Plain English Meaning

An instrument approach that uses a localizer-style signal for left-right guidance, but the signal is not lined up with the runway. The pilot follows it down toward the airport and then either lines up with the runway visually for landing, or circles to land if the approach course points well off to one side.

Full Definition

An instrument approach procedure that uses a Localizer-Type Directional Aid for lateral guidance. An LDA transmits a signal comparable in accuracy to an ILS localizer but is not aligned with the runway centerline, typically because terrain or other obstacles make a localizer installation impractical. An LDA approach may be published with or without guidance; when a glideslope is provided, the approach is designated . If the differs from the by more than 30 degrees, the approach is published as a .