I got it too (well the first! There are only 9 left to get the Decathlon).
But the principle remains uncertain, we see that it is produced manually and that it can only exist with an intervention on demand. The current challenge is still very much linked to the new SU7 planes. Hopefully there will be more, but also that it will be set up automatically.
I took some screenshots , for later remembrance (if it ever goes away), how it looks.
For the “weekly activity” challenge (FR: "vivement le week-end "), it appears in the main window. It’s a precision landing challenge “MCAS MIRAMAR”:
All you have to do, is similar to others landing challenge. Land on the runway, as much precise as you can. You will get a score, and a note (A, B or C).
Once landed and stopped on the runway, you get the result:
And here is the fun : the achievment doesn’t pop-up immediatly… there is a delay.
As I was not very comfortable, I started again four times! one crash beside the runway, and three landings where I only ever got “C” ratings. I never got a “B” or a “A”.
I left FS in standby (on the main menu) and wanted to start over later in better conditions.
Exactly an hour later, I was surprised to receive the pop-up telling me that I had passed my first “weekly challenge”.
So indeed, there is a delay … 1/4 of an hour didn’t seem abnormal to me, but an hour … it’s really long. So no need to have an “A” or a “B”. “C” should be enough … and patience