MOSCOW — As Capt. Arkadiusz Protasiuk peered down at a dense fog over the Russian city of Smolensk last April, weighing whether to land an aircraft carrying Poland’s president and dozens of other government officials, no one told him what to do.

But no one had to, according to a Russian-led investigation of the subsequent crash, which killed everyone on board.

Captain Protasiuk had been in an eerily similar position in 2008, according to the report on the inquiry, which was released Wednesday. Still a co-pilot then, he looked on as his captain defied President Lech Kaczynski’s order to make a risky landing in Georgia’s capital, Tbilisi. Mr. Kaczynski was reported by the Polish news media to be furious, remarking that “if someone decides to become a pilot, he cannot be fearful.”...