Next month marks three years since a China Eastern jet plunged into a hillside, killing 132 people, with relatives still waiting to learn what caused China's deadliest air disaster in three decades.
It is one of dozens of accidents worldwide in which investigators have yet to issue a final report designed to help prevent new accidents, despite a target of one year.
While recent deadly crashes in Kazakhstan, South Korea and the United States and the non-fatal flip of a crash-landed jet in Canada have thrust safety into the spotlight, the industry is worried that too many past accidents remain unresolved.
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