Pneumatic Systems

Question 1

The modern _ engine is effectively a very effective gas generator and this has led to the use of engine bleed air for a number of aircraft systems, either for reasons of heating, provision of motive power or as a source of air for cabin conditioning and pressurization systems.

Answer 1

turbofan

Question 2

extracted from the engine compressor and after cooling and pressure reduction/regulation, it is used for a variety of functions

Answer 2

bleed air

Question 3

In the engine, _ bleed air is used as the motive power – sometimes called ‘muscle power’ – for many of the valves associated with the bleed air extraction function.

Answer 3

high pressure

Question 4

_ bleed air is used to start the engine in many cases, either using air from a ground power unit, APU or cross-bled from another engine on the aircraft which is already running.

Answer 4

Medium-pressure

Question 5

used to provide anti-ice protection by heating the engine intake cowling and it is also used as the motive power for the engine thrust reversers

Answer 5

bleed air

Question 6

used as additional means of providing aircraft hydraulic power in some aircraft

Answer 6

air driven pumps (ADPs)

Question 7

have been used since the earliest days of flight using pneumatic, capsule based mechanical flight instruments

Answer 7

pitot systems

Question 8

the use of medium pressure air to perform certain functions within the aircraft

Answer 8

pneumatic power

Question 9

the ratio of bypass air to engine core air

Answer 9

bypass ratio

Question 10

a small turbojet engine, designed more from the viewpoint of an energy and power generator than a thrust provider which is the case for the main engines

Answer 10

auxiliary power unit (APU)

Question 11

primarily designed to provide electrical and pneumatic power by a shaft driven generator and compressor

Answer 11

auxiliary power unit (APU)

Question 12

able to provide an independent source of electrical power and compressed air while the aircraft is on the ground, although it can be used as a backup provider of power while airborne

Answer 12

auxiliary power unit (APU)

Question 13

Air conditioning ATA chapter

Answer 13

21

Question 14

Cargo compartment heating ATA chapter

Answer 14

21

Question 15

Wing and engine anti-icing ATA chapter

Answer 15

30

Question 16

Engine start ATA chapter

Answer 16

80

Question 17

Thrust reverser ATA chapter

Answer 17

78

Question 18

Hydraulic reservoir pressurization ATA chapter

Answer 18

29

Question 19

Rain repellent nozzles – aircraft windscreen ATA chapter

Answer 19

30

Question 20

Water tank pressurization and toilet waste ATA chapter

Answer 20

38

Question 21

Air driven hydraulic pump (ADP) ATA chapter

Answer 21

29

Question 22

At lower power settings, air is extracted from the _ pressure section of the compressor.

Answer 22

high

Question 23

At higher power settings, the air is extracted from the _ compressor stage.

Answer 23

intermediate

Question 24

A pneumatically controlled _ regulates the pressure of air in the engine manifold system to around 100 psi and also controls the supply of bleed air from the engine.

Answer 24

High Pressure Shut-Off Valve (HP SOV)

Question 25

It is common philosophy in civil aircraft bleed air systems, in common with other major aircraft subsystems, to display system synoptic and status data to the flight crew on the _ displays.

Answer 25

Electronic Flight Instrument System (EFIS)

Question 26

In the case of Boeing aircraft, the synoptics are shown on the _ display whereas for Airbus aircraft, the _ displays are used.

Answer 26

Engine Indication and Crew Alerting System (EICAS); Electronic Crew Alerting and Monitoring (ECAM)

Question 27

the largest subsystem user of bleed air

Answer 27

air system

Question 28

The availability of high pressure air throughout the bleed air system lends itself readily to the provision of _ to crank the engine during the engine start cycle.

Answer 28

motive power

Question 29

activated to supply bleed air to the engine starter

Answer 29

start valve

Question 30

commonly used to pressurize the aircraft hydraulic reservoirs

Answer 30

pneumatic pressure

Question 31

Some Boeing aircraft – usually the wide bodies – use pneumatic power or air-driven hydraulic pumps to augment the normal _ and _ for certain phases of flight.

Answer 31

Engine Driven Pumps (EDPs); AC Motor Driven Pumps (ACMPs)

Question 32

an instrumentation system used to sense air data parameters of the air through which the aircraft is flying

Answer 32

pitot static system

Question 33

the sum of local static pressure and the pressure caused by the forward flight of the aircraft

Answer 33

total pressure (Pt)

Question 34

the local pressure surrounding the aircraft and varies with altitude

Answer 34

static pressure (Ps)

Question 35

The forward speed of the aircraft is calculated by taking the difference between _ and _.

Answer 35

Pt; Ps

Question 36

situated such that it faces in the direction of the airflow, thereby being able to sense the variation in aircraft speed

Answer 36

pitot probe

Question 37

located perpendicular to the airflow and so is able to sense the static pressure surrounding the aircraft

Answer 37

static probe

Question 38

_ may be calculated from the deflection in the left hand instrument where Pt and Ps are differentially sensed.

Answer 38

Airspeed

Question 39

_ may be calculated by the deflection of the static capsule in the center instrument.

Answer 39

Altitude

Question 40

_ may be deduced in the right hand instrument where the capsule deflection is proportional to the rate of change of static pressure with reference to a case pressure, Pe.

Answer 40

Vertical speed

Question 41

Pitot-static sensing plates are able to derive data relating to:

Answer 41

* Pitot pressure * Static pressure * Angle of attack * Angle of sideslip