CLOVIS -- A Central California soldier was among 14 killed when a Black Hawk helicopter crashed in northern Iraq -- the second tragedy for his family, who lost another son to the war three years ago, family friends said.

The family of Spc. Nathan Hubbard, 21, was taking his death on Wednesday "very, very hard," said Clovis police spokeswoman Janet Stoll-Lee, who spoke on behalf of the Hubbards. The soldier's father, Jeff Hubbard, is a retired 30-year veteran of the police department.

The Hubbards lost Nathan's older brother, Marine Lance Cpl. Jared Hubbard, to a roadside bomb in downtown Ramadi in 2004. A third brother, Jason, will be returning home from Iraq to be with his family, Stoll-Lee said.

The UH-60 helicopter went down during a nighttime mission in the Tamim province that surrounds Kirkuk, an oil-rich city 180 miles north of Baghdad, said Lt. Col. Michael Donnelly, a military spokesman in northern Iraq.

He said facts gathered indicated it was almost certainly due to a mechanical problem and not hostile fire, although the final cause remained under investigation. The military did not immediately release the soldiers' identities pending notification of relatives.

Nathan Hubbard was assigned to the 25th Infantry Division in Hawaii, where officials said 10 of the soldiers killed in the crash were based.

Keith Butterfield, a family friend, said the Hubbards were worried for their sons but proud because they knew they were committed to going on behalf of their fallen brother.

"There is nothing anyone can say to make it better, but it's good to know that there are other families that can help you cope," said Butterfield, who became close to the Hubbards after his own son died in Iraq last year. "It's bringing up the feelings of everyone else's loss, but we will be there for them."

Nathan and Jason Hubbard joined the Army together in 2005, shortly after their brother was killed. Their mother, Peggy, told the Fresno Bee in a 2005 interview that she believed Jason joined in part to protect Nathan after not being there to help Jared.

The brothers said at the time that they didn't worry about dying in the war.

"People are going to be hurt, and people are going to be killed," Nathan Hubbard told the Bee. "That is a reality you have to accept, but not dwell on."