Narrative:

Upon returning to the airport environment from the completion of a maintenance test flight, the control tower was contacted approximately 7 mi northwest of the airport for landing instructions. Initial plan was for the aircraft to make a left base entry for runway 8. Continuing the descent for this approach, the tower later called back and advised that slower traffic would conflict and could we turn east and enter overhead the airport for a right downwind arrival. At this time, the aircraft was approximately 3 mi from the airport at approximately 1500 ft MSL. As we turned left (east) and continued on down to the pattern altitude of 1100 ft MSL, the TCASII began to show traffic both above and below us that might be a conflict. At this same time, the local tower controller advised us of lower traffic climbing out on a left downwind departure. This would put the aircraft on a heading toward our aircraft. At this time, we did not see this aircraft visually. While this aircraft target was depicted on the TCASII, the flight crew did not have a visual contact on it. Simultaneous conflicting commands from the TCASII advised us to first 'climb, climb' and then 'descend, descend.' not having a visual on any of the conflicting aircraft, it was noted that there were more targets above our aircraft than below. Noting that the lower traffic was climbing and within 200 ft of our altitude, I (as PIC of the flight) elected to descend to get below this aircraft rapidly. In doing so, we went below the prescribed pattern altitude by about 300 ft. At this time, we were also over higher terrain that exists near the airport and that probably had us within 500-600 ft of the terrain at that time. As soon as the conflict was resolved, we climbed back up to the requested pattern altitude and completed the overhead entry to the airport and subsequent landing. After landing, the tower advised that they appreciated our help in their traffic pattern. I replied that we were glad to help, but that they might get phone calls from residence in the nearby neighborhood that we had to overfly to make this all work out. The local controller indicated that they do indeed get calls, but that we had done what was required and no harm should befall us. It seems that someone did take offense and called the local FSDO to report us as a low flying aircraft. Since we are a jet, they are trying to invoke 91.515. We have been trying to figure out where we might have erred in this situation. Plenty of time was given the tower for notice of our arrival. We followed their instructions and at the same time tried to think ahead of a TCASII that gave conflicting information. This is not the first time a TCASII setup has done that. The question is, 'what do you do when it happens?' my decision was to descend the aircraft because I knew I could get below the conflict traffic faster and what I perceived to be a safer fashion than had I climbed up to avoid the traffic. I knew where this traffic was and where it was going. I did not know that for the other aircraft above me. I also knew that I didn't have to descend far to clear the traffic, and that I would still have adequate terrain clearance. Could we have entered from a different location? Certainly. But we had been in a position to make a safe and easy entry into the traffic flow and when that didn't work out, we did our best to avoid conflicting traffic and stay away from the noise sensitive areas. In the future, I will advise all our pilots that this area can be very busy and to contact the tower well in advance to see what their preference will be for our traffic pattern entry.

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Original NASA ASRS Text

Title: GLF-4 CREW HAD A TCASII RA ENTERING THE PATTERN AT CMA.

Narrative: UPON RETURNING TO THE ARPT ENVIRONMENT FROM THE COMPLETION OF A MAINT TEST FLT, THE CTL TWR WAS CONTACTED APPROX 7 MI NW OF THE ARPT FOR LNDG INSTRUCTIONS. INITIAL PLAN WAS FOR THE ACFT TO MAKE A L BASE ENTRY FOR RWY 8. CONTINUING THE DSCNT FOR THIS APCH, THE TWR LATER CALLED BACK AND ADVISED THAT SLOWER TFC WOULD CONFLICT AND COULD WE TURN E AND ENTER OVERHEAD THE ARPT FOR A R DOWNWIND ARR. AT THIS TIME, THE ACFT WAS APPROX 3 MI FROM THE ARPT AT APPROX 1500 FT MSL. AS WE TURNED L (E) AND CONTINUED ON DOWN TO THE PATTERN ALT OF 1100 FT MSL, THE TCASII BEGAN TO SHOW TFC BOTH ABOVE AND BELOW US THAT MIGHT BE A CONFLICT. AT THIS SAME TIME, THE LCL TWR CTLR ADVISED US OF LOWER TFC CLBING OUT ON A L DOWNWIND DEP. THIS WOULD PUT THE ACFT ON A HDG TOWARD OUR ACFT. AT THIS TIME, WE DID NOT SEE THIS ACFT VISUALLY. WHILE THIS ACFT TARGET WAS DEPICTED ON THE TCASII, THE FLT CREW DID NOT HAVE A VISUAL CONTACT ON IT. SIMULTANEOUS CONFLICTING COMMANDS FROM THE TCASII ADVISED US TO FIRST 'CLB, CLB' AND THEN 'DSND, DSND.' NOT HAVING A VISUAL ON ANY OF THE CONFLICTING ACFT, IT WAS NOTED THAT THERE WERE MORE TARGETS ABOVE OUR ACFT THAN BELOW. NOTING THAT THE LOWER TFC WAS CLBING AND WITHIN 200 FT OF OUR ALT, I (AS PIC OF THE FLT) ELECTED TO DSND TO GET BELOW THIS ACFT RAPIDLY. IN DOING SO, WE WENT BELOW THE PRESCRIBED PATTERN ALT BY ABOUT 300 FT. AT THIS TIME, WE WERE ALSO OVER HIGHER TERRAIN THAT EXISTS NEAR THE ARPT AND THAT PROBABLY HAD US WITHIN 500-600 FT OF THE TERRAIN AT THAT TIME. AS SOON AS THE CONFLICT WAS RESOLVED, WE CLBED BACK UP TO THE REQUESTED PATTERN ALT AND COMPLETED THE OVERHEAD ENTRY TO THE ARPT AND SUBSEQUENT LNDG. AFTER LNDG, THE TWR ADVISED THAT THEY APPRECIATED OUR HELP IN THEIR TFC PATTERN. I REPLIED THAT WE WERE GLAD TO HELP, BUT THAT THEY MIGHT GET PHONE CALLS FROM RESIDENCE IN THE NEARBY NEIGHBORHOOD THAT WE HAD TO OVERFLY TO MAKE THIS ALL WORK OUT. THE LCL CTLR INDICATED THAT THEY DO INDEED GET CALLS, BUT THAT WE HAD DONE WHAT WAS REQUIRED AND NO HARM SHOULD BEFALL US. IT SEEMS THAT SOMEONE DID TAKE OFFENSE AND CALLED THE LCL FSDO TO RPT US AS A LOW FLYING ACFT. SINCE WE ARE A JET, THEY ARE TRYING TO INVOKE 91.515. WE HAVE BEEN TRYING TO FIGURE OUT WHERE WE MIGHT HAVE ERRED IN THIS SIT. PLENTY OF TIME WAS GIVEN THE TWR FOR NOTICE OF OUR ARR. WE FOLLOWED THEIR INSTRUCTIONS AND AT THE SAME TIME TRIED TO THINK AHEAD OF A TCASII THAT GAVE CONFLICTING INFO. THIS IS NOT THE FIRST TIME A TCASII SETUP HAS DONE THAT. THE QUESTION IS, 'WHAT DO YOU DO WHEN IT HAPPENS?' MY DECISION WAS TO DSND THE ACFT BECAUSE I KNEW I COULD GET BELOW THE CONFLICT TFC FASTER AND WHAT I PERCEIVED TO BE A SAFER FASHION THAN HAD I CLBED UP TO AVOID THE TFC. I KNEW WHERE THIS TFC WAS AND WHERE IT WAS GOING. I DID NOT KNOW THAT FOR THE OTHER ACFT ABOVE ME. I ALSO KNEW THAT I DIDN'T HAVE TO DSND FAR TO CLR THE TFC, AND THAT I WOULD STILL HAVE ADEQUATE TERRAIN CLRNC. COULD WE HAVE ENTERED FROM A DIFFERENT LOCATION? CERTAINLY. BUT WE HAD BEEN IN A POS TO MAKE A SAFE AND EASY ENTRY INTO THE TFC FLOW AND WHEN THAT DIDN'T WORK OUT, WE DID OUR BEST TO AVOID CONFLICTING TFC AND STAY AWAY FROM THE NOISE SENSITIVE AREAS. IN THE FUTURE, I WILL ADVISE ALL OUR PLTS THAT THIS AREA CAN BE VERY BUSY AND TO CONTACT THE TWR WELL IN ADVANCE TO SEE WHAT THEIR PREFERENCE WILL BE FOR OUR TFC PATTERN ENTRY.

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.