Peculiarities Of Naviqation In Adverse Weather Conditions (Ifr) - Kazan Helicopters Mi-17-1V Flight Manual

M..-17-1B. Flight manual
(10) In all conditions of flying by night it is recommended to determine the
ground speed and drift angle in each route segment. For this purpose se-
lect the route check legs of 30 to 40 km long.
Select characteristic illuminated and natural reference objects as the ini-
tial and terminal reference objects of the route check legs.
(11) Check the on-course condition by using all the ways available in a given
flight.
The best accuracy is provided by the radio navigation means free from
night effects (such as radars, VHP locator beacons).
Employment of the above radio navigation means in combination with
visual orientation enables the crew to take decision for changing the flight
condition for the purpose of reaching the field (target) at estimated time.
4.24.8. Peculiarities of Navigation in Adverse Weather Conditions (IFR)
(1) The main peculiarity of helicopter navigation in adverse weather condi-
tions is limitation or complete precluding of possibility to check the on-
course condition through visual ground contact.
Dead reckoning and check of the on-course condition by means of radio
direction finders (omnirange stations, locator beacons) and radio direction
and range finders (radars) assume vital importance.
(2) Lay the course through characteristic area reference objects located on
the linear reference objects so as to make possible rapid and guaranteed
determination of the helicopter position when reaching the clouds.
(3) Use an omnirange station, locator beacon or an aerodrome coded neon
light beacon as the route initial and terminal waypoints. Select a route
check leg of 25 to 30 km long to refine the ground speed and drift (wind)
angle.
(4) Assume the initial waypoint as the initial reference object and a
characteristic linear or area reference object as a terminal reference
(5) lWi@w·clouds refine the ground speed without breaking them and use ra-
dio aids for the purpose.
(6) Assume the radio navigation station located at the initial waypoint as the
initial point of the route check leg. Determine the moment of reaching the
end of the route leg by using the slant distance to a ground radar or the
bearing to a side radio station.
(7) Determine the drift angle by selecting the heading with the helicopter
magnetic bearing remaining unchanged.
The difference between the helicopter magnetic bearing and the mag-
netic heading equals to the drift angle.
(8) Select radio navigation aids (main and standby) for each route segment
which are to be used for checking the on-course condition both in head-
ing and distance.
(9) Thoroughly study the. operational data of the alternate aerodromes radio
navigation aids, as well as descent and landing approach procedures es-
tablished for these aerodromes.
(10) Calculate the flight data considering the reported wind near the ground or
wind determined by the weather reconaissance aircraft. Write down the
estimated data such as a magnetic heading, ground speed and elapsed
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