ADS-B / Satellite Tracking / Traffic / Accidents - Started in Response to Caravan Crash Thread

[I WAS Pez]

Hello all,
I considered replying on the other thread about the recent Caravan crash, especially after some reports that the crash might have been survivable... Whether or not that was the case, I'd like to share some thoughts on the importance of modern satellite tracking technologies.

First, this won't be a full treatise on ADS-B, transponders, or traffic technology... I wrote one of those too...here - I'll focus on ADS-B traffic and tracking and skip over US based ground services - for most pilots, it's an alphabet soup of different standards, and the official publications don't really paint a clear picture on what it is or isn't...as a result there's a lot of confusion out there. I'll try and provide some fairly quick and clear answers, as well as reasoning for why lives can be saved by choosing to implement the right ADS-B systems across a fleet.

1. What is ADS-B vs a transponder?
-it's automatic and broadcast. The aircraft is constantly advertising its position, altitude, squawk code, and some more data...this spontaneous broadcast is called a "squitter"
-it does NOT require interrogation requests from a ground based radar or TCAS/TAS system.... it just happily squitters everything it has, usually every few seconds

2. ADS-B link standards
-the global standard is 1090ES (technically, ADS-B is the Extended Squitter, or ES in 1090ES), which is basically just the latest and greatest flavour of mode S transponder with a high accuracy (usually WAAS GPS in North America) position feed
-1090ES ADS-B IS your transponder too - it's not an addon - it's just the newest version of a mode S transponder - it responds like a transponder, and also happily squitters away its ADS-B and other mode S data every few seconds
-can be single link (just a bottom antenna) intended mostly for monitoring by ground stations and other aircraft
-******can also be diversity (top and bottom antennas, or special tail mounted up/down radiating antenna like tailBeaconX), intended for monitoring by ground stations, satellites, and other aircraft***** more on this later
-1090ES is basically aircraft position related info only

-978 / UAT is US ONLY - it is NOT the global standard, and is used ONLY in the US
-this is normally an ADDON to a traditional mode C or S transponder - you need a conventional transponder + the ADS-B "OUT" box, which usually piggybacks off the transponder code entered and automatically syncs
-basically just single link for ground and other aircraft monitoring - NO satellite tracking
-"IN" units capable of receiving other datalink services from US FAA ground stations, such as weather, NOTAMS, etc

3. ADS-B "OUT"
-this is an aircraft TRANSMITTING - squittering out - at a minimum, position, alt, squawk code...there's more included too, but those are the basics

4. ADS-B "IN"
-this is an aircraft, ground station, or portable device like Stratus, etc RECEIVING the ADS-B "OUT" transmissions from other aircraft (or ground stations in the US), for link types the receiver supports - REMEMBER - 1090ES and UAT are totally different and don't talk to each other!!!! Most modern receivers are "dual-link" and support both....but not all of them!!!
-once received, this information can be plotted, usually on a moving map like an iPAD or panel mount GPS screen for situational awareness
-this is even better than TCAS, in terms of range and accuracy - IF all the aircraft around are transmitting a compatible ADS-B link type
-this should be the case in almost all of the US, but is not presently so in Canada - ADS-B "IN" receivers will NOT see mode C or mode S traffic at all!
-to "see" mode C or S traffic, a more conventional TCAS or TAS active traffic system that actively interrogates transponders is required - these use sensitive directional antennas to determine range and bearing to target - ADS-B works better if everyone has it, but TCAS/TAS is the only thing that'll properly show you an electronic picture of mode C or S traffic

5. ATC monitoring - ground stations
-most worldwide jurisdictions that have implemented ADS-B (and it's more every day) have chosen to use a network of passive ground receivers to provide ADS-B coverage.... Canada has some of these - receiver range is much longer and more accurate than radar.... The US is covered in them
-private ground stations are around and feed the big public sites like FR24 and FlightAware...anyone can throw up an antenna and start receiving ADS-B transmissions
-in the case of Air Navigation Service Providers (ANSPs) such as Nav Canada or the FAA, those ADS-B ground feeds are, or are in the process of being, integrated along with the radar feeds to give controllers a cohesive picture. For the FAA, this should be everywhere now, for Nav Canada, it's here and there

6. ATC monitoring - satellite
-here's the good part - Canada is big, and Nav Canada decided it was uneconomical to cover the land mass with just ground stations.....
-their answer was to become a founding owner of Aireon, which is a global company owned by a few ANSPs
-they put ADS-B receivers on all the next gen Iridium satellites, which are all now in orbit
-Nav Canada is slowly integrating this data feed into their systems, but I'm not sure how many sectors its on for regular controllers so far... eventually it'll probably replace radar

7. Safety Implications
-Aireon CURRENTLY has 100% global satellite tracking coverage of ADS-B 1090ES diversity equipped aircraft, with about 8 second refresh rate
-again - everywhere in Canada, and everywhere on earth - if you have an aircraft with a 1090ES transponder w/diversity, you are being tracked by the Aireon system. Every 8 seconds. Everywhere. With just your regular 'ol 1090ES diversity transponder turned on
-So - what happens if your ADS-B 1090ES diversity equipped Caravan, for instance, goes missing in N Ontario? Well, once reported overdue, JRCC will be called. They'll look at the transponder code showing 1090ES diversity, then call up the number for Aireon Alert - https://aireon.com/media-kit-assets/Air ... eb_00c.pdf, operated by the IAA in Ireland (commercial operators that register their aircraft can also do this). They'll give them the aircraft ICAO address, and the operator will give them the last coordinates, and pull a report and email it within minutes. The report will have the last 15 minutes of the aircraft's flight. JRCC dispatches resources to the last known coordinates. Aircraft is located within minutes of rescuers showing up at last known position, pilot that survived crash is rescued. This exists. Today. In fact, JRCC Trenton wasn't aware of this a few years ago and didn't call them after an accident with an equipped aircraft, and were called out on it by the TSB in a report. So they should definitely be doing it now. No excuse for the operators to also not be aware though. Aireon also sells other safety and commercial monitoring services for a fee.

I mean.... I think that's the safety case for fitting ADS-B 1090ES diversity to aircraft NOW, regardless of whether the regulations require it for your operation yet or not. Can't really beat that for safety. It'll also need to be done eventually. Is already required over 12,500'

Common GA transponders that support this are:
-Garmin GTX330D / GTX33D with ES upgrade (if you have a GTX330D, you can have Garmin upgrade it, then it must be tied to a WAAS GPS source in the plane)
-Garmin GTX335D / GTX335DR
-Garmin GTX345D / GTX345DR
-L3 ACSS Lynx NGT-9000 / NGT-9000R with D enablement (this is my personal favourite - also does ADS-B dual-link "IN" with wifi to iPad... add the "+" enablement and antenna and it's a TAS active traffic or TCAS system too)
-uAvionix tailBeaconX


Beyond the wonders of ADS-B 1090ES diversity and satellite tracking, there's just no excuse to not have some kind of satellite tracking when operating in remote areas these days. Whether it's an expensive system installed in the aircraft, a SPOT, an InReach, a Zoleo... there are many 2 way tracking satellite communicators out there. Just because it's legal to operate an aircraft with an ELT removed for maintenance and no ADS-B 1090ES w/diversity or satellite tracking, doesn't mean it's a good idea in this day and age. No, more than that, it's stupid, and there's no excuse for it. Sure, it's how it's always been done...but there's no excuse for it with the technology now so readily available.


Ahhh, ok. That's enough for tonight.