We disregarded a bad forecast and busted into class C airspace
I'm not from the US
I'm on IFR training, but the flight school only allows VMC flights, for safety reasons and because the airfield we practice doesn't meet the requirements to operate under IMC, it's an IFR/VMC sort of thing.
There were three people: me, my CFI and my partner.
That being said, we met with the instructor at the uni where we get the theory classes at, and then headed to the airport. The original plan was to take the plane from maintenance to the airfield where the flight school's base is located; we'd go to the practicing airfield, do 2 or 3 approaches (2 minimum to make the lesson count, school policy), then land at another airfield to refuel and change crew so my partner could fly his lesson from there and then go back to our base.
We got to the airport, the instructor forgot the keys to the maintenance building where the plane's keys and dispatch note were. He had to go back to uni and came back an hour later
We were in a rush so the briefing was really short, mostly reviewing weather. We pointed out that even though the METAR said CAVOK, the TAF said BKN020 -SHRA. That's way below minimums for us, so he called Ops, then he chose to go anyways. We rushed to take off, even though the latest METAR showed the TAF was accurate.
On the airfield I was cleared for one approach (it was indeed broken and showering), Tower asked for intentions after go-around, I requested a different approach and they said "negative, can't authorize more practices, aerodrome under minimums" so we asked to go back to refuel.
The clouds started getting lower so the CFI said "my controls" and started maneuvering to stay under them, the weather kept worsening so we had to divert to our base. We chose to follow the published visual route chart to cross the city where the departure airport was at and head to our destination. We asked for one route and were cleared for another because we were closer to the starting point, the CFI got lost but he didn't want to admit it, the regional airport's runway line was on the way so there's a class C airspace to protect departures and arrivals. This space starts at 5000 ft, we were flying at 4500.
The visual route starting point was called Túnel Lo Prado, and the instructor thought we were at the other route's starting point which was called Cerro Lonquén, and it's 7 miles south of Lo Prado. He kept flying straight at 4500 ft, swearing we were at Lonquén even when I told him we were at Lo Prado multiple times. Suddenly we get called by the main airport's AFIS, we responded but we weren't heard, he called us 2 more times, each one angrier, until it finally heard us responding. "YOU'RE ENTERING CLASS C AIRSPACE, TURN RIGHT IMMEDIATELY AND DESCEND TO 2500 FT". We did, the instructor apologized to the AFIS guy and then asked me "do you know where we are" I said "yes, we're here" -while pointing at the visual route chart- "and we should be over there". He looked worried and he said "no, I know where we are". I loaded the cleared visual route points on the GPS for him to follow, he wasn't following them, suddenly he meets one of the points, 1000 ft below the published altitude (4500 ft from that point), and after levelling at the correct altitude he finally said "your controls". The rest of the flight was chill and we arrived fine
On the ground we refueled, he told my partner and I that what really happened was we were at Lonquén and he cleared us for the Lo Prado route (wasn't that way at all). After that he went to lunch and then to talk to Ops to see if the lesson could be graded although we needed one more approach. They agreed and I passed so it wasn't so bad after all. But at the debriefing he said "I noticed you were more focused on loading checkpoints rather than controlling power and airspeed" I didn't say anything because I was too tired to argue but I was like "Well of fucking course I'll be loading checkpoints if YOU don't know where the fuck you're at on a surveilled airspace
What worries me now is that I appear as PIC on the flight plan, so if the AFIS guy decides to report, I could get punished. So I'll file an event report tomorrow