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Atx X descent below assigned altitude had less than standard separation from aircraft Y. Pilot deviation. System error.
| Attributes | |
| ACN | 194075 |
| Time | |
| Date | 199111 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : dfw |
| State Reference | TX |
| Altitude | msl bound lower : 8000 msl bound upper : 9000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : zfw |
| Operator | common carrier : air carrier |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | descent other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller non radar : 4 controller radar : 2 |
| ASRS Report | 194075 |
| Person 2 | |
| Affiliation | company : air taxi |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : undershoot conflict : airborne less severe non adherence : required legal separation non adherence : clearance non adherence : published procedure |
| Independent Detector | other controllera |
| Resolutory Action | none taken : detected after the fact |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 18000 vertical : 700 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Pilot Deviation Operational Error |
Narrative:
Atx X was given a clearance to 70 then corrected to 90. Aircraft radio was weak, garbled and had a loud squeal. Aircraft acknowledged corrected clearance but was unintelligible on tape. Pilot advised he never received amended clearance but all official FAA personnel involved in investigation believed it was that pilot who acknowledged clearance. Aircraft radios must be constantly checked and I believe we must seek other tape verifications other than FAA tapes. All tapes I have ever reviewed are of extremely poor quality. We must insist on in-flight tapes being made available for other than aircraft accidents. I, as the controller, heard an acknowledgement to the clearance, but due to the recording process the FAA has, it was recorded as an operational error. Pilots must be advised and held more accountable for readbacks. Aircraft descended below assigned altitude of 90 and was less than standard separation from an aircraft Y at 80.
Original NASA ASRS Text
Title: ATX X DSCNT BELOW ASSIGNED ALT HAD LTSS FROM ACFT Y. PLTDEV. SYS ERROR.
Narrative: ATX X WAS GIVEN A CLRNC TO 70 THEN CORRECTED TO 90. ACFT RADIO WAS WEAK, GARBLED AND HAD A LOUD SQUEAL. ACFT ACKNOWLEDGED CORRECTED CLRNC BUT WAS UNINTELLIGIBLE ON TAPE. PLT ADVISED HE NEVER RECEIVED AMENDED CLRNC BUT ALL OFFICIAL FAA PERSONNEL INVOLVED IN INVESTIGATION BELIEVED IT WAS THAT PLT WHO ACKNOWLEDGED CLRNC. ACFT RADIOS MUST BE CONSTANTLY CHKED AND I BELIEVE WE MUST SEEK OTHER TAPE VERIFICATIONS OTHER THAN FAA TAPES. ALL TAPES I HAVE EVER REVIEWED ARE OF EXTREMELY POOR QUALITY. WE MUST INSIST ON INFLT TAPES BEING MADE AVAILABLE FOR OTHER THAN ACFT ACCIDENTS. I, AS THE CTLR, HEARD AN ACKNOWLEDGEMENT TO THE CLRNC, BUT DUE TO THE RECORDING PROCESS THE FAA HAS, IT WAS RECORDED AS AN OPERROR. PLTS MUST BE ADVISED AND HELD MORE ACCOUNTABLE FOR READBACKS. ACFT DSNDED BELOW ASSIGNED ALT OF 90 AND WAS LTSS FROM AN ACFT Y AT 80.
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.