Introduction. Installation variables have a real-world effect on the fixture’s Light Beam or the Field Photometrics. Disruption to the Photometric Beam effects the number of lights the pilot can see.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
“The secret of a good speech is to have a good beginning and a good ending; and to have the two as close together as possible” ….
George Burns (No Relation To Burns Engineering)
Pilot’s point of view in good weather.
Visibility of Runway Lights in Nighttime Fog.
Lower Photometric Angles are Blocked by Pavement if fixture elevation is low
Reduces the Number of LightsEffect Beam Blockage Has on Number of Lights Pilots Sees in Low Visibility
Transverse And Longitudinal Tilt
Fixture Elevation at Low Side of Pavement (FAA Req’t)
Tolerances of Surrounding Pavement
Design Percent Grade
Elevation of Fixture at Light Beam Exit To Adjacent Pavement
Effect on Field Photometrics & Pilots Field of View
Can the Pilot See The Lights?
Pavement Tolerances Visibility Grade Tolerance > Electrical TolerancePossible Reasons: Pavement Specifications/Tolerances
FAA Spec < ¼”
Pavement Tolerances Visibility Field ExperimentPavement Tolerances
Measure the pavement slope next to the light fixture using a digital level.
The results showed that, in many instances, the slope around the can was 2.3% whereas theoretical was 1.5%
~ 0.288 (< 3/8”)
Fixture Height Below Grade at Light Beam =
~ 3.2 °
Photometric Angle Blocked =
Measuring Fixture Height:
- The actual height will vary greatly depending on the measuring tool used. Can easily vary by 3/8”
Analyze Snow Plow Removal Procedures/Equipment
For new projects provide a detail to the Contractor or train the Contractor on the method to measure fixture elevation that most suites your Airport’s operational/snow plow removal constraints.
When performing the straightedge measurement of the pavement tolerances, survey the location of the lights and measure where the lights are going to be.
Ht Visibility D Ht D
Deg Grade for 12” for 6”
1/2 0.9% 0.1” 0.05”
1 1.75% 0.2” 0.1”Possible Reasons: Base Can Tilt.