GEN 2.1 MEASURING SYSTEM, AIRCRAFT MARKINGS, HOLIDAYS

1. UNITS OF MEASUREMENT

The table of units of measurement shown below will be used by aeronautical stations within Muscat FIR for air and ground operations.

FOR MEASUREMENT OF	UNITS USED
Distance used in navigation, position reporting, etc. generally in excess of 2 nautical miles	* Nautical Miles and tenths
Relatively short distances such as those relating to aerodromes (e.g., runway lengths)	Metres
Altitudes, elevations and heights	Feet
Horizontal speed including wind speed	Knots
Vertical speed	Feet per minute
Wind direction for landing and taking off	Degrees Magnetic
Wind direction except for landing and taking off	Degrees True
Visibility including runway visual range	Kilometres or Metres
Altimeter setting	Hectopascal
Temperature	Degrees Celsius (Centigrade)
Weight	Metric tons or Kilograms
Time	Hours and Minutes, beginning at midnight UTC

* International nautical miles, for which conversion into metres can be expressed by:

1 NM = 1852 M

2. TEMPORAL REFERENCE SYSTEM

Co-ordinated Universal Time (UTC) and the Gregorian calendar are used by air navigation services and in publications issued by the Aeronautical Information Service.

Reporting of time is expressed to the nearest minute,e.g., 12:40:35 is reported as 1241.

3. HORIZONTAL REFERENCE SYSTEM

3.1 Name/designation of system

All published geographical coordinates indicating latitude and longitude are expressed in terms of the World Geodetic System - 1984 (WGS-84) geodetic reference datum.

3.2 Parameters of the Projection

Projection is expressed in term of Universal Transverse Mercator (UTM).

3.3 Ellipsoid

An ellipsoid is expressed in terms of the World Geodetic System - 1984 (WGS-84) ellipsoid.

3.4 Datum

The World Geodetic System - 1984 (WGS-84) is used.

3.5 Area of application

The area of application for the published geographical coordinates coincides with the area of responsibility of the AIM, i.e., the entire territory of the Sultanate of Oman as well as the airspace over the high sea encompassed by the Muscat FIR in accordance with the regional air navigation agreement.

3.6 Use of an asterisk to identify published geographical coordinates

An asterisk (*) will be used to identify those published geographical coordinates that have been transformed into WGS-84 coordinates but whose accuracy of original field work does not meet the accuracy requirements in Annex 11, Chapter 2 and Annex 14, Volumes I and II, Chapter 2.

4. VERTICAL REFERENCE SYSTEM

4.1 Name/designation of system

The vertical reference system corresponds to mean sea level (MSL).

4.2 Geoid model

The geoid model used is the Earth Gravitational Model 1996 - (EGM-96).

5. AIRCRAFT NATIONALITY AND REGISTRATION MARKS

The nationality mark for aircraft registered in Oman is the letter A, followed by the figure 4, followed by the letter O, i.e. A4O. The nationality mark is followed by a hyphen and registration mark consisting of a two or three letter group e.g. A4O-AA.

6. PUBLIC HOLIDAYS

Friday and Saturday are the weekend for both public and private sectors. Other public holidays are not on fixed dates and will be announced by government with advanced notice.