IPAS

Question 0

Engine bleed air PRSOV

Answer 0

1-Located downstream of 5th stage
2-Reduces 45-55 psi to 25
3-During cross eng starts the start solenoid is de-energized while the ON solenoid remains energized which results in higher psi 28-35

Question 1

Where is the low pressure Venturi and what is its purpose?

Answer 1

Located on 5th stage bleed air

Limits total volume to 6.5% in the event of an IPAS leak.

Question 2

Engine and APU Bleed air check valves

Answer 2

Prevent back flow of air from engine to engine during single engine operation, and during APU operation to prevent back flow of APU air to the engines.

Question 3

ATS hang start will appear on UFD when?

Answer 3

Above 68% Ng and the ATS PRSOV is still open.

You will also get a fault on the fault page

Question 4

When does bleed air go thru the pre cooler?

Answer 4

It is always going thru the pre cooler. The pre cooler bypass valve is forced open by normal system pressure. When bypass over temp thermostat senses an over heat condition it causes the bypass control valve to close thereby increasing air thru the precooler.

Question 5

Primary and utility HYD relief valves open when?

Answer 5

55 psi

Question 6

Explain ice detector operation

Answer 6

When in Auto and temps are 5C or less, the anti system is commanded on. The ice detector resonates, the feedback coil sends a signal to the comparator which then converts the signal to DC voltage and sends it to the SP WHICH determines how much icing exists, (light trace moderate or sever). It continues to resonate for 60 seconds or until .005 inches of icing is left, whichever is less.

Question 7

What is supplying bleed air when both engines are at 101 and the APU is on?

Answer 7

High pressure IPAS is supplied by the eng diffuser while low pressure is still supplied by the APU