Aviation Survival Technician

Aviation Survival Technician (AST) is a rating or job specialty in the United States Coast Guard. Rescue swimmer is the collateral duty or aircrew position of the AST. They are trained at the U.S. Coast Guard's enlisted Aviation Survival Technician/Rescue Swimmer school at Coast Guard Aviation Technical Training Center, Coast Guard Air Station Elizabeth City in Elizabeth City, North Carolina. The challenging job is featured prominently in the 2006 film "The Guardian", starring Kevin Costner and Ashton Kutcher.
History.
The rating began in 1968 when the U.S. Coast Guard combined Parachute Rigger (PR) and Aviation Ordnanceman (AO) to create the Aviation Survivalman (ASM) Rating. In 1983, the disaster of the spawned a Congressional Inquiry that found the USCG was the only military service unable to deploy a member from an aircraft for search, rescue and recovery, and initiated a legal requirement for the armed force to do so. After much internal debate, the collateral duty of "Helicopter Rescue Swimmer" was issued to the ASM rating. Initially met with significant resistance throughout the USCG, the AST has become a durable and required part of Coast Guard rotary wing operations.
Initially, all new ASMs were required to complete US Navy Helicopter Rescue Swimmer school in Pensacola, Florida, prior to reporting to USCG ASM "A" School and EMT "C" School. After a few years, the differences between what the candidates were learning in the combat-oriented Navy school and what was being required of them during civilian rescues required an organic Coast Guard helicopter rescue swimmer school to be begun. An aquatic segment of training was merged into ASM "A" school in the late 1980s, and full initial rescue swimmer training was completed at the USCG's Elizabeth City training center. 
In 1999, along with the realignment of enlisted aviation rates throughout the USCG, the Aviation Survivalman rating was redesignated to Aviation Survival Technician.
In 2014, a state of the art training center was opened under the command of the Aviation Technical Training Center aboard BASE Elizabeth City, NC and houses AST "A" School as well as Underwater Egress "C" School.
Training and qualification.
The course is 24 weeks long. The course includes instruction on rescue techniques, helicopter deployment techniques, and myriad technical skills from small engine repair to parachute packing and maintenance. Successful completion of this course results in being awarded the Aviation Survival Technician rating, the technical rating for a variety of aircraft and survival equipment maintenance. 
After completion of A-School, all ASTs are sent to Training Center Petaluma, California to attend the Coast Guard's Emergency Medical Technician school. After seven weeks of EMT training, they must take and pass the National Registry of Emergency Medical Technicians-Basic (NREMT-B) test as part of their qualification as a helicopter rescue swimmer.
Full qualification as a rescue swimmer can take up to a year from graduation of A-School, as graduates must learn the aircraft systems and emergency procedures of their assigned aircraft. 
The rescue swimmer training program has a high student attrition rate averaging in the 80% range, similar to other special operations schools in the military.
Not all ASTs serve as rotary wing helicopter rescue swimmers. Many serve in other roles, including as aircrew on fixed-wing assets, at Coast Guard fire departments and as instructors at any of the various training commands.
Pop Culture.
The 2006 movie "The Guardian" featured Kevin Costner and Ashton Kutcher as well as a number of actual ASTs and Coast Guardsmen as extras, and told a fictional story of two rescue swimmers. 
In 2019, the Amazon Prime reboot of Jack Ryan featured a helicopter rescue swimmer in the pilot episode. 