021.06 PNEUMATICS - PRESSURISATION AND AIR-CONDITIONING SYSTEMS

Question 1

On modern large pressurised jet transport aeroplanes, the maximum cabin differential pressure is approximately (…) ​psi.

Answer 1

On modern large pressurised jet transport aeroplanes, the maximum cabin differential pressure is approximately (7-9) psi.

Question 2

The bleed air gauge measures air pressure relative to (cabin/atmospheric/total)​ pressure.

Answer 2

The bleed air gauge measures air pressure relative to (atmospheric) pressure.

Question 3

The excess cabin altitude alerting system must operate to warn the crew at (…) ​ft.

Answer 3

The excess cabin altitude alerting system must operate to warn the crew at (10 000) ft.

Question 4

Cabin air for modern transport airplanes is usually taken from the (low/high) pressure stage of the (LP/HP) compressor and from the (low/high) pressure stage of the (LP/HP)​ compressor if necessary.

Answer 4

Cabin air for modern transport airplanes is usually taken from the (low) pressure stage of the (HP) compressor and from the (high) pressure stage of the (HP) compressor if necessary.

Question 5

Name the two modes of operation used in most cabin pressurization systems and in which phase of flight it’s used.

Answer 5

Name the two modes of operation used in most cabin pressurization systems and in which phase of flight it’s used.

• isobaric mode → during cruise
• constant pressure differential mode → during climb/descent

Question 6

In a large transport aeroplane the main temperature reduction of the conditioned air is achieved in the (heat exchangers/expansion turbine/evaporator/condenser)​.

Answer 6

In a large transport aeroplane the main temperature reduction of the conditioned air is achieved in the (heat exchangers).

Question 7

In the pneumatic supply system of a modern transport aircraft, the air pressure is regulated. This pressure regulation occurs just before the manifold by the (high pressure bleed air/low pressure bleed air/intermediate pressure check/fan bleed air)​ valve.

Answer 7

In the pneumatic supply system of a modern transport aircraft, the air pressure is regulated. This pressure regulation occurs just before the manifold by the (low pressure bleed air) valve.

Question 8

Consider a piston engined aircraft. Pneumatic air is taken from (ram air/supercharger air/inlet air manifold)​.

Answer 8

Consider a piston engined aircraft. Pneumatic air is taken from (supercharger air).

Question 9

If the maximum certified altitude of an aeroplane is limited by the pressurised cabin, this limitation is due to the maximum (positive/negative)​ cabin differential pressure at maximum cabin altitude.

Answer 9

If the maximum certified altitude of an aeroplane is limited by the pressurised cabin, this limitation is due to the maximum (positive) cabin differential pressure at maximum cabin altitude.

Question 10

Under normal conditions (EASA CS-25) the cabin pressure altitude of a transport aeroplane is not allowed to exceed (…)​ ft.

Answer 10

Under normal conditions (EASA CS-25) the cabin pressure altitude of a transport aeroplane is not allowed to exceed (8000) ft.