HA420 flight crew reported performing a go-around due to traffic conflict and upon being in the traffic pattern for another approach; may have violated Class C airspace.
Synopsis
HA420 flight crew reported performing a go-around due to traffic conflict and upon being in the traffic pattern for another approach; may have violated Class C airspace.
Narrative
I am pilot in command typed in the HA-420 - second in command required - and hired as a second in command at my company. Today I was pilot flying and there was a company pilot in command who was pilot monitoring. On a no passenger; reposition flight from ZZZ1 to ZZZ we conducted a go-around due to a traffic conflict after cancelling IFR and potentially encroached into the ZZZ2 Class C airspace. After being cleared for the VOR/DME XX approach and the field was in sight; we cancelled IFR and continued VFR to ZZZ.We made two radio calls prior to being on a 5-mile final; noticing there were 2 other aircraft in the left downwind for Runway XX. Noting that no one was on base or final we elected to continue down and attempt to land. Soon after; the number 1 aircraft in the downwind; a Caravan; announced and turned base. At this point we were approximately 1300 ft. MSL / 1200 ft. AGL and on about a 3-mile final. Seeing the traffic conflict; I smoothly added power and climbed to a safe altitude away from traffic and normal turbine powered aircraft pattern altitude of 1600 ft. MSL / 1500 ft. AGL to join the left pattern in the upwind. The traffic passed underneath by approximately 600 ft. and landed. Once clear of conflict; we cleaned up the airplane and it was time to turn crosswind. During this time we both remembered the ZZZ2 C airspace was nearby and I asked for the moving map to be zoomed out as to check our position. It was in this moment we realized the Class C airspace began at 1600 ft. MSL. We had already drifted below 1600 ft. MSL and remained at 1500 ft. MSL until ready to descend for landing. After landing we noticed in the airport A/FD Chart Supplement the pattern altitude for all aircraft. I realize we potentially violated the Class C airspace at ZZZ2. I also realize that traffic pattern altitude for all aircraft may be different depending on airport needs. To prevent this in the future it would be wise to; on the approach brief; also brief how to enter the traffic pattern into an airport when going IFR to VFR; especially at non-towered airports. It would also be wise to brief how a VMC go-around would differ from the missed approach instructions for that approach.
Second reporter narrative
Utilized VOR XX approach at ZZZ. Approach was uneventful and was largely conducted under VMC conditions.Cancelled IFR approximately 8 NM southeast of the airport and had planned a straight-in landing on [Runway] XX subject to traffic. As we got closer to the airport it became apparent there were multiple aircraft in the pattern. On about a 3-mile final an aircraft cut in close to do a tight base leg to final in front of us and we were forced to go around.Turbine aircraft generally use 1500 ft. AGL in the traffic pattern so we climbed straight ahead to that altitude; which turns out to be 1600 ft. MSL. We simply remained in a left-hand pattern and landed on the next attempt.After landing the crew reviewed the A/FD entry for ZZZ; and discovered that the pattern altitude for ALL aircraft is 1000 ft. AGL. We would not have flown that low with another aircraft passing underneath us. However; if I had pre-briefed the VFR missed approach more thoroughly we would have realized at least that the base of the ZZZ1 Class C airspace was at 1600 ft. MSL and after resolving the potential traffic conflict we would've descended below that.We were both under the impression that turbine aircraft must always use 1500 ft. AGL as the pattern altitude; and there is an FAA Advisory Circular that says just that. However the regulation in Part 91 which stipulates it only mandates it for aircraft landing in Class B; C; and D airspace. NOT Class E airports; which is the airspace surrounding ZZZ. We did not climb above 1600 ft. MSL at anytime during the event.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.