Three members of a medical helicopter crew killed in a crash were returning the aircraft to its home base in Douglas, authorities said.
Alexander Kelley, 61, was flying the helicopter that had undergone routine maintenance in Marana and was en route to Douglas when it crashed Wednesday, said Craig Yale, vice president of corporate development for Colorado-based Air Methods.
The AS350 B3 Eurocopter went into service last year and had about 350 hours on the air frame, he said Thursday.
Kelley had 14,000 hours of flight experience.
Federal Aviation Administration spokesman Lynn Lunsford said conversations with air traffic controllers during the flight were routine and "there were no signs of trouble."
"It will be up to the investigators to determine whether something else went on when it crashed," he said.
Also aboard were flight nurse Parker Summons, 41, and paramedic Brenda French, 28. All were employees of the Air Methods LifeNet program that has served southern and central Arizona for more than 20 years, Yale said. Kelley started in 2002, Summons in 2007 and French in March.
The company was planning a memorial next week.
"We're deeply saddened by the tragic events," Yale said.
The National Transportation Safety Board was investigating. Yale said company representatives were fully cooperating.
The NTSB did not immediately return a message left Thursday.