Chile has three of the aircraft, bought in 2009 and took delivery of the first KC-135 to have undergone PDM just a week it was hit by a 8.8-magnitude earthquake in February 2010. The tanker plane's arrival gave quake relief efforts timely boost.
The Stratotankers are part of a multibillion-dollar military modernization that encompasses all Chilean armed forces and is seen by President Sebastian Pinera's administration as essential to the Latin American nation's defense needs.
Colombia's U.S.-aided crackdown on drug warlords has caused many of the organized gangs to disperse in neighboring countries and Chile is feeling the effect of the spillover.
Chilean defense chiefs said the country's security systems need to be modernized in response to the growing threat of what security experts call "narcoterrorism" -- a loose alliance of guerrilla and militant groups with varying grievances, organized crime, growers, middlemen and cross-border smugglers.
The Stratotankers are part of an effort that is seeing advances in Chilean air force development.
Boeing said it delivered the last of the Chilean air force's three KC-135E Stratotankers on March 9 after all the aircraft completed PDM in San Antonio.
The final aircraft arrived at Boeing's San Antonio facility in June last year for the maintenance work, which included a variety of depot-level inspections, repairs, maintenance, modification and repainting. The KC-135E was flown to Santiago, Chile, by a crew from the U.S. Defense Contract Management Agency's 313th Flight Test Squadron.
"Boeing worked with the Chilean air force to incorporate lessons learned on the first and second aircraft to deliver the final KC-135 and return it to doing what it does best," said Mike Wright, Boeing KC-135 program director.
"This highly dependable aircraft is a critical resource to Chile for refueling missions and humanitarian assistance."
KC-135 aircraft receive PDM after five years of service or 20,000 hours of flight time.
The Chilean government purchased the three KC-135 E-model aircraft on July 8, 2009, through the U.S. Air Force Foreign Military Sales Office at Tinker Air Force Base, Okla.
Chilean Defense Minister Andres Allamand visited Washington this month and told an Inter-American Dialogue meeting the country's defense and security priorities were changing fast.
From protecting scarce natural resources to fighting organized crime and drug trafficking, "the traditional boundary between defense and security has disappeared," Allamand said.
A Northern Border Plan launched year incorporates the use of drones to control borders with Bolivia and Peru to prevent drug trafficking.
He said despite having no wars against each other, Latin American and Caribbean countries had to keep their defense systems up to date to respond to the threat of violence from drug gangs and organized crime.
"Drug trafficking is a problem for Chile," Allamand said. "We're in a region where the world's largest and third-largest producers of cocaine are our neighbors. New approaches are needed, because the consumption of drugs in Chile is going up, not down."
Allamand is to meet with U.S. Defense Secretary Leon Panetta on his first official visit to Latin America next month.
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