Design considerations in achieving MLS category III continuity of service requirements

This paper addresses system design aspects that should be considered in designing Microwave Landing Systems (MLS) to meet Category III Continuity of Service Requirements. Experience with Instrument Landing Systems (ILS) has shown that the continuity of service achieved in the field is at least two times worse than performance prediction based on equipment reliability. This is primarily due to outages caused by environmental factors. In the development of MLS it has been assumed that it would be more immune to environmental outages than ILS. This paper addresses these and other factors that should be considered in designing MLS to achieve Category III continuity of service requirements.