CTLR MISREAD MODE C READOUT AND ALLOWED ACR-WDB TO PROCEED INTO CONFLICT WITH ACR-LGT BEFORE ALT SEPARATION EXISTED.

Narrative

WDB X WAS OVER EASTERN WA IN A CLB TO FL370 ON A FLT FROM SEA TO ORD. LGT Y WAS IN LEVEL FLT NBOUND ON J3 S OF GEG AT FL350. WDB X WAS TURNED NE; DIRECT MLP TO CROSS BEHIND LGT Y. THE JET STREAM WAS OVER THE AREA FROM THE SW AT OVER 100 KTS. THE TURN CAUSED THE SPD ON WDB X TO INCREASE BY OVER 80 KTS AND PUT THE PROJECTED COURSE EVEN CLOSER TOGETHER. WDB X WAS IN A VERY SLOW CLB OF UNDER 500 FPM BUT WAS ALREADY OUT OF FL332. THE RADAR CTLR TURNED WDB X TO A HDG 020 DEGS TO PARALLEL LGT Y. WDB X WAS TOLD TO RESUME OWN NAV DIRECT MLP UPON REACHING FL370. A FEW MINS LATER MODE C ON WDB X INDICATED FL367. THE RADAR CTLR INSTRUCTED WDB X TO PROCEED DIRECT MLP. BOTH DATA AND RADAR CTLR HAD THEIR ATTN OFF THE SCOPE FOR APPROX 20 SECS LOOKING AT AN OVERHEAD MAP. THE DATA BLOCKS BEGAN FLASHING ON THE SCOPE INDICATING A CA. MODE C ON WDB X THEN INDICATED FL360. MODE C WAS VERIFIED BY THE PLT WHO WAS THEN TURNED AND TOLD TO EXPEDITE CLB. SEP MINIMA WAS LOST. SUPPLEMENTAL INFO FROM ACN 88325: ONE ACFT WAS TURNED TO AVOID THE PROB; BUT MISREAD MODE C AND TURNED ONE ACFT TOO SOON.