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An air carrier large transport descended in response to a command from TCASII while in a holding pattern in VMC.
| Attributes | |
| ACN | 228331 |
| Time | |
| Date | 199212 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : smf |
| State Reference | CA |
| Altitude | msl bound lower : 9000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : smf tower : san |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 100 flight time total : 16000 flight time type : 7000 |
| ASRS Report | 228331 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : clearance non adherence : required legal separation other anomaly other |
| Independent Detector | other controllera other flight crewa other other : unspecified |
| Resolutory Action | controller : issued new clearance flight crew : took evasive action |
| Consequence | Other |
| Miss Distance | horizontal : 9000 vertical : 1000 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We were holding as published, inbound to metropolitan at 8 ILS DME north of smf. Another aircraft holding below us requested to leave holding and requested clearance out of area. We received a TA on TCASII. We looked at TCASII and determined the aircraft was at our altitude, position 2 O'clock about 3 mi. We looked out and saw an air carrier medium large transport turning toward us at our altitude. We received a TCASII RA commanding a descent, which we immediately executed. Smf approach told us to make an immediate descent to 9000 ft. The medium large transport passed over us about 1000 ft while we were in descent. The TCASII no doubt saved the day on this one for us. I feel the approach controller workload probably contributed to this loss of separation and inadvertently cleared aircraft to our altitude, and turned the other aircraft toward us. There were numerous aircraft in area holding and passing through.
Original NASA ASRS Text
Title: AN ACR LGT DSNDED IN RESPONSE TO A COMMAND FROM TCASII WHILE IN A HOLDING PATTERN IN VMC.
Narrative: WE WERE HOLDING AS PUBLISHED, INBOUND TO METRO AT 8 ILS DME N OF SMF. ANOTHER ACFT HOLDING BELOW US REQUESTED TO LEAVE HOLDING AND REQUESTED CLRNC OUT OF AREA. WE RECEIVED A TA ON TCASII. WE LOOKED AT TCASII AND DETERMINED THE ACFT WAS AT OUR ALT, POS 2 O'CLOCK ABOUT 3 MI. WE LOOKED OUT AND SAW AN ACR MLG TURNING TOWARD US AT OUR ALT. WE RECEIVED A TCASII RA COMMANDING A DSCNT, WHICH WE IMMEDIATELY EXECUTED. SMF APCH TOLD US TO MAKE AN IMMEDIATE DSCNT TO 9000 FT. THE MLG PASSED OVER US ABOUT 1000 FT WHILE WE WERE IN DSCNT. THE TCASII NO DOUBT SAVED THE DAY ON THIS ONE FOR US. I FEEL THE APCH CTLR WORKLOAD PROBABLY CONTRIBUTED TO THIS LOSS OF SEPARATION AND INADVERTENTLY CLRED ACFT TO OUR ALT, AND TURNED THE OTHER ACFT TOWARD US. THERE WERE NUMEROUS ACFT IN AREA HOLDING AND PASSING THROUGH.
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.