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Runway End Identifier Lights

AIM ¶ 2-1-3 — Runway End Identifier Lights

AIM 2-1-3 explains Runway End Identifier Lights (REIL): synchronized flashing lights at the runway threshold for rapid approach end identification.

In Plain English

Runway End Identifier Lights (REIL) help you quickly find and confirm the approach end of a runway during your final approach. The system is simple: a pair of synchronized flashing lights, one on each side of the runway threshold, that pulse together to catch your eye.

REILs come in two configurations:

  • Omnidirectional — visible from multiple angles
  • Unidirectional — aimed at the approach area only

Knowing when REILs help is important for operational decision-making. Per AIM 2-1-3, they are particularly effective for:

  • Identifying a runway surrounded by a lot of other lighting (e.g., city lights that wash out the airport)
  • Identifying a runway that lacks contrast with surrounding terrain (e.g., a runway blending into desert or snow)
  • Identifying a runway during reduced visibility (haze, rain, or low light)

For student pilots, recognizing REILs on a sectional or airport diagram (often noted in the Chart Supplement) and being able to identify them visually on approach is a practical skill — especially at night or when transitioning into an unfamiliar field.

AIM Source Text
FAA AIM ¶ 2-1-3
2-1-3. 2-1-3. Runway End Identifier Lights (REIL) REILs are installed at many airfields to provide rapid and positive identification of the approach end of a particular runway. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either omnidirectional or unidirectional facing the approach area. They are effective for: Identification of a runway surrounded by a preponderance of other lighting. Identification of a runway which lacks contrast with surrounding terrain. Identification of a runway during reduced visibility.
Oral Exam Questions a DPE Might Ask
Q1What are Runway End Identifier Lights (REIL) and how are they configured?
Per AIM 2-1-3, REILs are a pair of synchronized flashing lights installed laterally on each side of the runway threshold to provide rapid and positive identification of the approach end of a runway. They may be either omnidirectional or unidirectional facing the approach area.
Q2When are REILs most effective?
Per AIM 2-1-3, REILs are effective for identifying a runway surrounded by a preponderance of other lighting, identifying a runway that lacks contrast with surrounding terrain, and identifying a runway during reduced visibility.
Q3What is the difference between omnidirectional and unidirectional REILs?
Per AIM 2-1-3, omnidirectional REILs are visible from multiple directions, while unidirectional REILs face the approach area, meaning they are aimed specifically toward aircraft on final approach to that runway.
Related Paragraphs in AIM Chapter 2
2-1-1
Approach Light Systems
2-1-10
Taxiway Lights
2-1-2
Visual Glideslope Indicators
2-1-4
Runway Edge Lights
2-1-5
In-Runway Lighting
2-1-6
Runway Status Lights (RWSL)
2-1-7
Airport Lighting Control
2-1-8
Pilot Controlled Lighting
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AIM 2-1-3 — Runway End Identifier Lights (REIL)