ADS-B: Improving Controlled Airspace   

    Signed into law in December of 2003, the Century of Aviation Reauthorization Act introduced the concept of a Next Generation Air Transportation System (NextGen) (FAA, n.d.). NextGen aims to enable more efficient and safe management of the air transportation system. Since its inception, NextGen has grown and evolved to include various changes in the way air traffic is managed. One such recent mandate that has had an overwhelming impact on the safety of flight is the requirement for aircraft to utilize Automatic Dependent Surveillance-Broadcast (ADS-B) Out equipment. 

    ADS-B is a system that transmits an aircraft's GPS position to the ground to Air Traffic Controllers (ATC), enhancing their ability to safely direct air traffic through controlled air space. Another "mode", ADS-B "In", can also be used to enable air-to-air transmission of position data from one aircraft to another, greatly enhancing situational awareness. In the past, ATC relied solely upon radar-based systems and two-way radio communication to direct air traffic. The great benefit of ADS-B is that it is automatic and dependent, which means that in normal operation it requires no input from the pilot to transmit necessary data to ground stations about the aircraft's position, speed, or direction of flight.

    FAR § 91.225 mandates that after January 1, 2020, all aircraft operating within specific limits of various controlled airspace must be equipped with ADS-B "Out" equipment, unless otherwise authorized by the FAA (ADS-B, 2021). Specifically, aircraft are required to be equipped with ADS-B, and be operational, when they operate in the following controlled airspace areas:

• Class A, B, and C airspace;
• Class E airspace at or above 10,000 feet MSL, excluding airspace at and below 2,500 feet agl;
• Within 30 nautical miles of a Class B primary airport (the Mode C veil);
• Above the ceiling and within the lateral boundaries of Class B or Class C airspace up to 10,000 feet;
• Class E airspace over the Gulf of Mexico, at and above 3,000 feet MSL, within 12 nm of the U.S. coast. (AOPA, n.d.).

This graphical illustration helps to understand exactly where ADS-B Out is mandated to be used:

    

    This FAR has greatly benefitted the aviation industry on an international level. It has enhanced ATC's ability to safely direct air traffic both in the sky and on the ground, as well as enables reduced aircraft separation (Spire, 2022). Because ADS-B reduces the need for standard separation, aircraft can follow more direct flight routes, which lowers fuel consumption, further reducing operating costs and carbon emissions (Spire, 2022). ADS-B has also been proven to reduce aviation accident rates. In fact, when it was still being developed and tested, the accident rate in ADS-B-equipped locations in Alaska fell by nearly 50 percent (MITRE, 2015).

References:

ADS-B: Enabling the Next Momentous Transformation in Air Traffic. (2015, April 14). The MITRE Corporation. https://www.mitre.org/publications/project-stories/adsb-enabling-the-next-momentous-transformation-in-air-traffic-control

Automatic Dependent Surveillance-Broadcast (ADS-B) Out equipment and use, 14 U.S.C. 

            § 91.227 (2021). https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91/subpart- 

            C/section91.225

Spire. (2022, April 19). How ADS-B has Shaped the Modern Aviation Industry. Spire : Global Data and Analytics. https://spire.com/wiki/how-ads-b-has-shaped-the-modern-aviation-industry/

Where is ADS-B Out Required? (n.d.). AOPA. https://www.aopa.org/go-fly/aircraft-and-ownership/ads-

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