Engine Anti-Ice

Question 1

Where is the anti-ice start/bleed valve mounted

Answer 1

Bottom of the compressor

Question 2

How is hot air distributed

Answer 2

Through 2 solenoid-operated air valves, held electrically closed and controlled by ENGINE ANTI-ICE and DEICE MASTER switches

Question 3

3 methods of anti-ice

Answer 3

Engine anti-ice/start bleed valve
Inlet anti-ice valve
Circulation of oil through engine scroll vanes

Question 4

Where does the air for Engine anti-ice/start bleed valve come from

Answer 4

5th stage bleed air into swirl vanes and inlet guide vanes

Question 5

Engine anti-ice/start bleed valve open for?

Answer 5

Engine Starts
Open below 90% Ng to prevent compressor instability
Opens during loss of electrical power

Question 6

Could cause engine flameout at low collective settings

Answer 6

Temporary hang-up of the engine variable geometry VG

Question 7

Variable Geometry activated by____

Answer 7

fuel pressure from HMU

Question 8

To release the Variable Geometry VG system quickly from any temporary hangup while the collective is full down,_____

Answer 8

The HMU will schedule max fuel flow to the VG actuator creating a diversion from the scheduled fuel flow to the engine

Question 9

Could happen during minimum fuel flow regimes (autorotations, quick stops) as a result of max fuel to VG actuator

Answer 9

May cause engine flame out

Question 10

Malfunctioning anti-ice/start bleed valve indicated by?

Answer 10

ENG ANTI-ICE ON with above 90% Ng or above 94% Ng with OAT greater than 15*C
No ENG ANTI-ICE ON with Ng below 88 (may vary on a sliding scale based on OAT
No ENG ANTI-ICE ON with switch ON
No rise in TGT with switch ON

Question 11

Reduction of torque with ENG ANTI-ICE ON

Answer 11

Reduced up to 18% per engine

Question 12

Location of inlet anti-ice valve

Answer 12

engine inlet cowling

Question 13

Path of air for inlet anti-ice valve

Answer 13

Bleed air routed from compressor, through solenoid actuated valve then routed to inlet cowling and inlet fairing

Question 14

Where is temperature sensed for inlet anti-ice

Answer 14

inside the cowling

Question 15

What turns on #1/#2 INLET ANTI-ICE ON advisory

Answer 15

Engine inlet heated to 93C
however full inlet anti-ice capability may not be available above 4 and will not be available above 13*
Thermal switch does not have input to valve or freon bellows

Question 16

How is inlet anti-ice valve opened

Answer 16

Variably opened based on OAT with either ENGINE ANTI-ICE or DEICE MASTER switch on

Question 17

What does the freon bellows react to

Answer 17

Only ambient temperature

controls bleed air into cowling and fairing even if solenoid valve is deenergized

Question 18

OAT less than 4* - freon bellows

Answer 18

valve is open and INLET ANTI-ICE ON advisory appears when inlet temperature reaches 93* C

Question 19

OAT between 4 and 13

Answer 19

Valve controlled by a temperature compensating freon-filled bellows. Starts to close at 4 should be closed at 13

Question 20

OAT above 13*

Answer 20

Valve is closed

INLET ANTI-ICE ON advisory will extinguish when inlet cowling temperature drops below 93*

Question 21

Faulty inlet anti-ice valve

Answer 21

If advisory on above 13* C, may be indication of faulty system
Could result in a max loss of 49% torque

Question 22

Anti-ice with oil

Answer 22

Through engine scroll vanes

Air heated by scroll vanes vented overboard through the IPS and does not provide anti-ice protection