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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ARTCC controller believed that he had separated a CL65 climbing to 15000 ft with a cessna 421 level at 14000 ft until ARTCC controller supervisor noticed that the radar tags were showing both aircraft together. However, conflict alert had not indicated closure and the event happened at an earlier time when the controller had given separation changes to each aircraft.
| Attributes | |
| ACN | 468582 |
| Time | |
| Date | 200003 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : abb.vortac |
| State Reference | IN |
| Altitude | msl bound lower : 14000 msl bound upper : 15000 msl single value : 15000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dawn |
| Aircraft 1 | |
| Controlling Facilities | artcc : zid.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Regional Jet CL65, Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zid.artcc |
| Operator | general aviation : personal |
| Make Model Name | Golden Eagle 421 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other vortac |
| Flight Phase | climbout : vacating altitude cruise : enroute altitude change cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller military : 6 controller radar : 19 |
| ASRS Report | 468582 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe |
| Independent Detector | atc equipment other atc equipment : radar other controllera other controllerb |
| Resolutory Action | controller : separated traffic none taken : anomaly accepted |
| Consequence | Other |
| Supplementary | |
| Problem Areas | Navigational Facility ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
| Situations | |
| ATC Facility | computer equipment : zid.artcc radar equipment : zid.artcc |
Narrative:
C421 was level flight (slow morning) at 15000 ft. CL65 departed evv going to cvg, cleared to 15000 ft. I assumed by his (CL65) speed that he would quickly outrun the C421. Conflict alert activated and I reassessed the angle of each aircraft. Not being comfortable with it, I turned the CL65 70 degrees to the right and descended the C421. Believing these actions to be sufficient for separation I went on to other duties. Both aircraft at this time were around the hnb radar site. (Notorious for target jumps and mode C problems.) I thought the C421 showed an altitude more than 1000 ft below the CL65. A few mins later when questioned by my supervisor we saw C421 in the data block. We assumed a bad mode C hit was the problem. We later discovered that the problem was much earlier. Our conflict alert system does not respond well on overtaking aircraft. I believe this to be a big safety defect in the system and feel that this error could have been prevented if conflict alert was better adapted to overtaking aircraft.
Original NASA ASRS Text
Title: ARTCC CTLR BELIEVED THAT HE HAD SEPARATED A CL65 CLBING TO 15000 FT WITH A CESSNA 421 LEVEL AT 14000 FT UNTIL ARTCC CTLR SUPVR NOTICED THAT THE RADAR TAGS WERE SHOWING BOTH ACFT TOGETHER. HOWEVER, CONFLICT ALERT HAD NOT INDICATED CLOSURE AND THE EVENT HAPPENED AT AN EARLIER TIME WHEN THE CTLR HAD GIVEN SEPARATION CHANGES TO EACH ACFT.
Narrative: C421 WAS LEVEL FLT (SLOW MORNING) AT 15000 FT. CL65 DEPARTED EVV GOING TO CVG, CLRED TO 15000 FT. I ASSUMED BY HIS (CL65) SPD THAT HE WOULD QUICKLY OUTRUN THE C421. CONFLICT ALERT ACTIVATED AND I REASSESSED THE ANGLE OF EACH ACFT. NOT BEING COMFORTABLE WITH IT, I TURNED THE CL65 70 DEGS TO THE R AND DSNDED THE C421. BELIEVING THESE ACTIONS TO BE SUFFICIENT FOR SEPARATION I WENT ON TO OTHER DUTIES. BOTH ACFT AT THIS TIME WERE AROUND THE HNB RADAR SITE. (NOTORIOUS FOR TARGET JUMPS AND MODE C PROBS.) I THOUGHT THE C421 SHOWED AN ALT MORE THAN 1000 FT BELOW THE CL65. A FEW MINS LATER WHEN QUESTIONED BY MY SUPVR WE SAW C421 IN THE DATA BLOCK. WE ASSUMED A BAD MODE C HIT WAS THE PROB. WE LATER DISCOVERED THAT THE PROB WAS MUCH EARLIER. OUR CONFLICT ALERT SYS DOES NOT RESPOND WELL ON OVERTAKING ACFT. I BELIEVE THIS TO BE A BIG SAFETY DEFECT IN THE SYS AND FEEL THAT THIS ERROR COULD HAVE BEEN PREVENTED IF CONFLICT ALERT WAS BETTER ADAPTED TO OVERTAKING ACFT.
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.