One was a pilot from Bethlehem who died when the helicopter he was flying collided with another helicopter over Baghdad, the Defense Department said.

Chief Warrant Officer William Brennan, 36, was based in Hawai'i and deployed to Iraq, authorities said. The other soldier was identified as Capt. Christopher B. Johnson, 29, of Excelsior Springs, Mo.

The incident is under investigation.

Both were assigned to the 1st Battalion, 25th Aviation, 25th Infantry Division (Light) and based at Wheeler Army Air Field.

Brennan leaves behind a wife and two young daughters, who live at the Hawai'i base where he was stationed, said his sister-in-law, T.J. Brennan.

Brennan went to Roman Catholic schools in the Waterbury area and trained after high school for a career as an Army helicopter pilot, his sister-in-law said. He joined the military about 15 years ago, his family said.

"When he went into the Army, his ambition was to be an Army helicopter pilot. That's all he wanted to be," T.J. Brennan said.

Brennan had been flying night missions lately and frequently e-mailed his tight-knit family about how things were going.

"His e-mails have been saying its a little crazy over there right now," she said.

In addition to his work in Iraq, Brennan also flew surveillance helicopters around New York City after the Sept. 11, 2001, terrorist attacks. He brought a camera with him on every flight and took amazing pictures of the Statue of Liberty and other landmarks, T.J. Brennan said.

"He wanted one day to write a book about all that he's experienced and what he'd seen out there," she said. "He was proud of what he was doing over there — no question about it."

He leaves his wife, Kathy, and two daughters, 4-year-old Katelin and 2-year-old Cassidy.

Since the start of the war in Iraq in March 2003, 23 soldiers with notable Hawai'i ties have been killed in the Middle East, including 17 in Iraq. Of those killed, 15 were assigned to the 25th Infantry Division.