ATA 36 Pneumatic

Question 1

How many sources of pneumatic air do we have?

Answer 1

4: Engine 1 bleed air
Engine 2 bleed air
APU Bleed air system
Pneumatic ground air connection

Question 2

How is IASC’s primary system control achieved?

Answer 2

Through closed loop electrical control of these valves:
HPSOV
PRSOV
FAMV

Question 3

What are the engine compressor stage that can supply pneumatic air?

Answer 3

4th and 10th stage. 4th when RPM is up and 10th when RPM is down

Question 4

List the components in the pneumatic system that the IASC controls.

Answer 4

The HPSOV(High Pressure Shutoff Valve), with inputs from the Intermediate Manifold Pressure sensor(PI sensor).

Question 5

What is the position of the following valves when an engine is shut down?
HPSOV __________
PRSOV __________
FAMV_____________

Answer 5

HPSOV: Spring Loaded Closed
PRSOV: Closed(Solenoid is disabled)
FAMV: Closed?

Question 6

List the four sensors that input to the IASC for pneumatic system control.

Answer 6

Intermediate Manifold Pressure Sensor
Manifold Pressure Sensor(PM1)
Manifold Temperature Sensor
Manifold Pressure(PM2-Duct Pressure Transducer)

Question 7

Describe operation of the isolation valve when the control switch is in the
following positions
Closed
Open
Auto

Answer 7

Closed: Isolates left and right pneumatic manifold
Open: Connects left and right pneumatic systems
Auto: Valve opens automatically if an engine or pack bleed switch is in the OFF position.

Question 8

What is the purpose of the bleed air duct vent valve? (DVV)

Answer 8

Prevents bleed air over pressure shutdown during a “no-bleeds take off”

Question 9

List the conditions that will close the PRSOV

Answer 9

Engine not running
Engine fire switch pulled
Dual bleed
IASC not healthy
Engine bleed trip overtemperature conditions; (490F (254C)) overtemperature for more than 20 seconds
Engine bleed trip overpressure conditions; 170psi for 5 seconds from the PI sensor.

Question 10

Describe how pneumatic temperature is controlled.

Answer 10

The manifold temperature sensor gives inputs to IASC, if temperature in the manifold is excessive the IASC will close the HPSOV and the PRSOV and turn on the amber BLEED light on the air conditioning panel.

Question 11

What happens if pneumatic temperature reaches 440F (227C)?

Answer 11

PRSOV will restrict bleed air flow

Question 12

What are the indications for the pneumatic system? (include any lights)

Answer 12

Dual bleed light, dual duct pressure indicator and isolation valve switch. Refer to P5-10 for all indications and such

Question 13

What does the DUAL BLEED light mean?

Answer 13

It means the APU bleed valve is open and one of these conditions is present:
Number 1 engine bleed switch on
Number 2 engine bleed switch is on and isolation valve is open

Question 14

With an engine at idle speed, what is the source of the bleed air supply?

Answer 14

10th stage

Question 15

Why do some pneumatic ducts have a gold coating?

Answer 15

Protects ducts from hydrocarbon contamination(hydrogen embrittlement)
Reduces heat transfer

Question 16

The FAMV is a butterfly valve that is ___________ to the open position?

Answer 16

Spring loaded

Question 17

What is the APU check valve a part of and where is it located?

Answer 17

It is part of the APU bleed air duct and it is located on the keel beam between the air conditioning compartments.

Question 18

What is the purpose of the dual pressure needles?

Answer 18

To show the pressure in the right and left side of the pneumatic manifold