Flight Instruments Flashcards
What are the three instruments connected to the pitot-static system?
Altimeter, vertical speed indicator, airspeed indicator
What is the only instrument the pitot tube is connected to?
Airspeed indicator
What is the static port connected to?
What does it do?
ALT, VSI, ASI
It allows air pressure in the instruments to equalize with the outside ambient pressure
What will happen to each of the ALT, VSI, and ASI if the static port becomes blocked?
Altimeter will stop moving
Vertical speed indicator will reduce to zero if climbing or descending, or remain at zero
Airspeed indicator will under read more as you climb, over read more as you descend.
What will happen to each of the ALT, VSI, and ASI when the pitot tube becomes blocked?
Pitot tube affects airspeed ONLY
A blocked pitot will cause the airspeed indicator to act like an altimeter, increase with climb, decrease with descent.
What happens when a pitot tube is partially blocked?
Partial blockage with drain hole still open will slow dynamic pressure to slowly leak out. The ASI will decrease to zero, not instantly but very QUICKLY.
What happens if the static line becomes disconnected in flight?
It would indicate cabin pressure which is much lower than actual altitude
The VSI shows the rate of ascent or descent in?
Feet per minute
Typically due to the VSI lag, it takes about _ to _ seconds for the pressure differential to indicate a climb or descent.
6-8 seconds
What can large and abrupt pitch changes and turbulence do to the VSI?
can extend the lag period and cause erratic and unstable rate indications.
What is the reversal error on a VSI?
With sudden or abrupt pitch changes it will temporarily show the opposite of what the aircraft is doing.
The altimeter is an ____ ____ which measures the pressure of the atmosphere.
It is connected to the ____ ____ which allows atmospheric pressure to move in and out of the altimeter’s casing.
Aneroid barometer
Static port
It is important to remember the altimeter is designed with standard atmosphere in mind. Any deviations will cause?
A wrong reading
Due to changes in ISA and actual atmospheric conditions, what are several things that can lead to errors in the altimeter indication?
Low pressure systems
Temperature variations
Mountain effect and waves
Abnormally high pressure
After putting in the altimeter setting, verify that the altitude displayed is within __ feet of the field elevation.
If not the altimeter needs recalibration.
50 feet
If an altimeter setting is set too high, the altimeter will display a reading that is ___ ___
Too high
Flying from high pressure to low pressure and altimeter has not been adjusted, the altimeter will indicate a reading that is
Too high which means you are lower than the altimeter indicates
when an aircraft is flying from an area of low pressure into an area of high pressure, and the correct altimeter setting has not been obtained, the altimeter will read
Too low, which means you are higher than indicated on altimeter.
In the Northern hemisphere a drift to the ____ indicates that an aircraft is flying into an area of low pressure.
Right
The highest setting we can have on most altimeters is
31.00 in. Hg
In regards to true altitude indication, when air is warmer, your true altitude will be ____, whereas a colder temp will be ____.
Greater than indicated, less than indicated
What is mountain effect?
Winds that deflect around mountains or valleys increase in speed, causing a drop in local pressure. A pressure altimeter in these conditions would give a reading that is too high
Pressure within mountain waves can ___ significantly.
Downdrafts are most severe at ____ ____
And may reach an intensity of ____ feet per minute
The drop in pressure in a mountain wave can cause the altimeter to over read by as much as ____ feet
Decrease
Summit height
5,000 fpm
3,000 feet
Because mountain wave downdrafts can be quite smooth a pilot may not notice that the aircraft is in a downdraft.
> Although the aircraft is going down in the wave the altimeter ________ because of the decrease in pressure.
• The altimeter will not register the descent.
Stays the same.
What is indicated altitude?
The altitude read directly off the altimeter when the correct altimeter setting is used in the kollsman window.
What is pressure altitude?
Altitude indicated when the altimeter is set to 29.92 in Hg. It is based on standard atmosphere
What is true altitude?
It is the exact altitude above mean sea level.
If the altimeter setting was 29.92 in Hg and standard atmosphere prevailed, then true altitude would be ___ pressure altitude.
The same as
What is absolute altitude?
The actual height above the earth’s surface (AGL) with the altimeter setting correctly set and non-standard variations in temperature taken into consideration.
Basically, this is the true altitude subtracting out the height of the terrain below.
What is density altitude?
This is pressure altitude corrected for nonstandard temperature.
Hot days with low pressures and high humidity lead to (low/high) density altitude.
> That is, the ALTITUDE appears to be HIGH, although the actual density of the air is LOW.
High
What is an encoding altimeter?
Known as a mode c operation of a transponder, it lets ATC know pressure altitude and position of a transponder equipped aircraft
Given: Altimeter setting 29.94 in Hg
Indicated altitude 6 500 feet
The pressure altitude is
a.6 480 feet.
b.6 520 feet.
c.6 700 feet.
d.6 300 feet.
A
29.92 in Hg - 29.94 in Hg = -0.02 inch x 1 000 = -20 feet + 6 500 feet = 6 480 feet
Given: Altimeter setting 31.00 in Hg
Indicated altitude 8 500 feet
Temperature 5° F
The density altitude is
a.8 800 feet.
b.6 600 feet.
c.7 800 feet.
d.5 400 feet.
D
1st Calculate PA: 29.92 - 31.00 = -1.08 x 1 000 = -1 080 + 8 500 = 7 420 feet
2nd Convert temperature into Celsius: 5°F = -15°C
Match PA 7 420 feet with -15°C on right window of E6B
Read Density Altitude in small window 5 400 feet
Given: Altimeter setting: 29.92 in Hg
Indicated altitude 7 000 feet
Temperature -25°C
The true altitude is
a.6 300 feet.
b.7 750 feet.
c.7 350 feet.
d.8 100 feet.
A
Since altimeter setting is 29.92, indicated Altitude is same as PA
Match PA 7 000 feet with -25°C on left window of E6B
Opposite of Indicated/Calibrated Altitude on inner Circle (70), read True Altitude on outer circle 6 300 feet
Note: Make sure you use the left side of the flight computer for true altitude calculation. (Right side is for density altitude and TAS)
The ____ ____ is the only instrument in the aircraft by which the pilot determines the direction of flight.
Magnetic compass
What is magnetic dip?
The earth’s magnetic lines of force are nearly horizontal at the equator but become nearly vertical towards the magnetic poles.
• This causes the needle to try and follow these lines of force, and at higher latitudes it will dip downwards–that is, towards the ground.
What is magnetic variation?
The magnetic North Pole and the true North Pole are not located at the same place on the earth’s surface.
• Variation at any given location on the earth’s surface is the difference between true North and magnetic North.
• Lines of equal variation are called isogonic lines.
The ____ line is a line of zero variation.
Agonic
Variation values to the East of the agonic line are called _____ variation.
• This means the magnetic North is ____ of true North.
Westerly, west
the variation values West of the agonic line are called _____ variation.
Meaning the magnetic North is ____ of true North.
Easterly, east
When converting from true to magnetic heading, remember the saying
East is least, west is best
What is compass deviation?
the difference between the compass indications when installed in the aircraft compared to the indications when the compass is outside the aircraft.
• The difference is caused by the influence of the magnetic fields due to the metal of the aircraft and the electronic equipment.
• These magnetic disturbances may cause the compass readings to be slightly in error.
How often must a compass be swung?
Annually
For turns in the northern quadrant of the compass rose, a turn towards or from North, the compass will initially rotate in the ____ direction of the turn and then will Lag the turn by at most __°.
Opposite, 30 degree
for turns in the southern quadrant of the compass rose, a turn towards or from the South, the compass will initially rotate ____ of the turn and Lead the turn by at most __°.
• These effects are greatest on headings of ____ or ____ and least noticeable on headings within the ____ and ____ quadrants.
Ahead of the turn, 30 degrees
North or south
East and west
Northerly turning error is caused by
Magnetic dip
Accelerating the aircraft east/west heading will cause the compass to register a turn to the ____.
North
Decelerating the aircraft from east/west heading will cause the compass to register a turn to the ____.
South
A compass will read most accurately during turns when
Positioned over the equator ( no dip )
When converting from magnetic to true heading or track with easterly variation
a.add the variation.
b.subtract the variation.
c.multiply the variation.
d.none of the above apply.
A
True to magnetic conversion use east is least which means subtraction.
However, in this question the conversion is in the opposite direction, from magnetic to (or back to) true is asked for. So the opposite is used.
When turning from a heading of 020° to a heading of 090° the compass will?
Momentarily show a turn in the opposite direction
What is a gyroscope?
A rotor or spinning wheel rotating at a high speed
The attitude indicator and heading indicator are generally powered by vacuum or electrically?
Vacuum powered
What instrument is typically electrically driven ?
Turn coordinator
A gimbal is a gyroscopic mounting that
allows the gyros axis to pivot in any direction.
How does a heading indicator work?
How often should you check it against the compass?
The gyro inside of the instrument remains in the same place, while the entire aircraft and instrument case are actually turning about the gyro.
When speeding up, slowing down, or turning the compass will be in error.
• The Hi, however, is unaffected by these manoeuvres and errors.
Usually every 15 minutes in straight level unaccelerated flight
The gyro wheel in a heading indicator is mounted
a.horizontally and spinning about the vertical axis.
b.vertically and spinning about the horizontal axis.
c.canted at 30 to 35° and spins towards the pilot.
d.horizontally and spinning about the horizontal axis.
B
During acceleration the attitude indicator can be expected to indicate
a.a climb.
b.a turn to the north.
c.a turn to the south.
d.a descent.
A
The gyro in an attitude indicator is
a.mounted horizontally and spins about the vertical axis.
b.mounted vertically and spins about the horizontal axis.
c.mounted at a 30 to 35° angle and spins towards the pilot.
d.none of the above.
A
Primarily the difference between the turn and bank indicator and the turn coordinator is that the
a.turn coordinator also indicates rate of roll.
b.turn and bank indicator also indicates rate of roll.
c.turn coordinator indicates the quality of the turn.
d.turn and bank indicator indicates the quality of the turn.
A
The gyro in a turn coordinator is mounted
a.at a 30 to 35° angle from the horizontal axis while spinning away from the pilot.
b.vertically along the horizontal axis and spinning towards the pilot.
c.vertically along the horizontal axis with a canted gimbal.
d.none of the above are correct.
C
What bank angle is required for a standard rate turn at 90 KTAS?
a.14°
b.15°
c.16°
d.17°
C
KTAS / 10 + 7 = Bank Angle
90 / 10 + 7 = 16°
The correct answer is: 16°
What airspeed is required in order to perform a standard rate turn with 30° of bank?
a.60 KTAS
b.120 KTAS
c.230 KTAS
d.280 KTAS
C
Bank Angle - 7) x 10 = KTAS
(30 - 7) x 10 = 230 KTAS
What two instruments are considered control instruments? (Attitude + power =performance)
Attitude and manifold pressure
What are the five performance instruments?
Airspeed, turn coordinator, heading, altitude, vertical speed.
What are the three pitch instruments?
Attitude, altimeter, vertical speed indicator.
What are the three bank instruments?
Attitude, turn coordinator, heading indicator
What are the two power instruments?
Tachometer (manifold) and airspeed indicator
What’s it called when you fly without all 6 instruments? Which two are more likely to fail and why?
It’s called a partial panel, usually the attitude and heading indicator because they are run by vacuum and not electrically
ALT and VSI are reliable in unusual attitude recoveries. True or false?
False
