TM 55-1510-220-10
Figure 2-11. PT6A-41 Engine (Sheet 1 of 2)
above. The vanes should be either extended or retracted;
there are no intermediate positions.
(4)
If for any reason the vane does not
attain the selected position within 15 seconds, a yellow
No.1 VANE FAIL or No.2 VANE FAIL light illuminates on
the caution/advisory panel. In this event, the manual
backup system should be used. When the vane is
successfully positioned with the manual system, the
yellow annunciator lights will extinguish. During manual
system use, the electric motor switch position must match
the manual handle position for a correct annunciator
readout.
NOTE
Ice vane extension is confirmed by
a drop in torque, and a rise in TGT.
b.
Engine Air Inlet Deice System.
(1)
Description. Hot engine exhaust gas is
utilized for heating the air inlet lips to prevent the
formation of ice. Hot exhaust gas is picked up inside
each engine exhaust stack and carried by plumbing to the
inlet lip. The gas flows through the inside of the lip to the
bottom where it is allowed to escape.
(2)
Engine air inlet deice system switches.
These switches are not used.
(3)
Fuel heater. An oil-to-fuel heat exchanger,
located on the engine accessory case,
Change 2 2-22
