Military leaders, U.S. Coast Guard colleagues and families – coming from Virginia, Texas, the nearby Capay Valley and elsewhere – gather Friday in Sacramento to thank and remember the Guard's lost rescuers.

They'll honor seven crew members of a search-and-rescue plane from the McClellan Airport field station in North Highlands that collided last Thursday with a Marine helicopter over the ocean off San Diego.

Searchers have found aircraft pieces floating on the water, but no trace of the two crews. The helicopter had two aboard.

In recent days, the search has given way to formal investigation into the cause, a process that may take time, officials said.

"We all want to know" why this happened, said Lt. Josh Nelson, a Coast Guard spokesman. "None of us wants this to happen again."

The Friday ceremony in Sacramento is private, but it won't be small. More than 2,000 are expected to attend.

John Moletzsky and family flew in Tuesday from Pennsylvania, a Coast Guard liaison at their side, for the tribute to their son, Petty Officer 2nd Class Jason Moletzsky, 26.

They and other families will meet tonight at the station captain's home.

"Your heart hurts," Moletzsky said, "but everything they are doing for us, it's unbelievable."

One family will not have far to travel.

Carmichael's Jennifer Seidman – and her children Tamsen, 13; Gretel, 12; and Sven, 10 – will honor a lost husband and father, Chief Petty Officer John Seidman, 43, the plane's flight engineer.

Jennifer Seidman said she is grateful to the Coast Guard for the help it has given her in the last week, and for the opportunity to join others where her husband's humanitarian missions were based.

"To honor John, to feel close to him, it's everything to me right now," she said.

Officials have convened a joint Coast Guard and Marine Corps investigation team to piece together what happened. They declined to offer any preliminary conclusions.

Moletzsky, who said he has heard the investigation could take a year or more, looks forward to a resolution.

"It matters to me that they find out what happened to prevent this from happening in the future," the former military C-130 aviator said. "It doesn't matter to me to assign blame because it will not change the outcome. We lost nine brave kids."

The Coast Guard C-130 Hercules and the Marine AH-1W Super Cobra went down just after 7 p.m. near San Diego in a military training operations area known as Whiskey 291.

The Coast Guard plane was searching for a lost boater. The helicopter was training with three other Marine choppers.

Investigators are interviewing the three other Marine helicopter pilots in the training mission and going over air-traffic control records. Salvaged pieces of aircraft are "under lock and key" as part of the investigation, Nelson said.

Salvage crews were expected to search for the cockpit recorders each aircraft carried, likely on the ocean floor, 2,400 feet down.

Coast Guard officials in Washington, D.C., declined to say when they expect to issue a report on the crash.

"Everybody has speculative ideas on what may or may not have happened," said a spokesman, Lt. Cmdr. Chris O'Neill. "We are going to take our time because we want to get it right."

The Coast Guard plane had been in contact with air traffic controllers from the Federal Aviation Administration, but those controllers stopped communicating with the plane minutes before the crash when it passed into a military-controlled area.

Officials have not said whether the plane's crew or the Marine helicopters were in contact with military traffic controllers.

Coast Guard San Diego commander Capt. Tom Farris said the aircraft were operating on a "see-and-avoid principle."

In that scenario, it is up to each aircraft to see conflicting aircraft and avoid them, he said, something military pilots are trained to do.

Sacramento City College aeronautics department Chairman Phillip Cypret, a former Coast Guard reservist who has flown in C-130s and helicopters, said that even if the pilots were talking with air traffic controllers, they wouldn't be constantly in contact.

Pure accidents do happen on rare occasions, he said. Depending on angle of approach, and whether one aircraft is ascending or descending, there are blind spots, Cypret said.

"If you just happen to be lined up in a blind spot, it may get very close before you see it," Cypret said.

Ken Freeze, also a former Coast Guard C-130 crew member who is working on a book about the Coast Guard, said midair incidents typically happen because of multiple mistakes.

When the investigation is done, it could well determine the crash was caused by multiple errors, Freeze said.

For family members and Coast Guard colleagues, though, this week is for remembering and grieving.

Chief Petty Officer Seidman's wife, Jennifer, wonders about the last moments, but has faith in her husband's strength.

"I hope he didn't suffer," she said. "John and the crew members were so well trained. If they knew something was going wrong, he just would have gone into work mode, and he wouldn't have felt fear."

Call The Bee's Tony Bizjak, (916) 321-1059.