This handbook provides overall maintenance philosophy, general maintenance policy, procedures, and requirements essential for managing and maintaining the National Airspace System and complements related directives which provide detailed guidance in the specialized areas of administrative management and technical applications.

The Low Cost ILS Glide Slope and Marker development program was initiated to provide an ILS equipment capable of going into commission with only a fraction of the costs previously occurred in conventional procurements and installations. The program results in a solid state glide slope and marker systems of high commercial grade quality packaged in transportable shelters to minimize on-site costs. Improved antenna systems are developed to reduce siting effects on the glide slope and to improve the efficiency of the marker beacon. It is concluded that the objectives of the program have been achieved by providing a highly reliable glide slope and marker system capable of being inexpensively installed and maintained. Recommendations are made to value engineer certain subsystems of the glide slope equipment.