About 25 aircraft will take part in a joint FAA-Cargo Airline Association (CAA) airborne test of ADS-B on 10 July, claimed by the organisers to be the first large-scale operational test of the technology.
The test will be carried out in the skies around Wilmington, Ohio, where CAA member and ADS-B (automatic dependent surveillance - broadcast) supporter ABX Air is based.
According to the FAA, the main goal of the tests is to evaluate how ADS-B can assist pilots to become more aware of aircraft in their vicinity.
Using GPS position data received by an aircraft, ADS-B equipment is designed to send very accurate positional information along with speed and identification data to other similarly equipped aircraft and ADS-B ground receiving stations. However, ADS-B is not yet designed to serve as an airborne collision avoidance system.
In the Ohio test, participating flight crews will monitor aircraft in their area using a special cockpit display. Air traffic control stations will receive combined radar and ADS-B target information for evaluation, but will not use the ADS-B for live traffic handling.
Three FAA aircraft will take part in the test, along with 12 cargo airliners contributed by CAA members UPS, Federal Express and ABX Air.
The FAA says the Wilmington evaluation will be just the first of several tests planned for the Ohio River Valley area during the next three years under the agency's Safe Flight 21 programme.
It says future test sites will include Louisville - where UPS' air operations are based - and Memphis, home of Federal Express. Selection of these CAA members' bases is hardly coincidental: although at present regulations do not require US freighter aircraft to be fitted with TCAS equipment, the CAA on its own initiative is developing ADS-B to provide both collision avoidance capability and future 'Free Flight' performance.
Areas of Alaska are also installing equipment to let them participate in the ADS-B evaluations. The FAA says it hopes ADS-B can eventually be used on a wide scale throughout the USA, in accordance with its plans to modernise US airspace.
The FAA's Safe Flight 21 programme is a cooperative effort between the US government and aviation industry to develop and demonstrate a set of operational capabilities that will lead to implementation of the 'Free Flight' concept.