TM 1-1520-240-MTF
4-57
(10) Set the FLY-TO-DEST thumbwheel to
position “4”.
(11) Repeat step (7) for destination CP-4.
(12) Repeat step (8) for checkpoint CP-4.
b. Navigation Accuracy Test Legs — The
following navigation legs shall be flown in
the indicated numerical sequence.
(1) Leg Number 1 — Fly from CP-1 to CP-3
at normal cruising speed. Record the
displayed present position coordinates
at CP-3 flyover.
(2) Leg Number 2 — Fly from CP-3 to CP-4
at maximum helicopter speed. Record
the
displayed
present
position
coordinates at CP-4 flyover.
(3) Leg Number 3 — Fly from CP-4 to CP-1
at minimum safe speed (greater than 20
knots) of the helicopter. Record the
displayed present position coordinates
at CP-1.
c. Maximum cross track error is $5% of the
distance of the leg. Maximum error along
the track is 2% of the distance of the leg.
10. GPS/Doppler Flight Test Procedure.
a. Verify proper system operation with MODE
switch to TEST and display line 1 indicating
TEST COMPLETE and line 2 TEST OK.
b. Verify proper response of CDU panel
lighting to aircraft dimmer control and
Display lighting to CDU BRT control. Adjust
to comfortable level.
