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Level en route DHC8 makes evasive TCASII maneuver from descending LJ45 as ZTL applies visual separation criterion.
| Attributes | |
| ACN | 571306 |
| Time | |
| Date | 200301 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : gso.airport |
| State Reference | NC |
| Altitude | msl bound lower : 13000 msl bound upper : 17000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | other |
| Make Model Name | Learjet 45 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | descent : intermediate altitude |
| Route In Use | approach : circling arrival other arrival star : brook 2 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Dash 8 Series Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 100 flight time total : 12300 flight time type : 1000 |
| ASRS Report | 571306 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne critical other spatial deviation |
| Independent Detector | aircraft equipment : tcas other controllera other flight crewa other flight crewb |
| Resolutory Action | controller : issued advisory controller : separated traffic flight crew : took evasive action |
| Miss Distance | horizontal : 1000 vertical : 1000 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance ATC Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Our aircraft was at 17000 ft MSL. Center controller asked us if we had our traffic in sight, approximately 2 O'clock position low. I visually acquired traffic and informed controller. PF asked me if I had the traffic. I pointed to the other aircraft and replied yes. We needed lower for crossing restr on the brook 2 arrival. Controller asked if we could maintain visual separation from other traffic. I replied yes. Controller told other aircraft 'lear has you in sight, will be descending through your altitude.' he then cleared us to descend to 15000 ft and maintained visibility separation with the dash 8 at 16000 ft. The dash 8 crew replied that they did not have us. We began a steep descent to quickly pass through the dash 8's altitude. The spacing looked good. All seemed normal, the dash 8 crew told the controller they were getting an RA and asked where is the traffic? The controller responded that yes the lear is descending with you in sight. At this point, we got a climb RA, but we were descending rapidly to get below the dash 8. I saw 2500 FPM on the vsi. This is when the dash 8 crew said they were getting a descend RA and were following it, they could not see their traffic. The controller said a third time -- 'the lear has you in sight and is descending through your altitude.' we began a left turn away from the dash 8. I believe they then saw us, as they began a divergent left turn. I was puzzled as to why he (dash 8) continued (apparently) to descend towards us. It just seemed the wrong thing to do. I have since learned that at some/all (?) airlines, the company rule is always follow RA's no matter what. In the vast majority of cases, that is probably the correct thing. In this instance, with 3 controller confirmation of our descent clearance, situational awareness was sacrificed for company policy. I believe that had we changed our actions, ie, followed the RA into a climb, we may have been putting both aircraft in more danger of a midair. We are currently considering carefully if this incident will force us to refuse such clrncs in the future, accept them day only, or what changes will come to our company's policies as a result of this.
Original NASA ASRS Text
Title: LEVEL ENRTE DHC8 MAKES EVASIVE TCASII MANEUVER FROM DSNDING LJ45 AS ZTL APPLIES VISUAL SEPARATION CRITERION.
Narrative: OUR ACFT WAS AT 17000 FT MSL. CTR CTLR ASKED US IF WE HAD OUR TFC IN SIGHT, APPROX 2 O'CLOCK POS LOW. I VISUALLY ACQUIRED TFC AND INFORMED CTLR. PF ASKED ME IF I HAD THE TFC. I POINTED TO THE OTHER ACFT AND REPLIED YES. WE NEEDED LOWER FOR XING RESTR ON THE BROOK 2 ARR. CTLR ASKED IF WE COULD MAINTAIN VISUAL SEPARATION FROM OTHER TFC. I REPLIED YES. CTLR TOLD OTHER ACFT 'LEAR HAS YOU IN SIGHT, WILL BE DSNDING THROUGH YOUR ALT.' HE THEN CLRED US TO DSND TO 15000 FT AND MAINTAINED VISIBILITY SEPARATION WITH THE DASH 8 AT 16000 FT. THE DASH 8 CREW REPLIED THAT THEY DID NOT HAVE US. WE BEGAN A STEEP DSCNT TO QUICKLY PASS THROUGH THE DASH 8'S ALT. THE SPACING LOOKED GOOD. ALL SEEMED NORMAL, THE DASH 8 CREW TOLD THE CTLR THEY WERE GETTING AN RA AND ASKED WHERE IS THE TFC? THE CTLR RESPONDED THAT YES THE LEAR IS DSNDING WITH YOU IN SIGHT. AT THIS POINT, WE GOT A CLB RA, BUT WE WERE DSNDING RAPIDLY TO GET BELOW THE DASH 8. I SAW 2500 FPM ON THE VSI. THIS IS WHEN THE DASH 8 CREW SAID THEY WERE GETTING A DSND RA AND WERE FOLLOWING IT, THEY COULD NOT SEE THEIR TFC. THE CTLR SAID A THIRD TIME -- 'THE LEAR HAS YOU IN SIGHT AND IS DSNDING THROUGH YOUR ALT.' WE BEGAN A L TURN AWAY FROM THE DASH 8. I BELIEVE THEY THEN SAW US, AS THEY BEGAN A DIVERGENT L TURN. I WAS PUZZLED AS TO WHY HE (DASH 8) CONTINUED (APPARENTLY) TO DSND TOWARDS US. IT JUST SEEMED THE WRONG THING TO DO. I HAVE SINCE LEARNED THAT AT SOME/ALL (?) AIRLINES, THE COMPANY RULE IS ALWAYS FOLLOW RA'S NO MATTER WHAT. IN THE VAST MAJORITY OF CASES, THAT IS PROBABLY THE CORRECT THING. IN THIS INSTANCE, WITH 3 CTLR CONFIRMATION OF OUR DSCNT CLRNC, SITUATIONAL AWARENESS WAS SACRIFICED FOR COMPANY POLICY. I BELIEVE THAT HAD WE CHANGED OUR ACTIONS, IE, FOLLOWED THE RA INTO A CLB, WE MAY HAVE BEEN PUTTING BOTH ACFT IN MORE DANGER OF A MIDAIR. WE ARE CURRENTLY CONSIDERING CAREFULLY IF THIS INCIDENT WILL FORCE US TO REFUSE SUCH CLRNCS IN THE FUTURE, ACCEPT THEM DAY ONLY, OR WHAT CHANGES WILL COME TO OUR COMPANY'S POLICIES AS A RESULT OF THIS.
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.