Accuracy Assessment of Aircraft Transponder–Based Devices for Measuring Airport Operations

Abstract

Accurate counts of aircraft operations at unmonitored or partially monitored general aviation airports are difficult to achieve, but they are important because of their effect on the allocation of federal and state airport improvement funds. Impediments to correctly counting aircraft operations include inaccuracies related to the acoustic counters that are commonly used to collect data and errors in the statistical procedures that extrapolate the sample data into meaningful counts. In response to these impediments, the authors developed a measurement technique that uses data from aircraft transponders to determine the occurrence of aircraft operations at these airports. To validate the accuracy of this technique, operations counts calculated from its use at a general aviation airport in the state of Indiana were compared with those obtained from the FAA’s Air Traffic Activity Data System database, which contains official operations data reported by airports with towers. This comparison, which was conducted using data for April 2016, indicated that the new technology provided values within 5% of the 7,837 total operations reported by tower operators. The transponder signal–counting technology thus appears to be an effective and inexpensive means of establishing accurate operations counts not only at these airports but potentially at the more than 2,800 of the 3,331 airports in the National Plan of Integrated Airport Systems that lack associated air traffic control towers.