Hi!
I was lloking through data for the Yak-42 because I thought 120 passengers was too many (it isn't), and I've found several inconsistencies.
Yakovlev itself states the maximum range of 2790km (or 1506nm), but AM data states a range of 1372mi.
The older version of the Yak-42D has a shorter range of 2150km (1161nm), different from the one stated in the game
For the Yak-42, the range should be 1530km (826nm) according to
Yakovlev, but in the game it is 1178mi.
The data for the Yak-40D is also incorrect, as
Yakovlev itself states that up to 36 seats is possible with a range of 1280km (691nm)*; the -40 is supposed to have a range of 1700km (918nm)
(source)The Yakovlev 42M seems not to have flown, so I suppose you don't want it in the system?
I'm sorry to ruin years of data research

*) I suppose the data on the webpage is for the -40D, as the historical page of the -40 says 32 passengers.