AVN 2100 Flight Instruments Flashcards
What are the six basic flight instruments?
Attitude Indicator, Turn Coordinator, Heading Indicator, Air Speed Indicator, Vertical Speed Indicator, Altimeter
What three categories are basic instruments grouped into?
Gyroscopic, pressure, and magnetic
What are the pressure instruments?
Altimeter, air speed indicator, and vertical speed indicator
What is static pressure?
The result of the weight of air molecules in the atmosphere
Static pressure ______ approximately ___ in of mercury every 1000 ft rise in altitude
Decreases, 1 inch
What measure static pressure?
The static ports
What is dynamic pressure?
Pressure resulting from air molecules relatively moving and crashing into what ever is moving through it.
What is the equation to calculate dynamic pressure?
1/2 (air density) * V^2
The faster the air flow the ______ the dynamic pressure.
Greater
The greater the air density to ______ the dynamic pressure.
Greater
Total pressure =
Static pressure + dynamic pressure
The pitot tube measures ________
Total pressure
On light aircraft the pitot tube is usually located _______
Under the left wing
The air speed indicator displays _______
Dynamic pressure converted to units of nautical miles per hour
The ASI cannot compensate for changes in _______
Temperature
The ______ system powers the ASI, Altimeter, and VSI
Pitot static system
The operation of the pressure instruments is based upon _______
Changes in pressure
Only the _____ uses pressure from the pitot tube.
Air speed indicator
Total pressure taken into the pitot tube is also referred to as _________
Ram air pressure
The green arc on the ASI is marked by the ____ and ____ speeds.
Vs1 and Vno
The white arc on the ASI is marked by the ___ and ___ speeds.
Vs0 and Vfe
The white arc on the ASI refers to the _____
Flap operating range
Vs0 is ______
The stalling speed in landing configuration
Vfe is ______
The maximum speed you can fly with flaps extended
The green arc on the ASI begins with ____
Vs1
Vs1 is ____
The stalling speed in clean configuration
The top of the green arc is ___
Vn0
Vn0 is _____
The maximum structural cruising speed
You should not exceed Vn0 except in ______
Smooth air
The green arc represents ________
Normal operating range of speeds
The yellow arc of the ASI begins with ____
Vn0
The top of the yellow arc is _____
Vne
Vne is ____
The never exceed speed
The yellow arc indicates the _________
Caution range
You should only fly at speeds in the yellow arc in _______
Smooth air
The red line is marked by the ______
Vne speed
Operating above the Vne _______
Should never be done and may result in structural damage
The six main V speeds on the ASI are:
Vs0 (dirty) Vs1 (clean) Vfe (max flaps extended) Vn0 (max structural cruising speed) Vne (never exceed)
What is Va?
Maneuvering speed
What is maneuvering speed?
The speed at which abrupt/full control movements will result in a stall before structural damage
Why is the Va not marked on the ASI?
It changes with weight, depends on the load factor.
The ASI displays ____
Indicated Air Speed (IAS)
IAS is referred to when discussing performance speeds such as:
Takeoff, landing, and stall speeds
True Airspeed takes into account
The density of the air
Is IAS or TAS more accurate?
TAS
What speed is important for navigational purposes?
True Air Speed
IAS will equal TAS only at_____
Sea level under standard conditions?
What does standard conditions refers to?
29.92 in in Hg and 15 deg. C
At higher altitude and aircraft must be flown at a higher ____ to maintain the same ____.
TAS, IAS
The difference between IAS and TAS is most noticeable when?
During takeoffs and landings at high altitude on warm days.
What is Calibrated Air Speed?
IAS corrected for installation and instrumentation errors
CAS can be determined from the _____
POH
Equivalent Air Speed is _____
Calibrated Air Speed corrected for compressibility errors.
When does EAS become a factor?
Above 200 kts
What is groundspeed?
TAS corrected for wind
TAS is the actual
speed through the air
With a tailwind, GS is _____ than TAS
Greater
With a headwind, GS is _____ than TAS
Less
When climbing with a blocked static port, the ASI will display a _____ than actual IAS
Lower
When descending with a blocked static port, the ASI will display a _____ than actual IAS
Greater
When climbing with a fully blocked pitot tube, the ASI will display a _____ than actual IAS.
Greater
When descending with a fully blocked pitot tube, the ASI will display a ______ than actual IAS.
Lower
With a partially blocked pitot tube, the ASI will eventually read _____
Zero
The altimeter displays altitude above the _____
Average height of the ocean, mean sea level, MSL
The altimeter must be set to a specific place and time, known as the ________
Kollsman window
The value displayed by the altimeter is known as the ______
Indicated altitude
The altimeter setting is the airport _______ corrected for _________
Barometric pressure, MSL pressure
If the pressure at an airport 500 feet above MSL is 28.3, what is the altimeter setting?
28.8
With the altimeter set to current conditions it should read within _____ feet of published field elevation.
75
If MSL pressure is 30 in, what is the altimeter setting?
30
In flight, to ensure accurate altimeter readings, the altimeter should be set to an appropriate setting for a current location within ____ miles.
100
At altitudes greater than 18000 MSL, altimeters are set to ____
29.92
Altitudes above 18000 MSL are referred to as _________
Flight levels
21000 MSL =
FL210
Pressure altitude is what the altimeter reads with what setting?
29.92
What is one equation for calculating pressure altitude?
Field Elevation - (((Altimeter setting) - 29.92)*1000)
Pressure altitude can also be referred to as the difference between indicated altitude and the _______
Standard datum plane
The ASI and altimeter are unable to adjust for changes in ________
Air density
Density altitude is pressure altitude corrected for ________
Non standard temperature
Temperature decreases ___ degrees C for every 1000 gain in elevation
2
True Altitude is the ______
Actual height above MSL
What altitude is displayed on navigational charts?
True altitude
The only two condition when IA will equal TA are:
When standard atmospheric conditions exist in flight or when on the ground with the correct altimeter setting.
Absolute altitude is _______
The actual height of an object above ground level (AGL).
Four causes of error in the altimeter are:
Instrument error, Instrument lag, position error, and temperature error
Position error refers to _______
Error from the position of the static port
As the saying goes, high to low, ______, low to high, ________
Look out below, in the sky
If the static port becomes blocked, the altimeter will read a ________
Constant altitude
The Vertical Speed Indicator displays what?
Rate of climb or decent once stabilized
Why does the VSI have 3-9 seconds of lag to display a stable rate of climb?
It measures the rate of static pressure change through use of a calibrated leak within the instrument
If the static port becomes blocked, the VSI will read _____
0
What two fundamental properties of gyroscopes are the operation of the gyro instruments based on?
Rigidity in space and Precession
Describe a gyro:
A rotating, wheel shaped, heavy rimmed mass mounted within lighter rings known as gimbals which rotate around the center of mass freely.
What does the principal if rigidity in space state:
Regardless of the position of its base, a gyro tends to remain spinning in its original plane with its axis of rotation pointed in a constant direction.
What does precession refer to?
The reaction of the spinning center mass of a gyroscope to the application of a force. When the direction of the airplane changes a slight tilting of the gyro occurs, which is precession.
What is the definition of precession?
A force applied to spinning object felt 90 degrees ahead in the direction of rotation.
What gyroscopic principle does the attitude indicator use?
Rigidity in space
What gyroscopic principal does the heading indicator use?
Rigidity in space
What gyroscopic principal does the turn coordinator use?
Precession
What powers the the turn coordinator?
The electric system
What powers the attitude indicator?
The vacuum system
What powers the heading indicator?
The vacuum system
What provides suction for the vacuum system?
The vacuum pump
What monitors the vacuum system?
The suction gauge
What does the vacuum relief valve do?
Prevents excessive pressures within the system
What is the only instrument that provides pitch and bank information?
The attitude indicator
Does the gyro spin horizontally or vertically in the AI?
Horizontally
Does the AI provide yaw information?
No
The angle of bank scale on the AI is marked in ___ degree increments
10
The angle of pitch scale on the AI is marked in ___ degree increments
5
Is the AI affected by precession?
Yes
When accelerating, the AI might show a small pitch ______
Up
When decelerating, the AI might show a small pitch _____
Down
An unusual or extreme attitude might cause the AI to _____
Tumble
The AI should be erect and stable within ____ minutes of engine startup
5
Should the AI indicate a pitch change during brake test?
Yes
Around what axis does the gyro in the HI spin?
Horizontal
Does the heading indicator seek magnetic north?
No
How often should the HI be checked and reset?
Every 15 mins
Why must the HI be reset?
Mechanical drift from precession caused by friction
What does the turn coordinator indicate?
Rate of turn, rate of roll, and quality of turn
What is a standard rate turn?
360 deg in 2 min = 3 deg per second
What indicated the quality/coordination of the turn on the turn coordinator?
Inclinometer Ball
Does the turn coordinator indicate bank angle?
No
Why do light aircraft typically spin the TC electrically?
So that not all gyro instruments depend on the vacuum system
During taxi turns, what should the TC indicate?
The TC wings should go in the direction of the turn while the ball should go in the opposite direction
In a coordinated turn, the centrifugal force equals what?
The horizontal component of lift
In a coordinated turn, where is the inclinometer ball?
Centered
In a slipping turn, is the centrifugal force greater or less than the horizontal component of lift?
Less
Where is the inclinometer ball in a slipping turn?
Toward the inside of the turn
What does a slipping turn indicate?
The angle of bank is too great for the rate of turn
Is a skidding turn a coordinated one?
No
In a skidding turn, the centrifugal force is ____ than the horizontal component of lift.
Greater
The inclinometer ball moves to the _____ of the turn in a skidding turn.
Outside
A skidding turn indicates what?
Rate of turn too great for the angle of bank.
What does the rate of turn refer to?
Number of degrees of heading changed per unit of time
For a constant bank angle, if the velocity increases, the rate of turn ______
Decreases
For a constant airspeed, if the angle of bank increases, the rate of turn ______
Increases
For a constant bank angle, if airspeed increases, the radius of turn ____
Increases
For a constant airspeed, if the angle of bank increases, the radius of turn ______
Decreases
What is magnetic variation?
The angular difference between true north and magnetic north at a given location
Charts reference ____ north, but pilots fly using _____ north
True, magnetic
What is magnetic deviation?
Error from interference of electrical and magnetic fields generated within the aircraft.
What does magnetic deviation cause?
The magnetic compass to not point directly to magnetic north
Is deviation constant?
No, it varies from plane to plane and heading to heading.
What is a deviation card?
A card posted near the magnetic compass displaying correction to be made to compass readings to compensate for deviation
Where does magnetic dip occur?
Near the poles.
The weight added to a compass to help with magnetic dip causes _______ when on _______ headings
Acceleration/deceleration East/west
When accelerating on a easterly or westerly heading, the compass will turn to the _____
North
ANDS stands for?
Acceleration North Deceleration South
Do compass turning errors exist on the equator?
No
When do compass turning errors increase?
When flying closer to the poles
Are there turning errors when flying east and west headings?
No
When rolling into or out of turns at northerly headings, the compass will ____
Lag
The compass will ____ the actual heading when rolling into or out of southerly headings.
Lead
What does UNOS stand for?
Undershoot north overshoot south
