Skilled hands drive a nail into the frame of a wheelchair ramp being constructed by volunteers from Joint Base Andrews April 2. In conjunction with Christmas in April * Prince George's County, volunteers helped make the Callahan residence, in Upper Marlboro, Md., wheelchair accessible. David Callahan, 19, was paralyzed in an automobile accident Jan. 23 on the Capitol Beltway. The accident also claimed the life of his 21 year old brother, David. The boys' mother works for the Judge Advocate General at the Washington Navy Yard on Joint Base Andrews. (U.S. Air Force Photo by Senior Airman Torey Griffith.)(Released)