Chapter 5.5 - Pressure, Temperature and Density

Question 1

What are the main elements to Air Density?

Answer 1

• Temperature.

- Pressure.

Question 2

What does ISA stand for?

Answer 2

International Standard Atmosphere.

Question 3

A decrease in pressure causes an (increase/decrease) to density?

Answer 3

Decrease.

Question 4

A decrease in temperature causes an (increase/decrease) in density?

Answer 4

Increase.

Question 5

Density (increases/decreases) with Height?

Answer 5

Decreases.

Question 6

Which rate of decrease is higher with Height (Temperature/Pressure)?

Answer 6

Pressure.

Question 7

What is the ISA MSL Pressure?

Answer 7

1013 hPa.

Question 8

What is the ISA MSL Temperature?

Answer 8

+15°C.

Question 9

What is the ISA Pressure Lapse Rate (2)?

Answer 9

• 30 feet is 1 hPa.

- 1000 feet is 30 hPa.

Question 10

What is the ISA Temperature Lapse Rate?

Answer 10

-2°C for every 1000 feet.

Question 11

What does PH stand for?

Answer 11

Pressure Height.

Question 12

Define PH?

Answer 12

The Height above sea level in the ISA.

Question 13

How does a Pilot find the Pressure Height using the Altimeter?

Answer 13

By setting 1013 hPa in the pressure-setting datum.

Question 14

True or False. If the pressure is higher than 1013 hPa, the calculation is to increase the difference?

Answer 14

False. Decrease.

Question 15

True or False. If the pressure is lower than 1013 hPa, the calculation is to increase the difference?

Answer 15

True.

Question 16

If an Aircraft is at 3000 feet with the pressure-setting datum set at 1003 hPa. What would be the Pressure Height?

Answer 16

3300 feet.

Question 17

If an Aircraft is at 3000 feet with the pressure-setting datum set at 1023 hPa. What would be the Pressure Height?

Answer 17

2700 feet.

Question 18

How can the Pressure Height be calculated without the use of an Altimeter (2)?

Answer 18

• QNH.

- Altitude/Elevation.

Question 19

How can QNH be obtained (2)?

Answer 19

• Aerodrome Forecast (TAF).

- Area Forecast (ARFOR).

Question 20

How can a Pilot find Temperature in the Cockpit?

Answer 20

Outside Air Temperature gauge (OAT).

Question 21

How can a Pilot find Temperature outside the Cockpit (2)?

Answer 21

• Aerodrome Forecast (TAF).

- Area Forecast (ARFOR).

Question 22

How do you convert °C to °F (3)?

Answer 22

• Divide °C by 5.
• Multiple this by 9.
• Add 32.

Question 23

How do you convert °F to °C (3)?

Answer 23

• Subtract 32 from °F.
• Multiple this by 5.
• Divide this by 9.

Question 24

What does DH stand for?

Answer 24

Density Height.

Question 25

Define DH?

Answer 25

The Pressure Height corrected for any difference between actual and ISA Temperature at that particular Pressure Height.

Question 26

When the atmosphere is warmer than the ISA, the Density Height will be (greater/lower) than the Pressure Height?

Answer 26

Greater.

Question 27

When the atmosphere is cooler than the ISA, the Density Height will be (greater/lower) than the Pressure Height?

Answer 27

Lower.

Question 28

Name three types of Atmospheric Conditions of Temperature, Pressure and Wind?

Answer 28

• Ambient Conditions.
• Forecast Conditions.
• Declared Conditions.

Question 29

What is meant by Ambient Condition?

Answer 29

The atmospheric conditions of Temperature, Pressure and Wind that apply to the air surrounding the Aircraft.

Question 30

What is meant by Declared Condition?

Answer 30

The atmospheric conditions of Temperature, Pressure and Wind declared by authorities.

Question 31

When must a Pilot convert to Density Height with regards to ISA Pressure?

Answer 31

+/- 8 hPa (1005 and 1021 hPa).

Question 32

When must a Pilot convert to Density Height with regards to ISA Temperature?

Answer 32

+/- 2°C.

Question 33

True of False. Density Height should be used to calculate Climb/Descent Heights?

Answer 33

False. Pressure Height should always be used.

Question 34

If QNH is between 1005 and 1020P hPa. What should be used as Height?

Answer 34

Elevation, Altitude or Pressure Height.

Question 35

If QNH is above 1020 hPa. What should be done to the Pressure Height?

Answer 35

Pressure Height = Elevation/Altitude – 500 feet.

Question 36

If QNH is below 1005 hPa. What should be done to the Pressure Height?

Answer 36

Pressure Height = Elevation/Altitude + 500 feet.