Faculty of air transport engineering the department of «air navigation systems»

1.1.3 Construction of flight diagrams by instruments.
The development of instrument flight plans includes the construction of routes, as well as arrival, departure and approach schemes. Such schemes consist of pre-established maneuvers performed only on flight instruments, subject to the established requirements for preventing collisions with obstacles.
Each State is responsible for ensuring that the aircraft concerned can safely operate all published instrument flight patterns in their airspace. Ensuring flight safety is achieved not only by applying the technical criteria contained in PANS-OPS (Doc 8168) and the relevant ICAO regulations, but also requires the adoption of measures that control the quality of the process used to apply these criteria, which may include regulation, monitoring of air traffic, testing on the ground and in flight. These measures should ensure the quality and safety of the developed scheme through analysis, verification, coordination and testing at certain stages of the process, so that adjustments can be made as soon as possible during the process.
The following paragraphs on instrument flight schematics describe the construction of conventional circuits and sensor-dependent RNAV circuits, as well as their shortcomings and problems that led to the use of PBN.
The construction of conventional circuits is used in applications that are not based on RNAV, when aircraft navigation is carried out by direct signals from ground-based radio navigation facilities. The disadvantage of this type of navigation is that the routes depend on the location of the navigation beacons (see Figure 3). As a result, the length of routes increases, since it is almost impossible to determine the optimal arrival and departure routes due to the

Figure 3. Navigation based on beacons.

restrictions associated with the choice of the location of ground-based radio navigation equipment and the associated costs. In addition, the obstacle protection zones are relatively large, and the error of the navigation system increases as a function of the distance of the aircraft from the navigation device.