Narrative:

There are facilities for offices; maintenance and assembly many airports. There has been an ongoing issue with a beacon code (transponder) apparently emanating from the ramp or facilities. This creates clutter on the radar scope for the controllers and located adjacent to runway with departures; arrivals and over flights. Additionally there is the risk of an aircraft receiving a TCAS alert. Normally a 1200 code at field elevation (900) feet radiates but on other occasions at 7700 code and a 0600 code has radiated. The facility has contacted a maintenance facility numerous times to resolve such a situation. A flight was cleared for takeoff. The stationary target over a local facility was squawking 0600 and rapidly climbing and descending from 900 feet to 9;700 feet. The departure was advised of the target by local control. A collision alert alarmed on the radar scope. The traffic was not a factor (could not playback situation on the falcon). The south radar controller asked the pilot if he received a TCAS RA and the pilot stated no. I was working another position and saw the situation take place. The overall flm in charge of the shift attempted to call the contacts at the facility and got voice mail. He filed an mor on the situation. Tech ops was shown the target on one occasion and stated it appeared to be an aircraft squawking a beacon code on the ramp. If these are transponder equipment tests; they are not coordinated with tower. This target clutters up the scope and has the potential to cause TCAS RA's to occur. This appears to be an issue with the local maintenance facility. Flight standards should contact the operator and resolve the issue and follow up to ensure it is eliminated. Tech ops should also examine the issue to ensure it is not radar related.

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Original NASA ASRS Text

Title: An ATC Tower Controller reported an aircraft maintenance facility located on airport tests transponders without coordinating with ATC which can interfere with normal flight operations.

Narrative: There are facilities for offices; maintenance and assembly many airports. There has been an ongoing issue with a beacon code (transponder) apparently emanating from the ramp or facilities. This creates clutter on the radar scope for the controllers and located adjacent to Runway with departures; arrivals and over flights. Additionally there is the risk of an aircraft receiving a TCAS alert. Normally a 1200 code at field elevation (900) feet radiates but on other occasions at 7700 code and a 0600 code has radiated. The facility has contacted a maintenance facility numerous times to resolve such a situation. A flight was cleared for takeoff. The stationary target over a local facility was squawking 0600 and rapidly climbing and descending from 900 feet to 9;700 feet. The departure was advised of the target by local control. A collision alert alarmed on the radar scope. The traffic was not a factor (could not playback situation on the falcon). The south radar controller asked the pilot if he received a TCAS RA and the pilot stated no. I was working another position and saw the situation take place. The overall FLM in charge of the shift attempted to call the contacts at the facility and got voice mail. He filed an MOR on the situation. Tech Ops was shown the target on one occasion and stated it appeared to be an aircraft squawking a beacon code on the ramp. If these are transponder equipment tests; they are not coordinated with tower. This target clutters up the scope and has the potential to cause TCAS RA's to occur. This appears to be an issue with the local maintenance facility. Flight standards should contact the operator and resolve the issue and follow up to ensure it is eliminated. Tech Ops should also examine the issue to ensure it is not radar related.

Data retrieved from NASA's ASRS site 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.