GEN 2.1 Measuring system, aircraft markings, holidays

2.1.1 Units of measurement

The units of measurement used within EMIRATES FIR conform to the ICAO Standards and Recommended Practices specified in Annex 5, Units of Measurement to be used in Air and Ground Operations.

Units of Measurement
Distance used in navigation, position reporting, etc., generally in excess of 2 to 3 NMNM and tenths
Relatively short distances such as those relating to aerodromes, e.g. runway lengthsMetres
* Altitudes, elevations and heightsFeet and Metres
Horizontal speed including wind speedKnots
Vertical SpeedFeet per minute
Wind direction for landing and take-offDegrees Magnetic
Wind direction except for landing and take-offDegrees True
Visibility including RVRKilometres or Metres
TemperatureDegrees Celsius
WeightMetric Tons or Kilograms
Altimeter setting, atmospheric pressureHectopascal
* unless otherwise stated, refer to AMSL

2.1.2 Temporal Reference System Co - ordinated Universal Time (UTC) is used in the air traffic communication services and in documents published by the Aeronautical Information Service. The day of 24 hours begins at midnight and is divided into hours, minutes and seconds. In reporting time, the nearest full minute is used. Time checks to aircraft are accurate to the nearest minute only. Local time in the United Arab Emirates is UTC plus 4 hours.

2.1.3 Horizontal Reference System Geographic co - ordinates for ATS airspace, prohibited, restricted and danger areas together with international airports are based upon the World Geodetic System - 1984 (WGS 84) spheroid. Published co - ordinates meet the accuracy requirements specified in ICAO Annexes 4 and 15. Other geographic co - ordinates including those for domestic airports are based upon unverified survey data. Accuracy requirements specified in Annexes 4 and 15 are not necessarily satisfied. Co - ordinates based upon unverified survey data or data of unknown accuracy are marked with an asterisk.

2.1.4 Vertical Reference System The vertical reference system corresponds to Mean Sea Level (MSL). EGM2008 is the Geoid Model used in OMDB and OMDW for determining elevations above MSL datum. MSL based on EGM2008 is 0.18 M lower than MSL based on EGM96 at OMDB and MSL based on EGM2008 is 0.98 M lower than MSL based on EGM96 at OMDW. EGM2008 contains high resolution gravity field data and provides more accuracy than EGM96 model.

2.1.5 Aircraft nationality and registration marks The nationality mark for aircraft registered in United Arab Emirates is A6 (ALPHA SIX)

2.1.6 Public Holidays Public holidays for religious events are based upon the Hijri Calendar which does not correspond with the Gregorian Calendar commonly used in aviation. The start of months in the Hijri year is dependent on moon sightings and cannot be accurately predicted in advance. A Hijri year is approximately 10 days shorter than the Gregorian year. The following is a list of national public holidays for 2019 with dates corresponding with the Gregorian Calendar. The dates of religious holidays are marked with an asterisk. These dates are based on the lunar calendar and may vary by 1 or 2 days from the dates indicated. These holidays move forward by approximately 10 days per year.
Public Holidays in UAE (2019)
DateName of HolidayDuration (Days)
JAN 01New Year Day1
APR 03Ascension of the Prophet *1
JUN 04-06Eid Al - Fitr *3
AUG 11-14Eid Al - Adha *4
SEP 01Hijri New Year Day *1
NOV 10Prophet Mohammed's Birthday *1
NOV 30Martyr's Day1
DEC 02-03National Day2