Narrative:

Flight had been cleared for a visual approach at yuma, az. We were cleared to proceed via bard (bza) VORTAC and from there enter a right downwind for runway 35. This runway is typically used by civilian aircraft. Approximately over bza (7 mi north of the field) we were instructed to contact the tower. Contact was established with the tower, we were again instructed to enter a right downwind for runway 35 and report 2 mi north of the field. We commenced a descent to pattern altitude for the right downwind. By using a right downwind, it placed our aircraft over the large military installation at the airport, including the tower, but more importantly, over the end of runways 3/21, which were presently in use by military aircraft (runway 3 active). At approximately 2 mi north of the airport, we were almost at pattern altitude and about to make our position report when our TCASII alerted us with a TA. Both pilots attempted to visually acquire the target aircraft, which the TCASII indicated was at our 10-11 O'clock position and 500 ft below us. Both my first officer and I acquired what we believed to be the threat aircraft. A fighter jet had performed a low approach (possibility a takeoff) on runway 3 (runway 3L or runway 3R is unknown), and on their climb out, had commenced a left turn towards our aircraft. We were able to hear the tower controller advise the military aircraft of our position. Before the controller was able to advise us, our TA now reverted to an RA, and we were instructed to reduce vertical descent. The first officer (PF) complied. We continued to visually acquire the aircraft, and reported to each other that we had the aircraft in sight. At this time our TCASII now commanded another RA, that in conjunction with the vsi required the aircraft to be placed into a 1500-2000 FPM climb. Full power was applied, and a climb commenced. At this time, yuma tower advised us of the conflict aircraft. We were advised that the aircraft was turning towards us on their climb out, and consisted of not one (as we had thought), but a flight of 3 aircraft! The captain (PNF) advised yuma tower that we had received an RA based on the intruder aircraft. After the TCASII reported clear of conflict we re-established our aircraft on the right downwind and conducted a normal landing. I found the advisories provided to us from the tower controllers unsatisfactory for a number of reasons. The dash is a relatively slow moving aircraft, and having established contact with tower approximately 7 mi north of the airport, I believe there was sufficient time to advise us of the potential conflict from the departing opposite direction traffic. Given that we were specifically instructed twice to perform a right downwind, why was the departing traffic required to make a left climbing departure directly into our flight path? I felt this was especially dangerous based on the fact that we were descending for our downwind entry, whilst they were climbing, making it increasingly difficult for either aircraft(south) to perform evasive maneuvers. Of greatest concern was the number of aircraft in the military flight. As a military flight operates with only 1 transponder active, our TCASII was unable to identify that there were numerous threat aircraft. Initially lead to believe that there was only 1 threat aircraft. It is estimated that the threat aircraft passed directly underneath us, with a vertical proximity of 300-400 ft. A contributing factor is that military aircraft operate on UHF, making operations at joint civil/military facilities more challenging due to the fact that pilots are unable to develop a mental image of local traffic conditions with the one-sided communications that are available on the civil frequency range.

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Original NASA ASRS Text

Title: NMAC IN THE YUMA TFC PATTERN BTWN A DHC8 ON DOWNWIND LEG AND 3 MIL FIGHTERS CLBING OUT AFTER TKOF FROM A CROSS RWY AND TURNING R TOWARD THE APCHING DASH 8.

Narrative: FLT HAD BEEN CLRED FOR A VISUAL APCH AT YUMA, AZ. WE WERE CLRED TO PROCEED VIA BARD (BZA) VORTAC AND FROM THERE ENTER A R DOWNWIND FOR RWY 35. THIS RWY IS TYPICALLY USED BY CIVILIAN ACFT. APPROX OVER BZA (7 MI N OF THE FIELD) WE WERE INSTRUCTED TO CONTACT THE TWR. CONTACT WAS ESTABLISHED WITH THE TWR, WE WERE AGAIN INSTRUCTED TO ENTER A R DOWNWIND FOR RWY 35 AND RPT 2 MI N OF THE FIELD. WE COMMENCED A DSCNT TO PATTERN ALT FOR THE R DOWNWIND. BY USING A R DOWNWIND, IT PLACED OUR ACFT OVER THE LARGE MIL INSTALLATION AT THE ARPT, INCLUDING THE TWR, BUT MORE IMPORTANTLY, OVER THE END OF RWYS 3/21, WHICH WERE PRESENTLY IN USE BY MIL ACFT (RWY 3 ACTIVE). AT APPROX 2 MI N OF THE ARPT, WE WERE ALMOST AT PATTERN ALT AND ABOUT TO MAKE OUR POS RPT WHEN OUR TCASII ALERTED US WITH A TA. BOTH PLTS ATTEMPTED TO VISUALLY ACQUIRE THE TARGET ACFT, WHICH THE TCASII INDICATED WAS AT OUR 10-11 O'CLOCK POS AND 500 FT BELOW US. BOTH MY FO AND I ACQUIRED WHAT WE BELIEVED TO BE THE THREAT ACFT. A FIGHTER JET HAD PERFORMED A LOW APCH (POSSIBILITY A TKOF) ON RWY 3 (RWY 3L OR RWY 3R IS UNKNOWN), AND ON THEIR CLBOUT, HAD COMMENCED A L TURN TOWARDS OUR ACFT. WE WERE ABLE TO HEAR THE TWR CTLR ADVISE THE MIL ACFT OF OUR POS. BEFORE THE CTLR WAS ABLE TO ADVISE US, OUR TA NOW REVERTED TO AN RA, AND WE WERE INSTRUCTED TO REDUCE VERT DSCNT. THE FO (PF) COMPLIED. WE CONTINUED TO VISUALLY ACQUIRE THE ACFT, AND RPTED TO EACH OTHER THAT WE HAD THE ACFT IN SIGHT. AT THIS TIME OUR TCASII NOW COMMANDED ANOTHER RA, THAT IN CONJUNCTION WITH THE VSI REQUIRED THE ACFT TO BE PLACED INTO A 1500-2000 FPM CLB. FULL PWR WAS APPLIED, AND A CLB COMMENCED. AT THIS TIME, YUMA TWR ADVISED US OF THE CONFLICT ACFT. WE WERE ADVISED THAT THE ACFT WAS TURNING TOWARDS US ON THEIR CLBOUT, AND CONSISTED OF NOT ONE (AS WE HAD THOUGHT), BUT A FLT OF 3 ACFT! THE CAPT (PNF) ADVISED YUMA TWR THAT WE HAD RECEIVED AN RA BASED ON THE INTRUDER ACFT. AFTER THE TCASII RPTED CLR OF CONFLICT WE RE-ESTABLISHED OUR ACFT ON THE R DOWNWIND AND CONDUCTED A NORMAL LNDG. I FOUND THE ADVISORIES PROVIDED TO US FROM THE TWR CTLRS UNSATISFACTORY FOR A NUMBER OF REASONS. THE DASH IS A RELATIVELY SLOW MOVING ACFT, AND HAVING ESTABLISHED CONTACT WITH TWR APPROX 7 MI N OF THE ARPT, I BELIEVE THERE WAS SUFFICIENT TIME TO ADVISE US OF THE POTENTIAL CONFLICT FROM THE DEPARTING OPPOSITE DIRECTION TFC. GIVEN THAT WE WERE SPECIFICALLY INSTRUCTED TWICE TO PERFORM A R DOWNWIND, WHY WAS THE DEPARTING TFC REQUIRED TO MAKE A L CLBING DEP DIRECTLY INTO OUR FLT PATH? I FELT THIS WAS ESPECIALLY DANGEROUS BASED ON THE FACT THAT WE WERE DSNDING FOR OUR DOWNWIND ENTRY, WHILST THEY WERE CLBING, MAKING IT INCREASINGLY DIFFICULT FOR EITHER ACFT(S) TO PERFORM EVASIVE MANEUVERS. OF GREATEST CONCERN WAS THE NUMBER OF ACFT IN THE MIL FLT. AS A MIL FLT OPERATES WITH ONLY 1 XPONDER ACTIVE, OUR TCASII WAS UNABLE TO IDENT THAT THERE WERE NUMEROUS THREAT ACFT. INITIALLY LEAD TO BELIEVE THAT THERE WAS ONLY 1 THREAT ACFT. IT IS ESTIMATED THAT THE THREAT ACFT PASSED DIRECTLY UNDERNEATH US, WITH A VERT PROX OF 300-400 FT. A CONTRIBUTING FACTOR IS THAT MIL ACFT OPERATE ON UHF, MAKING OPS AT JOINT CIVIL/MIL FACILITIES MORE CHALLENGING DUE TO THE FACT THAT PLTS ARE UNABLE TO DEVELOP A MENTAL IMAGE OF LCL TFC CONDITIONS WITH THE ONE-SIDED COMS THAT ARE AVAILABLE ON THE CIVIL FREQ RANGE.

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.