The table of units of measurement shown below are used by aeronautical stations within Brussels FIR/UIR 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 (NM) and tenths |
Relatively short distances such as those relating to aerodromes (e.g. runway lengths) | Metres (M) |
Altitudes, elevations and height | Feet (FT) |
Horizontal speed, including wind speed | Knots (KT) |
Vertical speed | Feet per minute (FPM) |
Wind direction for landing and take-off | Degrees magnetic (°) |
Wind direction, except for landing and take-off | Degrees true (°) |
Visibility, including RVR | Kilometres or metres (KM or M) |
Visibility, including RVR (MIL) | Kilometres or metres (KM or M) or nautical miles (NM) and tenths |
Altimeter setting | Hectopascal (HPA) |
Temperature | Degrees Celsius (°) |
Weight | Metric tonnes (T) or kilogrammes (KG) |
Weight (MIL) | Pounds or kilogrammes (KG) |
Time | Hours and minutes, beginning at midnight UTC |
Co-ordinated Universal Time (UTC) and the Gregorian calendar are used by air navigation services and in publications issued by the AIS. Reporting of time is expressed to the nearest minute, e.g. 12:40:35 is reported as 1241.
Due to the application of daylight saving time, the relation between UTC and local time is different during summer and the winter period. The summer period starts every year on the last SUN of MAR at 0100 UTC and ends on the last SUN of OCT at 0100 UTC.
During the winter period, local time is UTC + 1 HR. During the summer period, local time is UTC + 2 HR.
In the AIP and in AIC, UTC times applicable during the summer period will be added between brackets when different from those applicable during the winter period.
SUP will mention UTC times as applicable during their period of validity. If the period of validity overlaps the transition from summer to winter period or vice versa, the system used in the AIP will be applied.
NOTAM will mention UTC times as applicable during their period of validity. If item D or E of a NOTAM contains time information and the period of validity overlaps the transition between summer and winter period, a separate NOTAM will be published for each time period.
All published geographical co-ordinates indicating latitude and longitude are expressed in terms of the World Geodetic System of 1984 (WGS-84) geodetic reference datum.
An asterisk (*) will be used to identify those published geographical co-ordinates which have been transformed in to WGS-84 co-ordinates but whose accuracy of original field work does not meet the requirements in ICAO Annex 11, Chapter 2 and ICAO Annex 14, Volumes I and II, Chapter 2.
Mean sea level datum (MSL) is used as the vertical reference system.
In addition to elevation values referenced to MSL, geoid undulation (referenced to the WGS-84 ellipsoid) is published for specific surveyed ground positions.
MSL values refer to the Earth Gravitational Model 2008 (EGM-2008). Values of geoid undulations are computed on a 1’x1’ grid (equiangular spacing in terms of WGS-84 geodetic coordinates). At any point, this model provides trough interpolation the geoid undulation above the ellipsoid WGS-84. The accuracy of this model has been reported as to the order of 10 CM.
MSL values can be transformed to and from EGM-96 using the conversion grid in the following PDF: https://ops.skeyes.be/html/belgocontrol_static/eaip/eAIP_Product/Documents/Conversion EGM-96.pdf
The conversion grid covers the Brussels FIR, using rows and columns delimited by the geographical coordinates shown in the margin, expressed in degrees and minutes. By determining the applicable cell in the grid, MSL values and geoid undulation can be transformed between EGM-2008 and EGM-96 for each given position expressed in metres, using following formulas:
MSL value [EGM-96] = MSL value [EGM-2008] - value shown in grid
Undulation [EGM-96] = undulation [EGM-2008] + value shown in grid
The nationality mark for civil aircraft registered in Belgium is the letter combination “OO” and for civil aircraft registered in Luxembourg, the letter combination “LX”. The nationality mark is followed by a hyphen and a registration mark consisting of:
New Year's Day | 01 JAN | Belgium and Luxembourg |
Easter Monday | - | Belgium and Luxembourg |
King's Birthday | 15 APR | Belgian Defence |
Labour Day | 01 MAY | Belgium and Luxembourg |
Europe Day | 09 MAY | Luxembourg |
Ascension Day | - | Belgium and Luxembourg |
Day after Ascension Day | - | Belgian Defence |
Whit Monday | - | Belgium and Luxembourg |
National Holiday | 23 JUN | Luxembourg |
National Holiday | 21 JUL | Belgium |
Assumption Day | 15 AUG | Belgium and Luxembourg |
All Saints Day | 01 NOV | Belgium and Luxembourg |
All Souls Day | 02 NOV | Belgium(*) |
Armistice Day | 11 NOV | Belgium |
Dynasty Day | 15 NOV | Belgium(*) |
Christmas Day | 25 DEC | Belgium and Luxembourg |
Boxing Day | 26 DEC | Belgium(*) and Luxembourg |
Holiday period | 27 - 31 DEC | Belgian Defence |
(*) Public services only |
Note: Dates of Easter Monday, Ascension Day, day after Ascension Day, Whit Monday and any additional military closing days will be announced by SUP.