Pneumatics and Conditioning

Question 1

In the case of light single or multi engined aeroplanes fresh, or ventilated air, is usually supplied by -

Answer 1

ram air ducts

Question 2

Heating of the air is achieved by one of the following four methods:

Answer 2

1. Exhaust Gas Heaters
2. Combustion Heaters
3. Electrical Heaters
4. Compressed Air Heating(Boot-Strap System)

Question 3

Which type of heating system:

This simple heating system is used commonly on light aeroplanes. A hot air jacket is mounted around the engine exhaust tailpipe. Air which is routed through the jacket comes into contact with the heated metal surface and is the supplied to the cabin.

Answer 3

Exhaust gas heater

Question 4

Which type of heating system:

Although this type of heater may vary from aeroplane to aeroplane, four common requirements must be met; a supply of fuel to burn, a method to ignite the fuel, air to provide oxygen to burn and ventilating air to carry the heat around the cabin.

Answer 4

Combustion heater

Question 5

Which type of heating system:

This system comprises a series of high-resistant wire coils mounted in an air supply duct which, when fed with an electric current, becomes hot.

Answer 5

Electrical Heater

Question 6

Which type of heating system:

This the most common method of providing heat in modern large jet transport aeroplanes and comprises three parts: a compressor, and a turbine which are linked together and a heat exchanger.

Answer 6

Compressed air heating( boot-strap system)

Question 7

The most common heating system in modern large jet transport aeroplanes?

Answer 7

Compressed air heating(boot-strap system)

Question 8

The components involved in a boot-strap system?

Answer 8

A turbine, compressor(which are linked) and a heat exchanger.

Question 9

Bootstrap system:

Compressed air from the turbine can provide far more heat than is required and some cooling is necessary, hence the need for -

Answer 9

a heat exchanger to cool the air.

Question 10

ACU’s, or air conditioning packs, is provided in an aeroplane in order to maintain a comfortable environment in terms of -

Answer 10

air quantity, temperature and humidity.

Question 11

The most common system an ACU use is?

Answer 11

the Turbo-Compressor Bootstrap System

Question 12

The Turbo-Compressor Bootstrap System use?

Answer 12

bleed air from the low pressure compressor of one of the engines

Question 13

The Turbo-Compressor Bootstrap System(air cycle machine):

Bleed air from the low pressure section of the compressor of one of the aeroplanes engines is routed through a -

The bleed air then flows through a pressure regulator, the purpose of which -

From here the bleed air passes through a mass flow controller, which -

The bleed air then, before passing to the system’s compressor(which is linked by a common shaft to a turbine) enters the primary heat exchanger where it is -

The compressor then boosts the pressure and heats the air before passing it through the -

And then to the expansion turbine which causes the turbine and the compressor to rotate. As it does so the air -

Answer 13

non-return valve to a shut off valve which can be used to shut the system down

is to protect the system from excess pressure caused by high rpm

ensures that a constant mass of air is supplied irrespective of engine RPM

cooled by ram air, or during ground operations or slow flight, by cooling fans.

secondary heat exchanger where it is cooled by ram air

expands resulting in a drop in both pressure and temperature.

Question 14

On a modern large pressurized transport aircraft, the maximum cabin differential pressure is approximately:

Answer 14

7 - 9 psi

Question 15

In large modern aircraft, in the air conditioning system, reduction of air temperature and pressure is achieved by:

Answer 15

The heat exchangers

Question 16

In an aircraft air conditioning system the air cannot be treated for:

Answer 16

Humidity