Air crash investigations can take months, and federal investigators told reporters they would not speculate on the cause.

A midair collision between an Army helicopter and a jetliner killed all 67 people aboard the two aircraft, officials said, as they scrutinized<a class="excerpt-read-more" href=" More

A midair collision between an Army helicopter and an American Airlines flight killed all 67 people aboard the two aircraft, officials said Thursday, as they scrutinized the actions of the military pilot and reported that control tower staffing was “not normal” at the time of the country's deadliest aviation disaster in almost a quarter century.