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A DC9 descending to 10000 ft above a PA46 descending to 9000 ft overtakes the PA46 in descent resulting in a loss of separation.
| Attributes | |
| ACN | 493845 |
| Time | |
| Date | 200011 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : tvt.vortac |
| State Reference | OH |
| Altitude | msl bound lower : 9000 msl bound upper : 12400 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zid.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 | descent : vacating altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zid.artcc |
| Operator | general aviation : personal |
| Make Model Name | PA-46 Malibu |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other vortac |
| Flight Phase | descent : vacating altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 16 |
| ASRS Report | 493845 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure |
| Independent Detector | aircraft equipment : tcas other controllera other flight crewa other flight crewb |
| Resolutory Action | none taken : insufficient time |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Both aircraft were descending into cak. ZID/ZOB LOA requires that propellers cross the common center boundary at 9000 ft for propellers/single engine and 10000 ft for jets. I was step descending the DC9 on top of the PA46. During this time period I noticed an 11000 ft untracked target in confliction with the DC9. At the time I noticed the 11000 ft traffic, the DC9 was at FL190 descending to 13000 ft, and the PA46 was descending from 12400 ft to cross 10 mi northeast of tvt at 9000 ft. I continued to monitor the situation and made the decision to cross the DC9 10 mi northeast of tvt at 10000 ft. I felt that I had no other choice since cak was so close to the boundary to get the DC9 below the 11000 ft intruder. The PA46 shallowed his descent rate at 10500 ft and the DC9 must have increased his and separation was lost.
Original NASA ASRS Text
Title: A DC9 DSNDING TO 10000 FT ABOVE A PA46 DSNDING TO 9000 FT OVERTAKES THE PA46 IN DSCNT RESULTING IN A LOSS OF SEPARATION.
Narrative: BOTH ACFT WERE DSNDING INTO CAK. ZID/ZOB LOA REQUIRES THAT PROPS CROSS THE COMMON CTR BOUNDARY AT 9000 FT FOR PROPS/SINGLE ENG AND 10000 FT FOR JETS. I WAS STEP DSNDING THE DC9 ON TOP OF THE PA46. DURING THIS TIME PERIOD I NOTICED AN 11000 FT UNTRACKED TARGET IN CONFLICTION WITH THE DC9. AT THE TIME I NOTICED THE 11000 FT TFC, THE DC9 WAS AT FL190 DSNDING TO 13000 FT, AND THE PA46 WAS DSNDING FROM 12400 FT TO CROSS 10 MI NE OF TVT AT 9000 FT. I CONTINUED TO MONITOR THE SIT AND MADE THE DECISION TO CROSS THE DC9 10 MI NE OF TVT AT 10000 FT. I FELT THAT I HAD NO OTHER CHOICE SINCE CAK WAS SO CLOSE TO THE BOUNDARY TO GET THE DC9 BELOW THE 11000 FT INTRUDER. THE PA46 SHALLOWED HIS DSCNT RATE AT 10500 FT AND THE DC9 MUST HAVE INCREASED HIS AND SEPARATION WAS LOST.
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.