Yea, there is a battery in the trasponder that requires replacement
every 2 years whether it needs it or not. It is used to power the unit
in the event of a crash and no power from the ship is getting to it.
The new models use regular "D" cells while older ones (like mine)
require a proprietary battery for about $40.

Jon Kraus
'79 Mooney 201
4443H @ TYQ


Rip wrote:

Battery?

Rip

Jon Kraus wrote:

We had our transponder require some work and the A & P added a placard
as "transponder inop" until we got it back. As long as you stay clear
of B & C you should be OK.

I'm curious as to why you wouldn't just have the inspection done? I
don't think it is that expensive to do. We ended up buying a
remanufactured unit for about $400. So the battery in yours has lasted
10 years or is it dead?

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Matt wrote:

Looking over my 152's logs, it appears the transponder has not been
inspected since the altitude encoder was installed, about 10 years
ago. Is it legal (not necessarily smart) to pull the circuit
breaker, placard the transponder as inoperative, and continue to fly
until I get it inspected at the next annual? I would be staying
clear of class B and C.

FYI, the mode C is working fine.

Thanks for all comments.

Matt