Narrative:

After departure from bfi on climb out while still in the twenties we were cleared to climb unrestricted to FL390. We had intercepted our cleared route which initially was normy J90 mwh doxie...and at this point were west of moses lake (mwh) VOR headed southeast bound and seattle center instructed us to maintain FL330 for traffic. We reset our altitude alerter to comply with the revised clearance and scanned for traffic both visually and with TCAS and noted no obvious conflict. Our groundspeed was approximately 450+- knots at this point in the climb and the aircraft was being operated in daylight; VMC conditions. Time passed as we continued our climb and the right seat pilot who was the PIC/PNF noticed a contrail to the right of and above the height of our aircraft. The aircraft that was creating the contrail was spotted (the intruder aircraft itself was initially obscured from observation by a window post) and after a few seconds of observation to ascertain its direction of flight it was noted that the aircraft was generally northbound and at an approximate right angle to our flightpath. At this point our TCAS issued a 'traffic; traffic' advisory to bring attention to the conflict. I advised seattle that we had a conflict with an aircraft to our right as the following events quickly played out... The sic/PF was already in the process of reducing our rate of climb from 1600 feet per minute to near level flight at 32500 feet. The intruder aircraft appeared level at FL340. As the aircraft positions quickly closed with each other our TCAS issued a 'level off' command. Our aircraft was substantially in level flight at this point and the 'fly to' command box that the TCAS issued on the primary flight displays appeared around our current flight path requiring little to no further adjustment of our aircraft trajectory. The intruder aircraft was a [widebody transport]. After the intruder aircraft passed from right to left and exited our position to the north we continued our climb to FL330 and were shortly re-cleared to a higher altitude and at this point our position to be 25 miles (+-) west of mwh VOR. There was no damage to equipment and no persons were injured. Our large multifunction display map is our primary reference for TCAS traffic until the TCAS advises of proximity traffic. When in the enroute phase of flight this display is adjusted to view the proposed track of the cleared route in front of the aircraft. This compresses the relative positions of TCAS traffic. As you select longer and longer ranges TCAS traffic gets correspondingly more compressed. This makes it difficult to discover a conflict especially if it's a conflict that's not immediately obvious. When 'traffic; traffic' is issued to call out the proximity traffic a small window on the flying pilots primary flight display that is normally used to display engine instruments changes to a small TCAS display. This window could be used to display TCAS information at all times but it would displace three quarters of the engine instruments limiting the monitoring capability of engine instruments. Air traffic controllers do a very good job of separating participating traffic; however; I feel they do this irrespective of how a flights TCAS may or may not react to their positioning of the aircraft in relationship to each other. Had we been advised of a potential specific conflict rather than a generalized 'maintain FL330 for traffic' we would have reduced our climb rate to 1000 FPM or less to avoid an event. I'm sure the controller saw no issue; aircraft Y was at FL340; we were cleared to FL330 and hadn't even gotten there yet. When I queried the controller I felt he didn't understand the nature of our concern as he didn't see it as a conflict or issue it to us as such.

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Original NASA ASRS Text

Title: A corporate jet received a TA while approaching 1;500 FT below assigned altitude with crossing traffic. The compressed relative position of traffic on the map display and the small display of TCAS info on the PFD were contributing factors.

Narrative: After departure from BFI on climb out while still in the twenties we were cleared to climb unrestricted to FL390. We had intercepted our cleared route which initially was NORMY J90 MWH DOXIE...and at this point were west of Moses Lake (MWH) VOR headed southeast bound and Seattle Center instructed us to maintain FL330 for traffic. We reset our altitude alerter to comply with the revised clearance and scanned for traffic both visually and with TCAS and noted no obvious conflict. Our groundspeed was approximately 450+- knots at this point in the climb and the aircraft was being operated in daylight; VMC conditions. Time passed as we continued our climb and the right seat pilot who was the PIC/PNF noticed a contrail to the right of and above the height of our aircraft. The aircraft that was creating the contrail was spotted (the intruder aircraft itself was initially obscured from observation by a window post) and after a few seconds of observation to ascertain its direction of flight it was noted that the aircraft was generally northbound and at an approximate right angle to our flightpath. At this point our TCAS issued a 'traffic; Traffic' advisory to bring attention to the conflict. I advised Seattle that we had a conflict with an aircraft to our right as the following events quickly played out... The SIC/PF was already in the process of reducing our rate of climb from 1600 feet per minute to near level flight at 32500 feet. The intruder aircraft appeared level at FL340. As the aircraft positions quickly closed with each other our TCAS issued a 'Level Off' command. Our aircraft was substantially in level flight at this point and the 'fly to' command box that the TCAS issued on the primary flight displays appeared around our current flight path requiring little to no further adjustment of our aircraft trajectory. The intruder aircraft was a [widebody transport]. After the intruder aircraft passed from right to left and exited our position to the north we continued our climb to FL330 and were shortly re-cleared to a higher altitude and at this point our position to be 25 miles (+-) west of MWH VOR. There was no damage to equipment and no persons were injured. Our large multifunction display map is our primary reference for TCAS traffic until the TCAS advises of Proximity Traffic. When in the enroute phase of flight this display is adjusted to view the proposed track of the cleared route in front of the aircraft. This compresses the relative positions of TCAS traffic. As you select longer and longer ranges TCAS traffic gets correspondingly more compressed. This makes it difficult to discover a conflict especially if it's a conflict that's not immediately obvious. When 'Traffic; Traffic' is issued to call out the Proximity Traffic a small window on the flying pilots primary flight display that is normally used to display engine instruments changes to a small TCAS display. This window could be used to display TCAS information at all times but it would displace three quarters of the engine instruments limiting the monitoring capability of engine instruments. Air Traffic Controllers do a very good job of separating participating traffic; however; I feel they do this irrespective of how a flights TCAS may or may not react to their positioning of the aircraft in relationship to each other. Had we been advised of a potential specific conflict rather than a generalized 'maintain FL330 for traffic' we would have reduced our climb rate to 1000 FPM or less to avoid an event. I'm sure the controller saw no issue; Aircraft Y was at FL340; we were cleared to FL330 and hadn't even gotten there yet. When I queried the controller I felt he didn't understand the nature of our concern as he didn't see it as a conflict or issue it to us as such.

Data retrieved from NASA's ASRS site 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.