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United 737 > Bleed Air > Flashcards

Flashcards in Bleed Air Deck (28):
1

Which systems use bleed air?

Air conditioning/pressurization
Wing and Eng thermal anti-icing
Engine starting
hydraulic reservoirs pressurization
water tank pressurization
If installed, apsirated TAT probe

2

The ON position for both the APU and either engine bleed air switch will open only when any of them is _______.

operating.

3

How does the auto position of the ISOLATION VALVE work?

closes the isolation valve if both bleed engine air switches are ON and both air PACKS are either AUTO or HIGH. AUTO allows for opening of isolation valve if either bleed air or A/C pack is positioned off.

4

BLEED TRIP OFF

illuminates if excessive bleed air temp or pressure or both is sensed. If this happens the bleed air valve automatically closes.

5

What does the wing body OVHT TEST switch do?

test overheat detection circuits. The test should illuminate both WING-BODY OVERHEAT lights.

6

What does DUAL BLEED mean?

advises crew when both engine and APU are both supplying air to pneumatic manifold.

7

What causes Left WING-BODY OVERHEAT light?

Overheat from a duct leak in:
Left engine strut
Left inboard wing leading edge
Left air conditioning bay
Keel beam
APU bleed air duct

8

What causes Right WING-BODY OVERHEAT light?

Overheat from a duct leak in:
Right engine strut
Right inboard wing leading edge
Right air conditioning bay

9

Bleed air is supplied from which stages?

5th & 9th (9th is available should it be needed by demand)

10

Which valve makes available 9th stage bleed air?

High stage valve.

11

Where is the external air cart hook up?

underneath the plane near the forward left wing root.

12

The APU bleed valve is ______ controlled and _____ operated.

DC controlled and pressure operated.

13

When the APU is shut down, what happens to the APU bleed valve?

it will close automatically.

14

At idle thrust, the ___ stage valve would normally be _____.

9th, open.

15

If APU is providing bleed air at the same time as engine bleed, what happens to the 9th stage bleed valve?

back pressure in the duct will cause the 9th stage valve to close.

16

The engine bleed air valve is _____ activated and _____operated.

DC activated and pressure operated.

17

The engine bleed air shutoff valve acts in 2 ways:

acts as a shutoff valve and pressure regulator when engine BLEED switch is on.

18

What powers the isolation valve?

AC power.

19

T/F: The APU BLEED air switch affects isolation valve operation.

False.

20

What power setting must the engine thrust be if a DUAL BLEED light comes on?

IDLE.

21

T/F: Differences between left and right duct pressure on the duct press gauge are normal.

True, provided there is adequate flow for cabin pressurization.

22

How many overheat sensors are located at various locations throughout the aircraft?

8 sensors.

23

Where are the sensors that illuminate the LEFT WING-BODY OVERHEAT light?

L engine strut, L inboard wing leading edge, L air conditioning bay, Keel beam, bleed duct from the APU.

24

Where are the sensors that illuminate the RIGHT WING-BODY OVERHEAT light?

R engine strut, R inboard wing leading edge, R air conditioning bay.

25

What is the BLEED TRIP OFF non-normal checklist first step?

select WING ANTI-ICE off

26

If a BLEED TRIP OFF light remains illuminated, what happens.

The pack is selected off and the other pack that works goes to high flow in flight with flaps up. Avoid icing conditions...duh!

27

Use of Wing Anti-ice above ~ _____ may cause bleed trip off and possible loss of cabin pressure.

FL350.

28

T/F: The dual bleed light is a normal indication following engine start using APU bleed air and should extinguish once the APU BLEED air switch is selected off.

True.