NMAC WITH 4 FGT'S CLIMBING ACROSS REPORTER'S ROUTE OF FLT. NO TRAFFIC ADVISORY.

Narrative

FLT XYZ DEPARTED SFO RWY 1R AT XA14 LCL. FLT XYZ WAS ON AN IFR FLT PLAN; AND WAS OPERATING UNDER INSTRUMENT FLT RULES. AFTER TKOF; DEP CTL INSTRUCTED XYZ TO FLY HDG 340 DEGS UNTIL RECEIVING RBL SUITABLE FOR DIR; AND CLB AND MAINTAIN 8000' MSL. ABOUT 30 NM N OF SFO ON A 340 DEG HDG OUR ACFT WAS CLBING THROUGH 7500' MSL. WE WERE WINGS LEVEL IN A SHALLOW CLB ABOUT 500 FPM; AND INDICATED AIRSPD WAS 210 KTS WHICH AFFORDED US MORE FAVORABLE OVER-THE-NOSE FORWARD VIS. OUR POS WAS VERY NEAR SCAGGS ISLAND VOR WHEN OAK CENTER REQUESTED A FREQ CHANGE. MY COPLT WAS FLYING AND ALSO DIALED THE APPROPRIATE FREQ AS I ACKNOWLEDGED THE REQUEST TO OAK CENTER. SIMULTANEOUSLY I STARTED MY VISUAL SCAN OUTSIDE THE ACFT FROM LEFT TO RIGHT. AT 12 O'CLOCK; OUR ALT; I FIRST SPOTTED THE LEAD PAIR OF FGT'S. THEY WERE ON A HDG OF APPROX 250 DEGS. A MERE INSTANT THEREAFTER I SAW THE TRAILING PAIR OF FGT'S. THEY WERE EVEN CLOSER TO OUR ACFT DUE TO THEIR OFFSET POS OF 8 O'CLOCK RELATIVE TO THE LEAD FGT'S. WE WERE ON A COLLISION COURSE. I IMMEDIATELY GRABBED THE CTLS AND PULLED THE ACFT HARD RIGHT. MY COPLT NOW SEEING THE FGT'S; FOLLOWED THROUGH WITH ME. THE TRAILING FGT'S MUST HAVE ALSO SEEN US AT THAT SAME INSTANT BECAUSE THEY STARTED TO BREAK TO THEIR RIGHT AS WELL. OUR ANGLE OF BANK WAS APPROX 40-45 DEGS RIGHT; AND WE OFFSET OUR HDG AROUND 15 DEGS TO THE RIGHT. I WOULD ESTIMATE OUR ACFT PASSED WITHIN 300' OR LESS OF THE TRAILING FGT'S WITH A CLOSURE RATE AROUND 650 KTS. VIS AT THE TIME WAS CLR AND UNRESTRICTED. NAV LIGHTS ON MY ACFT WERE ON AS WELL AS WING-MOUNTED STROBES; ROTATING BEACON; BOTH RECOGNITION LIGHTS AND WINGS/ICE LIGHTS. MY ASSUMPTION IS THAT BECAUSE XYZ AND THE TRAILING FGT'S TOOK THE NECESSARY EVASIVE ACTION; A MIDAIR COLLISION WAS AVOIDED. ADDITIONALLY; NO TFC INFO WAS GIVEN REGARDING THE FGT'S. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: ARTCC RADAR CTLR CLAIMS TO HAVE NOT HAD THE ACFT ON RADAR UNTIL AFTER THE FACT. RPTED AS POP-UP TFC AFTER THE FLT CREW QUESTIONED WHERE THE FGT'S HAD COME FROM. HAS FILED A RPT WITH THE COMPANY AND AT THE REQUEST OF THE CTL FAC HAS FILED WITH FAA. NO FEEDBACK TO DATE OF THE FINDINGS. DOES NOT KNOW IF THE FGT'S FILED A RPT.