SAE ARP991C

This document covers the recommended lighting performance and design criteria for: a Left Forward Navigation Position Lights (Red) b Right Forward Navigation Position Lights (Green) c Rear Navigation Position Lights (White) d Anticollision Lights (1) Red Flashing Lights Top and Bottom Fuselage (2) White Flashing Strobe Lights Wing Tips and/or Tail (3) Red Flashing Beacon Light on Top of Vertical Tail This document is to provide the minimum design requirements with regards to Position and Anticollision light systems on fixed-wing aircraft. The minimum levels stated in this document are significantly above the minimum requirements outlined in the CFR publications. The rationale for this is to take into account real life factors that can impact the overall lighting output of the assembly (i.e., dirt, lamp degradation, etc.). New light assemblies should never be designed to meet the minimum requirements. In addition, with the use of LEDs as replacements for filtered incandescent lamps and strobe tubes, the design requirements need to be higher since LED assemblies do not have a single point failure mode like a burnt-out lamp but have degraded performance with some of the individual LEDs failing while the majority of LEDs continuing to operate. This degraded performance mode inherent with most LED assemblies shows the need to have higher initial design requirements to overcome the loss of some LEDs until the operator can make a determination to remove and replace the entire assembly.