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An air carrier aircraft overtook a corporate aircraft when the flight crew of the corporate aircraft missed the controller's clearance to turn to intercept the ILS final approach course. Less than standard separation occurred between the two aircraft.
| Attributes | |
| ACN | 169544 |
| Time | |
| Date | 199102 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : mdw |
| State Reference | IL |
| Altitude | msl bound lower : 4000 msl bound upper : 4000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : ord |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport |
| Flight Phase | cruise other |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Small Transport |
| Flight Phase | cruise other |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : radar |
| Experience | controller military : 4 controller non radar : 7 controller radar : 9 |
| ASRS Report | 169544 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance |
| Consequence | Other |
| Miss Distance | horizontal : 16800 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I was working combined positions sector 1 and 4 with heavy traffic. I had high workload of arrs and departures. I had small transport X on downwind to runway 31L at mdw I turned the aircraft base leg and told the aircraft to expect vectors across the localizer for spacing. Later I issued a turn to the final for small transport X and received no response from small transport X. I again turned small transport X to final and received a reply. A few seconds later I noticed that small transport X was turning slowly and I asked him the heading he was passing and he replied 020 degree which indicated he was turning at half standard rate turn. At this time, I turned small transport Y to the southeast to avoid conflict with the small transport X. I believe this was a result of combined positions and pilots slow turn of the aircraft in the approach pattern. Callback conversation with reporter revealed the following information. Reporter stated the location of the incident was 18 mi southeast of mdw airport. The closest point was 2.8 mi. Conflict alert sounded but too late to aid him in preventing loss of separation. Small transport X was a corporate aircraft. Reporter has 9 yrs of radar experience with 7 yrs non-radar and 4 yrs of military experience.
Original NASA ASRS Text
Title: AN ACR ACFT OVERTOOK A CORPORATE ACFT WHEN THE FLC OF THE CORPORATE ACFT MISSED THE CTLR'S CLRNC TO TURN TO INTERCEPT THE ILS FINAL APCH COURSE. LESS THAN STANDARD SEPARATION OCCURRED BETWEEN THE TWO ACFT.
Narrative: I WAS WORKING COMBINED POSITIONS SECTOR 1 AND 4 WITH HVY TFC. I HAD HIGH WORKLOAD OF ARRS AND DEPS. I HAD SMT X ON DOWNWIND TO RWY 31L AT MDW I TURNED THE ACFT BASE LEG AND TOLD THE ACFT TO EXPECT VECTORS ACROSS THE LOC FOR SPACING. LATER I ISSUED A TURN TO THE FINAL FOR SMT X AND RECEIVED NO RESPONSE FROM SMT X. I AGAIN TURNED SMT X TO FINAL AND RECEIVED A REPLY. A FEW SECS LATER I NOTICED THAT SMT X WAS TURNING SLOWLY AND I ASKED HIM THE HDG HE WAS PASSING AND HE REPLIED 020 DEG WHICH INDICATED HE WAS TURNING AT HALF STANDARD RATE TURN. AT THIS TIME, I TURNED SMT Y TO THE SE TO AVOID CONFLICT WITH THE SMT X. I BELIEVE THIS WAS A RESULT OF COMBINED POSITIONS AND PLTS SLOW TURN OF THE ACFT IN THE APCH PATTERN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR STATED THE LOCATION OF THE INCIDENT WAS 18 MI SE OF MDW ARPT. THE CLOSEST POINT WAS 2.8 MI. CONFLICT ALERT SOUNDED BUT TOO LATE TO AID HIM IN PREVENTING LOSS OF SEPARATION. SMT X WAS A CORPORATE ACFT. RPTR HAS 9 YRS OF RADAR EXPERIENCE WITH 7 YRS NON-RADAR AND 4 YRS OF MIL EXPERIENCE.
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.