U.S. Air Force Senior Airman Candace Obeginski, 757th Aircraft Maintenance Squadron crew chief, puts on personal protective equipment prior to cleaning an F-15E Strike Eagle at the wash rack here, Sept. 10, 2012, at Nellis Air Force Base, Nev. Washing aircraft every 180 days at Nellis AFB helps to extend its life and reliability by preventing corrosion build-up. The more exposure an installation has to salt water the more frequently the aircraft is required to be washed.