Counting OPS at GA Airports

Counting Ops at GA Airports

Current methods used by FAA, states need to be refined

By Dr. Maria Muia, Manager of Aeronautics Section, Indiana DOT

March 2001

In an industry with exploding growth and limited funding, it’s appropriate that measures be taken to accurately record growth and to ensure funds are allocated properly to accommodate this growth. That’s the opinion of Maria Muia, aviation manager for Indiana, who recently researched methods used to count aircraft operations. Here are some of her findings.

The U.S. accounts for 50 percent of all general aviation traffic in the world, and GA aircraft make up over 90 percent of all aircraft in this country. Almost 84 percent of the 5,357 airports open to the public in the U.S. are general aviation airports, and the vast majority of these airports do not have air traffic control towers. General aviation airports provide service to more than 5,300 communities while the airlines serve just a handful; yet, we don’t have a uniform way of counting the traffic that uses our general aviation airports.
Air traffic controllers count the aircraft that use the commercial airports, but who is counting the aircraft at the general aviation airports? In some cases the state aviation agency is, but in most cases the number of operations recorded at a general aviation airport is simply a guess. Albeit an educated guess in certain cases, but usually just a guess all the same.
We care about this information because it’s being used for a whole host of purposes: helping to justify airport development projects, air traffic control towers, and navigational aids. It’s being used in airport environmental documentation, forecasting, economic impact statements, airport planning, and the FAA Airport Master Records. If inaccurate methods are being used to estimate operations, then anything the resulting information is used for is questionable.

Surveying the States
I recently surveyed each state aviation agency in the country to determine exactly what method, if any, was being used to count and estimate aircraft operations at non-towered airports in their states. I further analyzed these methods for accuracy, efficiency, and cost-effectiveness.
The most popular method to estimate aircraft operations at non-towered airports is to simply ask someone at the airport what they think the operations are. Thirty states just ask the manager, the FBO, or other commercial operator. The accuracy of this method is highly questionable.
Ten states report that they multiply the airport’s based aircraft by a predetermined number of operations per based aircraft. For example, if an airport has 30 based aircraft and each aircraft is believed to perform 500 operations per year, then the airport records having 15,000 operations. The accuracy of this method is also questionable.
Three states base annual operations on information contained in guest logs at the airport. Many airports keep registers for pilots to sign when they come into the terminal. These are tallied to determine an annual estimate. But how many people actually sign these logs? (If I am typical of most pilots, I only sign them about 50% of the time.)
Eighteen states take a sample of actual operations and estimate annual operations from the sample. This method has some degree of statistical accuracy, but there are still concerns about how and when the samples are taken. Furthermore, there is concern about how the sample is expanded into an annual estimate.
Two states use information received in planning studies as their source for operations estimates. These studies include individual airport master plans, regional plans, and state system plans. One state contacts commercial carriers located at the airport and asks what the annual operations are. These are tallied into an annual count for commercial operations — but what about the non-commercial?
It’s interesting to note that of the states that responded to the questionnaire, 15 indicate that they use more than one method, making the results incomparable with other airports within the same state because of the different methods used.