These guidelines concern in particular
- uniform scales (e.g. 1: 200,000, 1: 500,000, 1: 1 million, 1: 2 million)
- Map projection and map cut (at a scale of 1: 1 million in middle latitudes e.g. 4 x 6 °)
- necessary content
- standardized signatures of the content
- Height reference and map legend .
The guidelines were first agreed in 1945 by the predecessor organization PICAO and in 1949 by the ICAO and published in ICAO Annex No. 4 Aeronautical Charts ( aeronautical charts ). Annex 4 will be adapted to technical developments at longer intervals.
Types of aeronautical charts
The ICAO maps include, for example, the visual flight maps for general aviation (most often scale 1: 500,000 or 1: 1 million), the smaller-scale enroute maps for instrument flight , overview maps , obstacle maps AOCs and PATCs as well as a few special maps (formerly e.g. B. important for radio direction finding or Decca location).
Official maps are issued exclusively by DFS Deutsche Flugsicherung on behalf of the BMVI and are binding with regard to the so-called air traffic control imprint. However, tickets for scheduled flights are issued by private companies (e.g. Jeppesen Sanderson ) or airlines and do not always follow ICAO guidelines. In the USA , for example, map scales with non-circular ratios are still in use, for example 1: 633,000 (1 inch = 10 miles) or similar display methods.
The ICAO maps 1: 500,000 serve in general aviation on the one hand as visual flight maps (orientation during the flight) by means of a map-terrain comparison, see also Visual Flight Rules (VFR), on the other hand for flight planning and preparation. Since the pilot is generally responsible for correctly flying the airspace , he must inform himself about the flight and weather conditions and ensure that he is equipped with suitable maps and navigation instruments .
ICAO cards in the narrower sense
The standard map for private VFR air traffic is the actual ICAO map on a scale of 1: 500,000. Here 1 cm on the map corresponds to 5 km in nature, what
- already gives a sufficient overview,
- at the same time still good representation of waters and important traffic routes .
The most frequently used scale for visual navigation is 1: 500,000, on which almost all countries map their national territory and its surroundings. Other scales are 1: 250,000 and 1: 300,000. If the map material is very good, 1: 1 million is just usable for rough visual navigation.
These maps are understood as ICAO maps in the narrower sense . They contain a good representation of the topography (terrain, water) in layer lines which are based on the official maps . Most of the time the terrain also has hillshades (incidence of light from NW) and always a forest print in soft green tones.
All medium-sized and larger bodies of water are shown in precise cartometry, the road network (state and federal highways, motorways), railways and other broad traffic routes is somewhat generalized . The town centers of all larger settlements are precisely mapped (depending on the type of country from around 2,000 to 5,000 inhabitants), as well as the outlines of the densely built-up area for cities .
Landmarks such as churches (usual signature circle + cross) and high-rise buildings - which are always drawn in as well as masts from 100 m high - as well as lookout points , road or rail crossings and underpasses are helpful for orientation at low altitudes .
Projection and height system
As a map projection, Lambert's conformal cone projection has prevailed, which has only minor distortions with two reference parallel circles north and south of the map center . It has projection formulas similar to the International World Map 1: 1 Million. In the polar regions from about 75 ° or 80 ° latitude , the polar stereographic projection is used (see also universal polar stereographic projection ).
In the altitude system , with the fall of the Eastern Bloc, the heights in feet (1000 feet = 304.8 meters) used by the USA have established themselves and are also the measure for the so-called flight levels FL . But because topographic maps are usually kept in the metric system, these round layer lines are taken over into the ICAO maps and simply written in feet. So the usual 100 m layer lines of the terrain become multiples of 328 foot layer lines.
Because of the lower flight altitude, there are also individual special maps for gliding at a scale of 1: 200,000 to 1: 300,000, which show the terrain more precisely, but also all cable cars and other aviation obstacles below 100 m in height. There are separate databases for the latter, but their completeness (despite the operator's obligation to report ) still leaves a lot to be desired.
To facilitate navigation in highly complex airspaces and for areas without modern navigation aids , large-scale approach maps of the airport surroundings should also be mentioned, as well as route maps on a scale of 1: 1 million or smaller for long-haul flights .
In addition to the use of maps for visual navigation, pilots must have the necessary knowledge and tools for other navigation methods. Most important are
- Combined navigation with compass and airspeed, combined with flight experience (sense of position and space, " seat meat " for changes in altitude)
- Radio navigation with VOR - and NDB - beacons (to be included on the cards)
- GPS- assisted satellite navigation
- as well as various approach aids in the vicinity of airports .
- The ICAO maps for Germany can be viewed after free registration on the AIS portal of the German Air Traffic Control .
- For Switzerland, the ICAO map for visual flight can be accessed on the federal geo-portal .
- For Austria, the ICAO map is offered as a free download for non-commercial purposes by Austro Control .