What the NTSB is examining as it investigates why a Learjet plunged into the ground

The NTSB is investigating why a Learjet carrying nine people—including a family with children—crashed nose-first into a roadway in South Florida on Sunday, killing everyone. Investigators are searching Palm Beach County for debris and analyzing the plane’s final radio calls to determine when and why the aircraft began to come apart. On Tuesday, NTSB member Tom Chapman said investigators recovered a critical piece: the left elevator from the tail, found in three sections far from the crater. Officials stress that probable cause may take one to two years, with a preliminary report expected in about a month. Weather, maintenance, cockpit decisions, and ATC communications are among key factors.