Narrative:

On mar/xa/00 flight from lax to ont, experienced an near midair collision with a private aircraft over seal beach VOR at XA00. The flight was normal except for moderate turbulence due to santa ana wind conditions from the northeast. The pilots switched frequencys as the aircraft leveled off at 6000 ft approximately 3 mi west of the sli VOR traveling nwbound. Just before checking in with the new ATC frequency, the pilots noted a small aircraft at just off the right about 20 degrees and also noted the TCASII displayed the aircraft 500 ft below. The small aircraft was observed passing to the left heading nwbound approximately 1/2 mi and the copilot checked in with the new socal approach control frequency and stated that the traffic passing right to left was in sight and level at 6000 ft. The controller acknowledged the transmission with 'roger.' the copilot then left the frequency to obtain the ATIS at ont. The captain stated that he had the #1 radio while the copilot was listening to ATIS. The captain then glanced to the left out the dv window and saw this aircraft (now idented as a wwii T6) performing an aerobatic maneuver in a near 90 degree left climbing turn only 200-300 ft away just in front of air carrier X's left wing and starting to roll wings level on an exact collision course with the aircraft. The captain noted just before the climbing right turn was started that the VFR traffic was also at 6000 ft, which would put the T6 in class B airspace without a clearance. The captain commanded 'set 100% torque' and rolled into a steep climbing right turn to avoid impact. As this maneuver was being performed, the captain notified ATC that an emergency climbing right turn had been initiated to avoid the VFR traffic. As soon as the right turn was initiated the captain lost sight of the T6, but multiple TCASII 'traffic, traffic' alerts were heard. The pilots noted the aircraft passing behind and still climbing on the TCASII as the flight progressed nebound to the pdz VOR. After the captain's initial radio call to ATC, the controller stated the VFR target was not in regulated airspace and was not in contact with socal approach control and there was not much that could be done about the close call. The controller, no more than 1 min later, called back to the air carrier X crew and stated the VFR target had climbed into the class B airspace and that the target would be tracked to landing for further investigation. The air carrier Y flight proceeded to ont as normal after this occurrence. After landing in ont, the crew thought maybe the T6 climbed so rapidly that the altitude on the radar screen was lagging behind the actual altitude of the T6 and it took a few seconds for ATC to get an accurate readout.

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Original NASA ASRS Text

Title: NMAC. CAPT OF AN EMBRAER EMB120 MADE A FULL PWR CLBING TURN TO AVOID AN ONCOMING NORTH AMERICAN T6 CLBING INTO CLASS B AIRSPACE ENGAGED IN AEROBATICS MANEUVER.

Narrative: ON MAR/XA/00 FLT FROM LAX TO ONT, EXPERIENCED AN NMAC WITH A PVT ACFT OVER SEAL BEACH VOR AT XA00. THE FLT WAS NORMAL EXCEPT FOR MODERATE TURB DUE TO SANTA ANA WIND CONDITIONS FROM THE NE. THE PLTS SWITCHED FREQS AS THE ACFT LEVELED OFF AT 6000 FT APPROX 3 MI W OF THE SLI VOR TRAVELING NWBOUND. JUST BEFORE CHKING IN WITH THE NEW ATC FREQ, THE PLTS NOTED A SMALL ACFT AT JUST OFF THE R ABOUT 20 DEGS AND ALSO NOTED THE TCASII DISPLAYED THE ACFT 500 FT BELOW. THE SMALL ACFT WAS OBSERVED PASSING TO THE L HDG NWBOUND APPROX 1/2 MI AND THE COPLT CHKED IN WITH THE NEW SOCAL APCH CTL FREQ AND STATED THAT THE TFC PASSING R TO L WAS IN SIGHT AND LEVEL AT 6000 FT. THE CTLR ACKNOWLEDGED THE XMISSION WITH 'ROGER.' THE COPLT THEN LEFT THE FREQ TO OBTAIN THE ATIS AT ONT. THE CAPT STATED THAT HE HAD THE #1 RADIO WHILE THE COPLT WAS LISTENING TO ATIS. THE CAPT THEN GLANCED TO THE L OUT THE DV WINDOW AND SAW THIS ACFT (NOW IDENTED AS A WWII T6) PERFORMING AN AEROBATIC MANEUVER IN A NEAR 90 DEG L CLBING TURN ONLY 200-300 FT AWAY JUST IN FRONT OF ACR X'S L WING AND STARTING TO ROLL WINGS LEVEL ON AN EXACT COLLISION COURSE WITH THE ACFT. THE CAPT NOTED JUST BEFORE THE CLBING R TURN WAS STARTED THAT THE VFR TFC WAS ALSO AT 6000 FT, WHICH WOULD PUT THE T6 IN CLASS B AIRSPACE WITHOUT A CLRNC. THE CAPT COMMANDED 'SET 100% TORQUE' AND ROLLED INTO A STEEP CLBING R TURN TO AVOID IMPACT. AS THIS MANEUVER WAS BEING PERFORMED, THE CAPT NOTIFIED ATC THAT AN EMER CLBING R TURN HAD BEEN INITIATED TO AVOID THE VFR TFC. AS SOON AS THE R TURN WAS INITIATED THE CAPT LOST SIGHT OF THE T6, BUT MULTIPLE TCASII 'TFC, TFC' ALERTS WERE HEARD. THE PLTS NOTED THE ACFT PASSING BEHIND AND STILL CLBING ON THE TCASII AS THE FLT PROGRESSED NEBOUND TO THE PDZ VOR. AFTER THE CAPT'S INITIAL RADIO CALL TO ATC, THE CTLR STATED THE VFR TARGET WAS NOT IN REGULATED AIRSPACE AND WAS NOT IN CONTACT WITH SOCAL APCH CTL AND THERE WAS NOT MUCH THAT COULD BE DONE ABOUT THE CLOSE CALL. THE CTLR, NO MORE THAN 1 MIN LATER, CALLED BACK TO THE ACR X CREW AND STATED THE VFR TARGET HAD CLBED INTO THE CLASS B AIRSPACE AND THAT THE TARGET WOULD BE TRACKED TO LNDG FOR FURTHER INVESTIGATION. THE ACR Y FLT PROCEEDED TO ONT AS NORMAL AFTER THIS OCCURRENCE. AFTER LNDG IN ONT, THE CREW THOUGHT MAYBE THE T6 CLBED SO RAPIDLY THAT THE ALT ON THE RADAR SCREEN WAS LAGGING BEHIND THE ACTUAL ALT OF THE T6 AND IT TOOK A FEW SECONDS FOR ATC TO GET AN ACCURATE READOUT.

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.