10 June 1969: The U.S. Air Force donated the first North American Aviation X-15, serial number 56-6670, to the Smithsonian Institution for display at the National Air and Space Museum.
The first of three X-15A hypersonic research rocketplanes built by North American for the Air Force and the National Advisory Committee (NACA, the predecessor of NASA), 56-6670 made the first glide flight and the first and last powered flights of the X-15 Program. It made a total of 82 of the 199 X-15 flights.
Scott Crossfield, North American’s Chief Engineering Test Pilot, made the first unpowered flight 8 June 1959 and the first powered flight, 17 September 1959. NASA Research Test Pilot William H. “Bill” Dana made the final X-15 flight on 24 October 1968.
19 April 2006: Former experimental test pilot Albert Scott Crossfield, Jr., was enroute from Prattville, Alabama, to Manassas, Virginia. Scott Crossfield¹ was flying his personal Cessna 210A, N6579X. The Cessna was cruising at 11,000 feet (3,353 meters) under Instrument Flight Rules (IFR), under the control of the Atlanta Air Route Traffic Control Center (ARTCC).
During the flight, he encountered a Level 6 thunderstorm.
Scott Crossfield requested to deviate from his planned course to avoid the severe turbulence. Atlanta Center authorized his request and he began to turn. Approximately 30 seconds later, at 11:10 a.m., radar contact was lost near Ludville, Georgia. The last indication was that the Cessna was descending through 5,500 feet (1,676 meters).
The wreckage of N6579X was located the following day by a Civil Air Patrol search team, 3.3 nautical miles (6.1 kilometers) northwest of Ludville at an elevation of 1,269 feet (386.8 meters) above Sea Level. [N. 34° 30.767′, W. 84° 39.492′] The airplane had descended through the forest canopy nearly vertically and created a crater approximately 4½ feet (1.4 meters) deep and 6 feet (1.8 meters) across. Albert Scott Crossfield’s body was inside.
N6579X was a Cessna Model 210A, serial number 21057579, built in 1960 by the Cessna Aircraft Company, Inc., of Wichita Kansas. It was a six-place, single-engine, high-wing monoplane with external struts to brace the wings, and retractable, tricycle landing gear. The airplane was certified for instrument flight by a single pilot. At the time of the crash, N6579X had been flown 4,987.4 hours, total time since new (TTSN).
The Cessna 210A was 28 feet, 2 inches (8.585 meters) long with a wingspan of 36 feet, 6 inches (11.125 meters) and overall height of 9 feet, 7 inches (2.921 meters). The airplane had an empty weight of 1,839 pounds (834.2 kilograms) and maximum gross weight of 2,900 pounds (1,315.4 kilograms). It had a fuel capacity of 65 gallons (246 liters), with 10 gallons (37.9 liters) unusable, and 12 quarts of engine oil (11.4 liters).
N6579X was powered by an air-cooled, fuel-injected, 471.239-cubic-inch-displacement (7.722 liters) Teledyne Continental IO-470-E horizontally-opposed six-cylinder direct-drive engine with a compression ratio of 8.6:1. The engine was rated at 260 horsepower at 2,625 r.p.m. for takeoff, using 100LL aviation gasoline. It weighed 429 pounds (195 kilograms). This engine, serial number 77583-0-E, was original to the airplane and accumulated 4,987.4 hours, total time since new (TTSN). It had been overhauled by Victor Aviation, Palo Alto, California, 1,259.8 hours prior to the accident (TSO). A three-bladed McCauley constant-speed propeller with a diameter of 6 feet, 10 inches (2.083 meters) was installed in 2005.
The Cessna Model 210A has a maximum structural cruise speed of 175 miles per hour (282 kilometers), and maximum speed (Vne) of 200 miles per hour (322 kilometers per hour). Maneuvering speed, which should be used in turbulent conditions, is 130 miles per hour (209 kilometers per hour). The 210A has a maximum rate of climb of 1,300 feet per minutes (6.6 meters per second) and service ceiling of 20,700 feet (6,309 meters). Its maximum range is 1,284 miles (2,066 kilometers).
Albert Scott Crossfield, Jr., was born 2 October 1921 at Berkeley, California. He was the second of three children of Albert Scott Crossfield, a chemist who was employed as the superintendant of the Union Oil Company refinery in Wilmington, California, and Lucia M. Dwyer Crossfield.
When he was five years old, young “Scotty” contracted pneumonia. He was comatose for a while and was not expected to survive, but after several weeks he began to recover. A year later, he again became seriously ill, this time with rheumatic fever. He was confined to total bed rest for four months, and continued to require extensive bed rest until he was about ten years old. It was during this time that he became interested in aviation.
Scott Crossfield attended Boistfort Consolidated School, southwest of Chehalis, Washington, graduating in 1939, and then studied engineering at the University of Washington until taking a job at Boeing in late 1941. During this time, Scotty learned to fly in the Civilian Aviation Training Program.
The week following the attack on Pearl Harbor and the United States’ entry into World War II, Scott Crossfield enlisted as an aviation cadet in the United States Army Air Corps. After numerous delays, he joined the United States Navy on 21 February 1942, and resigned from the Air Corps. He began aviation cadet training at NAS Sand Point, near Seattle, and then was sent to NAS Corpus Christi, Texas. In December 1942, he graduated, received his gold Naval Aviator wings and was commissioned as an Ensign, United States Naval Reserve.
Ensign Crossfield was assigned to NAS Kingsville as an advanced bombing and gunnery instructor. He was promoted to Lieutenant (junior grade), 1 March 1944. He continued as a gunnery instructor for two years before being transferred to Air Group 51 in the Hawaiian Islands, which was preparing for the invasion of Japan. He was promoted to Lieutenant, 1 August 1945, while serving aboard the Independence-class light aircraft carrier USS Langley (CVL-27). With the end of World War II, though, the Navy was cutting back. Lieutenant Crossfield was released from active duty 31 December 1945.
In April 1943 at Corpus Christi, Texas, Ensign A. Scott Crossfield married Miss Alice Virginia Knoph of Seattle. They would have five children.
Following the War, Scotty returned to the University of Washington to complete his degree. He took a part time job operating the University’s wind tunnel. At the same time, he remained in the Naval Reserve, assigned to VF-74, a fighter squadron which flew both the Grumman F6F Hellcat and Chance Vought F4U Corsair out of NAS Sand Point, back where his naval career began.
Crossfield graduated from the University of Washington with a bachelor’s degree in aeronautical engineering in June 1949, and a master’s degree in 1950.
In 1950 Crossfield joined the National Advisory Committee for Aeronautics (NACA) as a research test pilot at the High-Speed Flight Station, Edwards Air Force Base, California. He flew the Republic YF-84, F-84F Thunderstreak, and North American Aviation F-86 Sabre. Crossfield made 25 flights in the delta-winged Convair XF-92A, which he described as “the worst flying airplane built in modern times.” He also flew the Northrop X-4 and Bell X-5. He made 17 flights conducting stability tests in the Douglas D-558-1 Skystreak. Scotty made 65 flights in the North American Aviation F-100A Super Sabre, including a test series which discovered a fatal flaw which led to the death of North American’s chief test pilot, George S. Welch.
Crossfield is known as a rocketplane pilot. He made 10 flights in the Bell X-1, and 89 in the Douglas D-558-II Skyrocket. He became the first pilot to exceed Mach 2 when he flew the Skyrocket to Mach 2.005, 20 November 1953.
Crossfield flew for NACA for approximately five years. During that time, approximately 500 flights were made at Edwards by NACA test pilots. Scott Crossfield flew 181 of them.
Scott Crossfield left NACA in 1956 to join North American Aviation, Inc., as chief engineering test pilot for the X-15 project. Between 8 June 1959 and 6 December 1960, he made fourteen flights in the X-15. He reached a maximum speed of Mach 2.97 and altitude of 88,116 feet (26,858 meters). Once the contractor’s flight tests were completed and the rocketplane turned over to the U.S. Air Force and NACA, the customers’ test pilots, Joe Walker and Major Robert M. White, took over.
Albert Scott Crossfield made 114 flights in rocket-powered aircraft, more than any other pilot.
After completing his work on the X-15, Crossfield followed Harrison (“Stormy”) Storms, who had been the Chief Engineer of North American’s Los Angeles Division (where the X-15 was built) to the Space and Information Systems Division in Downey, California, where he worked in quality assurance, reliability engineering and systems testing for the Apollo Command and Service Modules and the Saturn S-II second stage.
Crossfield left North American at the end of 1966, becoming Vice President for Technological Development for Eastern Air Lines. In this position, he flew acceptance tests for new Boeing 720 and 727 airliners at Boeing in Seattle.
In The X-15 Rocket Plane, author Michelle Evans quoted Crossfield as to why he had not entered NASA’s space program as an astronaut:
One question that pressed was, with his love of flight and the early responsibility of going into space with the X-15, why would Scott not apply to the NASA astronaut office? He explained, “[Dr.] Randy Lovelace and General [Donald] Flickinger were on the selection board. They took me to supper one night and asked me not to put in for astronaut. I asked them, ‘Why not?’ and they said, ‘Well, we’re friends of yours. We don’t want to have to turn you down.’ I asked, ‘Why would you have to turn me down?’ and they said, ‘You’re too independent.’ “
—The X-15 Rocket Plane: Flying the First Wings into Space, by Michelle, Evans, University of Nebraska Press, 2013, Chapter 1 at Page 33.
The remains of Albert Scott Crossfield are interred at the Arlington National Cemetery.
¹ “Scott Crossfield” is the family name, going back for several generations.
13 April 1960: Major Robert M. White, USAF, made the first flight of an X-15 by an Air Force test pilot.
Carried aloft by a Boeing NB-52A Stratofortress, serial number 52-003, the first of three X-15 hypersonic research aircraft, 56-6670, was airdropped at 0915 above Rosamond Dry Lake. Major White ignited the two Reaction Motors XLR-11 rocket engines and with a burn time of 4 minutes, 13.7 seconds, the X-15 accelerated to Mach 1.9 (1,254 miles per hour/2,018 kilometers per hour) and reached 48,000 feet (14,630 meters). Both numbers were slightly short of the planned Mach 2.0 (1,320 miles per hour/2,124 kilometers per hour) and 50,000 feet (15,240 meters).
After 8 minutes, 52.7 seconds, Bob White and the X-15 touched down at Edwards Air Force Base.
Over the next 32 months Bob White made 16 flights in the X-15. He was the first pilot to fly faster than Mach 4, Mach 5 and Mach 6. He flew it to Mach 6.04, 4,093 miles per hour (6,587 kilometers per hour) and set a Fédération Aéronautique Internationale (FAI) altitude record of 314,750 feet (95,936 meters), for an altitude gain of 82,190 meters (269,652 feet).¹
White was one of three pilots awarded astronaut wings for his flights in the X-15.
7 March 1961: Launched over Silver Lake, a dry lake bed near the California/Nevada border, at 10:28:33.0 a.m., Pacific Standard Time, test pilot Major Robert M. White, U.S. Air Force, flew the number two North American Aviation X-15 hypersonic research rocketplane, 56-6671, to Mach 4.43 (2,905 miles per hour/4,675 kilometers per hour) and 77,450 feet (23,607 meters), becoming the first pilot to exceed Mach 4.
This was the first flight for the number two X-15 with the Reaction Motors XLR99-RM-1 engine, which was rated at 57,000 pounds of thrust (253.55 kilonewtons).
The flight plan called for a burn time of 116 seconds, an altitude of 84,000 feet (25,603 meters) and a predicted maximum speed of Mach 4.00. The actual duration of the engine burn was 127.0 seconds. Peak altitude was lower than planned, at 77,450 feet (23,607 meters). The longer burn and lower altitude translated into the higher speed.
The total duration of the flight, from the air drop from the Boeing NB-52B Stratofortress carrier, 52-008, to touchdown at Edwards Air Force Base, was 8 minutes, 34.1 seconds.
15 November 1967: Major Michael James Adams, United States Air Force, was killed in the crash of the number three North American Aviation X-15 hypersonic research rocketplane, 56-6672.
Flight 191 of the X-15 program was Mike Adams’ seventh flight in the rocketplane. It was the 56-6672’s 65th flight. The flight plan called for 79 seconds of engine burn, accelerating the X-15 to Mach 5.10 while climbing to 250,000 feet (76,200 meters). Adams’ wife, Freida, and his mother, Georgia Adams, were visiting in the NASA control room at Edwards Air Force Base.
Balls 8, the Boeing NB-52B Stratofortress, 52-008, flown by Colonel Joe Cotton, took off from Edwards at 9:12 a.m., carrying -672 on a pylon under its right wing, and headed north toward the drop point over Delamar Dry Lake in Nevada. The drop ship climbed to the launch altitude of 45,000 feet (13,716 meters).
The X-15 launch was delayed while waiting for the Lockheed C-130 Hercules rescue aircraft to arrive on station. This required Adams to reset the Honeywell MH-96 Automatic Flight Control System to compensate for the changing position of the sun in the sky.
56-6672 was launched by Balls 8 at 10:30:07.4 a.m., Pacific Standard Time. As it dropped clear of the bomber, the rocketplane rolled 20° to the right, a normal reaction. Within one second, Mike Adams had started the XLR99-RM-1 rocket engine while bringing the wings level. The engine ignited within one-half second and was up to its full 57,000 pounds of thrust (253.549 kilonewtons) one second later. The engine ran for 82.3 seconds, 3.3 seconds longer than planned, causing the X-15 to reach Mach 5.20 (3,617 miles per hour/5,821 kilometers per hour) and to overshoot the planned altitude to peak at 266,000 feet (81,077 meters).
With the X-15 climbing through 140,000 feet (42,672 meters), the Inertial Flight Data System computer malfunctioned. Adams radioed ground controllers that the system’s malfunction lights had come on.
The flight plan called for a wing-rocking maneuver at peak altitude so that a camera on board could scan from horizon to horizon. During this maneuver, the Reaction Control System thrusters did not respond properly to Adams’ control inputs. The X-15 began to yaw to the right.
As it reached its peak altitude, 56-6672 yawed 15° to the left. Going over the top, the nose yawed right, then went to the left again. By the time the aircraft has descended to 230,000 feet (70,104 meters), it had pitched 40° nose up and yawed 90° to the right its flight path. The X-15 was also rolling at 20° per second. The rocketplane went into a spin at Mach 5.
10:33:37 Chase 1: “Dampers still on, Mike?”
10:33:39 Adams: “Yeah, and it seems squirrelly.”
10:34:02 Adams: “I’m in a spin, Pete.” [Major William J. “Pete” Knight, another X-15 pilot, was the flight controller, NASA 1]
10:34:05 NASA 1: “Let’s get your experiment in and the cameras on.”
10:34:13 NASA 1: “Let’s watch your theta, Mike.”
10:34:16 Adams: “I’m in a spin.”
10:34:18 NASA 1: “Say again.”
10:34:19 Adams: “I’m in a spin.”
Adams fought to recover, and at 118,000 feet (35,967 meters) came out of the spin, but he was in an inverted 45° dive at Mach 4.7. The X-15’s MH-96 Automatic Flight Control System entered a series of diverging oscillations in the pitch and roll axes, with accelerations up to 15 gs. Dynamic pressures on the airframe rapidly increased from 200 pounds per square foot (9.576 kilopascals) to 1,300 pounds per square foot (62.244 kilopascals).
At 62,000 feet (18,898 meters), still at Mach 3.93, the aircraft structure failed and it broke apart.
10:34:59 X-15 telemetry failed. Last data indicated it was oscillating +/- 13 g. Radar altitude was 62,000 feet (18,898 meters). The aircraft was descending at 2,500 feet per second (762 meters per second) and broke into many pieces at this time.
10:35:42 NASA 1: “Chase 4, do you have anything on him?”
10:35:44 Chase 4: “Chase 4, negative.”
10:35:47 NASA 1: “OK, Mike, do you read?”
10:35:52 Chase 4: “Pete, I got dust on the lake down there.”
North American Aviation X-15A-3 56-6672 crashed in a remote area, approximately 5½ miles (9 kilometers) north-northeast of Randsburg, California, a small village along U.S. Highway 395.
Major Michael James Adams was killed. This was the only pilot fatality of the entire 199-flight X-15 program.
An investigation by NASA’s Engineering and Safety Center determined that,
“. . . the root cause of the accident was an electrical disturbance originating from an experiment package using a commercial-off-the-shelf (COTS) component that had not been properly qualified for the X-15 environment. . .”and that there is“. . . no conclusive evidence to support the hypothesis that SD [spatial disorientation] was a causal factor. On the contrary, the evidence suggests that poor design of the pilot-aircraft interface and ineffective operational procedures prevented the pilot and ground control from recognizing and isolating the numerous failures before the aircraft’s departure from controlled flight was inevitable.”
—A Comprehensive Analysis of the X-15 Flight 3-65 Accident, NASA/TM—2014-218538 (Corrected Copy)
Michael James Adams was born at Sacramento, California, 5 May 1930. He was the first of two sons of Michael Louis Adams, a telephone company technician, and Georgia E. Domingos Adams.
After high school, Mike Adams attended Sacramento Junior College, graduating in 1949. He was an outfielder for the college baseball team, and threw the javelin in track & field.
Adams enlisted in the United States Air Force in 1950. He completed basic training at Lackland Air Force Base, San Antonio, Texas. In October 1951, he was selected as an aviation cadet and sent to Spence Air Force Base, near Moultrie, Georgia, for primary flight training. Cadet Adams completed flight training at Webb Air Force Base, Big Spring, Texas. He graduated 25 October 1952. Adams was one of two distinguished graduates in his class and received a commission as an officer in the regular Air Force.
Second Lieutenant Adams was assigned to advanced flight training at Nellis Air Force Base, where he flew the Lockheed F-80 Shooting Star and North American Aviation F-86 Sabre.
In April 1953, Lieutenant Adams joined the 80th Fighter-Bomber Squadron at K-13, Suwon, Republic of Korea. He flew 49 combat missions.
Following the Korean War, Lieutenant Adams was assigned to the 613th Fighter Bomber Squadron, 401st Fighter-Bomber Group, at England Air Force Base, Alexandria, Louisiana. The Squadron initially flew the F-86F Sabre and then transitioned to the Republic F-84F Thunderstreak. Adams deployed to Chaumont Air Base, France, for a six-month temporary assignment.
While stationed at England AFB, Lieutenant Adams met Miss Freida Beard. They were married in a ceremony at the Homewood Baptist Church in Alexandria, 15 January 1955. They would have three children, Michael James, Jr., Brent, and Liese Faye Adams.
In 1958, Adams graduated from the University of Oklahoma at Norman, with a bachelor’s degree in aeronautical engineering. He was a member of the university’s Institute of Aeronautical Sciences. Adams was next assigned to the Massachusetts Institute of Technology, Cambridge, Massachusetts, where he studied astronautics.
Adams’ next military assignment was as a maintenance officer course instructor at Chanute Air Force Base, Rantoul, Illinois.
In 1962, Captain Adams entered an eight-month training program at the Air Force Test Pilot School, Class 62C, at Edwards Air Force Base in the high desert of southern California. He was awarded the A.B. Honts Trophy as the class’s outstanding graduate.
On 17 June 1963, Captain Adams entered the Aerospace Research Pilots School, which was also at Edwards. This was a seven-month course that taught flying skills in advanced vehicles, with an aim to prepare the graduates for space flight, and to create a pool of qualified military test pilots to be selected as astronauts. The Air Force estimated a need for 20 pilots a year for the upcoming X-20 Dyna-Soar and Manned Orbiting Laboratory (M.O.L.) programs. Adams graduated with the second of the four ARPS classes.
Adams then became an operational test pilot, conducting stability and control tests for the Northrop F-5A Freedom Fighter. That was followed by an assignment as a project pilot for the Cornell Aeronautical Laboratory.
On 13 November 1963, it was announced that Michael Adams was on of the selectees for the M.O.L. program. As a designated Air Force astronaut, Adams was involved in lunar landing simulations during the development of the Apollo Program lunar lander.
Major Adams was selected as a pilot of the NASA/Air Force X-15 Hypersonic Research Flight Program. (He was the twelfth and final pilot to be accepted into the project.) He made his first X-15 flight on 6 October 1966. He flew the first X-15, 56-6770. A ruptured fuel tank forced him to make an emergency landing at Cuddeback Dry Lake, one of several pre-selected emergency landing sites, about 40 miles (64 kilometers) northeast of Edwards. The duration of the flight was 8 minutes, 26.4 seconds. The X-15 had only reached an altitude of 75,400 feet (22,982 meters) and Mach 3.00.
His second flight took place on 29 November 1966. On this flight, he took the # 3 ship, 56-6672, to 92,100 feet (28,072 meters) and Mach 4.65. The flight lasted 7 minutes, 55.9 seconds.
For his third flight, Mike Adams was back in 56-6670, which had been repaired. He flew to an altitude of 133,100 feet (40,569 meters) and reached Mach 5.59 (3,822 miles per hour/6,151 kilometers per hour). This was Adams fastest flight. He landed at Edwards after 9 minutes, 27.9 seconds.
Flight number four for Adams took place on 28 April 1967. Again he flew the # 1 X-15. On this flight, he reached 167,200 feet (50,963 meters) and Mach 5.44. Elapsed time was 9 minutes, 16.0 seconds.
On 15 June 1967, Adams flew # 1 to 229,300 feet (69,891 meters) and Mach 5.14. Duration 9 minutes, 11.0 seconds.
On 25 August 1967, Adams made his sixth flight, his second in the third X-15, 56-6672. The rocket engine shut down after sixteen seconds and had to be restarted. The maximum altitude was 84,400 feet (25,725 meters) and Mach 4.63. The duration of this flight was 7 minutes. 37.0 seconds.
Mike Adams’ seventh flight in an X-15 took place 15 November 1967. This was the 191st X-15 flight, and the 65th for X-15 56-6672. Tests to be conducted were an ultraviolet study of the rocketplane’s exhaust plume; solar spectrum measurements; micrometeorite collection, and a test of ablative material for the Saturn rocket.
Adams reached 266,000 feet (81,077 meters) and Mach 5.20.
Having met the U.S. Air Force qualification for flight in excess of 50 miles (80.47 kilometers), Michael Adams was posthumously awarded the wings of an astronaut.
Major Michael James Adams, United States Air Force, was buried at Mulhearn Memorial Park, in Monroe, Louisiana.