Boeing still has to make “significant changes” to improve the quality and safety of its airplanes, according to the head of the Federal Aviation Administration.

The head of the Federal Aviation Administration told a U.S. House subcommittee Tuesday that safety culture improvements at Boeing may take three to five years to complete. "It is not a six month program -- it is a three-year to five-year program,

The US Federal Aviation Administration is working to overhaul its internal processes for managing safety risks, the head of the agency plans to tell lawmakers at a hearing on Tuesday.