Definitions

Landing Distance. The horizontal distance traversed by the aeroplane from a point on the approach path at a selected height above the landing surface to the point on the landing surface at which the aeroplane comes to a complete stop.

(Source: ICAO Annex 8 Part IIIA Paragraph 2.2.3.3. and Part IIIB Sub-part B Paragraph B2.7 e)

Landing Distance Available (LDA). The length of the runway which is declared available by the appropriate Authority and is suitable for the ground run of an aeroplane landing.

Source: EASA AIR-OPS Annex I - Definitions

Landing Distance at time of arrival (LDTA). Means a landing distance that is achievable in normal operations based on landing performance data and associated procedures determined for the prevailing conditions at the time of landing.