(b.) Outside the limiting Meridians and Parallels.-A title. consisting of the name designating the locality and the index numbers of the sheet; a border scale graduated to minutes; the names of the neighbouring sheets; latitude, South Polar distance. old and new notation of longitude (see paragraph 7); scale of kilometres; legend of symbols in English or French and in the language of the country publishing the map; magnetic variation diagram; key map showing abridged numbers of the sheet concerned and the eight surrounding sheets; frontiers and the names of the countries, parts of which are embraced by the key map; publisher's name and date of publication.

10. The forms of the general and local maps, titles, marginal notations, diagrams and legends shall be as shown by the accompanying illustrations.

11. The general and local aeronautical maps and guide books of the areas traversed by the most important routes which may be established by international agreement shall be prepared first.

NOTE.-On account of the inadequacy of the usual methods of topographic mapping for making aeronautical maps, it is strongly recommended that steps be taken to survey from the air the areas along the most important international routes. Such surveys would furnish indispens able information regarding the features necessary to be shown on the maps the aviator is to use.

Section II.-Universal System of Ground Marks.

1. All ground marks shall conform with the scheme of numbering adopted for the unit sheets of the local international aeronautical maps. For this purpose each mark shall show (see

the diagrams*) :

(a.) The abridged number which designates the sheet within which it lies;

(b.) An open rectangle, whose short sides shall be oriented northsouth; the frames shall be open towards the opposite half of the unit sheet;

(c.) A dot indicating the approximate position of the mark on the north or south of the corresponding unit sheet.

The numbers shall be placed close to the frame at the top. bottom or sides, but not inside.

Where marks are placed so close to each other as to admit of possible confusion, the round dot may be replaced by a square, triangular or star-shaped dot.

It is recommended that the minimum dimensions of the marks be those indicated in the sketches.

2. Special attention shall be given to the distribution of marks along chosen international routes.

NOTE.-Steps to establish suitable marks for landing at night shall be eventually taken, in accordance with the decision of the International Commission for Air Navigation.

Not reproduced.

ANNEX (G).

Collection and Dissemination of Meteorological Information.

1. Nature and object of meteorological information to be furnished by Contracting States.

(4.) Statistical is required for the purpose of indicating the degree of safety and convenience of different routes of aerodromes for different types of aircraft.

It consists of :

(a.) Analysis and summaries of past meteorological records. (b.) Summaries of current observations.

(B.) Current" is required for the purpose of :

(a.) Keeping a current record of the weather.

(b.) Making forecasts.

It consists of :

(1.) The results of daily observations.

(2.) Lists of active stations at which these observations are taken.

same.

(C.) " Forecasts" are for the purpose of telling all concerned when and where flying is possible and the best conditions for the They are statements of conditions anticipated :(a.) Short period" during the next three or four hours. Normal" during the next twenty to thirty hours. (c.) Long period" during the next two or three days.

(b.)

64

(d.) "Route for particular region or route during the next

six hours.

2. Methods and times of furnishing the different types of information.

(4.) Statistical " is furnished by Central Meteorological Offices for general information.

(a.) Analysis and summaries of past records-by the publication of special handbooks giving averages, frequencies and extremes of the principal meterological elements, together with charts and diagrams; prominence to be given to meteorological conditions of areas known to have special meteorological peculiarities.

(b.) Summaries of current observations-by the monthly publication of the information obtained each month.

(B.) "Current" is furnished by meteorological offices to meteorological offices.

(a.) Results of daily observations, telegraphically, by :(1.) Regular reports at fixed hours (see Appendix I), and

(2.) By special reports at intermediate times when requested (see Appendix II).

(b.) Lists of stations whenever necessary, to keep other countries informed where observations are being taken, giving also local and topographical details affecting weather conditions at each station.

44

(c.) Forecasts are furnished by Meteorological Offices for general information by publication in the public press, telegraphically to other countries if required, or any other, the best. means to bring them to the notice of those requiring them (see Appendix III).

APPENDIX I.

Regular Reports.

These are of two kinds :

(1.) Individual station reports.
(2.) Collective station reports.

1. Individual station reports are the results of observations of individual stations, taken at 0100, 0700, 1300, and (1800 or) 1900 G.M.T. The reports are made as soon as the observation has been taken and are rendered to a central collecting station or office; where reports for only two of these hours are possible or sufficient, the hours should be separated by an interval of twelve hours. (It is recommended that the standard hours be changed to 0800, 0900, 1500 and 2100 G.M.T. by international agreement.)

Reports will give information on the following, whenever

possible

(1.) Wind;

(2.) Pressure;

(3.) Temperature and humidity;

(4.) Fog and visibility;

(5.) Clouds;

(6.) Precipitation;

(7.) Thunderstorms, hurricanes, tornadoes, dust-storms;
(8.) Other weather phenomena;

(9.) State of sea,

and also on upper air currents and upper air temperature and humidity, from stations where facilities are available for

observation.

Reports will be made in the general form and in the codes given in Appendix IV.

2. Collective reports are a collection of the individual reports received by a central station or office and transmitted to other central offices. They are of three classes :

Class 1.—The central office in this case is usually the main office of a country; it transmits its reports, within 14 hours of the time the observations are taken at the individual stations, to all main offices of other countries within a radius of 1,500 kilometres.

countries over 1,500 kilometres distant information essential to Class 2.--These are reports made for the purpose of giving making their own forecasts. The central office is that of a selected State which possesses a high-power wireless station capable of world-wide ranges (minimum range 3.000 kilometres). The report is made within three hours of the observations, and is a collection of reports selected from the Class 1 reports and abridged (see

Appendix IV). It should include a forecast of conditions in the country of origin.

Class 3.-These are local reports made by local centres to other local centres (any within 500 kilometres). The report is a collection of reports, selected from the Class 1 reports from stations in the vicinity and abridged (see Appendix IV). It is made within thirty minutes of the time of observation.

APPENDIX II.

Special Reports.

Special reports give the results of continuous observations at aerodromes having meteorological stations on recognised air routes. They are to be rendered within thirty minutes of a request from a central office on a specified aerodrome on the route. The maximum distance from which these reports will be required is 500 kilometres. The requests may take the form of a demand for hourly reports.

The reports are rendered by telephone or wireless, and may be from one country to another in the case of an international air route. The reports when made by telegram will be in the form and code given in Appendix IV.

APPENDIX III.

Forecasts.

Short-period forecasts covering three to four hours will give a statement of the anticipated conditions of cloud, weather, surface wind, and visibility, together with direction and speed of wind at heights of 1,000 and 2,000 metres, and an estimate of meteorological fitness for different types of aircraft.

Normal forecasts for twenty to thirty hours will give similar information, but in more general terms.

Long-period forecasts give a general statement of the prospects for the next two or three days.

Route forecasts are made twice daily by central offices from information received from individual stations and will give a statement of conditions anticipated in the different regions or routes of the country for about six hours ahead.

APPENDIX IV.

General Form in which Reports are to be Rendered and Codes for their Transmission.

[Not printed.]

ANNEX (H).

Customs.

General Provisions.

1. Any aircraft going abroad shall depart only from aerodromes specially designated by the customs administration of each contracting State, and named "customs aerodromes."

Aircraft coming from abroad shall land only in such aerodromes. 2. Every aircraft which passes from one State into another is obliged to cross the frontier between certain points fixed by the contracting States. These points are shown on the aeronautical

maps.

3. All necessary information concerning customs aerodromes within a State, including any alterations made to the list and any corresponding alterations necessary on the aeronautical maps and the dates when such alterations become valid, and all other information concerning any international aerodromes which may be established, shall be communicated by the State concerned to the International Commission for Air Navigation, which shall notify such information to all of the contracting States. The contracting States may agree to establish international aerodromes at whic there may be joint customs services for two or more States.

4. When, by reason of a case of force majeure, which must be duly justified, an aircraft crosses the frontier at any other point than those designated, it shall land at the nearest customs aerodrome on its route. If it is forced to land before reaching this aerodrome it shall inform the nearest police or customs authorities.

It will only be permitted to leave again with the authorisation of these authorities, who shall, after verification, stamp the log book and the manifest provided for in paragraph 5: they shall inform the pilot of the customs aerodrome where he must necessarily carry out the formalities of customs clearance.

5. Before departure, or immediately after arrival, according to whether they are going to or coming back from a foreign country, pilots shall show their log books to the authorities of the aerodrome and, if necessary, the manifest of the goods and supplies for the journey which they carry.

6. The manifest is to be kept in conformity with the attached

form No. 1.

The goods must be the subject of detailed declarations in conformity with the attached form No. 2, made out by the senders. Every contracting State has the right to prescribe for the insertion either on the manifest or on the customs declaration of such supplementary entries as it may deem necessary.