OTTAWA—Canada’s Transportation Safety Board says a report from Iran on the downing of a passenger jet by its military in January 2020 doesn’t explain why the tragedy happened. Board chair Kathy Fox says the final report does not include a detailed explanation or evidence about the underlying factors that caused Iran’s military to fire two surface-to-air missiles at Ukraine International Airlines Flight 752. All 176 people on board the jetliner were killed, including 55 Canadian citizens, 30 permanent residents and dozens of others bound for Canada. Fox says the TSB, Canada’s air-safety investigator, does not believe the results from the review will reduce the risk to commercial airlines operating in Iran’s airspace. It is unusual for the TSB to comment on the results of a report into an incident that took place in another country. Under international civil aviation rules, the country where the incident took place is in charge …