It’s a new year, and that means it’s time for new regulations to go into effect. One of the big aviation-related regulations involves the required use of Automatic Dependent Surveillance-Broadcast (only slightly less-awkwardly referred to as ADS-B) in the US. This may sound like some technical program that doesn’t matter to the layperson, but it has had big implications. If you’ve heard about Bahamasair having planes banned from US airspace, this is why.
What is ADS-B?
Remember how Gogo inflight internet used to exclusively use those ground-based towers to provide service but then satellite options became available? ADS-B is the satellite upgrade… but for navigation, not internet.
For ages, the air traffic control system has used ground-based radar to track airplanes. That meant coverage was limited to where ground stations existed, and it wasn’t great at low altitudes, especially in mountainous areas where terrain blocked signals. As part of the long-touted NextGen program to bring air traffic control into the 20th century (and I do mean 20th), air traffic control would rely on satellite-based technology. ADS-B is what was settled on, and it became mandatory for use in most cases on January 1 of this year.
Who Needs ADS-B?
Anyone flying in this airspace requires ADS-B onboard:

In other words, it’s pretty much everyone except for small airplanes flying out of small airports that avoid all the restricted airspace around.
I should note a couple of caveats here. What is required is just the use of ADS-B Out which means that the airplanes broadcast to air traffic control. ADS-B In brings data into the aircraft from the outside, but that isn’t required.
Also, while ADS-B Out has to be installed, if it’s broken, it is still allowed to fly in the US until it gets fixed (for the most part). Here’s how American’s ops team describes it. Note that an ANSP is the “air navigation service provider” – basically, check with the countries to which you’re flying to see what their rules are.
If the ADS-B equipment is INOP, FAA does not require ATC approval to operate in domestic airspace For international operations with ADS-B INOP, the flight operator must determine the ANSP requirements
Why is ADS-B Good?
While every technology has its issues, the mandatory adoption of ADS-B is a good development. It will give more accurate positions over a broader area. This is a stepping stone that will allow for better navigation in the future as we try to move away from defined airways to more direct routes. Having accurate, satellite-based navigation is a cornerstone of that plan, so this is a big deal.
For those airplanes with ADS-B In, that further enables better information to be displayed in the cockpit. That provides a big boost to safety efforts. The only people who really object here are the private/corporate aircraft owners who find the technology too expensive. They think it’s an unfair burden, but that ship has sailed. This has been known for years, and it’s finally going into effect.
What’s the Problem?
Alright, so this is good, then why are we even talking about this? Well, naturally, there are issues. The rules say that you have to have ADS-B Out installed to fly in controlled US airspace. New commercial aircraft are all delivered with the technology, but for older airplanes, it can be an expensive upgrade.
Case-in-point: Many people figured American would delay retiring its MD-80s in light of the 737 MAX being grounded. After all, didn’t American need extra capacity? Well, there were issues around maintenance checks that were coming due, but one big hurdle was that this fleet did not have ADS-B installed. That’s the same reason Southwest couldn’t really ponder bringing its 737-300s out of retirement to fill the MAX capacity gap.
The kits reportedly cost about $200,000 per airplane, but then there’s the work involved to actually install them. I’m told on the MD-80s, it would require extensive modifications to wiring and avionics to make this happen. It’s hard to justify that for what would really just be a temporary capacity fix while the MAX sits on the ground.
It’s one thing to retire airplanes as planned, but it’s a whole different thing to get caught with your pants down. That’s what happened to Bahamasair. The airline has some turboprops alongside one 737-700 and three 737-500s. Those 737-500s do not have ADS-B installed, so they are currently banned from US airspace. Oopsie daisy.
If you want to know more, here’s a whole list of FAQs straight from the Federal Aviation Administration. In summary, ADS-B good… even if the timing with the MAX grounding is unfortunate. If others can’t keep up with the requirements, that’s on them.