INTRODUCTION

This document contains brief flight path histories and other reference and derived data of approximately 1200 3-dimensional radar tracks taken at general aviation airports: Salisbury-Wicomico Airport; Montgomery County Airpark; and Hyde Field. The SalisburyWicomico Airport is located eight kilometers southeast of Salisbury, Maryland in a relatively low traffic density region. It has three 1600 meter runways which serve private aircraft and commuter traffic to Baltimore, Washington, and Philadelphia. A flight school, air taxi, and an FAA Flight Service Station are available. The Traffic Pattern Altitude (TPA) is designated as 260 meters (800 feet). The Montgomery County Airpark located in Gaithersburg, Maryland, is a very high traffic density general aviation airport. With a single 1400 meter runway, it services corporate, private and sales aircraft, repair and maintenance facilities, and a flight school. The airpark also features left and right hand traffic patterns and a designated TPA of 195 meters (600 feet). Hyde Field is located in Clinton, Maryland and falls within the Washington, DC Terminal Control Area (TCA). Consequently, it exhibits traffic patterns constrained by adjacent airports, the TCA Corridor and the 490 meter (1500 foot) TCA floor overhead. It has two runways less than 900 meters long which are used by private aircraft and a flight school and operates with a TPA of 260 meters (800 feet). These airports were selected because each represented different uncontrolled air traffic situations and each was within 250 kilometers of Wallops Flight Center, thereby facilitating the collection and reduction of data.

Data were collected at each airport for a period of approximately three weeks between October 1971 and March 1972. Date, time, flight number and runway number were logged manually along with such items as pattern type, aircraft type, visibility, cloud condition and wind. Positional histories were obtained automatically using an MPS-19 tracking radar and data van. This equipment recorded on magnetic tape radar slant range, azimuth, and elevation at one second intervals. Table 1 presents selected distributions of data recorded at each airport. These tables present as a function of each airport the distribution by aircraft manufacturer, aircraft type, and pattern type.

The tapes and logs were returned to Wallops Flight Center for further processing. Radar data were edited, smoothed, and differentiated using standard techniques. They were then transformed to a runway relative coordinate system (Figure 1) enabling direct comparison of data regardless of runway used. Logged data were converted to a common format and used to form four identifying headers for each flight. Some reduced positional data were also placed in the headers including maxia and minia, and the start and stop times for each take-off or landing pattern leg. The headers and reduced positional data, presented as a series of detailed records, were then incorporated on an Indexed Sequential Processor (ISP)*

language data base, references. The format for the data base may be inferred from the key (see Appendix A).

The data are now available in two media. The data base has been implemented on disc for access through the Wallops Flight Center HW-625 computer. The second media is hard copy. It has been reduced in volume by including only every fifth detailed record. Microfiche records for each radar track in excess of sixty seconds are available on request from NASA. Requests for the supplement should be addressed to:

NASA Scientific and Technical Information Facility

Attn: Distribution and Control

Post Office Box 8757

Baltimore/Washington International Airport,

Maryland 21240

The records are contained on ten (10) microfiche. A printed sample is presented

in Appendix B.

*Indexed Sequential Processor, Honeywell Series 600/6000 Software, August 1973.