Teramae said investigators earlier provided preliminary information to Maj. Gen. James Dubik, commander of the 25th Infantry Division (Light) at Schofield Barracks, after completing on-site work, and now are continuing the investigations at the Army Safety Center at Ft. Rucker, Ala.

Whether the preliminary findings will reveal the cause of the crashes is not clear, Teramae said, adding that some details may not be known until a final report is completed.

"Our goal is to be as open as possible while ensuring the integrity of the investigations and respecting privacy concerns," said Teramae, chief of media relations for the division.

One investigation, by a safety team from Ft. Rucker, is intended to determine whether the Army needs to make any changes in its regulations or safety procedures, she said. No operational changes have been announced by the Army since the crash, however.

The second, collateral investigation, by Col. Terry Peck of the safety center, will help preserve evidence that could be used for a variety of purposes, including establishing responsibility for the crash.

Investigators are waiting for reports on the engines from Sikorsky Aircraft Corp., manufacturer of the UH-60 Black Hawk, and on the aircraft crews' night-vision goggles from the Soldier Systems Center laboratory in Natick, Mass.

Such equipment reviews are routine and do not in themselves indicate either the engines or the goggles are suspect in the incident, Teramae said.

Brig. Gen. William Caldwell, assistant division commander for operations, said the investigation will be "very careful and thorough" to ensure "that we learn everything we can about how this tragic accident happened.