When will mode C be obsolete

[kanders]

I just bought an older Cessna 172 to take my flight training in. The airport I will be flying out of is controlled, so I will need to install a transponder. If I have a used mode C installed (to save $$) how long will it still be useful for?

[avyonx]

If you're under the impression Mode C will be obsolete don't you think it would be best then to install a Mode S??

[ahramin]

There is only one place in the world that is mandating an upgrade to transponders: The US. By 2020 all aircraft in controlled airspace will need ADS-B to fly down there. The kicker is, even with the new technology, you will still need a mode C transponder as well.

So to make a long story short, mode A and C transponders are so far from being obsolete in Canada that it is beyond any possible planning horizon.

Just installed a transponder in my plane this week and got a good deal on a used KT-76A. There are deals to be found out there however for a new install in a certified aircraft the cost of the parts is only becomes a small proportion of the costs over the life of the plane. Get a new Garmin pushbutton and save some headaches down the road.

[kanders]

Avyonx

Maybe I forgot to mention that I wanted to save money. There are some good deals out there on used mode C's like the one Ahramin mentioned.

[photofly]

I'd go for a used transponder but make sure to buy a shiny new altitude encoder to go with it.

[kanders]

I'd go for a used transponder but make sure to buy a shiny new altitude encoder to go with it.

Thanks, I was sort of thinking that way as well, they don't seem too expensive new.

[cgzro]

Think the mode C will be around for a while. If you can swing it Id get a Garmin. They have excellent degugging modes that allow you to see what the encoder is saying without any disassembly so you can quickly diagnose a poor connection, broken encoder, encoder which is way off etc. Since Avionics technician time is expensive you can quickly get your money back.

[DonutHole]

I would go with a new transponder.

They're cheap used... but the second something goes wrong with it you'll wish you got new. Bench time and parts are expensive. Really really expensive.

[torquey401]

Follow on question. Is the altimeter supposed to be certified every two years as well as the encoder? Assuming vfr puddle jumper.

[cgzro]

Yes - anywhere you need the xponder mode C the Altimeter must be accurate too .. kinda makes sense otherwise you could not fly an assigned altitude accurately enough.

Usually you pull the Altimeter have it checked. put it back then the xpdr etc check is done.

[Posthumane]

Can an altimeter calibration be checked with it in the aircraft? I seem to remember having that done using a portable pitot-static calibration set, but it's possible my memory is weak and that it was only for the leakdown test.

[photofly]

The several biennial pitot-static checks on my aircraft have always been done without removing the altimeter. We had a discussion on AvCanada last year about whether this was permissible or not, but the very expensive no-corners-cut-ever AMO that does my recert does it like that, and I'm not going to go and argue with them.

[DonutHole]

It's been awhile since I've delved into avionics but I seem to remember one altimeter test being difficult to do properly with the instrument in the aircraft, or at the very least isolated from the rest of the pilot static system.

[plhought]

I've only ever done & seen the 2-year checks with the instruments in the aircraft. From 35 year old King Airs to big iron. Never done one on smaller stuff.

If you are having problems in a getting the altimeter/encoder to pass in-situ but fine on the bench...then I would suspect you have have pitot/static issue out there.

[CID]

The only time you would take the altimeter out (and the other air data instruments) is if you suspect contamination and what to "blow out" the lines. Otherwise, the instruments should remain installed while doing a leak check. Logically, if you do a leak check with them removed, you'd just need to do another leak check when you re-install them.

Mode A/C transponders will be around for awhile. If you want to meet the ADS-B mandate in the US, you can use a UAT compatible device or upgrade to an "extended squitter" type which is also available for little airplanes.

If you settle for a used KT-76A like one poster, put some money away for a tube replacement. You will need it some day. It's better to have a transponder with a solid-state transmitter like the newer Garmins.

But...Mode A/C isn't going anywhere anytime soon.

[avyonx]

To perform a proper 24 Month Altimeter test the Altimeter must be removed from the aircraft to follow the manufacturers recommendations for adding the vibration portion...

That being said, if you're an appropriately rated AMO as CAR 571 App B requires...then that step can be avoided and signed off as such. The Altimeter MUST be isolated from the Static system (not necessarily removed) because to perform the hysteresis test properly you will damage the VSI (unless it can handle 5000-20000ft/min. For other obvious reasons as well such as the case leak test which allows ONLY for a 100ft leak at 18,000ft...

Cheers,

[NeverBlue]

To perform a proper 24 Month Altimeter test the Altimeter must be removed from the aircraft to follow the manufacturers recommendations for adding the vibration portion

Huh?

CARs is the standard for 24 month recert...not the manufacturer. I'm sure 99% of owners have no manufacturer's maintenance manual for their Altimeters.

they do not have to be removed for any test...just repair

they are easy to isolate in the aircraft...just hook up directly...and nobody says they can't be removed from the panel in the aircraft for testing in the aircraft if need be.

https://buy.garmin.com/en-CA/CA/in-the- ... od201.html

and this one will solve all of your problems....