ADS-B Explained by Matt Goodrich
My name is Matt Goodrich and I’m a Helicopter Instrument Flight Instructor. This video is made in conjunction with Pilot In Command LLC and Cleveland Helicopter Services. email, call, or text me to schedule your helicopter training today.
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ADS-B is a modern approach to position reporting. Providing various benefits, it’s part of the FAA’s Next Gen Airspace Overhaul Program, which is making America's air transportation system even safer, more efficient, and more predictable. ADS-B lets big brother see us better, in a good way.
Before ADS-B, other forms of tracking existed, such as radar (radio detection and ranging). This was required to allow ATC to view our position, which they would use for traffic separation. With radar, an antenna transmits or shoots out electromagnetic waves. These waves bounce off objects and return to usually the same antenna. A processor then determines properties of the object. Primary functions include distance and location, and secondary functions include altitude, speeds, ground-track, and more.
For example, if a wave bounces back, or echos, after 1 second, ATC can tell the object it bounced off is closer than another object with a 2 second echo.
A common ATC radar display shows circles with distance from some center, usually a tower, and an overlaid image of aircraft and various properties, such as altitude.
If ATC sees this helicopter and this airplane on a collision course, they could order “helicopter 23V, turn right 30 degrees”, avoiding an accident.
ADS-B provides the same benefits of radar and more. To understand ADS-B, we can break down the acronym.
A stands for automatic . Aircraft with ADS-B Out will automatically transmit their position, 12 times more often than radar usually detects.
D stands for dependent. Aircraft using ADS-B Out require a high integrity position source, such as WAAS/GPS.
S stands for surveillance. ADS-B provides a “radar-like” surveillance for ATC to have aircraft position, as explained before.
B stands for broadcast. The aircraft broadcasts its position info and unique ID. The position information includes latitude, longitude, altitude, velocity, and more. The broadcast travels from air-to-air and air-to-ground, which we’ll discuss next.
Let’s take a look at an example system using ADS-B. We’ll have a helicopter with only ADS-B Out, an airplane with only ADS-B In, a satellite, an ATC tower, and an ATC ground station.
The D in ADS-B was dependent, and the helicopter with ADS-B out will depend on our satellite for position information.
The B in ADS-B was broadcast, and the helicopter will broadcast its position from both the air to the air and air to the ground, hence air-to-air and air-to-ground.
The ATC ground station receives the air-to-ground signal, which is relayed to the ATC tower. The controller can now see the aircraft’s position.
The air-to-air signal reaches the airplane’s ADS-B In receiver. The pilot of the airplane can see the helicopter’s position on their in-flight display.
This display looks similar to an ATC radar. For example, I use ForeFlight with a Sentry ADS-B In receiver. I’m able to see an updated picture of other aircraft with ADS-B Out. In uncontrolled airspace I can then play the role of ATC for myself. Especially flying airplanes with less outside visibility, this has helped me avoid collisions with other traffic out of my view, such as to my side or below.
Other information is sent from the ground station to the airplane, including weather. My handheld GPS then shows me weather radar and satellite in-flight. I have adjusted my flight path in the past using this information.
The FAA has published regulations for the use of ADS-B Out. These can be found in Title 14 of the Code of Federal Regulations under Part 91.225.
The acronym I’ve made to remember ADS-B Out requirements is ABCABC1CG. This expands to Alpha, Bravo, Charlie, Above, Bravo, Charlie, 10,000 MSL, Mode C, Gulf. ADS-B Out is required in Class Alpha, Bravo, and Charlie airspaces. It’s also required above Class Bravo and Charlie. It’s required in Class E airspace above 10,000’ MSL, excluding below 2,500’ AGL. It’s required within Mode C veils, which have a 30 NM radius of primary Class B airports as published. Lastly, it’s required in Class E airspace over the Gulf of Mexico, above 3,000’ MSL and within 12 NM of the U.S. Coast.
ADS-B In isn’t required, but highly recommended. If you’re flying frequently, it will definitely pay off, from helping you choose more efficient routes, avoiding aircraft damage, or even preventing a mid-air collision and saving your life. I definitely personally recommend it.
ADS-B offers a wide range of benefits. Updates are considered real-time, providing ATC and pilots with accurate pictures of traffic. With a clear picture, ATC predictability increases, separation decreases, departure and arrival times decrease, and environmental impact decreases. FIS-B gives GA pilots “free weather”. Operators can track their own fleets. The FAA will spend less on ADS-B equipment, moving from $950 million/yr on its ground-based network to ⅓ that amount. Surveillance has become available in remote and inhospitable areas, including Alaska, mountains, and the Gulf. It assists with increased congestion. Safety has increased. Lastly, search and rescue has more accurate last-position info.
If you have questions, you can email me at email@example.com. I’m available for helicopter ground and flight training. Don’t forget to like and subscribe if you found this helpful. Thanks for watching and good luck with your flying.
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