A CFI ACTING AS SAFETY PLT ALONG WITH C310 OWNER ACTING AS PLT; VIOLATED THE TFR AROUND A PWR PLANT.

Narrative

WAS SAFETY PLT/CFI FOR OWNER/PLT AND FRIEND WHO WAS THE FLYING PLT ATTEMPTING TO LEARN THE USE OF A NEW GPS (APCH CERTIFIED). WE WERE BOTH AWARE OF THE TFR (FLT RESTR) AROUND THE NNN PWR PLANT AND THOUGHT WE WERE OUTSIDE THAT AREA AT ALL TIMES. WE WERE TRYING TO FIND AN AREA BETWEEN XYZ AND XZZ. TO SET UP THE GPS FOR APCHS AND FOLLOW THE SEQUENCING OF THE UNIT WHILE VISUALLY BACKING UP OUR POSITION RELATIVE TO THE VOR-A AT XYZ AND THE NDB AT XZZ; PLUS COMPARING THE NDB AND VOR INDICATIONS TO THOSE PROVIDED BY THE GPS. AIRSPACE AT XZZ WAS BUSY WITH TOUCH AND GO WE STAYED AT 3000 MSL TO AVOID THE TFC PATTERN CONGESTION; AND WENT BACK AND FORTH BETWEEN XYZ AND XZZ. OUR INTENT WAS TO REMAIN OUTSIDE THE TFR BY VISUALLY KEEPING ALERT AND OUR POSITION. WE WERE NOT IN CONTACT WITH ATC; ONLY MONITORED CTAF AND UNICOM AT XZZ AND XYZ; AND WERE SURPRISED TO LEARN ON LNDG AT BCD (HOME BASE) THAT WE HAD PENETRATED THE TFR. IT WAS UNINTENTIONAL; WE BOTH OBSERVED OUR POSITION VISUALLY TO BE SAFE. HOWEVER; IT APPEARS TO BE IN ERROR. MY APOLOGIES.