Anti-ice controls

STUDENT GUIDE T-39N/G NATOPS

C. Anti-ice controls

1. ENGINE & RAM AIR INLET switch.

a. Opens each engine's ANTI-ICE SHUTOFF VALVE, providing bleed air to each

engine. (ENG inlet, flow straighteners, inlet guide vanes, and bullet nose). With a

TOTAL electrical failure, only inlet guide vanes and bullet nose will be anti-iced.

b. Provides electric heat to AC/DC generator inlets and ram air inlet on vertical tail.

c. If either forward windshield heater is inop, and window is unheated, do not exceed

250 KIAS below 10,000'.

D. De-icing system

1. Removes accumulated ice on:

a. the wing slats

b. under slat surfaces and leading edge of wing roots

c. vertical and horizontal tail leading edges.

2. Electrically controlled, pneumatically operated with engine bleed air.

3. Automatic operation - PNEU BOOTS LT/HVY/OFF switch.

a. Each set-of boots (wing, slat, empennage) is pressurized for 5 seconds, with a dwell

time of 45 seconds (HVY) or 165 seconds (LT).

b. WING/SLATS/EMP lights will be on.

c. Automatic operation is powered by DC SECONDARY BUS.

d. Can be inflated on deck to check operation.

4. Manual operation - depress each WING/SLATS/EMP light for 5 seconds, repeating as

necessary.

a. Manual operation is powered by DC ESSENTIAL BUS.

5. For most effective operation, use pneumatic boots when ice thickness reaches 1/4

inch.

6. For de-icing operations (pneumatic boots) engine RPM must be > 75%.

7. Ice check lights

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ANTI-ICE/DE-ICE SYSTEMS