Transponder test after static system opened?

wrote:
On 9-Mar-2004, dave wrote:


No!

If the static system has been opened, and resealed, it should have no
effect on the operation of your encoder or transponder. There is no
requirement to get either checked.

If you have had your transponder checked in the last 24 months it is
still good until the end of the 24th month.

Paragraph "b" has nothing to do with the static system being opened.
They are talking about a "data correspondence error" which is the way
the encoder talks to the transponder.



I am not qualified to answer the original question, but I believe that there
may be an error in the above statement. The encoder is, in fact, connected
to the static system. That is where it gets its pressure reading for
altitude, just like the panel altimeter. It would thus seem logical that
its operation SHOULD be tested if the static system is "unsealed". The
obvious way to test the encoder would be by observing transponder return
altitude codes in mode C operation while testing the static system.
However, the transponder test involving verification of output power level,
etc. probably does not need to be done.


hi Elliott,

The fact the static system has been opened, resealed and verified there
are no leaks has no effect on the encoder at all. It has the same air
pressure on its pressure transducer as it had before the system had been
opened. The encoder will operate the same whether or not there is a
static system attached to it at all. It senses a pressure and reports it
to the altimeter.


BTW, I operate a repair station doing the 91.411 and 91.413 inspections
and certifications.
I have turned down work because of this.

Cheers
Dave