Definition
A simplified approach lighting system used at non-precision instrument runways, consisting of seven omnidirectional sequenced flashing lights. One light is positioned on the runway centerline extended at 100-foot intervals out to a distance of 600 feet from the runway threshold, and a cluster of lights forms a visual aiming point. The flashing pattern guides the pilot toward the runway during the final stages of an instrument approach.
Plain English
A row of bright lights that flash in sequence toward the runway, helping the pilot see and line up with the runway when finishing an instrument approach. The lights are visible from many angles, not just straight ahead.
Context Anchor
Seen on airport lighting descriptions, approach charts, airport facility information, and NOTAMs about runway lighting outages.
Derivation
Omnidirectional comes from the Latin omnis (all) and direction — meaning the lights can be seen from all directions, not just along a narrow line of approach. This matters because a pilot circling or maneuvering toward the runway can pick up the lights from a wider range of angles than a standard approach lighting system allows.
Why Pilots Care
Provides essential visual guidance for safe runway alignment during night or reduced-visibility approaches, reducing the risk of runway incursion or misalignment.
Intuition Check
Do not read “omnidirectional” as meaning you may approach or land from any direction. It means the lights themselves are visible from all directions.
Example Sentence 1
The chart shows ODAL serving Runway 14, so we should pick up the sequenced flashing lights as we break out of the clouds on final.
Example Sentence 2
Smaller airports often install ODAL systems to improve landing safety without the complexity of sequenced flashers.