IPAS Flashcards
(39 cards)
What does the advisory BLD AIR1 on the EUFD indicate?
The mission processor commanded the engine 1 bleed PRSOV OPEN or CLOSED, and it did not move as directed.
What does the advisory BLD AIR OFF indicate?
Engine one and engine two bleed air have been manually shut off.
What does the advisory BLD AIR HOT indicate?
Mission processor has detected a bleed air overtemperature (> 490°F).
Where are the bleed air controls located?
Aircraft Utility Page or HITT Page
When one or both engines are at 101% Np and the APU is still operating, what supplies pressurized air to the low-pressure manifold?
The APU
When does air from the low-pressure manifold pressurize the primary and utility hydraulic reservoirs?
During APU only operations (no engines running).
Which components control the pressure of high-pressure air?
The Primary and Utility Hydraulic Reservoir Pressure Regulators.
What is the purpose of the Engine No.1 and Engine No. 2 high-pressure check valves?
Backflow of the 5th stage bleed air from engine to engine.
The primary and utility hydraulic reservoir pressure regulators reduce high-pressure bleed air to what pressure?
31± 3 psig.
What does the Environmental Control System (ECS) use IPAS air for?
Heating the crewstations and Air Particle Separator.
What does the Nitrogen Inerting Unit (NIU) do with IPAS air?
The NIU cools, dries, and removes oxygen from IPAS air then routes it to the fuel cells to inhibit explosive vapor build up.
What does the fuel system pressure regulator valve reduce IPAS pressure down to?
19± 3 PSIG.
Which components maintain the pressure of low pressure IPAS air?
Engine bleed air Pressure Regulator and Shutoff Valves (PRSOV)
Which component limits maximum normal bleed air supply temperature to 450ºF (231ºC)?
The bleed air precooler limits maximum normal bleed air supply temperature to 450°F (232°C) by utilizing a 115 Vac vane-axial fan to provide cooling air flow across the heat transfer surface.
When does the APU load control valve open during APU starts?
Closed during the initiation of the APU start sequence and opens when the ECU determines that the APU has reached 95% speed.
At what temperature does the overtemperature switch close?
The switch closes at 490°F (253°C), sending a signal to the MP which activates an advisory for display on the EUFD. The switch opens at 450°F minimum (231°C), removing the advisory message from the EUFD.
What is mounted directly on the engines at the low-pressure bleed air port and connects to the IPAS ducting leading to the engine bleed air PRSOVs?
Low-pressure Venturi
What is the primary pneumatic power source for the Integrated Pressurized Air System (IPAS)?
Engines 1 and 2
What is the secondary pneumatic power source for the IPAS?
A single running engine
What is used for external air source for the IPAS?
APU when performing ground operations. AGPU when APU or engine operation is not possible, required, or desired.
What is the function of the Low Pressure Venturi?
Connects from the engine to the IPAS ducting leading to the engine bleed air Presure Regulator Shutoff Valve (PRSOV)
What is the function of the Engine Bleed Air Pressure Regulator Shutoff Valve (PRSOV)?
Reduces incoming air pressure from 45 - 55 PSIG to 25 +/- 3 PSIG
What is the function of the Flow Share Sense Line?
Interconnects the PRSOVs to ensure both engines are supplying an equal amount of bleed air.
Keeps the PRSOVs synchronized.
What is the function of the Engine/ APU Bleed Air Check Valves?
Keep bleed air flowing in one direction to prevent backflow
