Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 30; Flight Crew Total 4000; Flight Crew Type 1200
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors
Summary of departure from SQL in a Cirrus SR22 filed IFR. Weather was approximately 1200 overcast; 6+ visibility. On taxi out; received the following clearance: Aircraft X on departure; fly runway heading until the diamond shaped waterway; then turn right to heading of 120 to stay within 2 miles of the airport. Radar vectors. Remain VFR at or below 1100 ft until the OAK 165 radial; then climb and maintain 2100. Expect 5000 five minutes after departure.Waited approximately 15 minutes for takeoff clearance awaiting ATC release. Takeoff was normal. After turning to 120 degrees; I leveled off at 1000 ft to stay VFR below 1100 as there was some scud above. I contacted departure and was told radar contact. Shortly thereafter; I was told to turn to heading 300 and I acknowledged that call. I turned left to 300. I have flown this departure before and thought for a moment that the heading of 300 was different than I anticipated but I let that thought go. Plus; I was IMC; so I was concentrating on flying instruments. Shortly thereafter; I was told to turn left to 100 and climb to 3000. Turing left to 100 was 'long way around' from current heading so I acknowledged with an emphasis on the word 'left'. After some vectoring south and handoff; we were headed on course. This was when I was told that there was a 'possible pilot deviation' and to contact ATC when I landed. For the next part of the flight; I was replaying the events in my head and realized that the vectoring was likely as a result of something that I did wrong but could not place what that was. Needless to say; I kept replaying the events in my head as I flew onwards. When I landed; the voice on the other end told me that they were submitting a possible pilot deviation. That the clearance was to climb to 5000 after the OAK 165 radial and that the turn to 300 was a deviation that put me in conflict with SFO traffic. She said that they would submit the facts and the recording and that I would hear back but the timeline was unknown. My understanding is that the 'expect climb to 5000; five minutes after departure' is an 'expected' and for lost comm. As I was in radar contact; at 1000; altitude is assigned by ATC. So; I first thought that this is where I deviated; but not so. I was told; it was the turn to 300 that created the problem as that turn put me into the SFO arrivals. I did hear the controller assign that 300 heading and I acknowledged '300' before starting the turn. So I must have miss-heard the heading or the call was not for me. I recall acknowledging the heading but the controller may not have heard it to correct me as he was busy. I have gone back several times to reconstruct the events; especially on a map to visualize the events. It is clear that there was a miss-communication about the turn to a heading of 300. Either I did not hear it correctly or it was not a transmission for me. I did acknowledge; but the controller was busy and did not catch the error until he saw the turn on the radar. I had a moment of second thought about that heading when it was assigned as it was different than I received before. But; I attributed it to flying to a different airport. The lesson: if it does not seem right for even a second; question it; even if ATC is busy because your experience should tell you that if something does not feel right; it likely is not...especially in a busy environment. Kudos to the busy controllers who calmly vectored me and only after I was en route did they come on line and ask me to call in.
Single engine aircraft pilot reported departing SQL and being instructed to turn to a 300 degree heading after an initial departure heading of 120 degrees. This was apparently not correct and resulted in a conflict with SFO arrivals.