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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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N90 controller experienced conflict at 7000 ft when aircraft descended to other than assigned altitude and conflict and or TCASII did not activate.
| Attributes | |
| ACN | 645045 |
| Time | |
| Date | 200501 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : n90.tracon |
| State Reference | NY |
| Altitude | msl single value : 7000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : n90.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach descent : intermediate altitude |
| Route In Use | arrival : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : n90.tracon |
| Operator | general aviation : personal |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : developmental |
| Experience | controller military : 8 controller radar : 10 |
| ASRS Report | 645045 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | none taken : anomaly accepted |
| Miss Distance | horizontal : 18000 vertical : 600 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance FAA |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
| Situations | |
| ATC Facility | radar equipment : n90.tracon |
Narrative:
Aircraft #1 was being vectored for approach and was assigned 13000 ft. I wasn't able to find out why the aircraft descended below the altitude assigned; but I assume he descended to 3000 ft instead. Both 3000 ft and 13000 ft are altitudes used commonly on this position. The most significant part of this incident was that neither the conflict alert or TCASII alarms worked. The conflict alert system is widely considered useless by controllers. It seldom gives warning and usually goes off only when the aircraft have already passed by one another or they are diverging. The other problem was that TCASII warnings were not a factor either. There was not an RA or any other warning.
Original NASA ASRS Text
Title: N90 CTLR EXPERIENCED CONFLICT AT 7000 FT WHEN ACFT DSNDED TO OTHER THAN ASSIGNED ALT AND CONFLICT AND OR TCASII DID NOT ACTIVATE.
Narrative: ACFT #1 WAS BEING VECTORED FOR APCH AND WAS ASSIGNED 13000 FT. I WASN'T ABLE TO FIND OUT WHY THE ACFT DSNDED BELOW THE ALT ASSIGNED; BUT I ASSUME HE DSNDED TO 3000 FT INSTEAD. BOTH 3000 FT AND 13000 FT ARE ALTS USED COMMONLY ON THIS POS. THE MOST SIGNIFICANT PART OF THIS INCIDENT WAS THAT NEITHER THE CONFLICT ALERT OR TCASII ALARMS WORKED. THE CONFLICT ALERT SYS IS WIDELY CONSIDERED USELESS BY CTLRS. IT SELDOM GIVES WARNING AND USUALLY GOES OFF ONLY WHEN THE ACFT HAVE ALREADY PASSED BY ONE ANOTHER OR THEY ARE DIVERGING. THE OTHER PROB WAS THAT TCASII WARNINGS WERE NOT A FACTOR EITHER. THERE WAS NOT AN RA OR ANY OTHER WARNING.
Data retrieved from NASA's ASRS site as of January 2009 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.