Evaluation of Supplemental Lights for Caution Bars

Caution Bars (stop bars or hold bars) are used to identify taxiway hold, lines and warn pilots of an approaching runway. Caution Bars are difficult to see when they are covered by snow. or sand, or when a high-cockpit aircraft is at or close to the caution bars. Under these conditions, supplemental lights (taxi-holding position lights) could help. This project was to determine the desired characteristics of horizontal and vertical coverage, intensity, flash rate, and orientation of the supplemental lights. The results indicated that these characteristics were acceptable or desired:

Horizontal and vertical coverage: ±15 degrees (as shown by photometric data) Intensity: 30-percent night; 100-percent day (1600 candela light) Flash rate: 58 flashes/minute (off the shelf equipment) Orientation: toe-in 20 degrees toward taxiway pitch-Up 10 degrees above horizon

The results also indicated that the lights would enhance identification of the taxiholding position.