Narrative:

I was flying for practice with an instructor, on the ttn ILS 6. We were talking to phl approach. We were level, on the localizer, and were supposed to circle to runway 34. I was under a hood. The handoff from approach to ttn tower was unusually late, and by the time we were told to change frequencys, we were well past the OM, descending. When I changed frequencys to contact ttn tower, I accidentally tuned 121.7 instead of 120.7. I didn't realize this until my 2ND or 3RD call and then tuned the proper frequency. By this time, I had flown past the circle-to-land minimum altitude, and was about 1/2 mi from the threshold of runway 6. The tower controller was frantically calling for us to turn left and climb to avoid pattern traffic, and I complied. The basic cause of the problem was my lack of currency (which is why I was practicing, of course). The 121.7 on the radio 'looked' right, but of course, it's a common ground control frequency which I should have realized (maybe that's why it looked good?), and I should have checked against the approach plate after the first failure to get a response from ttn tower. The fact that we got the handoff to ttn so late aggravated the situation by decreasing the time I had available to catch my frequency error. Also, I should have flown the missed approach at 680 ft instead of waiting so long, also attributable to my getting behind and thinking slowly. If it had been actual IMC, and I had broken out of clouds below 700 or so without recognizing the frequency error, I suppose I should have circled to runway 34 and landed, based on the assumption that I had lost communication. Also, I had begun my descent down the GS late (I was out of practice and getting a little behind the plane), and I picked up some extra speed intercepting the GS. This also compressed the time I had for decision making. Despite what occurred, I don't believe a dangerous situation ever existed, since we were VMC, and my instructor could see all traffic. I can understand why the tower controller would have had a different perspective, of course.

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Original NASA ASRS Text

Title: AN SMA TRNEE PLT DIALED IN THE WRONG FREQ FOR TWR AND FOULED UP THE TFC PATTERN.

Narrative: I WAS FLYING FOR PRACTICE WITH AN INSTRUCTOR, ON THE TTN ILS 6. WE WERE TALKING TO PHL APCH. WE WERE LEVEL, ON THE LOC, AND WERE SUPPOSED TO CIRCLE TO RWY 34. I WAS UNDER A HOOD. THE HDOF FROM APCH TO TTN TWR WAS UNUSUALLY LATE, AND BY THE TIME WE WERE TOLD TO CHANGE FREQS, WE WERE WELL PAST THE OM, DSNDING. WHEN I CHANGED FREQS TO CONTACT TTN TWR, I ACCIDENTALLY TUNED 121.7 INSTEAD OF 120.7. I DIDN'T REALIZE THIS UNTIL MY 2ND OR 3RD CALL AND THEN TUNED THE PROPER FREQ. BY THIS TIME, I HAD FLOWN PAST THE CIRCLE-TO-LAND MINIMUM ALT, AND WAS ABOUT 1/2 MI FROM THE THRESHOLD OF RWY 6. THE TWR CTLR WAS FRANTICALLY CALLING FOR US TO TURN L AND CLB TO AVOID PATTERN TFC, AND I COMPLIED. THE BASIC CAUSE OF THE PROB WAS MY LACK OF CURRENCY (WHICH IS WHY I WAS PRACTICING, OF COURSE). THE 121.7 ON THE RADIO 'LOOKED' RIGHT, BUT OF COURSE, IT'S A COMMON GND CTL FREQ WHICH I SHOULD HAVE REALIZED (MAYBE THAT'S WHY IT LOOKED GOOD?), AND I SHOULD HAVE CHKED AGAINST THE APCH PLATE AFTER THE FIRST FAILURE TO GET A RESPONSE FROM TTN TWR. THE FACT THAT WE GOT THE HDOF TO TTN SO LATE AGGRAVATED THE SIT BY DECREASING THE TIME I HAD AVAILABLE TO CATCH MY FREQ ERROR. ALSO, I SHOULD HAVE FLOWN THE MISSED APCH AT 680 FT INSTEAD OF WAITING SO LONG, ALSO ATTRIBUTABLE TO MY GETTING BEHIND AND THINKING SLOWLY. IF IT HAD BEEN ACTUAL IMC, AND I HAD BROKEN OUT OF CLOUDS BELOW 700 OR SO WITHOUT RECOGNIZING THE FREQ ERROR, I SUPPOSE I SHOULD HAVE CIRCLED TO RWY 34 AND LANDED, BASED ON THE ASSUMPTION THAT I HAD LOST COM. ALSO, I HAD BEGUN MY DSCNT DOWN THE GS LATE (I WAS OUT OF PRACTICE AND GETTING A LITTLE BEHIND THE PLANE), AND I PICKED UP SOME EXTRA SPD INTERCEPTING THE GS. THIS ALSO COMPRESSED THE TIME I HAD FOR DECISION MAKING. DESPITE WHAT OCCURRED, I DON'T BELIEVE A DANGEROUS SIT EVER EXISTED, SINCE WE WERE VMC, AND MY INSTRUCTOR COULD SEE ALL TFC. I CAN UNDERSTAND WHY THE TWR CTLR WOULD HAVE HAD A DIFFERENT PERSPECTIVE, OF COURSE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.