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Air carrier Y descent to occupied altitude had less than standard separation from atx X. System error.
| Attributes | |
| ACN | 220138 |
| Time | |
| Date | 199209 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : mfd |
| State Reference | OH |
| Altitude | msl bound lower : 16000 msl bound upper : 16000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air taxi |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors enroute airway : zob |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller military : 4 controller non radar : 4 controller radar : 2 |
| ASRS Report | 220138 |
| Person 2 | |
| Affiliation | company : air taxi |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation non adherence : published procedure |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 18000 vertical : 700 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error Intra Facility Coordination Failure |
Narrative:
D side was combined with radar at the marion position. Atx X was issued a clearance direct to rod VOR. His course would keep him clear of the mnn sectors. ZID took the handoff on the aircraft, then later decided they would not take the aircraft on that course. So atx X was put on a heading to join V72 inside mnn sector airspace. ZID was unable to hand the aircraft back to ZOB, the aircraft drop from ZOB track. Another track had to be started. Since the D side control position had previously been combined with the radar, all coordination was going on with ZID and mnn radar controller. Air carrier Y was on a northwest heading south of mfd, also going to rod. After a couple of radar updates past mfd the aircraft was still nwbound. I then turned the aircraft direct rod with a descent from FL200 to 14000 ft. Taking into account the turn and descent rate of the aircraft I assumed these aircraft would not be in conflict and turned my attention to the D side functions. Air carrier Y made a tighter turn than expected and caught up to atx X. Air carrier Y was turned to a heading 330 degrees, which the pilot questioned, but then turned. Atx X was turned to a 180 degree heading.
Original NASA ASRS Text
Title: ACR Y DSCNT TO OCCUPIED ALT HAD LTSS FROM ATX X. SYS ERROR.
Narrative: D SIDE WAS COMBINED WITH RADAR AT THE MARION POS. ATX X WAS ISSUED A CLRNC DIRECT TO ROD VOR. HIS COURSE WOULD KEEP HIM CLR OF THE MNN SECTORS. ZID TOOK THE HDOF ON THE ACFT, THEN LATER DECIDED THEY WOULD NOT TAKE THE ACFT ON THAT COURSE. SO ATX X WAS PUT ON A HDG TO JOIN V72 INSIDE MNN SECTOR AIRSPACE. ZID WAS UNABLE TO HAND THE ACFT BACK TO ZOB, THE ACFT DROP FROM ZOB TRACK. ANOTHER TRACK HAD TO BE STARTED. SINCE THE D SIDE CTL POS HAD PREVIOUSLY BEEN COMBINED WITH THE RADAR, ALL COORD WAS GOING ON WITH ZID AND MNN RADAR CTLR. ACR Y WAS ON A NW HDG S OF MFD, ALSO GOING TO ROD. AFTER A COUPLE OF RADAR UPDATES PAST MFD THE ACFT WAS STILL NWBOUND. I THEN TURNED THE ACFT DIRECT ROD WITH A DSCNT FROM FL200 TO 14000 FT. TAKING INTO ACCOUNT THE TURN AND DSCNT RATE OF THE ACFT I ASSUMED THESE ACFT WOULD NOT BE IN CONFLICT AND TURNED MY ATTN TO THE D SIDE FUNCTIONS. ACR Y MADE A TIGHTER TURN THAN EXPECTED AND CAUGHT UP TO ATX X. ACR Y WAS TURNED TO A HDG 330 DEGS, WHICH THE PLT QUESTIONED, BUT THEN TURNED. ATX X WAS TURNED TO A 180 DEG HDG.
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.