Narrative:

On final approach for runway 17L at centennial airport (kapa) during VMC conditions, we were cleared to land 17L by apa tower controller. As we turned from base to final, I saw a remote control model airplane (yellow) flying about 200 ft below at a model airplane park with hard surface runways. When we were directly over the right/C model airplane we got a TCAS resolution advisory (RA)-'monitor verial descent.' because we had visual contact with the model a/C, and were cleared to land with no other reported traffic, I continued the approach and landing. When we advised the ground controller of the TCAS right/a he suggested we file this NASA report. This incident is the forth time I have received a TCAS right/a, the last three resulted in three go-arounds. My suspection is that the right/C transmitter frequencies are causing anomalous TCAS right/a's. Callback conversation with reporter revealed the following information: reporter stated over the past 4 to 5 yrs he has executed 4 or 5 go-arounds associated with TCAS 'RA's'. All taking place in the vicinity of cherry creek lake, site of a right/C aircraft airport. Although in 'VMC' during these go-arounds, the TCAS traffic was never observed until this last occurrence, leading him to believe there may be a connection between the right/C aircraft and the TCAS 'RA's'. The reporter doesn't rule out a possible problem with his aircraft equipment, the same aircraft was flown during each 'RA'. Supplemental information: a 'TCAS' specialist advises that the right/C aircraft should not affect TCAS operation, suggesting the problem may lie in the hawker 800's 'TCAS suppression buss.'

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Original NASA ASRS Text

Title: A 'H25B' CREW EXPERIENCED A TCAS 'RA' RELATIVE TO A (R/C) REMOTE CONTROLLED ACFT.

Narrative: ON FINAL APCH FOR RWY 17L AT CENTENNIAL ARPT (KAPA) DURING VMC CONDITIONS, WE WERE CLRED TO LAND 17L BY APA TWR CTLR. AS WE TURNED FROM BASE TO FINAL, I SAW A REMOTE CONTROL MODEL AIRPLANE (YELLOW) FLYING ABOUT 200 FT BELOW AT A MODEL AIRPLANE PARK WITH HARD SURFACE RWYS. WHEN WE WERE DIRECTLY OVER THE R/C MODEL AIRPLANE WE GOT A TCAS RESOLUTION ADVISORY (RA)-'MONITOR VERIAL DSCNT.' BECAUSE WE HAD VISUAL CONTACT WITH THE MODEL A/C, AND WERE CLRED TO LAND WITH NO OTHER RPTED TFC, I CONTINUED THE APCH AND LNDG. WHEN WE ADVISED THE GND CTLR OF THE TCAS R/A HE SUGGESTED WE FILE THIS NASA REPORT. THIS INCIDENT IS THE FORTH TIME I HAVE RECEIVED A TCAS R/A, THE LAST THREE RESULTED IN THREE GO-AROUNDS. MY SUSPECTION IS THAT THE R/C TRANSMITTER FREQUENCIES ARE CAUSING ANOMALOUS TCAS R/A'S. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED OVER THE PAST 4 TO 5 YRS HE HAS EXECUTED 4 OR 5 GO-AROUNDS ASSOCIATED WITH TCAS 'RA'S'. ALL TAKING PLACE IN THE VICINITY OF CHERRY CREEK LAKE, SITE OF A R/C ACFT ARPT. ALTHOUGH IN 'VMC' DURING THESE GO-AROUNDS, THE TCAS TFC WAS NEVER OBSERVED UNTIL THIS LAST OCCURRENCE, LEADING HIM TO BELIEVE THERE MAY BE A CONNECTION BTWN THE R/C ACFT AND THE TCAS 'RA'S'. THE RPTR DOESN'T RULE OUT A POSSIBLE PROB WITH HIS ACFT EQUIP, THE SAME ACFT WAS FLOWN DURING EACH 'RA'. SUPPLEMENTAL INFO: A 'TCAS' SPECIALIST ADVISES THAT THE R/C ACFT SHOULD NOT AFFECT TCAS OP, SUGGESTING THE PROB MAY LIE IN THE HAWKER 800'S 'TCAS SUPPRESSION BUSS.'

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.