On Jul 8, 6:41 am, Mike Spera wrote:
They are R-12 systems in most planes...R-134? Many techs will not do a conversion because they can
screw up some systems irreparably. Even though many have converted
Pipers, the local auto tech has no experience and likely will not want
to "experiment" with a very expensive airplane...
Mike

I can't imagine that converting an R-12 system to R-134 wouldn't
require an STC.