Needs to be installed, on the aircraft. A lot of the issues are coax, encoder/altitude, antenna, etc. There are many tech?s with portable equipment, they?ll come to you.
Also consider turning the XPNDR off and flying it to the nearest shop within your P1 area for the test to be done.
And placard it as ?inop?. Unless you?re located within a transponder-required airspace (class B, C, 30 mile mode C veil). Your DAR should be okay with this.
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Often you can get a waiver for one flight to a facility by calling the controlling facility.
Often you can get a waiver for one flight to a facility by calling the controlling facility.
I'm exploring that... my FSDO inspector wants to inspect my transponder before flight.