Anti-Ice Flashcards
What is the purpose of the anti-ice system?
Prevent ice on components of the engine inlet section
What are the ways to anti-ice the engine? (3)
- Engine anti-ice/start bleed valve
- Scroll Vanes
- Engine inlet anti-ice valve
How many solenoid air valves are there?
2
What 2 switches control the solenoid air valves?
ENG ANTI-ICE
DE-ICE MASTER
both are held closed electrically
What happens when ENG ANTI-ICE ON?
Valve is de-energized open, bleed air is routed to a separate modulating valve in the inlet section
What happens if DE-ICE MASTER is ON?
Both solenoids are controlled by the ice detector
How does the Scroll Vanes (air/oil cooler) anti-ice?
Continuous circulation of hot oil through the scroll vanes cools the oil and heats up the main frame.
Air is then vented overboard by the IPS and does not proved anti-ice to the air entering the compressor
What are the indications of a malfunctioning engine anti-ice valve? (4)
- ENG AINTI-ICE ON above 90 or 94% Ng (OAT above 15 C)
- No ENG ANTI-ICE ON when Ng below 88%
- No ENG ANTI-ICE ON when switch is ON
- No TGT rise (30-100 C) when switch is ON
What is the reduction of TRQ available when ENG ANTI-ICE ON?
up to 18% per engine
How does the HMU compensate for Variable Geometry hangup at the ENG ANTI-ICE Valve?
When collective is full down, HMU schedules max fuel flow
Where is the Inlet Engine Anti-Ice Valve located?
Inlet cowling
How does the Inlet Engine Anti-Ice Valve work?
It senses air temp inside the cowling via Freon Bellows
When does the #1/#2 INLET ANTI-ICE ON illuminate?
Turns on when bleed air heats the inlet to ~93%
Is the Inlet Engine Anti-Ice Valve energized if both ENG ANTI-ICE switches are OFF?
No, because the solenoid is electrically closed
If ENG ANTI-ICE switches are OFF and DE-ICE ON, how does Inlet Engine Anti-Ice Valve work?
Freon Bellows work ONLY when ICE DETECTED illuminates