Crew of fatal U.S. military crash included Ohio Air National Guard members and a pilot with three small children

A pilot from Alabama had just been promoted to major in January and had been deployed less than a week when the refueling aircraft he was aboard crashed in Iraq this week, killing him and five others, his brother-in-law said Saturday.

Alex Klinner, 33, leaves behind three small children: 7-month-old twins and a 2-year-old son, his brother-in-law, James Harrill, said Saturday while confirming his death.

“It’s kind of heartbreaking to say: He was just a really good dad and really loved his family a lot — like a lot,” Harrill said.

Also aboard the aircraft was an Ohio man whose loved ones remembered him for his smile, his parents said.

The Pentagon hasn’t yet revealed the identities of the six, but families began revealing who had died Saturday.

The aircraft was in “friendly” airspace, supporting operations against Iran, when an unspecified incident involving another aircraft occurred, according to U.S. Central Command. The other plane landed safety, U.S. military officials said.

The Ohio Air National Guard’s 121st Air Refueling Wing said in a Facebook post late Friday that three of the dead were airmen who served in the Columbus-based unit.

“We share in the sorrow of their loved ones, and we must not forget the valuable contributions these Airmen made to their country and the impact they have left on our organization,” according to the 121st Air Refueling Wing’s post.

A new father and a new major

Klinner, an eight-year U.S. Air Force veteran from Birmingham, Alabama, had just moved with his family into a new home, his wife, Libby Klinner, said in an Instagram post mourning his death.

An outdoorsman who enjoyed hiking, Klinner was also ready to help others. When Harrill last saw him in January, Klinner had shoveled Harrill’s vehicle out of the snow during a family wedding.

“Alex was one of those guys that had this steady command about him,” said Harrill, who helped set up a GoFundMe site for Klinner’s family. “He was literally one of the most kindest, giving people.”

Libby Klinner said in a post that her heart is broken for their children, who will grow up not knowing their father.

“They won’t get to see firsthand the way he would jump up to help in any way he could,” she wrote. “They won’t see how goofy and funny he was. They won’t witness his selflessness, the way he thought about everyone else before himself. They won’t get to feel the deep love he had for them.”

A man with a ready smile

Sgt. Tyler Simmons of Columbus, Ohio, also was among six service members who died Thursday in the crash of a KC-135 Stratotanker, his mother, Cheryl Simmons, confirmed on Saturday. Cheryl Simmons said she was making funeral plans for her son.

In a statement obtained by WCMH-TV in Columbus, Tyler Simmons’ family said it was saddened beyond measure to hear of the fatal crash.

“Tyler’s smile could light up any room, his strong presence would fill it. His parents, grandparents, family and friends are grief stricken for the loss of life,” they said.

The refueling aircraft is a mainstay in the US military

U.S. Central Command, which oversees the Middle East, has said the crash occurred on a combat mission but was over “friendly” territory in western Iraq. Military officials said it is being investigated and was “not due to hostile or friendly fire.”

The KC-135 aircraft refuels other planes in midair, allowing them to fly longer distances and sustain operations without landing. The plane can also be used to transport wounded personnel and conduct surveillance missions, according to military experts.

The Congressional Research Service says the Air Force last year had 376 KC-135s, including 151 on active duty, 163 in the Air National Guard and 62 in the Air Force Reserve. It has been in service for more than 60 years.

This story was originally featured on Fortune.com