ANT-20bis
A replacement aircraft, designated ANT-20bis had begun production the following year and first flew in 1938. It was largely identical in design but with six more powerful engines. This plane, renumbered PS-124, served with Aeroflot on transport routes in Russia and Uzbekistan. On December 14, 1942, it too crashed after the pilot allowed a passenger to take his seat momentarily and the passenger apparently disengaged the automatic pilot, sending the ship into a nosedive from an altitude of 500 m (1,500 ft) and killing all 36 on board.
Plans to build a fleet of ANT-20bis aircraft were abandoned in 1939 as Joseph Stalin's purges of the aviation industry had resulted in a shortage of qualified engineers.
Read more about this topic: Tupolev ANT-20