Improving low visibility operations

Low visibility is a major limiting factor on aircraft operations. Although there are several definitions of low visibility, in this paper it is defined as values less than a runway visual range (RVR) of 2400 feet. These conditions only occur a small percentage of the time, but they can have a major impact on the National Airspace System (NAS). The impact of reduced arrival rates as a result of low visibility operations at a major hub airport impacts a large geographic area. Departure airports, enroute airspace, diversion airports and adjacent smaller airports can all be significantly impacted from the reduction of capacity at the primary destination. The costs associated with the resultant delays, cancellations and diversions are substantial. The Federal Aviation Administration (FAA), in an effort to reduce these impacts and harmonize with Europe's Joint Aviation Authorities (JAA), has undertaken the task of updating the requirements for low visibility operations. This activity focuses on utilizing advanced flight deck technologies in lieu of ground based lighting and navigation components. Specific advanced flight deck technologies such as head-up displays (HUD), flight directors, auto-land systems, and enhanced flight vision systems for use in low visibility approach and landing in civil operations are being researched by the FAA and The MITRE Corporation's Center for Advanced Aviation System Development (CAASD). Benefits are enabled for operators by allowing certain Category I instrument approaches to be flown with suitable advanced flight technology in lower visibility conditions and to operate to lower decision heights. This paper reports on the extent of benefits found through analysis of weather conditions, equipage rates, demand for access, and the importance of flight schedule integrity. This paper also discusses related technologies and research that can be utilized for low visibility operations and the key considerations important to utilizing these systems for the approach and landing phases of flight.