DynCorp provides aircraft maintenance, fleet testing and evaluation for rotary, fixed, "lighter-than-air", and unmanned aircraft. Specifically, they provide on-site work for project testing, transient, loaner, leased and tested civilian aircraft services. DynCorp also performs supportability and safety studies as well as off-site aircraft safety and spill containment patrols and aircraft recovery services. DynCorp has received contracts for aircraft maintenance with the United States Navy, the U.S. Air Force, the U.S. Army, and NASA. DynCorp provides aircraft maintenance in countries including the Republic of the Philippines, the United States, throughout Europe, Southwest Asia, the Middle East, and Africa. Additionally, DynCorp provides aircraft maintenance support to facilities including the NAS Patuxent River, Johnson Space Center in Houston, the Langley Research Center in Hampton, Virginia, NASA facilities in El Paso, Texas, Edwards Air Force Base in California, and Robins Air Force Base (AFB) in Georgia.