Study of Optical Techniques for Indirect Generation of Runway Approach Lights

摘要

The steel towers which are currently used to support runway approach lights present a significan collision hazard to landing aircraft, and are being replaced by frangible towers which reduce, but do not eliminate, this hazard. This study analyzes optical concepts for indirect generation of runway approach lights which would reduce the tower height or the mass of elevated components. Three concepts are investigated: projection of images with mirrors, use of a ground based lamp in conjunction with a diverging mirror in the light plane, and use of a fiber optic light pipe. The projection of images can achieve a height reduction of several feet, but would require the construction and maintenance of large mirrors. The other two techniques could eliminate wiring from elevated structures, but would require more complex optics and higher levels of power consumption. None of these techniques appears to be practical when the marginal benefits are weighted against their complexity and cost. (Author)