(Story updated at 3:15 p.m. ET.)
Investigators returned Wednesday to the scene of a medical helicopter crash that killed three people in West Tennessee, but an official said the preliminary cause of the crash was not expected for more than a week.
Two hospital workers and a pilot died Tuesday when the helicopter crashed en route to pick up an ailing child in Bolivar.
National Transportation Safety Board spokesman Keith Holloway said investigator Ralph Hicks was working at site of the crash in a wooded area of Somerville, about 45 miles east of Memphis. Hicks is expected to give a briefing Wednesday afternoon, though a preliminary cause of the crash is not expected for roughly 10 days, Holloway said. A final report on the crash could take a year or more, Holloway said.
Meri Armour, president and CEO of Le Bonheur Children's Hospital, said the Hospital Wing helicopter was cleared for both weather and flight plans when it took off. Authorities began searching when the helicopter didn't respond during a routine 10-minute check-in.