DRAFT Proposal for Amendment to Annex 4 (Aeronautical Charts)

Symbols on Aeronautical Chart - ICAO 1:500 000

1. Proposals

As anticipated, the ICAO Chart Harmonization Focus Group revealed many differences in the way airspace structure and further navigational information is depicted on the various ICAO Charts. During the discussion it also became obvious that ICAO Annex 4 do not give adequate answers to all questions emerging, and that the group had to find its own solution which led to the following proposal for amendment of ICAO Annex 4:

Annex 4, Chapter 17, 17.9.1 General

Following sentences should be added:

The upper limit of the airspace shown on the chart should be labeled clearly identifiable on the chart.

Note. – Whenever possible the upper limit of the airspace depicted on the chart should read FL100

Background:

The primary information transfer to pilots should be the upper level of airspace structure noticeably depicted on the cover sheet of an ICAO Chart.

Most VFR-traffic operates below FL 100 due to limited performance of the piloted aircraft. Because of this, more often than not the display of airspace structure on the ICAO Chart above FL 100 is nonessential. Yet, mountainous areas like the Alps or military requirements are providing good reasons to display airspace above FL 100. Therefore FL 100 as the upper limit of the displayed airspace structure is considered as recommendation only.

Annex 4, Appendix 2, aerodromes, symbol 91

The symbol for abandoned aerodromes shall be displayed with thin crossed lines extending to a circle (instead of thick lines, which could be misinterpreted as crossed runways).

Background:

The symbol for abandoned aerodromes given by Annex 4, Appendix 2, may possibly be mistaken as an aerodrome with crossing runways, given that the lines of the cross marking the aerodrome closure are very thick.

Annex 4, Appendix 2, aerodromes, symbol 95

The aerodrome samples shown as symbol 95 shall be used for major or international airports only.

The runway pattern of aerodromes not classified as major or international airports shall be displayed together with the aerodrome symbol.

Paved runways shall be shown with a solid line while unpaved runways shall be shown with an encircled line.

Except for aerodromes classified as major or international airports, the main runway only shall be displayed on a chart, even if more than one runway exists. The paved runway is considered the main runway, even if the length of an unpaved runway exceeds the length of the paved runway.

Background:

Annex 4, Appendix 2 provides no clear indication of how to show the runways of big airports and small aerodromes. Symbol 95 is just an example; no distinction between paved and unpaved runways has been made.

Annex 4, Appendix 2, Aerodrome data, symbol 96

Following data shall be displayed in association with aerodrome symbols: Name of aerodrome Location indicator of aerodrome Frequency of aerodrome Elevation of aerodrome Length of the longest runway

Background:

Since it is recommended to show paved and unpaved runways together with the aerodrome symbol as mentioned above, there is no need to add a letter “H” for hard surface as required by ICAO Annex 4, Appendix 2.

Furthermore the required letter “L” indicating “minimum lighting” at an aerodrome could be omitted. Lighting information should be shown only when required for special operations at night. In addition there is no clear indication what “minimum lighting” means.

To facilitate satellite navigation the four letter aerodrome location indicator should be added.

In addition the frequency of the aerodrome service unit should be displayed to assistant pilots when contacting the aerodrome.

Annex 4, Appendix 2, Airspace classifications, symbol 126

The boundaries of airspace class E shall be shown as a thick blue line (instead of a blue line with blue shading).

The boundaries of airspace class G shall be shown as a blue line (instead of a blue line with ticks).

Background:

Annex 4, Appendix 2 requires blue lines with blue shadings for airspace classes C, D and E. This colour coding does not give adequate distinction between airspace requiring ATC clearance (C, D) and airspace not requiring any clearance (E). However, this kind of distinction appears to be urgently necessary. Therefore the boundaries of airspace class E should be shown as a thick blue line only.

ICAO Annex 4, Appendix 2 requires a blue line with ticks for the boundary of airspace class G. Since this line could be misread as FIR boundary, the ticks along the blue line should be omitted.

Annex 4, Appendix 2, Airspace restrictions, symbol 128

The boundaries of restricted airspace shall be shown as a red line with a red hatched band (instead of a blue line with a blue hatched band).

Background:

Although Annex 4, Appendix 2 specifies blue colour, many ICAO Charts show prohibited, restricted and danger areas as well as military used airspace with a red hatched band in order to indicate that a high risk may arise from these areas.

Annex 4, Appendix 2 specifies the use of blue colour for almost all aeronautical symbols and airspace elements. Especially in case of a complex airspace structure, it is difficult to identify all airspace elements on a chart and to filter the airspace restrictions. By using red instead of blue colour prohibited, restricted and danger areas are easier to identify.

Annex 4, Appendix 2, Obstacles, symbol 136

The elevation of the top of an obstacle shall be shown if known. The display of the height of an obstacle above a specified datum should be optional.

Background:

Even though the elevation of the top of an obstacle as well as the height above a specific datum shall be displayed according to Annex 4, Appendix 2, numerous States publish the elevation of the top only due to lack of data available.

Annex 4, Appendix 2, Miscellaneous, symbol 137

The symbol 137 (prominent transmission line) of Annex 4, Appendix 2 should be replaced by symbol 166 (transmission line or overhead cable).

Background:

Annex 4, Appendix 2 specifies two different symbols as transmission lines: symbol 137 for prominent transmission lines, symbol 166 for transmission lines or overhead cables to be used for obstacle charts only. Only one symbol should be used.

Attachment A:

Proposal for amendment to ICAO Annex 4, Chapter 17, Aeronautical Chart – ICAO 1:500 000, page 17-4

Attachment B:

Proposal for amendment to ICAO Annex 4, Appendix 2

Attachment A ICAO Annex 4, Aeronautical Charts

Chapter 17, Aeronautical Chart – ICAO 1.500 000

17.9 Aeronautical data

17.9.1 General Aeronautical information shall be consistent with

the use of the chart and the revision cycle. The upper limit of the airspace shown on the chart should be labeled clearly identifiable on the chart.

Note. – Whenever possible the upper limit of the airspace depicted on the chart should read FL100

Attachment B ICAO Annex 4,

Aeronautical Charts Appendix 2