CLASS 1 vs Class 2 Transponder

[RV-4]

Gents

Can anyone tell me why you guys south of the border have to have a Class 1 (250 Watts) Transponder vs a Class 2 (130 Watts) ??

Take for example the Dynon Transponders,except for the extra power, aren't they both able to send traffic info to your EFIS as both of them are ADS-B OUT??

I know the FAA is mandating all ''US'' registered AC to have a class 1 model but what about a Canadian registered AC flying in US airspace...Is he visible to everyone eventough he's not 2020 US compliant??

Just wondering why I should spend an extra $1000 if I don't have to..

Thanks

Bruno
rv4@videotron.ca

[Mel]

Class I and Class II were both originally OK'ed for 2020 compliance.
The FAA decided somewhere along the road that Class II wasn't good enough.
I don't know about others, but the 2 Trig transponders (TT21 & TT22) are exactly the same except for power out.
The Dynon transponders are built by Trig, and I'm pretty sure that they are built to the same specs.

I don't know about Canadian rules.

[RV-4]

Hi Mel

Thanks you for the info.

Here in Canada, our glorified Gouvernment doesn't plan on going ADS-B except for a few specific areas of the Country ( Hudson Bay been one ) so I don't think it really matters which class of TXPR one decide to install but what I would like to confirm is if a Canadian AC flies in US Airspace in 2020, will he be legal because he's not US Registered???

I'll try to get an answer via the FAA if it is possible.

Thanks again

Bruno

[jliltd]

I guess I haven't heard anything about this. I know that an existing Class 1 legacy Mode C transponder can be combined with a UAT transmitter for 2020 compliance. How can this be?

[dynonsupport]

This all comes from the FAR's. 91.227:

(2) Aircraft operating in airspace designated for ADS-B Out, but outside of Class A airspace, must have equipment installed that meets the antenna and output power requirements of either:

(i) Class A1, A1S, A2, A3, B1S, or B1 as defined in TSO-C166b; or

(ii) Class A1H, A1S, A2, A3, B1S, or B1 equipment as defined in TSO-C154c, Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B) Equipment Operating on the Frequency of 978 MHz.

Transponders are (i). These classes all define the higher (250W+) transponders. It doesn't say "US registered aircraft" or anything like that, so Canadian planes don't get a break. After 2020 if you want to be legal in ADS-B airspace in the USA, you need a high powered transponder OR you can have a UAT if it has enough output power.

The lower powered transponders put out identical information. They still make you visible. They are just not legal per the FAR. They are legal in non-ADS-B areas.

FYI, the Dynon higher powered transponder is $400 more, not $1000 more.

[Mich48041]

if a Canadian AC flies in US Airspace in 2020, will he be legal

It depends on where you fly, not where the aircraft is registered. Without the required ADS-B equipment, you can still fly in the U.S. but will have to stay away from areas that require ADS-B, basically airports with control towers or near large cities. That leaves OSH out.

[az_gila]

Q. for our Canadian cousins...

I found this on a Canadian ADSB site -

The Iridium-NAV CANADA joint venture is called Aireon. It will add 1090ES ADS-B receivers to each of the 66 satellites (and backups) destined to form the Iridium ?Next? constellation. The low-earth-orbiting Iridium satellites will offer worldwide coverage, including Polar Regions, and with the ADS-B payloads will provide complete visibility to all aircraft everywhere. This will help ANSP?s (air navigation service providers) increase efficiencies. This new capability will extend the benefits of current radar-based surveillance systems (which presently cover less than 10 percent of the world) to entire planet coverage. Aireon is expected to become operational in 2018.

If all monitoring for ADSB is via satellite and not ground stations, does that mean that "C" registered planes will need a top mounted (or dual top/bottom) antenna for their Mode S transponders?

[dynonsupport]

Originally Posted by Mich48041

That leaves OSH out.

Oshkosh is class D airspace. ADS-B is not required.

[flightlogic]

Seeing the changes the FAA throws out randomly regarding ADS-B requirements... I don't trust that anyone will be flying around Oshkosh without a UAT transmitter or Squitter...after the "Next Gen" deadline. Class D or not.
I toss this comment in this thread about transponders because I noticed in the Navworx (and other) transmitter spec sheets, that one unit has 20 watts of power and another has 40. Now where did that come from??????
When transponders were proposed as required equipment, the end users threw a fit. AOPA got behind them and complained long and hard. We know where that went. What most of us never knew after that ... was that not all transponders were required to be the same. Now, it is coming to light slowly.
This portion of the avionics landscape is a complete mine field presently. And when a mine goes off, we start writing checks.

[dynonsupport]

As much as I respect Mel, the FAA didn't change the rules. The FAA published the ADS-B final rule in 2010, and that rule included 91.227 which sets out the required power classes for Transponder and UAT. 91.227 has not been revised a single time since then.

Transponders have had power classes since the 1970's, if not before. Making sure you have the right one for your type of aircraft is something that the aircraft manufacturer or avionics shop does for you if you're in certified aircraft, but something you need to do for yourself when you're the manufacturer. If the FAA didn't allow power classes, we'd all need to run the most expensive transponders (read: airliners).

There's a lot to be frustrated about with ADS-B, but the idea that the FAA has changed the allowed power classes isn't one of them in my opinion.

--Ian Jordan
Dynon Avionics