U.S. Air Force Senior Airman Candace Obeginski, crew chief, and Airman 1st Class Garrett Sterba, electronic environmental journeyman, both from the 757th Aircraft Maintenance Squadron clean the tires of 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.