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ARTCC radar controller handling a DC10 sbound and a DC9 northbound attempted to maintain separation with vectors.
| Attributes | |
| ACN | 484880 |
| Time | |
| Date | 200009 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : sby.vor |
| State Reference | MD |
| Altitude | msl single value : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | climbout : vacating altitude |
| Route In Use | enroute : on vectors enroute airway : j79.airway |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : level |
| Route In Use | enroute : on vectors enroute airway : j79.airway |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 21 |
| ASRS Report | 484880 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne critical non adherence : published procedure |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | none taken : insufficient time |
| Miss Distance | horizontal : 28200 vertical : 300 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Air carrier Y, a DC9 northbound on J79, and air carrier X, a DC10 sbound on the sby 220 degree radial, deviated from their assigned rtes and resulted in an apparent loss of lateral separation. Both aircraft were assigned vectors to provide lateral separation, when their deviations became apparent. The DC9 was turned 3 times, first 10 degree left, then an additional 5 degrees, then 10 degrees more to the left. The DC10 was turned 20 degrees left. Despite these turns, separation was lost as the aircraft passed each other. The 5 mi halo was in use. The problem is a combination of factors. Fist, the sby VORTAC has been an unreliable NAVAID for many yrs. Yet, heavy traffic daily overflies sby on a parallel route with additional heavy traffic. Secondly, swap rtes were in use, which means arc X (ewr direct hou) was on an unfamiliar route. Air carrier Y, because of the NAVAID (or pilot error) drifted east into air carrier X. Air carrier X had trouble navigating the sby 220 degree radial (overshoot into air carrier Y).
Original NASA ASRS Text
Title: ARTCC RADAR CTLR HANDLING A DC10 SBOUND AND A DC9 NBOUND ATTEMPTED TO MAINTAIN SEPARATION WITH VECTORS.
Narrative: ACR Y, A DC9 NBOUND ON J79, AND ACR X, A DC10 SBOUND ON THE SBY 220 DEG RADIAL, DEVIATED FROM THEIR ASSIGNED RTES AND RESULTED IN AN APPARENT LOSS OF LATERAL SEPARATION. BOTH ACFT WERE ASSIGNED VECTORS TO PROVIDE LATERAL SEPARATION, WHEN THEIR DEVS BECAME APPARENT. THE DC9 WAS TURNED 3 TIMES, FIRST 10 DEG L, THEN AN ADDITIONAL 5 DEGS, THEN 10 DEGS MORE TO THE L. THE DC10 WAS TURNED 20 DEGS L. DESPITE THESE TURNS, SEPARATION WAS LOST AS THE ACFT PASSED EACH OTHER. THE 5 MI HALO WAS IN USE. THE PROB IS A COMBINATION OF FACTORS. FIST, THE SBY VORTAC HAS BEEN AN UNRELIABLE NAVAID FOR MANY YRS. YET, HVY TFC DAILY OVERFLIES SBY ON A PARALLEL RTE WITH ADDITIONAL HVY TFC. SECONDLY, SWAP RTES WERE IN USE, WHICH MEANS ARC X (EWR DIRECT HOU) WAS ON AN UNFAMILIAR RTE. ACR Y, BECAUSE OF THE NAVAID (OR PLT ERROR) DRIFTED E INTO ACR X. ACR X HAD TROUBLE NAVING THE SBY 220 DEG RADIAL (OVERSHOOT INTO ACR Y).
Data retrieved from NASA's ASRS site as of July 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.