Studied by 7 peopleInstruments in pilot-static system
Air Speed Indicator (ASI)
Vertical Speed Indicator (VSI)
Altimeter
Impact pressure
Used to sense the airspeed of an aircraft
Pilot Tube
Forward pointing tube that senses impact pressure
Air Speed Indicator (ASI)
Only instrument that uses the pilot tube
Static pressure port
Small sensor with a hole located in a place that is relatively undisturbed in terms of air flow
Pilot-Static instruments
Variations in pressure affects . . .
Vertical Speed Indicator (VSI)
In an emergency, when the static port i sblocked, to restore static pressure a pilot is to break the glass of the . . .
Altimeter
Shows the altitude of the aircraft, relative to sea level, based on pressure changes with altitude
Decreases
As an aircraft climbs, the outside air pressure ________
29.92 in/Hg.
The aneroid chamber of an altimeter contains a reference pressure of . . .
Altimeter
As ambient pressure changes, the aneroid will expand or contract in direct response
Climb
When pressure decreases, in a _____, the aneroid expands (altimeter)
Descent
During a ______, as pressure increases, the aneroid will contract (altimeter)
Aneroid (altimeter)
Internal pressure does not change
Case (altimeter)
Sealed except that it is open to static pressure, internal pressure will change as the aircraft climbs or descends
Altimeter will "freeze" reading the pressure of the air trapped in the case
What will happen to the altimeter if the static port becomes covered with ice?
Altimeter will give higher readings than what is accurate (non-pressurized aircraft)
What will happen to the altimeter if the static port is disconnected?
Adjusting the altimeter
Using small knob and a window that allows the instrument to be set for the actual outside air pressure
Kollsman Window
Altimeter
Behaves like a barometer
Altimeter reading will decrease
If you fly from a low pressure area into a high pressure area, how will the altimeter reading change?
Altimeter reading will increase
If you fly from high pressure to low, how will the altimeter reading change?
Altimeter
Air temps. impact the _________ readings
Increase
Cold temperatures ________ the air density (true altitude is lower than the altimeter indicated)
Decrease
Warm temperatures ________ the air density (true altitude is higher than the altimeter indicates)
Ground level
Altimeter settings are adjusted according to barometric pressure readings at . . .
Indicated altitude
Altitude read directly from the altimeter
True altitude
Actual altitude above sea level (MSL) (all altitudes on charts)
Absolute altitude
Actual altitude above the ground (AGL)
Pressure altitude
Altitude indicated when the altimeter is set to 29.92 in/Hg (Used above 18,000 feet)
Density altitude
Pressure altitude corrected for non-standard temperatures
75
Altimeter reading must be correct within __ feet to be considered safe for flight
Vertical Speed Indicator (VSI)
Indicates rate of climb or descent, if the aircraft is in level flight, it will indicate zero (0 fpm)
Vertical Speed Indicator (VSI)
Connected to the static air source
Vertical Speed Indicator (VSI)
Diaphragm is sealed and connected to static pressure
Vertical Speed Indicator (VSI)
Inside of the case is vented to static air through a calibrated vent (slows the equalization of pressure in the case)
Vertical Speed Indicator (VSI)
No power source is required
Vertical Speed Indicator (VSI)
Slowed response to pressure changes causes instrument to indicate when the diaphragm is expanding or contracting
Airspeed Indicator (ASI)
Shows airspeed by comparing pilot tube pressure to ambient pressure
Airspeed Indicator (ASI)
Only instrument that uses both pilot tube and static port air pressures
Airspeed Indicator (ASI)
Pilot pressure increases as the forward speed increases
Vs0 (ASI)
Stall speed, flaps deployed (Bottom of white arc.)
Vs1 (ASI)
Stall speed, flaps retracted (Bottom of green arc.)
White arc. (ASI)
Flap operating range
Vfe (ASI)
Max speed with flaps deployed
Green arc. (ASI)
Normal operating range
Vno (ASI)
Normal operating max speed
Yellow arc. (ASI)
Caution range (smooth air only)
Vne (ASI)
Never Exceed speed
Indicated Airspeed (IAS)
Uncorrected airspeed read directly from the instrument (used for performance data, including takeoff, landing, and stall speeds as listed in POH/AFM)
Calibrated Airspeed (CAS)
Airspeed corrected for installation errors and instrument errors (error greatest at low airspeed)
True Airspeed (TAS)
CAS corrected for altitude and temperature (increases with altitude), can be calculated with a flight computer or estimated by adding 2% for each 1000 ft of altitude
Design Maneuvering Speed - Va
Max speed at which the structural limit load can be imposed without structural damage
Landing Gear Operating Speed - Vlo
Max speed at which the aircraft landing gear may be safely operated (extended or retracted)
Landing Gear Extended Speed - Vle
Max speed at which the aircraft can be safely flown with gear extended
Best Angle of Climb - Vx
Speed at which aircraft gains the most altitude in a given distance
Best Rate of Climb - Vy
Speed at which aircraft gains the most altitude in a given time
Single Engine Best rate of climb - Vyse
Best rate of climb (or minimum sink rate) on a single engine
Minimum Control Speed - Vmc
Minimum speed at which a twin can maintain directional control on a single engine
EFD or EFIS “glass cockpit" display
Attitude Indicator
Altimeter
VSI
Heading Indicator
Turn Indicator
Tachometer
Slip/Skid Indicator (inclinometer)
Turn Rate
Air Data Computer (ADC)
Drives Multifunction Displays
Takes information from various sensors on board the aircraft and combines all of the data into the display shown to the pilot
Most common Gyroscopic Flight Instruments
Turn Coordinator
Heading Indicator
Attitude Indicator
Gyroscope
A rotating mass designed and mounted to use gyroscopic properties
Primary characteristics of a useful gyro.
Rotor has a high density and is able to rotate at a high speed
Classes of gyro. mount
Universal & Semi-rigid
Universal mount
Allows motion in any direction, has free motion in all three planes
Semi-rigid mounts
Restrict motion in one plane relative to a base, has two planes of freedom
Rigidity in space, and precession
The two fundamental properties of gyroscopic rotation . . .
Rigidity in space
Once spinning, a gyroscope tends to remain fixed in the plane in which it is spinning
As long as rotational velocity remains constant
No matter which direction the base is moved, the axis of rotation tends to remain in the same orientation . . .
precession
The motion of a gyroscope in response to an applied force
90°
When a force is applied to a spinning gyroscope, the reaction occurs ___ later in the direction of rotation (what makes a gyro useful for determining rate of turn)
Vacuum or electric
Gyros are generally powered with ______ or _______ power
Electric gyros.
Powered by simple motors.
Turn & slip indicator and turn coordinator
Two types of turn indicators (both marked to indicate a standard rate turn of 3° per second/ 2 minutes per 360°)
Turn and Slip Indicators
Gyros rotate in the vertical plane along the longitudinal axis of the aircraft, precession causes the pointer to tilt left or right as the aircraft turns.
Turn coordinator
Gyro is canted at an angle, when the aircraft is rolled, the indicator tilts in the direction of roll
Inclinometer
Detects yaw or uncoordinated turns
“Step on the ball”
Simple rule to remember when reading an Inclinometer
Attitude indicator
Represents the aircraft’s relationship to the horizon (indicates both pitch and roll)
Attitude indicator
Adjustment knob adjusts the pitch setting to account for changes in cruise pitch angle (typically used to set the wings in the instrument along the horizon line on the instrument face)
100°-110°
Attitude indicator limits in roll, and from 60-70° in pitch
60°-70°
Attitude indicator limits in pitch
Heading indicator
Depends on the principle of rigidity in space
Heading indicator
Meant to provide a more stable directional indication than the magnetic compass (is stable and provides clear directional guidance)
Heading indicator
It is set to match the magnetic compass when the aircraft is in a level, unaccelerated condition.
Heading indicator
Precession and friction will cause it to drift slowly from the original setting (pilots should compare the readings to the Mag Compass regularly while in flight)
Heading indicator
Reacts to the rotation of the earth (earth rotates at about 15° per hour, so the it will drift up to that much per hour of flight)
Horizontal Situation Indicators (HSI)
Heading indicators that have the ability to correct themselves automatically (have a magnetometer which detects and correct the reference to magnetic north automatically)
Electronci flight displays (EFD)
Use solid state laser gyros that are capable of flight in any attitude without failing (give accurate information in 360 degrees of roll or pitch and do not tumble)
Flux Valve
Larger aircraft may use a magnetic sensor called a ____ _____ which electrically determines the aircraft’s heading in relation to the earth’s magnetic field
Angle of attack indicator (AOA)
Give better situational awareness and stall margin indications than airspeed alone
Angle of attack indicator (AOA)
Indications do not change with weight, bank angle, temperature, density altitude or center of gravity
Magnetic compass
Required to be installed in all US certified aircraft (no matter how sophisticated)
Magnetic compass
Will point to the magnetic north pole (not the geographic north pole)
1,300
The magnetic north pole is located about ____ miles away from the geographic pole
Offset between the magnetic and geographic north pole
Causes the direction of magnetic north to vary from true north depending on where you are on the earth
Magnetic variation
This difference between true directions and magnetic directions is called (must be accounted for if you are to navigate successfully using magnetic compasses)
Isogonic lines
Lines where the magnetic variation is consistent
Agonic line
Any Isogonic Line where the variation is zero
Note
Flashcard