Exam quiz Principles of Flight (Balloon) - BPL Gas Balloon Pilot Licence

Question 1

What can solar heating of the lifting gas do to the pressure ceiling of a gas balloon before gas is released?

Accepted Answer

The pressure ceiling decreases

Answer

The pressure ceiling increases

Answer

The lifting gas always cools immediately

Answer

A sudden increase in rate of descent

Question 2

The aerostatic lift corresponds to which force?

Accepted Answer

The weight of the displaced air

Answer

The dynamic force due to airstream across the top of the hull

Answer

The drag due to airstream around the balloon envelope

Answer

The weight of the balloon less ballast

Question 3

In a simplified gas-balloon model, how does ascent below the pressure ceiling differ from ascent above it?

Accepted Answer

Below the pressure ceiling the lifting gas can expand; above it gas is released from the full envelope and lifting capacity decreases

Answer

Below the pressure ceiling the balloon can climb indefinitely without becoming fully inflated

Answer

Above the pressure ceiling the envelope expands indefinitely without releasing gas

Answer

Reaching the pressure ceiling has no effect on gas volume or lifting capacity

Question 4

With regard to gases, which statement is correct?

Accepted Answer

Volume increases with increasing temperature and constant pressure

Answer

Temperature decreases with increasing pressure and constant volume

Answer

Pressure decreases with increasing temperature and constant volume

Answer

Temperature increases with increasing volume and decreasing pressure

Question 5

What temperature is specified for gases under the IUPAC definition of standard temperature and pressure (STP, with a pressure of 100 kPa)?

Accepted Answer

0° C

Answer

15° C

Answer

5° C

Answer

25° C

Question 6

The force resulting from the (positive) difference from load-bearing capacity and weight force, is referred to as:

Accepted Answer

Climb force

Answer

Load force

Answer

Upper force

Answer

Lift force

Question 7

Aerostatic lift, amongst other factors, depends on...

Accepted Answer

Air density

Answer

On the speed

Answer

Balloon mass

Answer

Shape of the envelope

Question 8

How do volume, density and temperature change when a gas is being compressed?

Accepted Answer

Volume decreases, density increases, temperature increases

Answer

Volume decreases, density increases, temperature decreases

Answer

Volume increases, density decreases, temperature decreases

Answer

Volume decreases, density decreases, temperature decreases

Question 9

At which height the load carrying capability of a gas balloon is reduced by approximately 50% compared to MSL?

Accepted Answer

At 6500 m

Answer

At 11000 m

Answer

At 18000 m

Answer

At 1500 m

Question 10

With pressure and temperature given, any gas being heavier or lighter than air depends on what?

Accepted Answer

On the molecule mass of the gas

Answer

On the content of water vapour in the gas

Answer

On the mean kinetic energy of the molecules

Answer

On the number of gas molecules

Question 11

The dynamic lift created by airflow across the top of the envelope of a balloon on the ground is referred to as?

Accepted Answer

False lift

Answer

Upper lift

Answer

Anti-ballast

Answer

Lower lift

Question 12

How does a gas react when released from a pressurized container?

Accepted Answer

The gas cools adiabatically due to expansion

Answer

The gas heats adiabatically due to expansion

Answer

The gas condenses inside the envelope

Answer

The gas cools due to thermal contact with environmental air

Question 13

For a fully inflated gas balloon, what happens to its net lifting capacity when the lifting gas warms and excess gas is released, assuming unchanged envelope volume, ambient pressure and ambient temperature?

Accepted Answer

Load-bearing capability increases

Answer

Climb force decreases

Answer

Weight force increases

Answer

Lift force decreases

Question 14

According ISA, what is the density of air at MSL?

Accepted Answer

1.225 kg/m3

Answer

1.225 g/m3

Answer

1225 kg/m3

Answer

12.25 kg/m3

Question 15

What statement is correct with regard to the density of a gas?

Accepted Answer

The density decreases with increasing temperature and constant pressure

Answer

The density increases with increasing temperature and constant volume

Answer

The density decreases with increasing temperature and constant volume

Answer

The density decreases with decreasing volume and constant temperature

Question 16

Doubling the pressure of a dry gas at constant temperature results in a change of the volume to:

Accepted Answer

Half the previous value

Answer

Double the previous value

Answer

Four times the previous value

Answer

A quarter of the previous value

Question 17

A fully inflated gas balloon is in level equilibrium. Its mass is reduced by 1% and it rises to a new equilibrium while releasing gas. In a simplified model where a 1% pressure decrease corresponds to 80 m of height, what is the approximate change in equilibrium altitude?

Accepted Answer

Equilibrium altitude increases by 80 m

Answer

Equilibrium altitude increases by 800 m

Answer

Equilibrium altitude decreases by 800 m

Answer

Equilibrium altitude decreases by 80 m

Question 18

For a fully inflated gas balloon at constant ambient pressure and envelope volume, assume both the lifting gas and outside air are initially at 250 K. If both warm by 1 K while excess lifting gas is released, what is the approximate change in net lifting capacity?

Accepted Answer

The load capability decreases by 0.4% per K temperature change

Answer

The load capability decreases by 4% per K temperature change

Answer

The load capability increases by 4% per K temperature change

Answer

The load capability increases by 0.4% per K temperature change

Question 19

In a given height, a given amount of ballast is unloaded from a gas balloon. How is the increase in height at 5500 m different from the increase in height at MSL by unloading the same amount of ballast?

Accepted Answer

At 5500 m the increase in height is twice as high

Answer

At 5500 m the increase in height is three times as high

Answer

At both heights the same increase in height is observed

Answer

At 5500 m the increase in height is four times as high

Question 20

The vertical extent of air with pressure changing by 1% with 80 m difference in height is referred to as ...

Accepted Answer

Homogeneous

Answer

Unstable

Answer

Stable

Answer

Inhomogeneous

Question 21

What is the relationship between pressure and volume of a dry gas at constant temperature?

Accepted Answer

The volume is inversely proportional to pressure

Answer

The volume increases by a factor of 4 with double pressure

Answer

The ratio between pressure and volume is constant

Answer

The volume increases proportional with pressure

Question 22

At equilibrium the inner overpressure of a free balloon is highest at:

Accepted Answer

The upper pole

Answer

At the equator

Answer

At the center of the hull

Answer

At the lower opening

Question 23

For a gas balloon below its pressure ceiling, assume ideal-gas behaviour, constant pressure and a fixed amount of lifting gas initially at 250 K. What is the approximate volume change when the gas temperature increases by 1 K?

Accepted Answer

Volume increase by 0.4%

Answer

Volume decrease by 0.4%

Answer

Volume increase by 4%

Answer

Volume decrease by 4%

Question 24

The ratio between air pressures at different heights is referred to as:

Accepted Answer

Height number

Answer

Height value

Answer

Pressure number

Answer

Height ratio

Question 25

A fully inflated gas balloon rises to a new equilibrium after ballast is dropped. Assume lifting capacity is proportional to ambient pressure and a 1% pressure decrease corresponds to 80 m of height. Which approximate result is correct?

Accepted Answer

It increases by 80 m when total mass is reduced by 1%

Answer

It increases by 8 m when total mass is reduced by 10%

Answer

It decreases by 8 m when total mass is reduced by 10%

Answer

It decreases by 80 m when total mass is reduced by 1%

Question 26

What statement is correct with regard to change in temperature?

Accepted Answer

During descent, the carrying gas warms adiabatically

Answer

During climb, the carrying gas warms due to thermal exchange with environmental air

Answer

During descent, the carrying gas warms due to thermal exchange with environmental air

Answer

During climb, the carrying gas warms adiabatically

Exam simulation Principles of Flight (Balloon) - BPL Gas Balloon Pilot Licence

Exam simulation EASA BPL Gas Balloon Theory in English Principles of Flight (Balloon) 120 questions on 120 minutes

Exam simulation Principles of Flight (Balloon) - BPL Gas Balloon Pilot Licence

Exam simulation EASA BPL Gas Balloon Theory in English Principles of Flight (Balloon) 120 questions on 120 minutes

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