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Question 1

What is static pressure?

Answer 1

Where the pressure is exerted equally in all directions. (No movement)

Question 2

What is dynamic pressure?

Answer 2

The pressure due to relative movement. Dependent on the speed and density of the air.

Question 3

What is RAS?

Answer 3

Rectified air speed is the IAS corrected for instrument error.

Question 4

What is ground speed?

Answer 4

The speed of the a/c over the ground. TAS corrected for wind.

Question 5

When is ground speed used?

Answer 5

The speed seen on radar.

Question 6

What is airspeed?

Answer 6

The speed at which an a/c moves through the air mass.

Question 7

What is IAS?

Answer 7

Indicated air speed is the airspeed shown on the air speed indicator?

Question 8

What 4 errors can IAS suffer from?

Answer 8

• Instrument faults
• Poor positioning of the pitot head
• Density, height or temperature error
• compressibility error

Question 9

What is the TAS?

Answer 9

The true air speed is the RAS corrected for density error.

Question 10

What is compressibility error?

Answer 10

At speeds in excess of 300knts the air in front of the a/c becomes compressed causing errors in the reading.

Question 11

What is instrument error?

Answer 11

An error in the calibration of the instrument usually in the region of 2knts. Modern a/c have this corrected when testing instruments but some older a/c have a card for the pilot to know how far out it is.

Question 12

What is the Pitot tube?

Answer 12

A tube on the front of the a/c that uses an expanding diaphragm to measure the dynamic pressure. This pressure is then compared to static pressure and shown on the airspeed indicator as IAS.

Question 13

What is speed?

Answer 13

Rate of change of position.

Question 14

What is velocity?

Answer 14

Rate of change of position in a given direction.

Question 15

What is the most accurate representation of the Earth?

Answer 15

A sphere or globe.

Question 16

How is a projection made?

Answer 16

By placing a conical or cylindrical sheet of paper onto an illuminated globe and coping the projection onto a piece of paper. This can then be laid flat but will be distorted.

Question 17

What does conformal mean?

Answer 17

All angles and bearings are accurately represented.

Question 18

What is a meridian?

Answer 18

A straight line along the Earths surface from pole to pole.

Question 19

What is a parallel?

Answer 19

A straight line along the Earths surface that is parallel to the equator. Centres on the nearest poll.

Question 20

What is a graticule?

Answer 20

One square of the ‘mesh’ made up by parallels of latitude and meridians.

Question 21

What is ground velocity?

Answer 21

The track and the ground speed.

Question 22

What is a vector?

Answer 22

A graphical representation of velocity.

Question 23

What is mach numbers?

Answer 23

Mach number is a measurement relative to the speed of sound. At speeds close to and above Mach 1 Mach is used instead of Knots.

Question 24

What is the avg. speed of sound?

Answer 24

• 661 knots at MSL

- 589 knots at 30,000ft

Question 25

What is air velocity?

Answer 25

The heading and the TAS.

Question 26

What is a rumb line?

Answer 26

A line that intersects all meridians at the same angle.

Question 27

What is a great circle?

Answer 27

A circle that wraps around the Earth whose plane cuts directly through the centre of the Earth.

Question 28

What is a small circle?

Answer 28

A circle that wraps around the Earth whose plane does not cut through the centre of the Earth.