NMAC.

Narrative

IT WAS A ROUTINE FLT FROM ROC TO DCA. FOLLOWING ATC'S DIRECTIVES; THE F/O (PF) DSNDED THE ACFT TOWARDS THE ASSIGNED ALT OF 10000' MSL. ABOUT 15 MI N OF BALTIMORE VOR AND JUST PRIOR TO LEVELING AT THAT ALT THE JUMP SEAT PLT NOTICED TFC CONVERGING (AND APPARENTLY CLBING) FROM THE 11 O'CLOCK POS AND PROMPTLY ALERTED THE CAPT AND F/O OF THE IMPENDING CONFLICT. IMMEDIATELY UPON RECOGNITION OF THE SITUATION BOTH PLTS SIMULTANEOUSLY TOOK THE EVASIVE ACTIONS OF PULLING BACK ON THE CONTROL COLUMN TO STOP THE DSCNT AND TURNING THE ACFT TO THE RIGHT TO AVOID A TIP-TANKED; TWIN-ENG TYPE ACFT. AT THE SAME TIME THE PLT OF THE LIGHT TWIN APPEARED TO DIVE AWAY TO ITS RIGHT. AFTER THE OTHER ACFT (AN SMT) PASSED OFF TO THE LEFT; THE CAPT QUESTIONED THE CTLR IF THERE HAD BEEN ANY INDICATION OF THE OTHER ACFT ON HIS RADAR SCREEN. INITIALLY; THE CTLR RESPONDED THAT THERE WAS NOT; BUT SECS LATER CONFIRMED ANOTHER TARGET AT 10300'. THE FLT CONTINUED TO DCA NORMALLY THEREAFTER. SEE AND AVOID--3 WORDS ALL PLTS (AND THEIR PAX) CAN LIVE BY. IT REALLY IS ESSENTIAL AND IT WORKS. THE MAIN QUESTION IN THIS SITUATION IS WHY ATC DID NOT DETECT THE CONFLICT AND ALERT THE FLT BEFORE THE NEED FOR EVASIVE MANEUVERING. COMPUTER GLITCH? CTLR WORKLOAD? CONTRIBUTING FACTORS (BESIDES NO RADAR CTLR CALLOUT OF TFC WHICH HE APPARENTLY DID NOT DETECT): THE LIGHT TWIN SEEMED TO BE CLBING DIRECTLY INTO HAZY SUNSHINE WHICH MAKES FOR VERY POOR FORWARD VIS FOR HIM. THE MLG WAS LEVELING OFF FROM DSCNT AND AT RELATIVELY LOW AIRSPD (CLEAN CONFIGN AND DECELERATING TO 250 KTS). THIS PUTS IT NOSE HIGH MAKING IT MORE DIFFICULT TO DETECT TFC AHEAD OF AND BELOW THE NOSE. TO PREVENT RECURRENCE: ELIMINATE RADAR FAULTINESS; CONTINUE SEEING AND AVOIDING; DECREASE CTLR WORKLOAD.