The pilots of the twin-rotor Chinook known as "Big Windy 25" were switching to instrument flight and over-controlled the aircraft in the southern Afghan desert of Ghazni province, the military said in a statement.

All aboard were killed in the fiery crash, including five Army crew members, six soldiers, one Marine, two Army National Guard soldiers, one Army reservist and three civilian contractors.

Among the dead were Master Sgt. Edwin A. Matoscolon, 42, of Juana Diaz, Puerto Rico; and Sgt. Maj. Barbaralien Banks, 41, of Harvey, La.

The veteran soldiers belonged to Headquarters and Headquarters Battery, Division Artillery, with the 25th Infantry Division (Light).

They were the 14th and 15th fatalities among 5,800 Hawai'i-based soldiers who deployed to Afghanistan for a year in early 2004. The last of those soldiers returned in June.

Banks, a senior food-management supervisor, entered the Army in 1988 and was the mother of two grown children and a grandmother of three.

Matoscolon was a mechanical-maintenance supervisor who had entered the Army in 1984. He had a 9-year-old daughter and a fiancee waiting for him back home.

The Chinook was taking passengers and supplies from Forward Operating Base Orgun-E near the Pakistan border to Forward Operating Base Sarhawdza in Ghazni province.

"We mourn the loss of this crew and its passengers and will never forget their selfless service and sacrifice," said Army Maj. Gen. Jason Kamiya, a 1972 St. Louis School graduate and the No. 2 U.S. commander in Afghanistan. "We have already implemented, or are in the process of implementing, the recommendations of the investigation team to preclude tragedies such as this from occurring in the future."