Narrative:

For the past 3 yrs we have had a frequency skipping problem between gfk ATCT and fargo ATCT. Both have ground control frequency of 121.9. The problem is at its worst from 0500 to 0700. Due to staffing, tower and ground are usually combined. Gfk has 60 aircraft at their flight school with the last 2 digits of the call sign of 'xx.' both facilities have air carrier jets on the ground. The 2 airports are only 80 mi apart. It is not uncommon for both airports to be talking to 'xx' aircraft on tower and ground at the same time. We have filed endless FAA forms 6050-3 frequency interference reports over the past 3 yrs. All we are asking is for one of the facilities to change their ground control to 121.7 before this becomes a safety incident. Ywg- gfk-far all use 121.9 -- each are 80-90 mi apart. It seems right to change gfk as they are in the middle. Callback conversation with reporter revealed the following information: reporter described skipping as xmissions bouncing off the atmosphere. Reporter indicated that during these periods they have heard ground vehicles at gfk call for runway xings. Far has 2 of the same runways. Reporter stated that there was an occasion when a student pilot under gfk's control miscopied an instruction by reporter's facility for another aircraft. Far caught the mistake and corrected it with the pilot. Reporter indicated controllers in both facilities are aware of the problem. Reporter alleged that airways facilities says to keep the forms coming as it will help with getting a frequency change. Reporter indicated that the transmitting levels at both facilities were turned down but it did not have any effect on the problem.

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Original NASA ASRS Text

Title: RPTED SIT OF 3 FACILITIES 80-90 MI APART HAVE THE SAME GND CTL FREQ. RPTR SAYS THERE IS A FREQ SKIPPING PROB PRIMARILY DURING A 2 HR EARLY MORNING PERIOD WHEN THE LCL CTL AND GND CTL POS ARE COMBINED. RPTR IMPLIES THAT THIS COULD LEAD TO A SAFETY SIT INVOLVING ACFT WITH SIMILAR CALL SIGNS IN CONTACT WITH DIFFERENT FACILITIES. RECOMMENDATION IS TO CHANGE ONE OF THE FACILITY'S GND CTL FREQS.

Narrative: FOR THE PAST 3 YRS WE HAVE HAD A FREQ SKIPPING PROB BTWN GFK ATCT AND FARGO ATCT. BOTH HAVE GND CTL FREQ OF 121.9. THE PROB IS AT ITS WORST FROM 0500 TO 0700. DUE TO STAFFING, TWR AND GND ARE USUALLY COMBINED. GFK HAS 60 ACFT AT THEIR FLT SCHOOL WITH THE LAST 2 DIGITS OF THE CALL SIGN OF 'XX.' BOTH FACILITIES HAVE ACR JETS ON THE GND. THE 2 ARPTS ARE ONLY 80 MI APART. IT IS NOT UNCOMMON FOR BOTH ARPTS TO BE TALKING TO 'XX' ACFT ON TWR AND GND AT THE SAME TIME. WE HAVE FILED ENDLESS FAA FORMS 6050-3 FREQ INTERFERENCE RPTS OVER THE PAST 3 YRS. ALL WE ARE ASKING IS FOR ONE OF THE FACILITIES TO CHANGE THEIR GND CTL TO 121.7 BEFORE THIS BECOMES A SAFETY INCIDENT. YWG- GFK-FAR ALL USE 121.9 -- EACH ARE 80-90 MI APART. IT SEEMS RIGHT TO CHANGE GFK AS THEY ARE IN THE MIDDLE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR DESCRIBED SKIPPING AS XMISSIONS BOUNCING OFF THE ATMOSPHERE. RPTR INDICATED THAT DURING THESE PERIODS THEY HAVE HEARD GND VEHICLES AT GFK CALL FOR RWY XINGS. FAR HAS 2 OF THE SAME RWYS. RPTR STATED THAT THERE WAS AN OCCASION WHEN A STUDENT PLT UNDER GFK'S CTL MISCOPIED AN INSTRUCTION BY RPTR'S FACILITY FOR ANOTHER ACFT. FAR CAUGHT THE MISTAKE AND CORRECTED IT WITH THE PLT. RPTR INDICATED CTLRS IN BOTH FACILITIES ARE AWARE OF THE PROB. RPTR ALLEGED THAT AIRWAYS FACILITIES SAYS TO KEEP THE FORMS COMING AS IT WILL HELP WITH GETTING A FREQ CHANGE. RPTR INDICATED THAT THE XMITTING LEVELS AT BOTH FACILITIES WERE TURNED DOWN BUT IT DID NOT HAVE ANY EFFECT ON THE PROB.

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.