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TCASII. Flight crew advised by ATC of traffic, but VFR traffic didn't appear on cockpit scope until 2 mi. Flight crew had to evade when traffic commenced climb into their altitude.
| Attributes | |
| ACN | 331904 |
| Time | |
| Date | 199603 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : pmd |
| State Reference | CA |
| Altitude | msl bound lower : 8000 msl bound upper : 8900 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Route In Use | enroute airway : edw |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 331904 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : took evasive action flight crew : returned to intended course or assigned course |
| Consequence | faa : reviewed incident with flight crew |
| Miss Distance | vertical : 500 |
| Supplementary | |
| Air Traffic Incident | other |
Narrative:
Aircraft level at 8000 ft on the palmdale 240 degree radial 30 mi when approach called VFR traffic 12 O'clock 500 ft below. The TCASII was in the 10 mi range and below selected but the VFR target did not appear until the 2 mi range. The target started climbing and neither crew member acquired it visually when the TCASII commanded a climbing RA. We initiated the climb and leveled at 8900 ft. When TCASII advised clear of conflict began a descent when another VFR target appeared below and TCASII commanded a level off RA. When clear of conflict from TCASII was announced we descended back to 8000 ft and made a normal approach and landing into bur. I advised approach of the climbing RA and also the level off RA. The total time of this event was 1-2 mins and it appeared TCASII did not acquire the lower VFR target until 2 mi as it did not appear on the scope before 14 mi. Information on the parameters of TCASII acquisition and command would be appreciated.
Original NASA ASRS Text
Title: TCASII. FLC ADVISED BY ATC OF TFC, BUT VFR TFC DIDN'T APPEAR ON COCKPIT SCOPE UNTIL 2 MI. FLC HAD TO EVADE WHEN TFC COMMENCED CLB INTO THEIR ALT.
Narrative: ACFT LEVEL AT 8000 FT ON THE PALMDALE 240 DEG RADIAL 30 MI WHEN APCH CALLED VFR TFC 12 O'CLOCK 500 FT BELOW. THE TCASII WAS IN THE 10 MI RANGE AND BELOW SELECTED BUT THE VFR TARGET DID NOT APPEAR UNTIL THE 2 MI RANGE. THE TARGET STARTED CLBING AND NEITHER CREW MEMBER ACQUIRED IT VISUALLY WHEN THE TCASII COMMANDED A CLBING RA. WE INITIATED THE CLB AND LEVELED AT 8900 FT. WHEN TCASII ADVISED CLR OF CONFLICT BEGAN A DSCNT WHEN ANOTHER VFR TARGET APPEARED BELOW AND TCASII COMMANDED A LEVEL OFF RA. WHEN CLR OF CONFLICT FROM TCASII WAS ANNOUNCED WE DSNDED BACK TO 8000 FT AND MADE A NORMAL APCH AND LNDG INTO BUR. I ADVISED APCH OF THE CLBING RA AND ALSO THE LEVEL OFF RA. THE TOTAL TIME OF THIS EVENT WAS 1-2 MINS AND IT APPEARED TCASII DID NOT ACQUIRE THE LOWER VFR TARGET UNTIL 2 MI AS IT DID NOT APPEAR ON THE SCOPE BEFORE 14 MI. INFO ON THE PARAMETERS OF TCASII ACQUISITION AND COMMAND WOULD BE APPRECIATED.
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.