Narrative:

We were established in cruise at 16000 ft, flying northwest along the bridge 5 arrival into tampa, fl, the WX was VMC with haze. After passing lbv, we heard ATC vector the B767 on its climb out from rsw. A few minutes later, ATC asked the B767 if they had a 'beech 1900' (us) in sight, to which they said 'negative'. About this time, my first officer saw the B767 and pointed it out to me. It was several miles away to the west and lower, and it seemed to be climbing. ATC then advised us of the B767, which we reported in sight-it appeared that its path would pass behind and below us. ATC then asked us if we could maintain visual separation so that he could climb it through our altitude. We said we could, based on the rate of convergence we observed. The B767 was then instructed to continue climbing to an altitude above ours. Within a few seconds, it became apparent that the B767's rate of climb increased substantially and soon it would become dangerously close to us: its relative motion stopped, and it began 'blossoming' in the window. Although we had the aircraft in sight, haze and sunlight reflections from water beyond the B767 hindered a clear view of it, the first officer and I both agreed we should advise ATC of the changing conditions and have them stop the B767's climb, as we were now having difficulty seeing what the converging aircraft was doing and we felt limited in how we could react. ATC stopped the B767 at 15000 ft and it passed directly below us moments later. Its flight crew later remarked to ATC that they had us sight at all times, and did not 'even receive an RA' from their TCAS. (Our TCAS-I is not equipped with RA capability, it did call out 'traffic' as we advised ATC to stop the B767's climb). While it appears that IFR separation was always maintained, we felt that this was an example of how not to control air traffic. In this situation, responsibility for maintaining separation could fall on the shoulders of any involved, but all are not equal choices: if ATC is controling, it can alter course and altitude of all participating aircraft to avoid conflicts. This offers the most control, but is not always preferable because it can cause delays. If the climbing ('variable') aircraft has the other traffic in sight, it can adjust its rate of climb as necessary to maintain visual separation. It remains in full control of the situation. The cruise ('steady state') aircraft is the least capable of all three to maintain separation, as it is flying on an assigned heading at an assigned altitude. As such, its crew may be less likely to initiate a change, particularly a climb or descent, until a flight-saving maneuver is called for. It appears that ATC did follow this prioritized list: it first advised the B767 it could not climb to cruise altitude immediately due to conflicting traffic, but then offered the climb if they could see us. They could not, so then ATC asked if we could maintain visual separation. We said we could, based on what we observed at that time: a B767 in a shallow climb which would pass beneath and behind us. After we accepted that responsibility, the conditions changed substantially (both with regard to the B767 and to how well we could see it) suddenly we were in a new situation with the B767 bearing down (er, up) and we had nowhere to go. The only alternatives to a near miss were to take drastic evasive action (without knowing what drastic evasive action the B767 might take in response-remember, we don't have TCAS-ii capability) or have ATC stop the B767's climb until it passed us. We chose the latter. I would discourage ATC from asking the 'steady state' aircraft to accept responsibility for visual separation (unless it's clear that there won't be a conflict, and after considering the likely performance of both aircraft) initially, the assignment might be accepted because there is little or no apparent conflict, but it remains very hard for the 'steady state' aircraft to anticipate what the other 'variable' aircraft is going to do afterwards. Callback conversation with reporter revealed the following information: reporter advised that this was his first real concernof ZMA's application of visibility separation. The reporter emphasized that ATC needs to take into account issues such as the phenomena of sun glare off the ocean. He advised that an acfts physical visual signature diminishes as the aircraft enters into glare area reflected sunlight.

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Original NASA ASRS Text

Title: B1900 FLC QUESTIONS ZMA APPLICATION OF VIS SEPARATION WITH HEAD-ON CLBING B767.

Narrative: WE WERE ESTABLISHED IN CRUISE AT 16000 FT, FLYING NW ALONG THE BRIDGE 5 ARR INTO TAMPA, FL, THE WX WAS VMC WITH HAZE. AFTER PASSING LBV, WE HEARD ATC VECTOR THE B767 ON ITS CLBOUT FROM RSW. A FEW MINUTES LATER, ATC ASKED THE B767 IF THEY HAD A 'BEECH 1900' (US) IN SIGHT, TO WHICH THEY SAID 'NEGATIVE'. ABOUT THIS TIME, MY FO SAW THE B767 AND POINTED IT OUT TO ME. IT WAS SEVERAL MILES AWAY TO THE W AND LOWER, AND IT SEEMED TO BE CLBING. ATC THEN ADVISED US OF THE B767, WHICH WE REPORTED IN SIGHT-IT APPEARED THAT ITS PATH WOULD PASS BEHIND AND BELOW US. ATC THEN ASKED US IF WE COULD MAINTAIN VISUAL SEPARATION SO THAT HE COULD CLB IT THROUGH OUR ALTITUDE. WE SAID WE COULD, BASED ON THE RATE OF CONVERGENCE WE OBSERVED. THE B767 WAS THEN INSTRUCTED TO CONTINUE CLBING TO AN ALTITUDE ABOVE OURS. WITHIN A FEW SECS, IT BECAME APPARENT THAT THE B767'S RATE OF CLB INCREASED SUBSTANTIALLY AND SOON IT WOULD BECOME DANGEROUSLY CLOSE TO US: ITS RELATIVE MOTION STOPPED, AND IT BEGAN 'BLOSSOMING' IN THE WINDOW. ALTHOUGH WE HAD THE ACFT IN SIGHT, HAZE AND SUNLIGHT REFLECTIONS FROM WATER BEYOND THE B767 HINDERED A CLR VIEW OF IT, THE FO AND I BOTH AGREED WE SHOULD ADVISE ATC OF THE CHANGING CONDITIONS AND HAVE THEM STOP THE B767'S CLB, AS WE WERE NOW HAVING DIFFICULTY SEEING WHAT THE CONVERGING ACFT WAS DOING AND WE FELT LIMITED IN HOW WE COULD REACT. ATC STOPPED THE B767 AT 15000 FT AND IT PASSED DIRECTLY BELOW US MOMENTS LATER. ITS FLT CREW LATER REMARKED TO ATC THAT THEY HAD US SIGHT AT ALL TIMES, AND DID NOT 'EVEN RECEIVE AN RA' FROM THEIR TCAS. (OUR TCAS-I IS NOT EQUIPPED WITH RA CAPABILITY, IT DID CALL OUT 'TRAFFIC' AS WE ADVISED ATC TO STOP THE B767'S CLB). WHILE IT APPEARS THAT IFR SEPARATION WAS ALWAYS MAINTAINED, WE FELT THAT THIS WAS AN EXAMPLE OF HOW NOT TO CTL AIR TRAFFIC. IN THIS SIT, RESPONSIBILITY FOR MAINTAINING SEPARATION COULD FALL ON THE SHOULDERS OF ANY INVOLVED, BUT ALL ARE NOT EQUAL CHOICES: IF ATC IS CTLING, IT CAN ALTER COURSE AND ALTITUDE OF ALL PARTICIPATING ACFT TO AVOID CONFLICTS. THIS OFFERS THE MOST CTL, BUT IS NOT ALWAYS PREFERABLE BECAUSE IT CAN CAUSE DELAYS. IF THE CLBING ('VARIABLE') ACFT HAS THE OTHER TFC IN SIGHT, IT CAN ADJUST ITS RATE OF CLB AS NECESSARY TO MAINTAIN VISUAL SEPARATION. IT REMAINS IN FULL CTL OF THE SIT. THE CRUISE ('STEADY STATE') ACFT IS THE LEAST CAPABLE OF ALL THREE TO MAINTAIN SEPARATION, AS IT IS FLYING ON AN ASSIGNED HEADING AT AN ASSIGNED ALTITUDE. AS SUCH, ITS CREW MAY BE LESS LIKELY TO INITIATE A CHANGE, PARTICULARLY A CLB OR DSCNT, UNTIL A FLT-SAVING MANEUVER IS CALLED FOR. IT APPEARS THAT ATC DID FOLLOW THIS PRIORITIZED LIST: IT FIRST ADVISED THE B767 IT COULD NOT CLB TO CRUISE ALTITUDE IMMEDIATELY DUE TO CONFLICTING TFC, BUT THEN OFFERED THE CLB IF THEY COULD SEE US. THEY COULD NOT, SO THEN ATC ASKED IF WE COULD MAINTAIN VISUAL SEPARATION. WE SAID WE COULD, BASED ON WHAT WE OBSERVED AT THAT TIME: A B767 IN A SHALLOW CLB WHICH WOULD PASS BENEATH AND BEHIND US. AFTER WE ACCEPTED THAT RESPONSIBILITY, THE CONDITIONS CHANGED SUBSTANTIALLY (BOTH WITH REGARD TO THE B767 AND TO HOW WELL WE COULD SEE IT) SUDDENLY WE WERE IN A NEW SIT WITH THE B767 BEARING DOWN (ER, UP) AND WE HAD NOWHERE TO GO. THE ONLY ALTERNATIVES TO A NEAR MISS WERE TO TAKE DRASTIC EVASIVE ACTION (WITHOUT KNOWING WHAT DRASTIC EVASIVE ACTION THE B767 MIGHT TAKE IN RESPONSE-REMEMBER, WE DON'T HAVE TCAS-II CAPABILITY) OR HAVE ATC STOP THE B767'S CLB UNTIL IT PASSED US. WE CHOSE THE LATTER. I WOULD DISCOURAGE ATC FROM ASKING THE 'STEADY STATE' ACFT TO ACCEPT RESPONSIBILITY FOR VISUAL SEPARATION (UNLESS IT'S CLR THAT THERE WON'T BE A CONFLICT, AND AFTER CONSIDERING THE LIKELY PERFORMANCE OF BOTH ACFT) INITIALLY, THE ASSIGNMENT MIGHT BE ACCEPTED BECAUSE THERE IS LITTLE OR NO APPARENT CONFLICT, BUT IT REMAINS VERY HARD FOR THE 'STEADY STATE' ACFT TO ANTICIPATE WHAT THE OTHER 'VARIABLE' ACFT IS GOING TO DO AFTERWARDS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT THIS WAS HIS FIRST REAL CONCERNOF ZMA'S APPLICATION OF VIS SEPARATION. THE RPTR EMPHASIZED THAT ATC NEEDS TO TAKE INTO ACCOUNT ISSUES SUCH AS THE PHENOMENA OF SUN GLARE OFF THE OCEAN. HE ADVISED THAT AN ACFTS PHYSICAL VISUAL SIGNATURE DIMINISHES AS THE ACFT ENTERS INTO GLARE AREA REFLECTED SUNLIGHT.

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.