B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 240; Flight Crew Type 1584
Confusion; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Company Policy; Chart Or Publication; Airspace Structure; Procedure
We flew the new SID out of SJC. We were number 2 behind a Company aircraft on the TECKY 2 SID. As they were headed southeast to SPTNS; we were cleared for takeoff and flew the SID in accordance with Company policy. We were following the FMS guidance while hand flying. Approach queried us about Company departure procedures. There were two previous Company flights earlier in the week that looked like they were turning early on the new SJC2 SID that would have potentially caused traffic alerts. They were the same situation as ours; a SJC2 SID following a TECKY 2 SID. We both looked at the different departures on our flight home; and we noticed that the SJC 2 SID has a 113 degree heading intercept to OAK R121 outbound to MOONY. This puts the aircraft on an intercept heading with an aircraft on the TECKY 2 SID flying a wider turn to a 125 degree heading to SPTNS. The Controller was trying to understand what could be causing the traffic conflicts; whether it was hand flying with an early turn; or a FMS coding error.
We originally were filed to fly the LOUPE 4 Departure. Our CPDLC (Controller Pilot Datalink Communications) was amended for us to fly the San Jose 2 (a new departure procedure). Our original clearance was 'LOUPE 4 BMRNG TIPRE Q126' etc. Our new clearance was 'SAN JOSE 2 MOONY SJC BMRNG TIPRE' as filed. We acknowledged the change and loaded it properly and triple checked our work. We took off; flight director on; LNAV engaged as per procedures and normal operations. I was flying and followed the flight directors diligently; without deviation for it was properly following the FMC programmed routing and LNAV was verified as the current navigational mode. We climbed out; cleaned up at 1000 ft. as normal and then the flight directors commanded a turn so I followed. We contacted Departure and they asked us if we were hand flying the aircraft. We said 'yes; we are hand flying the depicted FMC routing as per the procedure.' The Controller said that we are another Company aircraft turning early on the departure. Our turn began after clean-up as well. The flaps were up and accelerating. The First Officer distinctly remembers turning off the autobrakes and the landing gear hydraulics before the turn. The flight directors were followed. He said that it could be very bad; for we can turn into traffic on the TECKY Departure; which the aircraft in front of us was on. He said he will fill out his paperwork and we should do the same. We did not receive any TCAS Alerts or any turn off course due to traffic. Again; the flight director was followed perfectly as depicted. We leveled off at 5000 ft.; and then he climbed us to 16;000 ft. with a turn direct to SJC. He continued on about the early turn out which we believe we did not commit. The First Officer and I did have a good discussion about the procedure and we came to this conclusion. The SAN JOSE 2 Departure is not designed well and puts you on a direct convergence course with traffic on the TECKY Departure. As we looked at the departure on the ground; since I was following the flight directors an early turn would not be possible unless the FMS began an early turn. The TECKY Departure has a turn beginning at MLPTS; which is slightly off center of the runway. It then begins a large sweeping turn towards SPRTNS; the course to intercept in on the 125 degree radial. A normal turn would have the aircraft proceeding further north and east than an aircraft on the SJC2 (SAN JOSE 2). Check the overlays on the charts and the low IFR chart. The courses differ. It will ensure a sharper turn and a quicker angle to intercept the course. Since the course is inside and the TECKY; it will provide a direct convergence to traffic on that SID. You are essentially turning inside and tighter than the traffic on the TECKY; even if at the same speed and turn radius. SPRTNS is even more south east than MOONY is; for again it adds that it is a tighter course and will bring aircraft in closer; if one is on the TECKY to follow the depicted course. If I did turn early; it was because I was following the flight directors and that is where it led us and apologies then; but I did follow the flight directors.
B737 flight crew reported the SJC2 SID route provides a turn that could lead into converging traffic.