Date: 201907
Local time of day: 0001-0600
Location: SQL.Airport, CA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Personal
Flight phase: Takeoff / Launch
Airspace: Class D ZZZ
ATC / advisory: Tower SQL
Second aircraft: Helicopter
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Confusion; Communication Breakdown; Situational Awareness; Time Pressure
Anomaly: ATC Issue All Types; Conflict NMAC
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Procedure; Human Factors
Primary problem: Ambiguous

Narrative: When I got my taxi clearance from the SQL Tower; I had to ask for it to be repeated; because the Controller was speaking so fast - and I didn't fully catch what he'd said the first time.After my run up; I received clearance from the Tower for departure. I climbed out of Runway 30; and at about 700 ft. altitude; began to turn to crosswind. As I rolled out; I was confronted with what I believe was a military helicopter just slightly above my altitude passing diagonally in front of me - coming from my right to my left. I immediately banked hard into my downwind turn; and the helicopter passed to my left. We were both at about 800 ft. at that point.As I was completing my downwind turn; I received a call from the Controller asking for a radio check. I responded 'affirmative radio check;' and was then chastised by the Controller for not responding to an earlier call he'd made. He asked if I was aware that I missed that helicopter by about 100 ft. I responded that I was indeed aware of the helicopter when it first appeared in my windscreen and made my immediate right turn to avoid it. The Controller then went on to call another aircraft in the pattern and chastised him for missing two radio calls; followed by a request to stand by for a telephone number to call the Tower after he landed. At this point; I made my left turn to depart the pattern toward the east without further contact to me from the SQL Tower. The rest of my flight over the next two hours was uneventful; and quite enjoyable.However; during the following two days; I got to thinking more about the incident; and thought I ought to see if I could find out more about what had happened. Obviously; I'd missed a radio call from the Controller - as did at least one other pilot in the pattern. The Controller had been speaking unnecessarily fast to everyone prior to this (from the time of my engine start) - even faster than the ZZZ Controllers I occasionally deal with during Class B transitions. It had also been 2-1/2 months since I'd flown in bay area airspace; so I was probably not as attuned to the radio traffic and pace as I might have been otherwise.But still; I wondered what the hell a military helicopter was doing crossing diagonally through the crosswind / downwind pattern at SQL at pattern altitude; and why had the Tower cleared me for takeoff knowing we'd be on a likely collision course. Even if I had heard the missed call from the SQL Controller; what would the instruction have been? If I'd continued straight on my upwind leg; I'd have likely collided with the helicopter coming from slightly above and behind me to my right; or passed immediately under his rotor wash; which also could have been disastrous. I'd have never seen him through my right wing. I suppose the Controller could have instructed me to make an immediate left turn; but I'm only guessing; at this point.I phoned the SQL Tower; briefly explained what happened; and that I'd like to speak with someone who might help me get a better understanding of the incident in the hopes of avoiding a similar situation in the future. The Controller I spoke with said he wasn't in the Tower on that day so he couldn't speak from firsthand experience; but said I should call back the following few days when the Tower Manager; was available.The Controller added that there are literally hundreds of these military helicopters that fly though Bay Area controlled airspaces; including ZZZ Class B; without ever being in touch with the Towers. They basically go where they want whenever they want; he said; and Tower personnel wind up having to scramble pretty hard to divert traffic away from them. That's certainly news to me; but definitely valuable information to have.I spoke on the phone briefly with Tower Manager [in the following days]. He informed me he was unaware of this incident; but promised to investigate it; listen to 'the tape;' and call me back. Tower Manager; phoned me the following day after reviewing the tape and speaking with the Controller on duty.He informed me that the incident actually happened at about XA:05 hrs. (I'd requested my ground clearance around XX:50). Apparently; the SQL Tower was in contact with the military helicopter when it reported inbound toward SQL from ZZZ1. He said the helicopter was instructed by the SQL Controller to cross over the SQL pattern 'at or above 1;200 ft.' It did not do this; and passed through the crosswind & downwind legs of the SQL pattern at pattern altitude (800 ft.); directly in front of me.Tower Manager also said that the Controller had made two radio calls to me during my climb from Runway 30 advising me to 'remain below 800 ft.' He said the Controller also made two calls to another aircraft in the pattern; which were also missed by that pilot; but that this other pilot responded to one of the Controller's calls to me asking if he was supposed to remain below 800 ft. (This was apparently the pilot who was asked to call the Tower after landing at SQL.) Tower Manager acknowledged that the Controller's speech was extremely fast and not well-enunciated; which probably contributed to the confusion. He also acknowledged my request for this Controller to repeat my ground clearance when I didn't understand him the first time.I asked [Tower Manager] whether the Tower could see the altitude of the incoming military helicopter as being at 800 ft.; rather than at the 1;200 ft. it had been assigned; and he said 'yes; of course.' I asked him 'couldn't the Controller have instructed me to hold short; or line up and wait on Runway 30 until after the helicopter had passed?' He agreed that would have been better.I have to be way more attentive to radio calls in the pattern; particularly when the Controller is difficult to understand; whether due to speed; lack of enunciation; accent; etc. [Tower Manager] said he's been a Controller for 25 years; but it's only been in the last 10 that he's learned how to better enunciate his radio communication; which also slows his speech down somewhat - even during frantic traffic periods.I need to get back in the habit of lifting a wing for a clearing turn while in a Tower controlled pattern. Had I lifted my right wing and looked to the side and backward before making my right crosswind turn; I might have seen the helicopter approaching me sooner. Simply remaining below 800 ft. (as the Controller was apparently instructing me); would still have put me on a collision course (or immediately under the helicopter's rotor wash) no matter whether I'd continued straight ahead or turned to crosswind. Had I actually seen the helicopter before turning crosswind; I could have made a hard left evasive turn (if I'd had the presence to recognize the conflict and react quickly enough). I'd mistakenly become complacent when flying in a controlled tower pattern; assuming that the Controllers were keeping aircraft separated. They make mistakes; too.Before ending our call; I asked [Tower Manager] if I should file a NASA ASRS form. He paused; and said that he'd reviewed the incident; spoken with the Controller and me; and that we'd pretty much worked everything out - that we'd all learned lessons from it.[Tower Manager] also asked whether I was flying solo that day; as he knew it was a training aircraft. I said I was. He then told me that when there's a student and an instructor flying together; 'they often turn down the radio volume so they can better talk with each other; and that means they miss Controller calls more often.' I told him that was not my experience at all - that every instructor I'd ever flown with over the last 20 years emphasized the sterile cockpit concept with no unnecessary conversation during critical flight phases such as takeoffs and landings. I said; in fact; that we generally turn the radio volume up when within or approaching the pattern; specifically to help avoid missing radio calls.




Synopsis: Pilot reported a NMAC immediately after takeoff with a helicopter that was crossing the traffic pattern.