Figure B-1. Illustration of Acquisition Distance Calculation
B-4. Definitions.
Note: The 2,000-foot avoidance distance comes from the guy wires of a 2,000-foot structure. The guy wires at a 45-degree angle would be at a distance of 1,500 feet from the structure at a 500-foot elevation. Since the aircraft is to be 500 feet clear of obstacles (the guy wire), the distance of avoidance from the structure is 1,500 + 500 = 2,000 feet (see Figure B-1).
B-4.1 Flight Visibility.
The average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.
Reference: Airman’s Information Manual Pilot/Controller Glossary.
B-4.2 Meteorological Visibility.
A term that denotes the greatest distance, expressed in statute miles, that selected objects (visibility markers) or lights of moderate intensity (25 candelas) can be seen and identified under specified conditions of observation.
B-4.2 Lighting System Configuration.
1. Configuration A. Red Obstruction Lighting System.
2. Configuration B. High-Intensity White Obstruction Lights for structures with appurtenance 40 feet or less.
3. Configuration C. High-Intensity White Obstruction Lights for structures with appurtenance greater than 40 feet.
4. Configuration D. Medium-Intensity White Obstruction Lights.
5. Configuration E. Medium-Intensity Dual White and Red Obstruction Lights.
6. Configuration F. High-Intensity Dual Obstruction Lights for structures with appurtenance greater than 40 feet.
7. Configuration G. High-Intensity Dual Obstruction Lights for structures with appurtenance 40 feet or less.
Example: “Configuration B 3” denotes a high-intensity lighting system with three levels of light.
APPENDIX C: ACRONYMS
Abbreviation Meaning AC Advisory Circular ADLS Aircraft Detection Lighting System AGL Above Ground Level AMSL Above Mean Sean Level CFR Code of Federal Regulations CM Centimeter DSP Defense Standardization Program F Flashing Lights FAA Federal Aviation Administration FCC Federal Communications Commission FPM Flashes Per Minute IFR Instrument Flight Rules IR IFR Military Training Route KHZ Kilohertz KM Kilometers KPH Kilometre Per Hour KV Kilovolts LED Light Emitting Diode LUX Lumen Per Square Meter M Meter MET Meteorological Evaluation Tower MHZ Megahertz MPH Miles Per Hour NAS National Airspace System NAVAIDS Navigational Aids NM Nautical Mile NOTAM Notice to Airmen NVG Night Vision Goggles OEG Obstruction Evaluation Group SM Statue Mile URL Uniform Resource Locator UV Ultra Violet US United States VFR Visual Flight Rules