Small Transport; Low Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Chart Or Publication; Procedure
Aircraft X departed SJC on SJC2 Departure. After radar contact I noticed that the aircraft appeared to be in a turn earlier than what is depicted on the SID. It was turning inside of a previous SJC Departure already established southeast bound. I amended Aircraft X's altitude to maintain 4000; as the previous departure was already level at 5000; and turned it to heading 100 for divergence. Once deconflicted; I vectored it back to course. Yet again another San Jose departure does not fly the departure procedure correctly. This happens far too many times and causes a lot of controllers to work extremely hard to maintain separation standards. Separation is lost on many of these same instances if the departure controller is not scanning the critical area where the aircraft are supposed to turn. To make matters worse; SJC Tower will continue to launch departures regardless of what's going on unless the departure controller remembers (or has enough time) to cancel automatic release's. Again I recommend that SJC Tower ensure aircraft are de-conflicted prior to a frequency change. I feel that they should ensure the aircraft are in the appropriate turn prior to a communication transfer. Until something of this nature happens; pilots will continue to make errors to these sometimes confusing departure procedures. This event happened to be on a SJC2 departure; most of these events take place during the LOUPE4 Departure. Departures off Runway 30 at SJC are in a very critical area in NCT airspace. The airspace is extremely complex with SFO arrivals bearing over the top of SJC departures; and OAK arrivals turning final less than 10 miles from mid field SJC. The margin for error is minimal in Toga Sector.
NCT TRACON Controller reported an aircraft turned early on the SJC2 SID and into confliction with a previous departure.