Definition
A simplified approach lighting system consisting of seven omnidirectional flashing lights: five lights spaced at 300-foot intervals along the extended runway centerline outward from the runway threshold, and two lights placed one on each side of the runway threshold. The lights flash in sequence from the outermost light toward the threshold to guide the pilot's eyes inbound to the landing runway. ODALS is typically installed at non-precision instrument runways at smaller airports.
Plain English
A short, simple set of seven flashing lights that lead the pilot's eye toward the runway during an approach. Five flash in sequence along the centerline ahead of the runway, and two more sit on either side of the runway's beginning.
Context Anchor
Seen in instrument approach information and outside the cockpit near the runway during the final part of an approach.
Derivation
"Omnidirectional" comes from the Latin omnis (all) and direction — meaning the lights are visible from all directions, not just along a narrow beam. This matters because the pilot can pick up the lights even when slightly off the final approach course.
Why Pilots Care
Provides reliable visual cues for runway alignment and identification when weather or darkness reduces natural references.
Intuition Check
Omnidirectional does not mean the system lets you approach from any direction. It means the individual lights shine so they can be seen from many directions.
Example Sentence 1
The approach chart noted ODALS at the destination, so the pilot expected sequenced flashing lights leading to the runway threshold.
Example Sentence 2
Unlike unidirectional systems, ODALS remains visible from any angle during the initial approach.