Bonanza 33
Flight Crew Private
Flight Crew Last 90 Days 9; Flight Crew Total 180; Flight Crew Type 9
No Specific Anomaly Occurred All Types
Flight Crew Took Evasive Action
Airspace Structure; Procedure
Utilizing VFR flight following and Class B transition from ADS. Requested altitude was 4;500 feet. Initial clearance from ADS was runway heading (150); at or below 2;000 feet. After takeoff; was switched to Approach. On initial contact with Approach; was cleared to 2;500 feet. I was still in climbout from ADS and continued my climb. As I was passing 2;200 feet; Approach called traffic at 10 o'clock; a B737. Approach also called me out to the aircraft. Traffic was abeam on the left; with a strong left bearing rate (drawing aft from my perspective) and was not a horizontal collision threat. Additionally; the traffic appeared to be above me. I called 'no factor' and continued my climb to 2;500 feet. At this point; the Controller cleared the B737 to descend on their approach. The crew then told the Controller that they had to climb for a Resolution Advisory. I also heard one 'traffic' alert from the Garmin. At no point did Approach direct me or the B737 to initiate evasion maneuvers ('Descend Immediately'.) I believe that I was flying in accordance with my clearance and that this was an inadvertent Resolution Advisory for the B737 crew. Looking at tracks for these planes; when they are on downwind for 13L at DAL; they cross a narrow strip at 3;000 feet. If I am climbing to a point 500 feet below and perpendicular to their flight path; TCAS may see me as a 'maneuvering' target with potential collision and provide an RA to the crew. With 500 feet separation being common in DFW Class B and TCAS seeing me 'climbing' into their flight path (before level off;) the system provided them an RA. Even if I was level; 500 feet separation may set off a TCAS. With the recent reduction in the Class B ceiling over ADS (2500) and a common VFR route through this approach corridor; minimal separation like this is likely to become more common. I recommend ATC review the altitude clearances for crossing traffic from ADS (departing 15 southbound) and DAL (downwinds for 13L.)
BE33 pilot departing ADS in compliance with ATC instructions is made aware that a B737 on downwind for 13L at DAL had a TCAS RA caused by his aircraft. At no time was vertical separation less than 500 feet but the BE33 was climbing and may trigger the TCAS RA.