When the following terms are used in this regulation they have the following meanings:

Accuracy. A degree of conformance between the estimated or measured value and the true value.

Note – For measured positional data, the accuracy is normally expressed in terms of a distance from a stated position within which there is a defined confidence of the true position falling.

Aerodrome. A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft.

Aerodrome beacon. Aeronautical beacon used to indicate the location of an aerodrome from the air.

Aerodrome certificate. A certificate issued by the Minister of Traffic and Transport under established regulations for the safe operation of an aerodrome within the Netherlands Antilles.

Aerodrome elevation. The elevation of the highest point of the landing area.

Aerodrome identification sign. A sign placed on an aerodrome to aid in identifying the aerodrome from the air.

Aerodrome reference point. The designated geographical location of an aerodrome.

Aerodrome traffic density.

a) Light. Where the number of movements in the mean busy hour is not greater than 15 per runway or typically less than 20 total aerodrome movements.

b) Medium. Where the number of movements in the mean busy hour is of the order of 16 to 25 per runway or typically between 20 to 35 total aerodrome movements.

c) Heavy. Where the number of movements in the mean busy hour is of the order of 26 or more per runway or typically more than 35 total aerodrome movements.

Note – The number of movements in the mean busy hour is the arithmetic mean over the year of the number of movements in the daily busiest hour.

Note 2 – Either a take-off or a landing constitutes a movement.

Aeronautical beacon. An aeronautical ground light visible at all azimuths, either continuously or intermittently, to designate a particular point on the surface of the earth.

Aeronautical ground light. Any light specially provided as anaid to air navigation, other than a light displayed on an aircraft.

Airplane reference field length. The minimum field lengthrequired for take-off at maximum certificated take-off mass, sea level, standard atmospheric conditions, still air and zero runway slope, as shown in the appropriate airplane flight manual prescribed by the certificating authority or equivalent data from the airplane manufacturer. Field length means balanced field length for airplanes, if applicable, or take-off distance in other cases.

Note – Attachment A, Section 2 provides information on the concept of balanced field length and the Airworthiness Manual (Doc 9760) contains detailed guidance on matters related to take-off distance.

Aircraft Classification Number (ACN). A number expressingthe relative effect of an aircraft on a pavement for a specified standard subgrade category.

Note – The aircraft classification number is calculated with respect to the center of gravity (CG) position which yields the critical loading on the critical gear. Normally the aft most CG position appropriate to the maximum gross apron (ramp) mass is used to calculate the ACN. In exceptional cases the forward most CG position may result in the nose gear loading being more critical.

Aircraft stand. A designated area on an apron intended to beused for parking an aircraft.

Apron. A defined area, on a land aerodrome, intended to accommodate aircraft for purposes of loading or unloading passengers, mail or cargo, fuelling, parking or maintenance.

Apron management service. A service provided to regulatethe activities and the movement of aircraft and vehicles on an apron.

Barrette. Three or more aeronautical ground lights closely spaced in a transverse line so that from a distance they appear as a short bar of light.

Calendar. Discrete temporal reference system that provides the basis for defining temporal position to a resolution of one day (ISO 19108*).

Capacitor discharge light. A lamp in which high-intensityflashes of extremely short duration are produced by the discharge of electricity at high voltage through a gas enclosed in a tube.

Certified aerodrome. An aerodrome whose operator has beengranted an aerodrome certificate.

Clearway. A defined rectangular area on the ground or waterunder the control of the appropriate authority, selected or prepared as a suitable area over which an airplane may make a portion of its initial climb to a specified height.

Cyclic Redundancy Check (CRC). A mathematical algorithmapplied to the digital expression of data that provides a level of assurance against loss or alteration of data.

Data quality. A degree or level of confidence that the dataprovided meet the requirements of the data user in terms of accuracy, resolution and integrity.

Datum. Any quantity or set of quantities that may serve as areference or basis for the calculation of other quantities (ISO 19104*).

Declared distances.

a) Take-Off Run Available (TORA). The length of runway declared available and suitable for the ground run of an airplane taking off.

b) Take-Off Distance Available (TODA). The length of the take-off run available plus the length of the clearway, if provided.

c) Accelerate-Stop Distance Available (ASDA). The length of the take-off run available plus the length of the stopway, if provided.

d) Landing Distance Available (LDA). The length of runway which is declared available and suitable for the ground run of an airplane landing.

Displaced threshold. A threshold not located at the extremity of a runway.

DCA NA. The Directorate of Civil Aviation Netherlands Antilles.

Effective intensity. The effective intensity of a flashing light is equal to the intensity of a fixed light of the same color which will produce the same visual range under identical conditions of observation.

Ellipsoid height (Geodetic height). The height related to thereference ellipsoid, measured along the ellipsoidal outer normal through the point in question.

Fixed light. A light having constant luminous intensity whenobserved from a fixed point.

Frangible object. An object of low mass designed to break,distort or yield on impact so as to present the minimum hazard to aircraft.

Note – Guidance on design for frangibility is contained in the Aerodrome Design Manual, Part 6 (in preparation).

Geodetic datum. A minimum set of parameters required todefine location and orientation of the local reference system with respect to the global reference system/frame.

Geoid. The equipotential surface in the gravity field of theEarth which coincides with the undisturbed mean sea level (MSL) extended continuously through the continents.

Note – The geoid is irregular in shape because of local gravitational disturbances (wind tides, salinity, current, etc.) and the direction of gravity is perpendicular to the geoid at every point.

Geoid undulation. The distance of the geoid above (positive)or below (negative) the mathematical reference ellipsoid.

Note – In respect to the World Geodetic System – 1984 (WGS-84) defined ellipsoid, the difference between the WGS-84 ellipsoidal height and orthometric height represents WGS-84 geoid undulation.

Gregorian calendar. Calendar in general use; first introduced in 1582 to define a year that more closely approximates the tropical year than the Julian calendar (ISO 19108*).

Note – In the Gregorian calendar, common years have 365 days and leap years 366 days divided into twelve sequential months.

Hazard beacon. An aeronautical beacon used to designate adanger to air navigation.

Heliport. An aerodrome or a defined area on a structureintended to be used wholly or in part for the arrival,

departure and surface movement of helicopters.

Holding bay. A defined area where aircraft can be held or bypassed, to facilitate efficient surface movement of aircraft.