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Cos departure controller felt a B727 pilot's response to a TCASII RA was unnecessary because he had ensured separation and issued traffic to both aircraft.
| Attributes | |
| ACN | 618837 |
| Time | |
| Date | 200405 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : cos.tracon |
| State Reference | CO |
| Altitude | msl single value : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : cos.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Route In Use | arrival : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : cos.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : departure controller : approach |
| Qualification | controller : radar pilot : instrument |
| Experience | controller limited radar : 6 controller non radar : 2 controller radar : 9 controller supervisory : 2 flight time total : 200 |
| ASRS Report | 618837 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe other anomaly other |
| Independent Detector | atc equipment other atc equipment : radar/ mode c aircraft equipment : tcas other controllera |
| Resolutory Action | controller : issued advisory flight crew : took evasive action flight crew : returned to assigned altitude |
| Miss Distance | horizontal : 0 vertical : 1000 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance ATC Human Performance |
| Primary Problem | Ambiguous |
Narrative:
Air carrier Y (B727) level at 11000 ft, heading 350 degrees. Air carrier Y (MD80) departed cos, heading assigned 120 degrees, altitude assigned 10000 ft. I issued traffic to both aircraft. Air carrier X reported air carrier Y in sight. Air carrier Y was level at 10000 ft. As targets merged, air carrier X climbed to 11500 ft and advised ATC they were responding to an RA. I questioned air carrier X if they had the traffic in sight. The pilot responded, 'yes we do, but have an RA and have to climb.' air carrier Y then informed me that they received a TA. The pilot's comment was 'just an FYI.' question: why would the B727 get an RA and the other only a TA?' I feel that since air carrier X reported the traffic in sight and was told that the MD80 was going to level at 10000 ft, the response to the RA was unnecessary. An RA in this case, had there been another aircraft at 12000 ft, would have caused a safety issue. I feel that TCASII is a good tool but sits like these cause me to build in more than standard IFR separation. Since the controller ensured separation, informed both crews, and the air carrier X crew had air carrier Y in sight, the TCASII RA climb is not justified.
Original NASA ASRS Text
Title: COS DEP CTLR FELT A B727 PLT'S RESPONSE TO A TCASII RA WAS UNNECESSARY BECAUSE HE HAD ENSURED SEPARATION AND ISSUED TFC TO BOTH ACFT.
Narrative: ACR Y (B727) LEVEL AT 11000 FT, HDG 350 DEGS. ACR Y (MD80) DEPARTED COS, HDG ASSIGNED 120 DEGS, ALT ASSIGNED 10000 FT. I ISSUED TFC TO BOTH ACFT. ACR X RPTED ACR Y IN SIGHT. ACR Y WAS LEVEL AT 10000 FT. AS TARGETS MERGED, ACR X CLBED TO 11500 FT AND ADVISED ATC THEY WERE RESPONDING TO AN RA. I QUESTIONED ACR X IF THEY HAD THE TFC IN SIGHT. THE PLT RESPONDED, 'YES WE DO, BUT HAVE AN RA AND HAVE TO CLB.' ACR Y THEN INFORMED ME THAT THEY RECEIVED A TA. THE PLT'S COMMENT WAS 'JUST AN FYI.' QUESTION: WHY WOULD THE B727 GET AN RA AND THE OTHER ONLY A TA?' I FEEL THAT SINCE ACR X RPTED THE TFC IN SIGHT AND WAS TOLD THAT THE MD80 WAS GOING TO LEVEL AT 10000 FT, THE RESPONSE TO THE RA WAS UNNECESSARY. AN RA IN THIS CASE, HAD THERE BEEN ANOTHER ACFT AT 12000 FT, WOULD HAVE CAUSED A SAFETY ISSUE. I FEEL THAT TCASII IS A GOOD TOOL BUT SITS LIKE THESE CAUSE ME TO BUILD IN MORE THAN STANDARD IFR SEPARATION. SINCE THE CTLR ENSURED SEPARATION, INFORMED BOTH CREWS, AND THE ACR X CREW HAD ACR Y IN SIGHT, THE TCASII RA CLB IS NOT JUSTIFIED.
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.