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Localizer-type Directional Aid (LDA) (GA100)

DGIF baseline 2026-1, the latest. Earlier baselines: timemap.

RDF: ga100.ttl

Name

LocalizerDirectionalAid

Kind

FeatureType

Definition

A Very High Frequency (VHF) transmitter, radiating signals in a particular direction in order to provide a straight line azimuth path in the horizontal plane to the centre line of a runway.

Description

The Localizer-type Directional Aid (LDA) is of comparable use and accuracy to a localizer but is not part of a complete Instrument Landing System (ILS). The LDA course usually provides a more precise approach course than the similar Simplified Directional Facility (SDF) installation, utilizing a course width of 3 to 6 arc degrees instead of the 6 to 12 arc degrees that a typical SDF may provide.

Synonyms

LDA

Accepted

2013-10-18

Geometry

point, multipoint, curve, multicurve, surface, multisurface, solid, multisolid

Subtype of

GA033 Aeronautical Radio Navigation Installation

Attributes

• CLW Localizer Course Width — multiplicity 0..1; datatype AngleMeasureMeta
• BEA Magnetic Bearing — multiplicity 0..1; datatype AngleMeasureMeta
• TBE True Bearing — multiplicity 0..1; datatype AngleMeasureMeta

Associations

• LocalizerDirectionalAidMagneticVariationInfo → ZI103 Magnetic Variation Information (0..*)
• LocalizerDirectionalAidRadioTransmissionInfo → ZI101 Radio Transmission Information (0..*)

RWOI terms naming it

• RWO_01903 LDA
• RWO_01996 Localizer-type Directional Aid (LDA)

Source: DGIF 2026-1 QEA model, DGIWG. Standard: DGIWG 206-3. Licence: CC BY 4.0, © DGIWG.