Aircraft 74-1686 started out as C-130H Lockheed construction number 4669. She was first assigned to the 463rd Tactical Airlift Wing at Dyess AFB, TX in 1976. She was then heavily modified and redesignated 4658, YMC-130H in secret for a special rescue mission called Credible Sport for a possible attempt to rescue the American hostages in Iran in 1980. Lockheed Aircraft put its most experienced people on the job, to modify several planes at its plant in Marietta, Georgia. The flaps were taken apart and reworked so the plane could make its final approach into the stadium at 80 knots instead of the normal 100 knots. A special refueling rig was attached to the top of the plane. The plane was fitted out with eight [Navy ASROC] rocket motors. They provided eighty thousand pounds of decelerating force to stop the plane. To cushion the landing, the plane was fitted with eight Shrike rocket motors, which were fired straight down just before the plane touched the ground. For takeoff, rocket motors provided 180,000 pounds of thrust for the first four seconds and 20,000 pounds of thrust for another twenty seconds. In October 1980, the plane, 74-1683, set a new record for STOL aircraft. Within ten feet of brake release, the nose wheel was six feet in the air. The entire plane was airborne within 150 feet, and, by the time it had gone the length of a soccer field, it was 30 feet in the air and flying at 115 knots. A small rocket motor in the tail pushed the tail up to help the pilot level off from the steep climb out of the stadium. The plan was for the plane to dive in steeply, clearing the stadium wall by eight feet, land, taxi to the other end, turn around and prepare for takeoff. Inside, the plane was braced with a massive steel box frame to absorb the violence of the landing and takeoff. Special aluminum seats were designed so the hostages could be strapped in quickly and braced for the takeoff. A final full-scale test of the system ended with a disappointing accident. The test plane (74-1683) had taken off from one of the auxiliary fields at Eglin Air Force Base, gone through its paces, and returned for a landing. On the final approach, there was a malfunction in the firing sequence of the retrorockets. This resulted in the aircraft crashing on the runway and ripping one of the wings off. The aircraft burned up and was a loss, the crew was unharmed. work continued on the second aircraft, 4658, but Iran announced plans to free the hostages. "Credible Sport" stayed in the test phase. Further tests on the plane were conducted in the following months, but it was never used in an actual operation. Aircraft 4658 was taken out of storage and placed on display at the Museum of Aviation in 1988.