Narrative:

Aircraft #1 (small transport) was being vectored for ILS 33 final approach course at jst. Current heading 230 degrees, altitude 7000 to 5000'. Aircraft #2 (medium large transport) was 4 mi in trail on same heading, altitude 8000'. Transponder on small transport X fails and radar controller a loses radar contact. Medium large transport Y is then descended to 6000', causing a possible operational error because small transport X's position and altitude was now unknown. Small transport X cancels IFR, but remains on frequency for VFR advisories. Controller a does not re-establish radar identify of small transport X. Controller B arrived to assume control responsibility. After an incomplete sector briefing where controller a stated that small transport X had cancelled, controller a departed the sector (end of controller a's shift). Controller B is now responsible for section operation. Controller B turned medium large transport Y to heading 315 degrees. Controller B then observed a primary radar return west of localizer and at 12 O'clock position of medium large transport Y at 3 mi. Assuming primary return to be that of small transport X controller calls traffic for both aircraft. The assumption was correct and small transport X visually acquired medium large transport Y. Small transport X then states that medium large transport Y B 'coming directly at us.' small transport X instructs medium large transport Y to initiate a left turn (evasive maneuver) with no reply. Small transport X again instructed medium large transport Y to make a left turn. Controller then instructed medium large transport Y to turn left to heading of 270 degrees, which resulted in sep and averted collision. Contributing factors: 1) low visibility, 2) failure of controller a to maintain positive radar identify of small transport X, 3) low experience and skill level of controller a (total radar certified time 6-8 weeks), 4) incomplete sector relief briefing, 5) failure to re-identify the small transport X, 6) controller a's belief that when an aircraft cancels IFR, no further consideration for sep exists, regardless of airport proximity or aircraft proximity, 7) inadequate training on non radar procedures of controller a and failure to adhere to national and facility training guidelines, 8) radar certification of controller a prior to this individual being capable of satisfactory performance, and over the objection of several fpl's, 9) inexperienced controller working 3 sectors in a combined confign (westmoreland, tyrone and indianhead sectors #54, 52 and 53 respectively), 10) unwillingness of supervisory personnel to initiate investigation upon notification of the above incident (indirectly a factor). To prevent recurrence: de-certification of radar controller a and retraining, including lost radar contact procedures, sector relief briefing, traffic advisories, requirements to ensure that national/facility training guidelines are followed written rules to prohibit a new controller from working combined confign until attaining a predetermined amount of hours at each sector individually.

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Original NASA ASRS Text

Title: EVASIVE ACTION REQUIRED TO PREVENT COLLISION WHEN ACR-MLG OVERTAKES VFR CPR-SMT ON FINAL APCH COURSE.

Narrative: ACFT #1 (SMT) WAS BEING VECTORED FOR ILS 33 FINAL APCH COURSE AT JST. CURRENT HDG 230 DEGS, ALT 7000 TO 5000'. ACFT #2 (MLG) WAS 4 MI IN TRAIL ON SAME HDG, ALT 8000'. TRANSPONDER ON SMT X FAILS AND RADAR CTLR A LOSES RADAR CONTACT. MLG Y IS THEN DSNDED TO 6000', CAUSING A POSSIBLE OPERROR BECAUSE SMT X'S POS AND ALT WAS NOW UNKNOWN. SMT X CANCELS IFR, BUT REMAINS ON FREQ FOR VFR ADVISORIES. CTLR A DOES NOT RE-ESTABLISH RADAR IDENT OF SMT X. CTLR B ARRIVED TO ASSUME CTL RESPONSIBILITY. AFTER AN INCOMPLETE SECTOR BRIEFING WHERE CTLR A STATED THAT SMT X HAD CANCELLED, CTLR A DEPARTED THE SECTOR (END OF CTLR A'S SHIFT). CTLR B IS NOW RESPONSIBLE FOR SECTION OPERATION. CTLR B TURNED MLG Y TO HDG 315 DEGS. CTLR B THEN OBSERVED A PRIMARY RADAR RETURN W OF LOC AND AT 12 O'CLOCK POS OF MLG Y AT 3 MI. ASSUMING PRIMARY RETURN TO BE THAT OF SMT X CTLR CALLS TFC FOR BOTH ACFT. THE ASSUMPTION WAS CORRECT AND SMT X VISUALLY ACQUIRED MLG Y. SMT X THEN STATES THAT MLG Y B 'COMING DIRECTLY AT US.' SMT X INSTRUCTS MLG Y TO INITIATE A LEFT TURN (EVASIVE MANEUVER) WITH NO REPLY. SMT X AGAIN INSTRUCTED MLG Y TO MAKE A LEFT TURN. CTLR THEN INSTRUCTED MLG Y TO TURN LEFT TO HDG OF 270 DEGS, WHICH RESULTED IN SEP AND AVERTED COLLISION. CONTRIBUTING FACTORS: 1) LOW VIS, 2) FAILURE OF CTLR A TO MAINTAIN POSITIVE RADAR IDENT OF SMT X, 3) LOW EXPERIENCE AND SKILL LEVEL OF CTLR A (TOTAL RADAR CERTIFIED TIME 6-8 WKS), 4) INCOMPLETE SECTOR RELIEF BRIEFING, 5) FAILURE TO RE-IDENT THE SMT X, 6) CTLR A'S BELIEF THAT WHEN AN ACFT CANCELS IFR, NO FURTHER CONSIDERATION FOR SEP EXISTS, REGARDLESS OF ARPT PROX OR ACFT PROX, 7) INADEQUATE TRNING ON NON RADAR PROCS OF CTLR A AND FAILURE TO ADHERE TO NATIONAL AND FAC TRNING GUIDELINES, 8) RADAR CERTIFICATION OF CTLR A PRIOR TO THIS INDIVIDUAL BEING CAPABLE OF SATISFACTORY PERFORMANCE, AND OVER THE OBJECTION OF SEVERAL FPL'S, 9) INEXPERIENCED CTLR WORKING 3 SECTORS IN A COMBINED CONFIGN (WESTMORELAND, TYRONE AND INDIANHEAD SECTORS #54, 52 AND 53 RESPECTIVELY), 10) UNWILLINGNESS OF SUPERVISORY PERSONNEL TO INITIATE INVESTIGATION UPON NOTIFICATION OF THE ABOVE INCIDENT (INDIRECTLY A FACTOR). TO PREVENT RECURRENCE: DE-CERTIFICATION OF RADAR CTLR A AND RETRAINING, INCLUDING LOST RADAR CONTACT PROCS, SECTOR RELIEF BRIEFING, TFC ADVISORIES, REQUIREMENTS TO ENSURE THAT NATIONAL/FAC TRNING GUIDELINES ARE FOLLOWED WRITTEN RULES TO PROHIBIT A NEW CTLR FROM WORKING COMBINED CONFIGN UNTIL ATTAINING A PREDETERMINED AMOUNT OF HRS AT EACH SECTOR INDIVIDUALLY.

Data retrieved from NASA's ASRS site as of August 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.