The zoom climb maneuver was planned to begin with the NF-104A in level flight at 0.85 Mach and 35,000 feet (10,668 meters). The pilot would then accelerate in Military Power and light the afterburner, which increased the J79 turbojet engine’s 9,800 pounds of thrust (43.59 kilonewtons) to 15,000 pounds (66.72 kilonewtons). The modified Starfighter was to continue accelerating in level flight. On reaching Mach 2.2, the Colonel Yeager would ignite the Rocketdyne AR2–3 rocket engine, which burned a mixture of JP-4 and hydrogen peroxide to produce 6,600 pounds of thrust (29.36 kilonewtons).
When the AST reached Mach 2.5, Yeager was to begin a steady 3.5G pull-up until the interceptor was in a 70° climb. At 75,000 feet (22,860 meters), he would shut off the afterburner to avoid exceeding the turbojet’s exhaust temperature (EGT) limits. Yeager would then gradually reduce the jet engine power to idle by 85,000 feet (25,908 meters), and then shut it down. Without the engine running, cabin pressurization would be lost and his A/P22S-2 full-pressure suit would inflate.
The NF-104A would then continue to zoom to an altitude where its aerodynamic control surfaces were no longer functional. It had to be controlled by reaction jets in the nose and wing tips. The pilot had to use the reaction control thrusters to pitch the AST’s nose down before reentering the atmosphere, so that it would be in a -70° dive. The windmill effect of air rushing into the intakes was used to restart the jet engine.
The 10 December flight did not proceed as planned. Chuck Yeager reached a peak altitude of approximately 108,000 feet (32,918 meters), nearly two miles (3.2 kilometers) lower than the record altitude set by Major Robert W. Smith just four days earlier.
On reentry, Yeager had the Starfighter incorrectly positioned with only a -50° nose-down pitch angle, rather than the required -70°.
The Starfighter entered a spin.
Without air flowing through the engine intakes because of the spin, Yeager could not restart the NF-104’s turbojet engine. Without the engine running, he had no hydraulic pressure to power the aerodynamic flight control surfaces. He was unable to regain control the airplane. Yeager rode the out-of-control airplane down 80,000 feet (24,384 meters) before ejecting.
“The data recorder would later indicate that the airplane made fourteen flat spins from 104,000 until impact on the desert floor. I stayed with it through thirteen of those spins before I punched out. I hated losing an expensive airplane, but I couldn’t think of anything else to do. . . I went ahead and punched out. . . .”
— Yeager, An Autobiography, by Brigadier General Charles E. Yeager, U.S. Air Force (Retired) and Leo Janos, Bantam Books, New York, 1985, at Pages 279–281.
NF-104A 56-762 crashed at N. 35° 7′ 25″, W. 118° 8′ 50″, about one mile (1.6 kilometers) north of the intersection of State Route 14 and State Route 58, near California City. The airplane was completely destroyed.
Chuck Yeager was seriously burned by the ejection seat’s internal launch rocket when he was struck by the seat which was falling along with him. This incident was dramatized in the 1983 movie, “The Right Stuff,” (based on Tom Wolfe’s book of the same title), with Yeager portrayed by actor Sam Shepard.
56-762 was a Lockheed F-104A-10-LO Starfighter, one of three taken from storage at The Boneyard at Davis-Monthan Air Force Base, Tucson, Arizona, and sent to Lockheed for modification to Aerospace Trainers (ASTs).
These utilized a system of thrusters for pitch, roll and yaw control at altitudes where the standard aerodynamic control surfaces could no longer control the aircraft. This was needed to give pilots some experience with the reaction control system for flight outside the Earth’s atmosphere.
The F-104A vertical fin was replaced with the larger fin and rudder from the two-place F-104B for increased stability. The wings were lengthened for installation of the Reaction Control System. The fiberglass nosecone was replaced by an aluminum skin for the same reason. The interceptor’s radar and M61 Vulcan cannon were removed and tanks for rocket fuel and oxidizers, nitrogen, etc., installed in their place. The standard afterburning General Electric J79-GE-3B turbojet engine remained, and was supplemented by a Rocketdyne AR2–3 liquid-fueled rocket engine which produced 6,600 pounds of thrust (29.36 kilonewtons) for up to 100 seconds.
On 13 December 1958, prior to its modification to an AST, Lockheed F-104A-10-LO Starfighter 56-762 was flown by 1st Lieutenant Einar K. Enevoldson, USAF, to seven Fédération Aéronautique Internationale (FAI) time-to-altitude world records at Naval Air Station Point Mugu, Californa (NTD).