Piloting the great circle
Piloting the great circle using the exchange rate systems

Orthodromy airplane guidance using course systems


Preparing the card for flight on the great circle track. The maps used for flights in civil aviation (1 scale: 1 000 000 and 1: 2 000 000), orthodromy length 1000 - 1200 kilometers is practically a straight line. This makes it possible to lay the cards on the great circle plots graphically (with a ruler), without payment of intermediate points on formulas. On the same path length can be performed with the flight orthodromic roadway around the corner from one reference meridian section.




The recommended laying system orthodromic travel angles on the flight map. If the flight path is not laid on the great circle, t. E. Must pass through certain specified items, it is divided into separate sections, where the great circle length should not exceed 1000-1200 km.


It is desirable that the initial plot point coincided with the turning points of the route (ISP). The division is not the route to the ISP points shall be permitted only at great length of straight sections of track.


Meridian starting points orthodromy area considered the reference meridians for measuring the travel angle. Great circle track angle from the first reference meridian to the first waypoint is measured directly from the reference meridian. Travel angles to the next waypoint is defined as the sum of the first track angle with the angle of the turn track on the first MRP:


For the flight back pad angles of travel performed by the reference meridians, which are finite in flight in the original direction. Therefore, the travel angle reverse direction will differ from the original direction on 180 ° plus correction for convergence of the meridians.


If the entire flight route passes along the Great Circle and has MRP, the laying of the travel angle is greatly simplified. In this case, the route should be divided into sections on the great circle 1000-1 200 km. Meridian initial plot points are considered in the calculation of the reference meridians orthodromic travel angles for the forward and reverse directions; these meridians and measured orthodromic travel angles.


Marking the route for flight travel from the great circle angle is the same as for a flight with magnetic loxodromic travel angles. Line path is divided into segments according 50 km from digitization through 100 km. To the right of each section between the APM feature is applied, over which states racesdistance between PPM and below the line - the set of flight time on the site. To the right is written GTC features.


The general procedure for the preparation of maps for the flight by ortodromicheskon track is recommended as follows:

1. Regardless of the presence of kinks, connect a 1200 m section of the route with a straight line on the map. The straight line laid on the map will be the orthodrome of the section. In the future, all calculations of track angles should be carried out from this line.

2. Measure the azimuth of the orthodrome on the meridian passing through the starting point of the site using a protractor.

3. Plot the specified track line on the map. To do this, connect the turning points of the route with straight lines.

4. For each segment of the given track line, calculate the orthodromic track angle. This angle for each segment, except for the first one, is measured and calculated from the azimuth of the orthodromy of the site, from the first orthodromic track angle or from any meridian, taking into account the correction for the convergence of the meridians.

5. Record orthodromic path angles on the map to the right of the route.

6. The reference meridians of each site shall be marked on the map in red.

7. Apply at each meridian to the right of the route the value of the correction for the convergence of this and the reference meridians and the magnetic declination. When flying to the east, the amendment is recorded with a minus sign, while flying to the west - with a plus sign. The recorded corrections for the convergence of this and the reference meridians are used when calculating and plotting the actual track and radio bearings on the map, and the corrections are taken into account with their sign.

8. In case it is necessary to switch from orthodromic reckoning to flight with magnetic track angles, a table of magnetic track angles is compiled for segments of the path of such length that the MPUs of neighboring segments differ by no more than 3-4a.


flight operations. Flying in great circle track with coursework gyroscopic instruments, including CCP-52, carried out under the following scheme, which remains the same for all ortodromichesknh areas:

1. Prior to the passage of the reference meridian for 20-30 km to agree on the COP. Set the initial data on the CS, GPK, NI-50, DAK-DB-5.

2. When passing the reference meridian, set the plane along the USh to the calculated orthodromic course, check the correctness of the taken course using all duplicate course instruments.

3. Following the orthodromic track line.

4. Correction of the gyro unit KS and GPK-52.

5. Control and correction of the path.

6. Exit to the reference meridian of the route turning point.


If orthodromic path portion has fractures, t. E. Route turning points, these points in the plane to be installed on the corresponding rate GIC, which is the same as the azimuth of the great circle portion counted from a reference meridian.


In accordance with this general scheme and procedure execution method on each flight orthodromic site are as follows:

1. All course instruments must be turned on on the ground after starting the engines. After warming up the instruments and accelerating the gyro rotors, set the rounded value of the latitude f of the starting point of the section on the control panels GPK-52 and KS.

For example, if the latitude of the site's terms 53 ° 32 ', it is necessary to establish the breadth of 54 °.

On DAK-DB set: latitude and longitude of the start point of the site, declination and Greenwich hour angle of the Sun, as well as to reset the trip distance to zero and set the calculated ground speed of the travel corrector.

On the scale of the declination to set the declination of the starting point of great circle area.

2. When crossing the reference meridian of the section, set the aircraft to the calculated true heading equal to the track angle of the specified orthodrome corrected for the drift angle. Strictly maintaining this course, set the GPK-52 to the countdown corresponding to the true course, and switch the CS to the "GPK" operating mode.

3. Performing a flight along the GPC with the calculated heading, determine the drift angle and make an amendment to the calculated heading.

4. To reach the next set track angle, turn the aircraft along the GPC to the right or left to a new calculated course.

When the flight speed aircraft must begin a turn to exit to the next predetermined track angle to span the MRP according to the pre-calculated line turn anticipation (LUR).

5. Having set the airplane on the GPC on a course equal to the new preset track angle of the orthodrome corrected for drift, fly with this course until the next turning point, specifying the value of the taken correction.

6. With the change in the latitude cp of the aircraft seat by an amount equal to the next closest division value on the "Latitude" scale, set a new latitude value on the control panels GPK-52 and KS1.

7. Performing a flight along the GPC with the calculated course, periodically monitor the GPC readings in the following ways:

a) by comparing the magnetic heading of the aircraft according to the magnetic compass with the true orthodromic heading according to the GPC - At each separate moment, the magnetic heading according to the magnetic compass should differ from the orthodromic heading according to the GPC by the sum of corrections for the angle of convergence of the reference meridian, the meridian of the aircraft position and the magnetic declination of the MS:

For ease of comparison, the testimony of CPC and the magnetic compass is expedient to amend the total install on a scale of declinations VIII, after which the testimony of these devices must be the same within the accuracy of their work. The exchange rate systems that aggregate amendment may be added to the testimony of a magnetic course of CAA t. E. OK = MC + A, the result is compared with the testimony of NL (operating in the "GIC"). In the event of discrepancies in the testimony to make a correction;

b) comparing the orthodromic course on the astrocompass with the orthodromic course on the GPK. At each separate moment, these readings should coincide within the accuracy of the instruments.

8. Periodically, after 10-15 years of flight, determine the drift angle and, according to the data obtained, refine the course.

9. To ensure the most accurate exit of the aircraft to the starting point of the next orthodromic section, keep track of the track and periodically determine the calculated position of the aircraft.

When flying on a great circle GIC rate, measured from the reference meridian great circle area, the calculation of the airplane and the radio bearing gasket on the map must be in the following order:

a) determine the heading angle of the radio station or landmark using the ARC or onboard radar


b) determine the orthodromic bearing of the RNT or landmark as the sum of the orthodromic course (OC) according to the GPK and the heading angle (KUR) KUO): OPR = OK + KUR (KUO);

c) to plot the true radio bearing on the map from the RNT meridian or landmark, determine the true bearing of the aircraft, taking into account the correction for the angle of convergence of the reference meridian of the orthodromic section and the meridian of the radio station or landmark

b) set the true heading on the ARC heading scale or on the radar indicator as the sum of the orthodromic heading and the correction for the convergence of the meridians taken from the map;

c) read the true bearing of the aircraft by the position of the ARC arrow or the line of the radar indicator.

When used for radio direction-finding system COP-great-circle bearing the aircraft is measured directly on the Status arrow ARC (opposite end), and to obtain the true bearing of the aircraft is taken into account by

its sign Discontinued map correction for the angle of convergence of the meridian and the reference meridian station;

d) plot the calculated true bearing of the aircraft on the map using a protractor, superimposing it on the meridian passing through the radio station.

10. Exit to the starting point of the next great circle area.

11. Set the plane on course Usha controlling the magnetic compass and astronomical. Set GIC per sample, corresponding to the MC during the flight of LPA; and en-loss - the value of the MC + Lm.o.m.

12. In the future, to fly in the same manner as described above in paragraphs. 3-10.


On airplanes with automatic guidance system of the course coordinator NO-50BM included in the VIII COP. Therefore, these aircraft corner of the card on the machine and the set point of the course winds NO-50 trip ticket is set to the great circle reckoning angle and range and lateral deviation is conducted with respect to a given great circle track.


On airplanes with autonomous operation of exchange rate instruments, where automatic exchange NO-50 included in the NL remote magnetic compass reckoning will be the coordinator of the magnetic heading. Since the actual flight will be operated with a constant great circle course and readings magnetic compass will change continuously in the reckoning path toward any mistakes, since the integration path will run along a curve, convex in the direction opposite to the magnetic rhumb line.


In order to ensure that no-50 readings can be used to control the way in the direction of, for example, to measure wind speed and direction at altitude, angle of the map NOR-50 should be set equal to the income statement, and in reading the magnetic compass periodically through 100-150 kilometers enter the total correction:

This total correction in magnetic compass readings entered via VIII declination scale.

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