Flight Instruments

Question 1

What are the 2 principles of a gyroscope?

Answer 1

1. Rigidity in space

2. Precision

Question 2

Which gyroscopic instruments operate on the principle of rigidity in space?

Answer 2

Attitude indicator and heading indicator

Question 3

Which gyroscopic instruments operate on the principle of precession?

Answer 3

Turn indicator

Question 4

What does the attitude indicator display?

Answer 4

• vacuum driven(may be electrical in other GA)

- displays bank and pitch information

Question 5

What does the heading indicator display?

Answer 5

• reflects changes in heading
• vacuum driven
• has to be calibrated with a magnetic compass in order for it to indicate correctly

Question 6

What does the turn indicator display?

Answer 6

• rate of turn

- rate of roll

Question 7

What does the altimeter display?

Answer 7

• shows the height above a given pressure level

- regularly set the altimeter to a station within 100 NM

Question 8

How does the altimeter work?

Answer 8

• wafers expand and contract with changes in atmospheric pressure received from the static port
• mechanical linkage translates the sensed pressure to an altitude indication
• pressure setting is displayed in the “kollsman window” inches of Mercury Hg

Question 9

When flying from high pressure to low pressure areas what should you be concerned about?

Answer 9

• altitude will indicate higher, causing the pilot to fly lower

“High to low, Watch out below!”

• flying from hot to cold areas results in the same error

Question 10

What are the types of altitudes?

Answer 10

Indicated altitude - altitude indicated on the dial when set to local pressure

Pressure altitude - 29.92

Density altitude - pressure alt. Corrected for non standard temperature

True altitude- actual altitude above mean sea level(MSL)

Absolute altitude - height above airport (AGL)

Question 11

What does VSI(vertical speed indicator) display?

Answer 11

• indicates rate of climb in FPM

Question 12

How does the VSI(vertical speed indicator) work?

Answer 12

• a diaphragm is connected directly to the static source
• also receives static pressure via a calibrated leak
• this configuration responds to static pressure change over time
• the diaphragm expands or contracts, and the mechanical linkage moves the needle

Question 13

What does the ASI(airspeed indicator) display?

Answer 13

• measures the difference between (ram) air pressure from the pitot tube and ambient pressure from the static port
• dynamic pressure

Question 14

How does the ASI(airspeed indicator) work?

Answer 14

• diaphragm receives ram pressure from the pitot tube
• area outside the diaphragm is connected to the static port
• mechanical linkage converts expansion and contraction of diaphragm to airspeed on the dial

Question 15

What are the types of speeds?

Answer 15

Indicated airspeed - indicated on the airspeed
Calibrated airspeed - indicated airspeed corrected for errors
True airspeed - actual speed through the air
Mach number - ratio of True airspeed to the speed of sound
Ground speed - actual speed over the ground

Question 16

What happens if there’s a static port blockage?

Answer 16

Airspeed indicator - will indicate correctly at blockage altitude, will indicate lower for higher altitudes and higher for lower (aka reverse sensing)

Altimeter - freeze on the altitude where it was blocked

VSI - zero

Question 17

What should you look out for while using the alternate static source?

Answer 17

Airspeed indicator - indicate a faster speed

Altimeter- indicate higher

VSI - momentarily show a climb

Question 18

What happens when the pitot tube is blocked?

Answer 18

Only instrument affected is the airspeed indicator

• airspeed drops to zero if the air inlet is blocked
• both air inlet and drain hole blocked the airspeed indicator will act like an altimeter

Question 19

Airspeed marking indicators

Answer 19

White arc -flap operating range
Green arc - normal operating range
Yellow arc - caution range
Red line - Vne

Question 20

V- speeds

Answer 20

Va maneuvering speed
Vs stall speed
Vso stall speed landing configuration 
Vfe max flap extended speed
Vno max structural cruise
Vne never exceed speed
Vx best angle of climb
Vy best rate of climb

Question 21

What are the magnetic compass errors and limitations?

Answer 21

Deviation 
Variation 
Magnetic dip
Oscillation 
North/south turn errors (unos)
Acceleration errors (ands)

Question 22

What electronic flight instruments are there?

Answer 22

Attitude heading reference system (AHRS)
Air data computer (ADC)
Flight director
Flight management system (FMS)
Electronic flight instrument systems (EFIS)
Primary flight display (PFD)
Multi function displays (MFD)

Question 23

What does the AHRS do?

Answer 23

Provides accurate reliable altitude and heading data