With the resurgence of this thread thought I’d add that yes they did use the 733’s on charter work. 722’s were used on NCL - DBV through the 80’s until 87 when the 733’s took over and were used until 89 or 90. As a youngster flew This route on the 733 in 89.
Have some great pictures of DBV on a Saturday morning with equal measures of Jat, aviogenex and Adria on the ramp.
My my dad had always wanted to go to Yugoslavia but I was terrefied of ending up on an AGX tu134 (both ugly, scarily noisy and I was aware of dubious Russian safety records!). Luckily he never pursued Bulgaria as a Balkan tu154 was also on my avoid list...
also in 89 AGX had virtually retired their tu134’s and were using 737’s and 727’s. A friend was travelling back from SPU to NCL when the usual
737 Yu-anx went tech (couldn’t shut the door). with minimal delay two Tu134’s which were just sitting at Spu were mobilised to operate the flight..would have been my worst nightmare!