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Pit approach controller described near separation loss at 3000 ft when trying to conduct visual side-by approachs during marginal WX conditions.
| Attributes | |
| ACN | 696129 |
| Time | |
| Date | 200605 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : pit.airport |
| State Reference | PA |
| Altitude | msl single value : 3000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : pit.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | BAe 146 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : pit.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Beech 1900 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : radar |
| Experience | controller radar : 22 controller time certified in position1 : 15 flight time total : 150 |
| ASRS Report | 696129 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne less severe |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued new clearance controller : issued alert flight crew : took evasive action |
| Supplementary | |
| Problem Areas | Weather ATC Human Performance Flight Crew Human Performance |
| Primary Problem | ATC Human Performance |
Narrative:
The pit primary radar site was OTS for maintenance. We were operating on the oakdale backup radar system. The pit SOP restricts the use of simultaneous approachs while using the backup radar system. WX was marginal for visual approachs; but improving. Traffic volume was moderate and the runway 28L final was extended 15-20 mi in a single arrival runway confign. A B737 reported the airport in sight on a 10 mi final at 3300 ft. This led me to believe that visual approachs were feasible for runway 28R which would reduce the delaying vectors and speed control for 2 aircraft in my sector. I changed their arrival runway assignments to visual approachs to runway 28R and vectored them accordingly. The #1 aircraft (a BA146) was on a right downwind for runway 28R. I coordination an early descent for this aircraft to get down below the bases and allow the pilots time to see the airport. I turned the BA146 right to 200 degrees for a right base entry to runway 28R. There was a strong northwest upper level flow which caused the aircraft's ground speed to increase as it turned to the south. The winds aloft and the use of the back-up radar system caused the target to appear to jump and the ground speed increased to 320 KTS at 3000 ft. This alarmed me and I began an early turn to the airport anticipating a possible loss of separation from a B190 established on the runway 28L final. I combined an airport position report to the pilot in conjunction with the turn so that the pilot could be cleared for a visual approach prior to losing radar separation from the B190 on the runway 28L final. The pilot stated they were in and out of the bases. The aircraft entered an area of lower MVA and I immediately descended the aircraft to 2500 ft and alerted the controller responsible for the B190. The BA146 pilot reported the airport in sight and was cleared for a visual approach to runway 28R. The conflict alert went off; but I was unsure if this was due to the target jump and subsequent quickly changing ground speed of the BA146 or that separation was lost.
Original NASA ASRS Text
Title: PIT APCH CTLR DESCRIBED NEAR SEPARATION LOSS AT 3000 FT WHEN TRYING TO CONDUCT VISUAL SIDE-BY APCHS DURING MARGINAL WX CONDITIONS.
Narrative: THE PIT PRIMARY RADAR SITE WAS OTS FOR MAINT. WE WERE OPERATING ON THE OAKDALE BACKUP RADAR SYS. THE PIT SOP RESTRICTS THE USE OF SIMULTANEOUS APCHS WHILE USING THE BACKUP RADAR SYS. WX WAS MARGINAL FOR VISUAL APCHS; BUT IMPROVING. TFC VOLUME WAS MODERATE AND THE RWY 28L FINAL WAS EXTENDED 15-20 MI IN A SINGLE ARR RWY CONFIGN. A B737 RPTED THE ARPT IN SIGHT ON A 10 MI FINAL AT 3300 FT. THIS LED ME TO BELIEVE THAT VISUAL APCHS WERE FEASIBLE FOR RWY 28R WHICH WOULD REDUCE THE DELAYING VECTORS AND SPD CTL FOR 2 ACFT IN MY SECTOR. I CHANGED THEIR ARR RWY ASSIGNMENTS TO VISUAL APCHS TO RWY 28R AND VECTORED THEM ACCORDINGLY. THE #1 ACFT (A BA146) WAS ON A R DOWNWIND FOR RWY 28R. I COORD AN EARLY DSCNT FOR THIS ACFT TO GET DOWN BELOW THE BASES AND ALLOW THE PLTS TIME TO SEE THE ARPT. I TURNED THE BA146 R TO 200 DEGS FOR A R BASE ENTRY TO RWY 28R. THERE WAS A STRONG NW UPPER LEVEL FLOW WHICH CAUSED THE ACFT'S GND SPD TO INCREASE AS IT TURNED TO THE S. THE WINDS ALOFT AND THE USE OF THE BACK-UP RADAR SYS CAUSED THE TARGET TO APPEAR TO JUMP AND THE GND SPD INCREASED TO 320 KTS AT 3000 FT. THIS ALARMED ME AND I BEGAN AN EARLY TURN TO THE ARPT ANTICIPATING A POSSIBLE LOSS OF SEPARATION FROM A B190 ESTABLISHED ON THE RWY 28L FINAL. I COMBINED AN ARPT POS RPT TO THE PLT IN CONJUNCTION WITH THE TURN SO THAT THE PLT COULD BE CLRED FOR A VISUAL APCH PRIOR TO LOSING RADAR SEPARATION FROM THE B190 ON THE RWY 28L FINAL. THE PLT STATED THEY WERE IN AND OUT OF THE BASES. THE ACFT ENTERED AN AREA OF LOWER MVA AND I IMMEDIATELY DSNDED THE ACFT TO 2500 FT AND ALERTED THE CTLR RESPONSIBLE FOR THE B190. THE BA146 PLT RPTED THE ARPT IN SIGHT AND WAS CLRED FOR A VISUAL APCH TO RWY 28R. THE CONFLICT ALERT WENT OFF; BUT I WAS UNSURE IF THIS WAS DUE TO THE TARGET JUMP AND SUBSEQUENT QUICKLY CHANGING GND SPD OF THE BA146 OR THAT SEPARATION WAS LOST.
Data retrieved from NASA's ASRS site as of January 2009 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.