of this ferry flight is sometimes described as routine maintenance, in fact the aircraft had encountered severe turbulence on its previous operational mission and had been cleared for a one-time flight to be checked for possible structural damage at the main operating base. "Rivet Amber" was the heaviest 135 series aircraft ever built and was a highly sophisticated aircraft with a radar that weighed over 35,000 pounds and under each wing were specialized pods housing a heat-exchanger (right wing) and an additional electrical generator (left wing). During the flight all contact with 62-4137 was lost and the wreckage of the aircraft was never found. On 15 March 1981, USAF RC-135S, 61-2664, called "Cobra Ball", crashed on final approach in bad weather to Shemya Air Force Base, Alaska on a flight from Eielson Air Force Base, Alaska. The aircraft commander never established a proper glide path or descent rate on final and impacted the ground short of the runway. Of the twenty-four occupants of the aircraft, six were killed. On 25 February 1985, USAF RC-135T, 55-3121, operating out of Eielson AFB, Alaska, was flying practice approaches in very poor weather at the Valdez Municipal Airport, Alaska. This one-time "Speed Light" aircraft had been re-engined with P&W TF-33 engines but was at this time only used for proficiency training in landings and air refueling, not for operational reconnaissance missions, but was sometimes called "Rivet Dandy". The first two approaches were uneventful, but the crew apparently became disoriented and the third Microwave Landing System (MLS) approach was commenced some north of the prescribed MLS inbound course. The crew of three (two pilots and a navigator) were killed when the aircraft flew into the side of a mountain. The approach procedure being attempted was certified for a de Havilland Canada DHC-7, STOL airplane. Both the glide slope and missed approach flight path were too steep for an RC-135 aircraft. The wreckage was not located until 2 August 1985. On 3 March 2003, two MiG-29 and MiG-23 of North Korean KPAAF intercepted RC-135S in Sea of Japan with MiG-29 came within 50 feet of the aircraft with another locked onto it with fire control radar in preparation to conduct a shoot down, RC-135S changed course towards Japan and landed in Kadena airbase. On 30 April 2015, USAF RC-135V, 64-14848, operating out of Offutt AFB, NE aborted takeoff on a routine training mission when crewmembers observed