Its my understanding that an inadequate school gets interim visits, lots of guidance, and doesn't get signed off until they have met a certain standard and are still on an upward curve. Thus a school graded as inadequate because of an institutional failure which can be quickly rectified can be signed off within a year and then have another couple of years to make improvement before the next scheduled inspection. It should be possible to get an outstanding grade at that one..
I suggest you read the report and see why the school failed in the first place.
A lot depends on why a school failed its first OFSTED. For example something like failing to CRB check staff properly would automatically make a school inadequate. A school with outstanding teaching, but poor safety could quickly and easily be made outstanding with a really good head.
A change of head teacher and replacing all the staff changes a school beyound recongition. I am surprised as the affects of historically poor teaching hurts children for years.
DD's school was in special measures (as it was then, probably the equivalent of 4 in the current scale) and came out of it into Good/level 2 at the next inspection It has left me fairly sceptical about the value of OFSTED inspections tbh. It was a well-regarded school and locals were surprised that it had failed an inspection make of that what you will
Cotswold - our primary was deemed in need of special measures. A big surprise to all concerned. A year later it was 'good' and out of special measures. I am not sceptical enough to suggest it might have had something to do with the fact that by that time we were about to become an academy having been given no other option but the D of E.