The heading indicator may indicate as much as 15 degrees of error per every hour of operation.
How does the turn coordinator operate? (FAA-H-8083-25)
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 needle or miniature aircraft in proportion to the rate of turn. The slip/skid indicator is a liquid-filled tube with a ball that reacts to centrifugal force and gravity.
What information does the turn coordinator provide? (FAA‑H‑8083‑25)
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.
What will the turn indicator indicate when the aircraft is in a skidding or a slipping turn? (FAA‑H‑8083‑25)
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.
How does the magnetic compass work? (FAA‑H‑8083‑25)
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.
What limitations does the magnetic compass have? (FAA-H-8083-15)
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.
What are the various compass errors? (FAA-H-8083-15)
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
A ccelerate
N orth
D ecelerate
S outh
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
U ndershoot
N orth
O vershoot
S outh
What equipment would be considered hydraulic on this aircraft? (AFM/POH)
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
What provides hydraulic power to the landing gear system? (AFM/POH)
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.
Describe hydraulic power pack operation. (AFM/POH)
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.
Describe the landing gear system on this airplane. (AFM/POH)
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.
How is the landing gear extended and retracted? (AFM/POH)
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.
How is the gear locked in the down position? (AFM/POH)
Mechanical down locks are incorporated into the nose and main gear assembly.
How is the gear locked in the up position? (AFM/POH)
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.
How is accidental gear retraction prevented on the ground? (AFM/POH)
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.
How is the landing gear position indicated in the cockpit? (AFM/POH)
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.
What type of landing gear warning system is used? (AFM/POH)
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.
What is the normal length of time necessary for landing gear retraction or extension? (AFM/POH)
5 to 7 seconds for either extension or retraction of the landing gear.
Can the landing gear be retracted with the hand‑operated pump? (AFM/POH)
No, retraction of the landing gear cannot be accomplished with the emergency hand pump.
Describe the braking system on this aircraft. (AFM/POH)
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.
