SEATTLE -

Federal investigators are reviewing a number of scenarios to determine what caused a news helicopter to crash into the pavement near Seattle's Space Needle.

The National Safety Transportation Board's Dennis Hogenson told a news conference Wednesday they're confident they will figure it out.

Hogenson says they're looking at all possibilities, including what role, if any, construction cranes in the area played.

He says a crane operator was in radio contact with the pilot on a prior landing on the rooftop helipad, but that there's no significant evidence to link the cranes with the crash.

A preliminary report could be released as early as this week. A final report could take up to a year.

The helicopter wasn't equipped with a cockpit voice recorder or flight data recorder, which aren't required.