I also understand that you can still fit a new mode c transponder to an aircraft registered before Feb 2014, spend a bit more and get mode s makes more sense
My read of the rule was slightly different.
You can fit a NEW mode C transponder to an aircraft registered before Feb 2014, provided the aircraft was already equipped.
I.e you can REPLACE an existing unit with a new unit (not sure if it must be same make and model). You cannot, do an initial install regardless of registration date.
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