Air Force Secretary Michael Donley is stepping down after five years in the job marked by scandals surrounding its aircraft contracts, sexual assaults and the mishandling of war dead. He is credited for improving the service's handling of nuclear materials.

Donley will leave June 21 to return to private life.

Michael Donley, Secretary of the U.S. Air Force, gives the commencement speech at the U.S. Air Force Academy graduation ceremony on May 25, 2011 in Colorado Springs, Colorado. A total of 1,021 graduates were to receive their diplomas in front of their families, dignitaries and the public at the annual event at the Academy's Falcon Stadium. (Photo by John Moore/Getty Images)

He was serving as the Pentagon's director of administration in 2008 when then-Defense Secretary Robert Gates tapped him to take the Air Force post. Gates had fired the service's chief of staff and secretary amid an embarrassing series of nuclear-related errors.

Donley got the nuclear mission back on track and worked to resolve disputes that repeatedly stalled the refueling tanker contract. But he faced criticism over the loss of service member's body parts at the Dover Air Force Base mortuary.

Copyright 2013 by The Associated Press. All Rights Reserved.