The following question is perhaps one for you to ask some of your Russian contacts:
Irkutsk built the An12 from 1957-62.
According to a number of sources the An-12A went into production at Voronezh and Tashkent from 1961. Nothing mentioned at all for Irkutsk.
Certainly explains why all of the old Irkutsk An-12s in the registers have no sub-type with c/ns 8900xxx, 9900xxx , 090xxxx....as they were built as straight An-12s.
So my question is as follows:
Did Irkutsk actually produce the An-12A in 1961 or was the whole production run of straight An-12s (see perhaps the two exceptions below) ?
1901706 (1961 build) is given as a An-12P in official documents (the An-12P being an upgrade of the straight An-12 with an additional two tanks) so if they did, it was presumably from a higher batch than this one, although production stopped in 1962. The An-12P, I believe had 24 integral wing tanks.
We also have the following in the files:
1 9 018 01 not known An-12 unknown was the first aircraft with 26 integral wing tanks
2 9 019 05 not known An-12 unknown was the second aircraft with 26 integral wing tanks
The An-12A, I believe had 26 integral wing tanks, so perhaps these two above are An-12As?
At the end of the file we have all Irkutsk (except one) export machines most of which are Indian AF as 'BP's. However they were certainly not built as such....the BP was not built until circa 1964.
We have a few others, that I guess could have been converted to BPs, (see further below) but seems to me that the BP is often reported as the sub-type for military machines, which has not been checked.
However, at least one Irkutsk machine ER-ACL 0901306 is given as a BP in the Moldovan Register (might be others but not found any offical registers/document as yet)....so presumably proves conversion from a straight An-12 to An-12BP is/was possible ....this was the one with the strange mfd I mentioned earlier !
Adrian