But the discovery has led to more questions than answers as searchers battled another day of difficult weather conditions looking for the aircraft and the four people on board.

It proved another day of rain, snow and obscured mountains in western Prince William Sound, where the search focused largely on an area between Esther Island and Whittier.

A piece of unknown debris was discovered floating in the waters of Blackstone Bay.

Searchers said it was perhaps a piece of insulation but later said the chunk did not come from the chopper but maybe some on-board medical equipment.

State Troopers are delivering the debris to experts at Evergreen Helicopters, the company that operates LifeGuard Alaska for Providence Alaska Medical Center.

Blackstone Bay can be a spectacular place during the summer months. But Lt. Col. Tim O'Brien with the 210th Rescue Squadron said it has been shrouded in wet, turbulent weather this week, making for tense work as air crews scour the waters and shoreline.

"We've had a lot of snow, which hampers visibility," O'Brien said. "We've had high winds and turbulence, which increases workloads on crews. We've had rapid temperature changes, which has affected aircraft performance in some cases."

Chris Rosauer is the skipper on board the Intrepid, based in Whittier. He has been one of the good Samaritans taking time off to help in the search.

The four people on-board have been identified as pilot Lance Brabham, flight nurse John Stumpff, paramedic Cameron Carter and patient Gaye McDowll from Cordova.    

Rosauer doesn't know any of them but that doesn't deter him.

"This is one of those deals if we ever go down in the sound here," Rosauer said. "We'd really hope that people would spend the extra effort to come look for us."

The Seward Fire Department also sent sonar equipment on a boat to Whittier in order to assist in the search.    

The Alaska Railroad has dispatched snowmachiners into the area of Spencer Glacier, where a motorist on the Seward Highway reported seeing something.

Meanwhile, officials from Evergreen Helicopters of Alaska released a photo and brief statement on pilot Lance Brabham.    

Brabham has been with Evergreen since April of this year and lives in Soldotna with his fiance