Narrative:

This leg was my turn to fly. After departing psp we leveled off at 12000 ft MSL on V388 wbound, controled by ont approach control on frequency 119.65. At a certain point ont issued a clearance to descend to cross pdz VOR at 8000 ft to which we read back and executed. At approximately 20 NM east of pdz as we were descending through 10000 ft, ont issued traffic 11 O'clock, 3 mi, 9300 ft climbing opposite direction, type unknown. We responded, looking, and asked to stop descent immediately. So we leveled off at 9600 ft and stayed on the airway. I would like to add that my aircraft was equipped with an experimental TCASII made by bf goodrich. The TCASII was depicting the traffic but due to the tops of the cumulus clouds being ragged between 8500 ft and 9500 ft, we couldn't see the traffic. Ont continued to control other traffic and a few seconds later issued us frequency change to 135.40 but reversed the clearance and issued a TA 12 O'clock less than a mi to which we responded and looking. 5 seconds later that traffic passed at 2:30 - 3 O'clock, less than 1/8 of a mi. The traffic was at the same altitude, a marchetti SF260 painted military olive green with bright orange wingtips and spinner. Only then did the TCASII issue a voice advisory 'traffic, traffic.' I should mention that soon after ont issued the TA the controller issued the frequency change again and continued to control other traffic without him or us identing this traffic, and we couldn't transmit because of frequency congestion. Eventually we switched and proceeded normally.

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Original NASA ASRS Text

Title: NMAC BTWN AN LTT ACR AND A PVT SMA SEL ACFT ON BUSY AIRWAY DURING DSCNT OF THE LTT RPTING ACFT AND CLB OF THE OTHER SMA ACFT.

Narrative: THIS LEG WAS MY TURN TO FLY. AFTER DEPARTING PSP WE LEVELED OFF AT 12000 FT MSL ON V388 WBOUND, CTLED BY ONT APCH CTL ON FREQ 119.65. AT A CERTAIN POINT ONT ISSUED A CLRNC TO DSND TO CROSS PDZ VOR AT 8000 FT TO WHICH WE READ BACK AND EXECUTED. AT APPROX 20 NM E OF PDZ AS WE WERE DSNDING THROUGH 10000 FT, ONT ISSUED TFC 11 O'CLOCK, 3 MI, 9300 FT CLBING OPPOSITE DIRECTION, TYPE UNKNOWN. WE RESPONDED, LOOKING, AND ASKED TO STOP DSCNT IMMEDIATELY. SO WE LEVELED OFF AT 9600 FT AND STAYED ON THE AIRWAY. I WOULD LIKE TO ADD THAT MY ACFT WAS EQUIPPED WITH AN EXPERIMENTAL TCASII MADE BY BF GOODRICH. THE TCASII WAS DEPICTING THE TFC BUT DUE TO THE TOPS OF THE CUMULUS CLOUDS BEING RAGGED BTWN 8500 FT AND 9500 FT, WE COULDN'T SEE THE TFC. ONT CONTINUED TO CTL OTHER TFC AND A FEW SECONDS LATER ISSUED US FREQ CHANGE TO 135.40 BUT REVERSED THE CLRNC AND ISSUED A TA 12 O'CLOCK LESS THAN A MI TO WHICH WE RESPONDED AND LOOKING. 5 SECONDS LATER THAT TFC PASSED AT 2:30 - 3 O'CLOCK, LESS THAN 1/8 OF A MI. THE TFC WAS AT THE SAME ALT, A MARCHETTI SF260 PAINTED MIL OLIVE GREEN WITH BRIGHT ORANGE WINGTIPS AND SPINNER. ONLY THEN DID THE TCASII ISSUE A VOICE ADVISORY 'TFC, TFC.' I SHOULD MENTION THAT SOON AFTER ONT ISSUED THE TA THE CTLR ISSUED THE FREQ CHANGE AGAIN AND CONTINUED TO CTL OTHER TFC WITHOUT HIM OR US IDENTING THIS TFC, AND WE COULDN'T XMIT BECAUSE OF FREQ CONGESTION. EVENTUALLY WE SWITCHED AND PROCEEDED NORMALLY.

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.