Narrative:

We were cruising at 16000 ft when ATC notified a jet of our position. The jet acknowledged he had us in sight. ATC then called out the jet traffic to us, which I had in sight at my 1 O'clock position both visually and on my TCASII. I acknowledged I had the traffic in sight. It was 1000 ft below us according to my TCASII. ATC then cleared the jet traffic to climb to FL230 and maintain visual separation with us. I continued to watch the traffic outside when seconds later I got a TA followed by an RA telling us to climb. I began to climb. By this time the captain was back with me telling me to increase my climb, which I did. At the same time the captain alerted ATC that we were reacting to a TCASII RA and climbing through 17000 ft. By the time the TCASII told us to 'monitor vertical speed' and we leveled off, we were at 17600 ft. Just prior to leveloff, the jet traffic passed relatively close beneath our nose. When the TCASII reported 'clear of conflict' we proceeded to descend back to 16000 ft. During our reaction to the RA, ATC inquired as to why we were reacting as he felt there was going to be adequate separation. After the incident, the pilot of the jet explained that they were trying to climb above us but didn't realize or know they had set off our TCASII. He deduced that as they increased their climb to get above, our TCASII was telling us to increase our climb, so we were in essence trying to out-climb each other. He apologized for the incident. We also explained our side of the story. Solution: if ATC has to climb an aircraft in the vicinity of other traffic, either 1) hold them at their assigned altitude till safety clear of the traffic, or 2) clear the aircraft to climb and do it expeditiously, due to the 'traffic.' also, if an aircraft is given a TA then cleared to climb visually, that aircraft is not just obligated to maintain visual separation but to also stay well clear of that traffic. There is plenty of airspace, we don't have to see how close we can get to other airplanes. Supplemental information from acn 455085: level at 15000 ft at night, ATC called conflicting traffic at 16000 ft and we reported traffic in sight. ATC advised maintain visual separation, climb to FL230. I determined an expedited climb through 16000 ft would provide safe separation and executed climb. I expected a TCASII advisory but was surprised when an RA was received. I was even more surprised that the traffic appeared to be climbing at a rapid rate. Visual separation (especially at night) is not an easy task. There was no doubt in my mind that I could maintain safe separation from traffic. But because I did not consider how this visual climb would affect TCASII, I was wrong. As a result of this situation, I feel that en route visual separation at night is an unsafe situation and will never again rely on it for separation. Also, I feel ATC should use more discretion in issuing this clearance -- especially to obvious conflicting targets.

Google
 

Original NASA ASRS Text

Title: AN EMB120 FLC RECEIVED A TCASII RA FROM A REGIONAL JET CLBING WITH A VISUAL SEPARATION RESTR NEAR PSK.

Narrative: WE WERE CRUISING AT 16000 FT WHEN ATC NOTIFIED A JET OF OUR POS. THE JET ACKNOWLEDGED HE HAD US IN SIGHT. ATC THEN CALLED OUT THE JET TFC TO US, WHICH I HAD IN SIGHT AT MY 1 O'CLOCK POS BOTH VISUALLY AND ON MY TCASII. I ACKNOWLEDGED I HAD THE TFC IN SIGHT. IT WAS 1000 FT BELOW US ACCORDING TO MY TCASII. ATC THEN CLRED THE JET TFC TO CLB TO FL230 AND MAINTAIN VISUAL SEPARATION WITH US. I CONTINUED TO WATCH THE TFC OUTSIDE WHEN SECONDS LATER I GOT A TA FOLLOWED BY AN RA TELLING US TO CLB. I BEGAN TO CLB. BY THIS TIME THE CAPT WAS BACK WITH ME TELLING ME TO INCREASE MY CLB, WHICH I DID. AT THE SAME TIME THE CAPT ALERTED ATC THAT WE WERE REACTING TO A TCASII RA AND CLBING THROUGH 17000 FT. BY THE TIME THE TCASII TOLD US TO 'MONITOR VERT SPD' AND WE LEVELED OFF, WE WERE AT 17600 FT. JUST PRIOR TO LEVELOFF, THE JET TFC PASSED RELATIVELY CLOSE BENEATH OUR NOSE. WHEN THE TCASII RPTED 'CLR OF CONFLICT' WE PROCEEDED TO DSND BACK TO 16000 FT. DURING OUR REACTION TO THE RA, ATC INQUIRED AS TO WHY WE WERE REACTING AS HE FELT THERE WAS GOING TO BE ADEQUATE SEPARATION. AFTER THE INCIDENT, THE PLT OF THE JET EXPLAINED THAT THEY WERE TRYING TO CLB ABOVE US BUT DIDN'T REALIZE OR KNOW THEY HAD SET OFF OUR TCASII. HE DEDUCED THAT AS THEY INCREASED THEIR CLB TO GET ABOVE, OUR TCASII WAS TELLING US TO INCREASE OUR CLB, SO WE WERE IN ESSENCE TRYING TO OUT-CLB EACH OTHER. HE APOLOGIZED FOR THE INCIDENT. WE ALSO EXPLAINED OUR SIDE OF THE STORY. SOLUTION: IF ATC HAS TO CLB AN ACFT IN THE VICINITY OF OTHER TFC, EITHER 1) HOLD THEM AT THEIR ASSIGNED ALT TILL SAFETY CLR OF THE TFC, OR 2) CLR THE ACFT TO CLB AND DO IT EXPEDITIOUSLY, DUE TO THE 'TFC.' ALSO, IF AN ACFT IS GIVEN A TA THEN CLRED TO CLB VISUALLY, THAT ACFT IS NOT JUST OBLIGATED TO MAINTAIN VISUAL SEPARATION BUT TO ALSO STAY WELL CLR OF THAT TFC. THERE IS PLENTY OF AIRSPACE, WE DON'T HAVE TO SEE HOW CLOSE WE CAN GET TO OTHER AIRPLANES. SUPPLEMENTAL INFO FROM ACN 455085: LEVEL AT 15000 FT AT NIGHT, ATC CALLED CONFLICTING TFC AT 16000 FT AND WE RPTED TFC IN SIGHT. ATC ADVISED MAINTAIN VISUAL SEPARATION, CLB TO FL230. I DETERMINED AN EXPEDITED CLB THROUGH 16000 FT WOULD PROVIDE SAFE SEPARATION AND EXECUTED CLB. I EXPECTED A TCASII ADVISORY BUT WAS SURPRISED WHEN AN RA WAS RECEIVED. I WAS EVEN MORE SURPRISED THAT THE TFC APPEARED TO BE CLBING AT A RAPID RATE. VISUAL SEPARATION (ESPECIALLY AT NIGHT) IS NOT AN EASY TASK. THERE WAS NO DOUBT IN MY MIND THAT I COULD MAINTAIN SAFE SEPARATION FROM TFC. BUT BECAUSE I DID NOT CONSIDER HOW THIS VISUAL CLB WOULD AFFECT TCASII, I WAS WRONG. AS A RESULT OF THIS SIT, I FEEL THAT ENRTE VISUAL SEPARATION AT NIGHT IS AN UNSAFE SIT AND WILL NEVER AGAIN RELY ON IT FOR SEPARATION. ALSO, I FEEL ATC SHOULD USE MORE DISCRETION IN ISSUING THIS CLRNC -- ESPECIALLY TO OBVIOUS CONFLICTING TARGETS.

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.