This is just an academic question since I have to get my annual done now but I was curious as to how this would technically work out.

Last year we did our first annual. The log book entry was dated 2/24 and said the annual inspection was performed but the airplane was found to be un-airworthy due to a missing airworthiness certificate. The physical certificate was missing and we had to get a new one from the FISDO and it took a while. Anyway, the next entry was dated 3/11 indicating that we now had the airworthiness certificate and the plane is now legal.

My question is, is the date of the annual 2/24 when he entered into my log book he performed the inspection or is it 3/11 when he entered the plane passed the inspection and was no legal to fly? If the time-lag between the two dates was greater than a couple of weeks this could be more of a significant concern but in my case it simply a curiosity as to when exactly my annual is due this year.