Flight Instruments

Question 1

Pitot Static System has 3 instruments =

Answer 1

1) Airspeed indicator
2) Altimeter
3) Vertical Speed indicator

Question 2

What does the pitot tube measure?

Answer 2

Dynamic Pressure (the speed that air enters the tube)
*ONLY talks to the airspeed indicator

Question 3

Static Port in the pitot static system does what?

Answer 3

allows pressure in the pitot static system to equalize with outside atmosphere.
–Measures static outside air

Question 4

Airspeed Indicator

Answer 4

uses both pitot & static sources.
–determines pressure outside and then takes speed at which it is moving through the pitot to determine airspeeding

Question 5

IAS =

Answer 5

Indicated Airspeed
–uncorrected airspeed read from the indicator.
–This is what we actually reference when we fly.

Question 6

CAS =

Answer 6

Calibrated Airspeed
–IAS when corrected for instrument & install error in pitot static pressure system

Question 7

TAS =

Answer 7

True Airspeed
–Calibrated airspeed then corrected with density & temperature.

Question 8

EAS

Answer 8

Equivalent Airspeed
–Calibrated airspeed corrected for compressibility factor 250knots & above

Question 9

Pitot blockage =

Answer 9

ASI will “act like altimeter”
increase in a climb & decrease in a descent.
–will not affect vertical airspeed or altimeter

Question 10

Static blockage =

Answer 10

ASI will “act opposite of altimeter”
decrease in a climb & increase in a descent.
*Altimeter will freeze & airspeed will read zero.

Question 11

Fixing a blockage

Answer 11

1) focus on flying
2) determine cause
a) pitot blocked = try the pitot heat
OR switch to alternate pitot
b) static blockage = switch altnerate static source.
Emergency –> can break face ops VSI which will allow to read the static pressure in the plane.

Question 12

Airspeed indicator errors
1) Position errors

Answer 12

Higher angles of attack = relative air is not head on = seems slower than it is.
Use airspeed correction chart in POH to compensate.

Question 13

Airspeed indicator errors
2) Density error

Answer 13

ASI is calibrated to standard atmospheric conditions @ sea level.
To correct = add 2% of your airspeed / 1,000ft altitude.

Question 14

Vertical speed indicator

Answer 14

measures rate of climb/descend.
100s ft/min

Question 15

Altimeter errors
–blocks of pitot tube
–changes in temp
–changes in pressure

Answer 15

1) If static port were partially blocked = under read.
2) Statis port completely blocked = freeze.
3) Flying from warm to cold = being bold (it will over-read)
4) High pressure to relatively low pressure = over-read
high to low –> look out below!

Question 16

Altimeter errors
–Mechanical
–Hysterisis
–Reversal
–Mountain Effect

Answer 16

1) Mechanical - misalignment or slip in gears/links
2) Hysterisis = Lag in instruments due to elastic properties of materials used in aneroids
3) Reversal = during abrupt or rapid attitude changes.
4) Mountain effect = decrease pressure due to air flowing through mountains. Due to downdrafts.

Question 17

Altimeter encoding

Answer 17

relays altitude info to the transponder through altitude encoder. = ATC can see your position and altitude via the transponder.
Only works when switched to ALT - done prior to take off on every flight.

Question 18

Indicated Altitude

Answer 18

The altitude read off of the altimeter

Question 19

Pressure Altitude

Answer 19

altitude displayed on the altimeter when subscale is set to standard atmospheric conditions (29.92”hg)

Question 20

Density Altitude

Answer 20

Pressure altitude corrected for temperature “the altitude the plane thinks it is”

Question 21

True Altitude

Answer 21

Exact height above mean sea level (MSL)

Question 22

Absolute Altitude

Answer 22

Exact height over the surface of the earth

Question 23

Magnetic Variation

Answer 23

Angle between the true meridian & magnetic meridian

Question 24

Magnetic Dip

Answer 24

Tendency of the compass to align itself with the earth magnetic lines

Question 25

Magnetic compass error with turning (north & south)

Answer 25

Turn North = Lags.
–turns in the opposite direction
Turn South = Leads.
–turns extra
**North lags & South leads

ONLY trust magnetic compass in straight & level, unaccelerated flight

Question 26

Magnetic compass error with acceleration/deceleration

Answer 26

When heading East/West
-Accelerating = compass reads more north.
-Deceleration = compass reads more south.
**ANDS = acceleration north, deceleration south

ONLY trust magnetic compass in straight & level, unaccelerated flight

Question 27

What instruments use Gyroscopes

Answer 27

Attitude indicator
Heading indicator
Turn coordinator

Question 28

which Gyroscopes are powered by an aircraft vacuum system verse electronically?

Answer 28

Airplanes vacuum system =
Attitude & heading indicators
Electronically = Turn coordinator

Question 29

Heading Indicator

Answer 29

must be re-adjusted every 15mins.
unusual attitude may result in the gyro tumbling = erratic indications - just wait for it to settle.

Question 30

Attitude indicator

Answer 30

artificial horizon
provides indication of pitch & bank.

Question 31

Attitude indicator ERRORS

Answer 31

1) Acceleration = can falsely indicate nose up
2) Deceleration = falsely indicate nose down

Question 32

Turn Coordinator

Answer 32

electrically powered gyro.
info on roll, yaw & rate of turn
–rate of turn NOT amount of bank
Ball = if turn is coordinated or not.

Question 33

Skid =

Answer 33

Too much rudder or not enough aileron.
No practical value & can lead to spins.

Question 34

Slip =

Answer 34

Not enough rudder or too much aileron.
Slips are performed for crosswind landing & to shed excess altitude without gaining airspeed.

Question 35

Turn bank indicator

Answer 35

also electronically powered
–gives turn & yaw info - where as the turn coordinator also detects roll.

Question 36

Flight instruments
1) Control
2) Performance

Answer 36

Control =
Attitude Indicator
Tachometer/Manifold Pressure

Performance =
ASI
VSI
Altimeter
Heading indicator
Turn coordinator

Question 37

Selective Radial Scan

Answer 37

The attitude indicator is always the center of your scan.
from there radiate to other instruments depending on the task.

Question 38

Scanning - what 3 questions should you always ask yourself?

Answer 38

1) What info do I need?
2) Which instruments give me that info?
3) Is the info reliable?