Flight Instruments Flashcards

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1
Q

Explain the different in pressure between static air and air in motion

A

Air in motion exerts dynamic pressure. Static air exerts static pressure all around

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2
Q

What is the purpose of the pitot tube?

A

To measure ram air pressure (dynamic pressure due to forward motion)

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3
Q

What is the purpose of the static port?

A

To measure static or ambient air pressure through ports placed parallel to the relative airflow

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4
Q

How does the static port affect air pressure?

A

It allows air pressure inside the instruments to become equal with the air pressure outside the cases

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5
Q

What should be done in an emergency for an aircraft not equipped with an alternate static source?

A

Break the face glass of the VSI to provide static pressure from the cabin

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6
Q

Describe the set up of the pilot static system

A
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7
Q

Describe the VSI, ASI, and ALT readings when a pitot or static blockage occurs

A
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8
Q

When is pitot heat used?

A

Anytime ice is suspected in the pitot tube. The ice could create erroneous or no readings on the ASI

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9
Q

An aircraft is not in motion. What is the ASI reading?

A

0

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10
Q

In what unit does the ASI display airspeed?

A

knots or miles per hour

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11
Q

How does the ASI measure airspeed?

A

By measuring the difference between dynamic and static pressure. The larger the difference, the higher the reading

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12
Q

Describe the different ASI markings

A

Red line: VNE (never exceed)

Yellow arc: VNO - VNE (caution range)

Green arc: VS1 - VNO (normal operating range)

White arc: VSO - VFE (flap operating range)

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13
Q

List the causes of ASI errors

A

Position error (angle of attack)

Compressibility error (250kts+)

Density error (temperature, pressure)

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14
Q

What kind of instrument is the VSI? What does it display?

A

A trend instrument that displays the rate of climb or descent

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15
Q

Describe the set up of an aneroid barometer

A
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16
Q

List three things to do doing a VSI serviceability check

A

Check if VSI reads 0 on the ground

Check static port clean

Check alternate static source (VSI should jump)

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17
Q

What is the standard international atmosphere?

A
  • Perfectly dry gas
  • 15°C
  • Surface pressure of 29.92” Hg
  • Lapse rate of 2°C/1000’ within troposphere
  • Weight of column of air is 14.7lbs
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18
Q

Describe the purpose of the altimeter. When does it work properly?

A

Indicates correct altitude above sea level when conditions of temperature and pressure are those of the ISA

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19
Q

Describe what happens to the altimeter readins when pressure varies along the route

A
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20
Q

What happens to the altimeter reading if temperature is standard? Why is this dangerous?

A

Error in reading. This is dangerous because extreme variations in temperature may cause a 2500’ difference in indicated altitude

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21
Q

Describe the affect of nonstandard temperature and pressure on actual and indicated altitude

A
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22
Q

Where does a mountain wave form?

A

Where wind faster than 50 knots blows within 30 degrees of the perpendicular to the main axis of the mountain range

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23
Q

How far can the effect of a mountain wave extend?

A

As far as 100 miles downward of the moutains to altitudes many times higher than the mountain elevation

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24
Q

Describe the pre flight altimeter serviceability check

A

Must read within +/- 50’ of the field elevation

Static source checked clean and clear

Alternative static source checked (ALT should jump)

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25
Q

How often should the pilot static system and altimeter be calibrated for IFR flight?

A

Every 24 months

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26
Q

What should you do if you have no altimeter setting available at the aerodrome?

A

Adjust the altimeter setting knob to the known field elevation until the altimeter indicates that same elevation

27
Q

What is an advantage of the encoding altimeter?

A

Aircraft can be 3D identified by ATC

28
Q

Define the magnetic meridian and magnetic variation

A

Magnetic meridian - magnetic line in which in the compass needle lies in

Magnetic variation - angle between the true meridian and magnetic meridian

29
Q

List sources of compass error

A

Magnetic dip, deviation, turning error, acceleration error

30
Q

What is a cause of compass deviation? How can deviation from the magnetic meridian be determined?

A

The compass can be influenced by the aircraft’s metal frame, the engine, or electrical devices. Deviation can be determined by swinging the compass

31
Q

Describe what a compass correction card looks like

A
32
Q

Describe when an acceleration error occurs. What happens to the compass readings?

A
33
Q

Describe what happens during turning errors

A

On turns from north, northerly turning error causes the compass to lag
On turns from south, northerly turning error causes compass to lead

34
Q

Describe how a gyroscope is powered using the vacuum system

A
35
Q

What speed do gyros spin at?

A

12-20 thousand RPM

36
Q

Describe the principle of operation of the Heading Indicator

A

Gyro is gimbaled with one degree of freedom (yaw)

The spin axis is horizontal

The plane of rotation is vertical

Gyro remain fixed in space while the a/c rotates around it

A compass card is fixed to the gyro

37
Q

List some limits of the heading indicator

A

55 degrees pitch and bank in older types

85 degrees pitch and bank in newer types

If limits are exceeded, gyro may topple (spins, spirals, unusual attitudes)

38
Q

List some errors of the heading indicator

A

Precession due to friction

Apparent drift due to the earth’s rotation.

39
Q

How can you fix apparent drift due to earth’s rotation on the HI?

A

set the HI to the magnetic compass every 10-15 minutes

40
Q

List the serviceability checks for the HI

A

Check the HI indicates properly doing left and right turns while taxiing

Allow the gyro to reach normal operating speed ( 5 minutes for vacuum, and 3 min for electric)

Check suction during the run-up

Set the HI prior to taxi and take-off.

41
Q

What is the purpose of the attitude indication?

A

Provides pilot with articial horizon as means of reference when natural horizon cannot be seen

42
Q

Describe the principle of operation of the AI

A

Works on principle of rigidity in space

Aircraft moves about the fixed gyro

Horizon bar is connected to the gyro

Miniature aircraft is connected to the instrument case, which is attached to the aircraft

43
Q

List the limit of the AI. What happens when limits are exceeded?

A

Older types - 55 degrees pitch and bank

Newer types - 85 degrees pitch and bank

Aerobatic types - 360 degrees pitch and bank

If limits are exceeded, gyro may topple.

44
Q

List the serviceability checks for the AI

A

Allow the gyro 5 minutes to spool up if vacuum, or 3 minutes if electric

Check the suction gauge within limits during run-up

45
Q

What does the turn coordinator indicate?

A

The aircraft yaw rate (TBI) or both yaw and roll rate (TC)

46
Q

What is the ball in a turn coordinator used for?

A

The ball shows the quality of the turn and is used for yaw control

47
Q

How does the turn coordinator use the principle of gyroscopic precesion?

A

When the aircraft turns (yaws) precession causes the gyro to tilt slightly. The amount of needle deflection is proportional to yaw rate

48
Q

What is the difference between a slip and skid?

A

In a slip there is not enough rate of turn for the amount of bank

In a skid, the rate of turn is too high for the amount of bank

49
Q

Describe what the turn coordinator would show during a slip and skip

A
50
Q

What is a limit of the turn coordinator?

A

Not accurate beyong a Rate 1 turn

51
Q

Describe two errors turn coordinators are prone to. How is one of these errors fixed?

A

Needle oscillates from side to side in turbulent air

Fix: Average out the oscillations when interpreting the indication

Does not indicate bank attitude when the ball is not centered.

52
Q

Describe the serviceability checks for turn coordinators

A

Check deflections in left and right turns while taxiing

Allow gyro to attain normal operating speed (3 minutes if electric)

Can calibrate in flight by comparing indication with actual rate of turn

53
Q

Describe the direct and indirect information provided by different aircraft instruments

A
54
Q

Describe the relationship between control and performance instruments

A
55
Q

Describe the relationship between instruments during a straight and level flight

A
56
Q

Describe the relationship between instruments during a straight climb

A
57
Q

Describe the relationship between instruments when approaching desired altitude

A
58
Q

Describe the relationship between instruments when level and approaching desired altitude

A
59
Q

Describe the opposite turning illusion

A

Fluid in the ear slowly catches up with the rotating canal whereby the hairs stand straight up again and indicate no movement. If the rotation / turn now slows, you will register a movement in the opposite direction

60
Q

Describe the coriolis illusion

A

Associated with a sudden tilting (forward or backwards) of the pilot’s head while the aircraft is turning. This can produce an overpowering sensation that the aircraft is rolling, pitching, and yawing all at the same time. This illusion can make the pilot quickly become disoriented and lose control of the aircraft

61
Q

Describe the leans illusion

A

A pilot may not notice a slow turn or a bank maintained long enough. After the pilot levels the wings, there is an illusion that the plane is banking too much. Thus, the pilot leans in the direction of the original turn in an attempt to allow straight and level flight

62
Q

Describe somatogravic illusions

A

An optical illusion that can result in spatial disorientation. A rapid acceleration during takeoff can create an illusion of being in a nose-up attitude. The disoriented pilot will push the aircraft into a nose-low, or dive, attitude. A rapid deceleration by quick reduction of the throttles can have the opposite effect, with the pilot pulling the aircraft into a nose-up, or stall, attitude

63
Q

Describe how raising your during flight head can affect acceleration

A
64
Q
A