767 test airplane model. The Airborne Optical Adjunct (AOA) was built from the prototype 767-200. The aircraft was later renamed the Airborne Surveillance Testbed (AST). Modifications to the aircraft included a large "cupola" or hump which ran along the top of the aircraft from above the cockpit to just behind the trailing edge of the wings. Inside the cupola was a suite of infrared seekers that were used to track theater ballistic missile launches in a series of tests. The aircraft remained in storage at the Victorville Airport in California for a number of years before being scrapped in July 2007.