Approach To Field (Target) - Kazan Helicopters Mi-17-1V Flight Manual

M,,·17·1B. Flight
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(10) To facilitate determination of correction to course at the check points it is
advisable to plot track angle errors on the chart.
Corrections to course can be calculated by means of the Hfl - 10 naviga-
tion computer following the procedure below:
(a) If the actual magnetic track angle is known to the crew use the drift
scale to measure the track angle error (TKE) as the angular differ-
ence between the actual and desired tracks. Then calculate the cor-
rection to course (CC) from the track angle error, trip distance (TD),
distance flown (FD) by means of the Hll - 10 navigation computer.
For this purpose set the track angle error (TKE) on the tangent
scale against the trip distance (TD) and distance-to-go (GD), and
read the correction to course (CC) against the trip distance.
(b) If the cross track distance (XTK) is known, the correction to course
can be calculated as the sum of track angle error in degrees and
the additional correction (AC).
(c) The elapsed time (ET), time-to-go (GT), and trip time (TT) of the
route leg can be taken for calculation of the correction to course in-
stead of FD, GD and TD.
(11) Determine the ground speed and estimated time to waypoint (ETE) from
the distance flown and time elapsed when flying over the route check leg.
Determine the wind data from the ground speed and drift angle by means
of the wind drift computer. Using the known wind data calculate the
course and time for the next route leg, as well as the estimated time to
the field (target).
If it is impossible at a given moment to determine the helicopter position
visually or by moment of the radio navigation aids monitor the track sepa-
rately in direction and distance.
(12) Use one of the following methods to compensate for the error of the esti-
mated time to the field (target):
(a) Change in the route length.
(b) Change in the speed.
(c) Corrective tum of 60° from the course.
(d) s-turns.
4.24.4. Approach to Field (Target)
(1) The approach to the field (target) can be effected by the following meth-
ods whose selection depends on the actual conditions:
(a) By visual ground contact from the initial reference object with the
heading and elapsed time accounted for.
(b) With the use of the ,QlI1CC-15 doppler system.
(d) By means of two radio navigation stations, one of which is located
on the desired track and the second is aside of this track.
(2) The helicopter approach to the field (target) by the visual ground contact
from the initial reference object with the heading and elapsed time ac-
counted for is the basic method. It can be used both by day and night if
the ground reference objects are visible and a characteristic, easily identi-
fiable reference object is available near the field (target).
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