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A dc-9 flight crew received a TCASII RA alert for 2 aircraft and descended 400 ft in response. ATC stated separation lost with conflicting aircraft.
| Attributes | |
| ACN | 303279 |
| Time | |
| Date | 199504 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : luf |
| State Reference | TX |
| Altitude | msl bound lower : 28600 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zfw |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | other |
| Make Model Name | Cessna Citation Undifferentiated or Other Model |
| Operating Under FAR Part | other : unknown |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 120 flight time total : 6000 flight time type : 2400 |
| ASRS Report | 303279 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified |
| 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 | horizontal : 6000 vertical : 1000 |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
After flying the alamo 2 SID from sat (lufkin transition), we were cleared direct to luf while still short of elp. We approximately paralleled the luf transition. In the vicinity of luf, we were cleared to FL330 while climbing through the mid-twenties. At approximately FL275, we were advised to modify our level off and stop the climb at FL290 due to traffic above. As we cruised north of luf at FL290, we were advised of wbound traffic, a citation, at FL280. Since the citation advisory was to our right, I began to scan the sky for it. We abruptly had a TCASII descent advisory requiring a 1500-2000 FPM (green zone) adjustment. A quick glance at the vsi showed 2 blips. The captain began his descent as I saw the citation at our 3 O'clock position. As I watched the citation, who never turned, the TCASII advised 'monitor vertical speed.' I never saw the altimeter decrease below 28600 ft MSL. As the captain began his climb back to FL290, the center advised us to 'maintain FL290.' I then informed them of the TCASII advisory to descend. They said separation had been lost and gave a phone number. Center also stated no other traffic was in the area, but I still believe I saw 2 blips on the TCASII. This all happened in a 10-15 second time period. The captain's actions in response to the TCASII were correct. If we lost separation, ATC must have allowed the citation too close laterally. I cannot determine why we had a descent advisory if there was not an aircraft above us.
Original NASA ASRS Text
Title: A DC-9 FLC RECEIVED A TCASII RA ALERT FOR 2 ACFT AND DSNDED 400 FT IN RESPONSE. ATC STATED SEPARATION LOST WITH CONFLICTING ACFT.
Narrative: AFTER FLYING THE ALAMO 2 SID FROM SAT (LUFKIN TRANSITION), WE WERE CLRED DIRECT TO LUF WHILE STILL SHORT OF ELP. WE APPROX PARALLELED THE LUF TRANSITION. IN THE VICINITY OF LUF, WE WERE CLRED TO FL330 WHILE CLBING THROUGH THE MID-TWENTIES. AT APPROX FL275, WE WERE ADVISED TO MODIFY OUR LEVEL OFF AND STOP THE CLB AT FL290 DUE TO TFC ABOVE. AS WE CRUISED N OF LUF AT FL290, WE WERE ADVISED OF WBOUND TFC, A CITATION, AT FL280. SINCE THE CITATION ADVISORY WAS TO OUR R, I BEGAN TO SCAN THE SKY FOR IT. WE ABRUPTLY HAD A TCASII DSCNT ADVISORY REQUIRING A 1500-2000 FPM (GREEN ZONE) ADJUSTMENT. A QUICK GLANCE AT THE VSI SHOWED 2 BLIPS. THE CAPT BEGAN HIS DSCNT AS I SAW THE CITATION AT OUR 3 O'CLOCK POS. AS I WATCHED THE CITATION, WHO NEVER TURNED, THE TCASII ADVISED 'MONITOR VERT SPD.' I NEVER SAW THE ALTIMETER DECREASE BELOW 28600 FT MSL. AS THE CAPT BEGAN HIS CLB BACK TO FL290, THE CTR ADVISED US TO 'MAINTAIN FL290.' I THEN INFORMED THEM OF THE TCASII ADVISORY TO DSND. THEY SAID SEPARATION HAD BEEN LOST AND GAVE A PHONE NUMBER. CTR ALSO STATED NO OTHER TFC WAS IN THE AREA, BUT I STILL BELIEVE I SAW 2 BLIPS ON THE TCASII. THIS ALL HAPPENED IN A 10-15 SECOND TIME PERIOD. THE CAPT'S ACTIONS IN RESPONSE TO THE TCASII WERE CORRECT. IF WE LOST SEPARATION, ATC MUST HAVE ALLOWED THE CITATION TOO CLOSE LATERALLY. I CANNOT DETERMINE WHY WE HAD A DSCNT ADVISORY IF THERE WAS NOT AN ACFT ABOVE US.
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.