Definition
S-LDA is the straight-in landing minimums line published on an LDA (Localizer-Type Directional Aid) instrument approach chart. It gives the lowest altitude (DA or MDA) and visibility a pilot may use when flying the LDA approach to a runway whose final approach course is closely aligned with the LDA course, allowing a normal landing without circling. If the LDA course is not aligned closely enough with the runway, only circling minimums are published instead.
Plain English
S-LDA is the line on the approach chart that tells you the lowest you can come down on an LDA approach when the approach lines you up well enough with the runway to land straight ahead.
Context Anchor
Seen in the minimums section near the bottom of an LDA instrument approach chart.
Derivation
The 'S' stands for 'Straight-in,' a standard FAA chart prefix used on minimums lines (S-ILS, S-LOC, S-LDA, S-VOR) to mark the straight-in landing option. 'LDA' identifies the type of navigation aid being used for the approach.
Why Pilots Care
Allows safe instrument approaches at airports where a full ILS is not installed, expanding landing options in low visibility.
Intuition Check
Do not read the “S” as meaning “standard” or “special.” In this chart label, it means “straight-in.”
Example Sentence 1
Briefing the approach, the captain noted the S-LDA minimums of 680 feet MDA and 1 mile visibility.
Example Sentence 2
S-LDA minimums require an additional 50 feet of ceiling compared to a standard localizer.