Pneumatics

Question 1

T/F: The Pneumatics system provides air for airstair door seal pressurization.

Answer 1

TRUE

Question 2

T/F: The Pneumatics Electronic Control Unit (PECU) uses left and right digital channels for control with no associated back up channels.

Answer 2

FALSE, also has analog channels for back up

Question 3

Prior to engine start, what source provides bleed air for the pneumatic system?

Answer 3

APU

although ground air can also be used

Question 4

When BLEED 1 or BLEED 2 switches are selected OFF, what is the result in the associated bleed air system?

Answer 4

ECU closes the HPSOV (High Pressure Shut Off Valve) and NSOV (Nacelle Shut Off Valve)

Question 5

How many engine bleed ports are used to supply bleed air to the pneumatic system?

Answer 5

4
2 High pressure (HP) compressor port (1 each engine)
2 Low pressure (LP) compressor port (1 each engine)

Question 6

T/F: After engine start, bleed air is primarily provided by both engine bleeds and the APU bleed at the same time.

Answer 6

FALSE, if either bleed switch is set ON then APU bleed valve is closed and the BL AIR switchlight goes out

Question 7

T/F: Bleed air is continuously supplied to the deicing system, regardless of flightdeck bleed switch positions.

Answer 7

TRUE

Question 8

T/F: If the DC starter/generator were to fail, the engines can still be started using APU bleed air.

Answer 8

FALSE, bleed air cannot be used to start engines

Question 9

If one or more protective bleed air sensors exceed normal values, what will the ECU system do?

Answer 9

Automatically shut down by closing related NSOV (Nacelle Shut Off Valve)

Question 10

The ECU and _____ are used to determine whether the HP port or the LP port will be used for bleed air.

Answer 10

Power lever position

Question 11

During lower power settings the ECU uses which port(s) for bleed air?

Answer 11

High Pressure (HP) port

Question 12

During higher power settings, the ECU uses which port(s) for bleed air?

Answer 12

Low Pressure (LP) port

Question 13

T/F: Prior to engine start, the bleed control switches should be in the OFF position.

Answer 13

TRUE

Question 14

When the engines are running, the bleed control switches should be set to what position?

Answer 14

BLEED 1 - ON
BLEED 2 - ON
RECIRC - ON

Question 15

How many different positions are there on the bleed flow control selector?

Answer 15

3
MIN
NORM
MAX

Question 16

Which of the following does NOT use bleed air?

Answer what systems DO use bleed air

Answer 16

Pressurization/Air Conditioning
Door Seal
De-ice
Engine Oil cooling ejection system

Question 17

Which of the following is NOT a condition that will cause the pneumatics ECU to automatically shut down the affected bleed system?
(Answer what will shut down the bleed system)

Answer 17

Overtemperature
Overpressure
Bleed Leak

Question 18

The Pneumatic ECU uses _____ to determine whether the HP port or the LP port will be used for bleed air.

Answer 18

Power lever positions

Question 19

Which conditions will cause the ECU to shut down the bleed air system?

Answer 19

Overtemperature
Over pressure
Bleed Leak