By TOM HOFFMANN, Managing Editor, FAA Safety Briefing
Your aircraft’s registration number or approved call sign is critical to the integrity of the ADS-B Out system, defining who you are in the National Airspace System (NAS).
But what happens when your ADS-B name is different from your given name?A large number of operational inconsistencies with ADS-B Out result from a naming problem or Call Sign Mismatch (CSMM). This occurs any time the aircraft identification listed in a flight plan does not exactly match the ADS-B transmitted identification.
A 31-day snapshot of U.S. air traffic data in December 2017 revealed a total of 31,324 flights with a CSMM. Most — 67% — were from commercial operators using special call signs, while GA accounted for nearly 17%. Approximately 50% of these GA aircraft were improperly programmed during installation.
A CSMM can lead to significant operational difficulties for air traffic controllers, including distraction and increased workload.
For GA, the problem typically stems more from operators who use specialized call signs, like air ambulance flights, rather than most GA flyers.
For the average GA pilot however, the N-number is always the call sign. So, if you own your own aircraft and your ADS-B Out system was properly installed and configured to ensure your registration or N-number mirrors what your ADS-B unit is transmitting, you’re good to go.
The best way to verify this is to check your system with the FAA’s Public ADS-B Performance Report (PAPR) tool at ADS-B Performance.
Simply fly in an area of ADS-B coverage and then submit a request. PAPR reports are typically delivered within 30 minutes and can verify if your system’s call sign is matched properly with your aircraft, as well as detect any other operational deficiencies with your ADS-B transmitter.
Some CSMM issues are caused by a simple typo when the technician is first configuring the ADS-B unit. If that’s the case, your repair shop should be able to help correct it. If the aircraft identification input on your unit can be manually configured, you may be able to update it yourself.
Where the CSMM issue tends to be more frequent is with operators who use specialized call signs during a flight that differ from the aircraft’s registration number. For example, one of the more common special call signs, “Compassion,” is used by the many public benefit flying groups that make up the Air Care Alliance (e.g., Angel Flight, Pilots N Paws, etc.).
Special call signs are mainly used to enable priority handling by ATC. These might include civil aircraft used for law enforcement, supporting medical emergencies or disasters, or organized events. Operators flying civilian air ambulance flights, for example, might use the call sign “Medevac” or “Lifeguard” and coordinate with ATC on any expeditious handling required.
There are also local call signs which are used only for local flight operations as specified in a letter of agreement (LOA) between the local ATC facility and the requesting aircraft operator. Some larger flight schools might have an agreement to use a local call sign to reduce confusion and ambiguity among several similar sounding aircraft operating in close proximity.
“When the average GA pilot is authorized to use a special call sign, they don’t always realize that what they use as a name on their flight plan has to match what their ADS-B unit transmits,” says James Kenney, an aviation safety inspector with the FAA’s Flight Technologies and Procedures Division in Flight Standards. “If you’re transporting rescue dogs and using the call sign ARF234, that’s great. But just remember you have to change your ADS-B aircraft identification to match that call sign. If your ADS-B doesn’t allow you to update the name, you’ll have to revert to using your N-number instead.”
ADS-B was once a great idea, but not the way FAA has implemented it.
So an even better way to avoid a mismatch is to simply avoid installing ADS-B… at least until FAA comes to its senses, and completely revamps ADS-B, to match what’s been done in places like Canada and Australia.
FAA’s over-specified NIC and NAC needs to be relaxed, DO-260B shouldn’t be needed at all, and using any GNSS source should be adequate. There is simply no need for accuracy requiring SBAS or integrity set at FAA’s foolish levels of 1x10E-5 to -7/flight hour goal, or equivalent (due to FAA’s misuse of ADS-B as “pseudo-radar”). ADS-B was only ever intended to be a “Backup” air-air system anyway, …where ID shouldn’t even matter.
FAA created this entire problem by taking a fundamentally good idea, and fouling it up, by forcing a very bad overspecified design for ADS-B, misused in a foolish “pseudo-radar” concept. (Primary radars will always be needed for other reasons). Now, with DoD’s recent valid concerns about ADS-B, as well as the rest of the world NOT following FAA’s lead, and the clear ability of FAA’s version of ADS-B to be hacked and spoofed by even high-school kids or equivalent, it’s time for FAA to rescind 91.225/91.227 before it’s too late. FAA and the industry need to completely re-think this entire “surveillance” based approach to NextGen.
ADS-B as originally envisioned (in early FANS 1/A days), as part of the C-N-S triad, and only as a backup to surveillance, for air-air coordination,… was an excellent idea. But not the way FAA has now completely fouled it up.
So these kinds of ADS-B problems are just going to keep happening, if not even getting worse, until FAA admits its errors in prematurely implementing this seriously flawed rule and concept, and mends it’s ways. Millions of drones are going to make all this worse. No way can drones use FAA’s foolish version of ADS-B. FAA’s misguided version of ADS-B is now apparently turning into the next budding case of MLS.
Instead, we now need a new Presidential level commission completely outside of FAA’s influence, to sort out all this NextGen mess. Just like was done back in ’56, with the Curtis Commission, after the Grand Canyon accident, that led to the once good, but now massively obsolete ATS system we have today.
What do you expect from a bunch of Federal Bureaucrats that sit in their offices all day thinking up ways to screw things up, even if they really aren’t trying to, Many Decades ? I’m still sitting here wondering why the units used and approved in Sport Planes and Experimentals in the National Airspace System can’t be used in an every day Cessna 172, Piper, etc. Seems to me if they work in those planes they should work in the Cessna/Piper bunch. They would, too, except for the FAA’s expensive certification rule that requires expensive testing, etc. if used in a type certificated aircraft. Makes no sense to me at all. Reminds me of back when I was flying airline. My co-pilot & I had regular lightweight Telex headsets(needed in a 727 cockpit at .84 Mach) and an FAA inspector told us we couldn’t use them because they weren’t “approved” for use in airliners. This was over 20 years ago so maybe that has changed.
What do you expect from a bunch of Federal Bureaucrats that sit in their offices all day thinking up ways to screw things up, even if they really aren’t trying to? I’m still sitting here wondering why the units used and approved in Sport Planes and Experimentals in the National Airspace System can’t be used in an every day Cessna 172, Piper, etc. Seems to me if they work in those planes they should work in the Cessna/Piper bunch. They would, too, except for the FAA’s expensive certification rule that requires expensive testing, etc. if used in a type certificated aircraft. Makes no sense to me at all. Reminds me of back when I was flying airline. My co-pilot & I had regular lightweight Telex headsets(needed in a 727 cockpit at .84 Mach) and an FAA inspector told us we couldn’t use them because they weren’t “approved” for use in airliners. This was over 20 years ago so maybe that has changed.
Here’s how “technology “ works. You hire some person at a six figure salary and tell them to look over what you got and see if they can “improve “ it. If he comes back and says everything looks good, works fine, and I wouldn’t change a thing. He’s out of a job. So what happens is we get more complex, expensive equipment that really just complicates and makes things more expensive. The FAA will never make things simpler or less expensive. Some day only the rich will have GA airplanes.
I frequently fly missions for Angel Flight Southeast (Air Charity Network) using a specialized call sign: NGF3XXX, where the Xs represent other digits.
The ADS-B out transmits the aircraft registration N number, but the ADS-B in shows the NGF identification and I have no mismatch reports.
I have on file with the briefing system the crossover between the NGF and N identifications. Does this crossover apparently eliminate the issue discussed in the article?