5 November 1959: During his fourth X-15 flight—the third in the Number Two ship, 56-6671—North American Aviation chief test pilot Albert Scott Crossfield made an emergency landing at Rosamond Dry Lake after one of the two Reaction Motors XLR11-RM-13 rocket engines exploded, causing an engine compartment fire.
The X-15 had been launched by the Boeing NB-52A Stratofortress, 52-003, at 0.82 Mach and approximately 45,000 feet (13,716 meters) over Bouquet Canyon Reservoir, about 35 miles (56 kilometers) southwest of Edwards Air Force Base. Scott Crossfield ignited both XLR11 rocket engines and began to accelerate and climb, but one of four combustion chambers of the lower engine exploded almost immediately. He shut both engines down after 11.7 seconds. Crossfield kept the rocketplane in a level attitude for the 114 seconds it took to jettison the liquid oxygen and water-alcohol propellants to lighten the X-15 for the landing. The tanks could not fully drain and the aircraft remained approximately 1,000 pounds (455 kilograms) overweight.
The X-15 approached the emergency landing site at Rosamond Dry Lake, about ten miles (16 kilometers) southwest of Edwards, while Major Robert M. White, flying a Lockheed F-104 chase plane, called out Crossfield’s distance from the dry lake and his altitude. As he neared the touch down point, Crossfield raised the X-15’s nose to decelerate.
“I lowered the skids and nose wheel, pulled the flaps, and felt for the lake bed.
“The skids dug in gently. The nose wheel slammed down hard and the ship plowed across the desert floor, slowing much faster than usual. Then she came to a complete stop within 1500 feet instead of the usual 5000 feet. Something was wrong; the skids failed, I was sure. . . Quickly I scrambled out of the cockpit. What I saw almost broke my heart. The fuselage had buckled immediately aft of the cockpit, two hundred and thirty inches back from the nose. Her belly had dragged in the sand, causing the abrupt deceleration on the lake. The rocket chambers which had exploded at launch were a shambles.”
—Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960, Chapter 41 at Pages 383–384.
It was determined that the engine had exploded due to an ignition failure, a relatively simple problem not connected to the design of the X-15. But there remained the question as to why the rocketplane had broken in half. The investigation found that the rapid extension of the nose wheel strut when lowered caused the oil inside the strut to foam and vaporize, providing almost no shock absorption. This was corrected and the check list changed to lower the gear sooner.
The total duration of this flight was 5 minutes, 28.0 seconds. The peak altitude was 45,462 feet (13,857 meters) and the maximum speed was 660 miles per hour (1,062 kilometers per hour).
56-6671 was taken back to the North American Aviation plant for repair. It returned to flight operations three months later.
Albert Scott Crossfield, Jr., was born at Berkeley, California, 2 October 1921, the second of three children of Albert Scott Crossfield and Lucia Dwyer Scott Crossfield. (“Scott Crossfield” is the family name, going back for many generations.) His father was a chemist who was the superintendent of the Union Oil Refinery in Wilmington, California. At the age of 5 years, the younger Scott Crossfield contracted pneumonia. He was comatose for a time and not expected to survive. When he finally began to recover, he was confined to bed for many months. The effects of this illness lasted throughout his childhood.
It was during this time that he developed his interest in aviation. He learned to draw, studied airplanes, and built scale models. Charles Lienesch, who was a pilot for the Union Oil Company, gave Scotty his first ride aboard an airplane at age 6. As a teenager, he took flight lessons in an Inland Sportster at the Wilmington Airport.
After his family bought a farm in Oregon, Scott Crossfield continued flight lessons and soloed a Curtis Robin at the age of 15. He earned his private pilot certificate at 18. After graduating from high school, he helped his father with the family farm before attending the University of Washington as a student of aeronautical engineering. He took a job at Boeing to pay his tuition and support.
After America’s entry into World War II, Scott Crossfield enlisted in the U.S. Army Air Corps as an aviation cadet, but quickly transferred to the U.S. Navy. He completed military flight training and was commissioned an Ensign, United States Navy, in December 1942.
During World War II, Scott Crossfield served as a fighter pilot, flight and gunnery instructor, flying the Chance Vought F4U Corsair and Grumman F6F Hellcat. Though he was assigned overseas, he did not serve in combat. After the war he joined the Naval Reserve and flew the Goodyear Aircraft Co. FG-1D Corsair at NAS Sand Point, Washington. During this time he resumed his education at the University of Washington and graduated with a bachelor’s degree in aeronautical engineering in 1949 and a master’s degree in 1950. As a graduate student he was the operator of the university’s wind tunnel.
In 1950 Scott Crossfield joined the National Advisory Committee for Aeronautics (NACA, the predecessor of NASA) as an Aeronautical Research Pilot at the NACA High Speed Flight Station, Edwards Air Force Base, California. He flew many high-performance jet aircraft like the North American Aviation F-100 Super Sabre, and experimental airplanes such as the Convair XF-92, Douglas X-3, Bell X-4 and X-5. He also flew the research rocketplanes, making 99 rocket flights in the Bell X-1, Douglas D-558-I Skystreak and D-558-II Skyrocket, more than any other pilot.
On 20 November 1953, Scott Crossfield became the first pilot to fly faster than twice the speed of sound (Mach 2). The D-558-II was carried aloft by a Boeing P2B-1S Superfortress drop ship (a four-engine B-29 heavy bomber which had been transferred from the U.S. Air Force to the Navy, then heavily modified by Douglas) to 32,000 feet (9,754 meters) and then released. Scotty fired the LR8 rocket engine and climbed to 72,000 feet (21,945 meters). He put the Skyrocket into a shallow dive and, still accelerating, passed Mach 2 at 62,000 feet (18,898 meters). After the rocket engine’s fuel was expended, he flew the rocketplane to a glide landing on Rogers Dry Lake.
In 1955 Crossfield left NACA and joined North American Aviation, Inc., as Chief Engineering Test Pilot. He planned and participated in the design and operation of the X-15 hypersonic research rocketplane for the Air Force and NASA. He also worked closely with the David Clark Co., in the development of the projects’ full-pressure suits.
Milton O. Thompson, another X-15 test pilot, wrote in At the Edge of Space, “. . . he was intimately involved in the design of the aircraft and contributed immensely to the success of the design, as a result of his extensive rocket airplane experience. . . Scott was responsible for a number of other excellent operational and safety features built into the aircraft. Thus, one might give Scott credit for much of the success of the flight program.”
In 1959–1960, Scott Crossfield flew all of the contractor’s demonstration phase flights in the X-15, including 16 captive carry flights under the wing of the NB-52A Stratofortress while systems were tested and evaluated, one glide flight, and thirteen powered flights. He reached a maximum speed of Mach 2.97 (1,960 miles per hour/3,154 kilometers per hour) on Flight 26 and a maximum altitude of 88,116 feet (26,858 meters) on Flight 6. The X-15 was then turned over to NASA and the Air Force. The X-15 Program involved a total of 199 flights from 1959 until 1968.
After leaving the X-15 Program, Scott Crossfield continued as a Systems Director with North American Aviation, Inc., working on the Apollo Command and Service Module and the S-IVB second stage of the Saturn V rocket. He left North American in the late ’60s and served as an executive with Eastern Air Lines and Hawker Siddeley. He also continued as a aeronautical engineering consultant to private industry and government.
Among many other awards, Scott Crossfield was received the Harmon International Trophy and the Collier Trophy.
In 1980 Crossfield resumed flying when he purchased a 1960 Cessna 210A Centurion, N6579X, serial number 21057579, a single-engine, four-place light airplane, powered by an air-cooled Continental six-cylinder engine. He had flown more than 2,000 hours in this airplane when it crashed during a severe thunderstorm, 19 April 2006, while on a flight from Prattville, Alabama to Manassas, Virginia.
Albert Scott Crossfield, jr., was killed. He is buried at Arlington National Cemetery.
Highly recommended: Always Another Dawn: The Story Of A Rocket Test Pilot, by Albert Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960.
17 September 1959: After previously making one glide flight, North American Aviation Chief Engineering Test Pilot Albert Scott Crossfield made the first powered flight of an X-15 hypersonic research rocket plane.
Carried aloft under the right wing of an eight-engine Boeing NB-52A Stratofortress bomber, USAF serial number 52-003, the first of three North American Aviation X-15s, 56-6670, was airdropped from 35,000 feet (10,668 meters) over Rosamond Dry Lake, 40 miles (64 kilometers) north of Edwards Air Force Base. Launch time was 08:08:48.0 a.m., Pacific Daylight Savings Time (15:08.48.0 UTC).
The X-15 was designed to use the Reaction Motors XLR-99 rocket engine, but early in the test program that engine was not yet available so two smaller XLR-11 engines were used. This was engine the same type used in the earlier Bell X-1 rocket plane that first broke the sound barrier in 1948. Though producing just one-fourth the thrust of the XLR-99, it allowed the functional testing of the X-15 to proceed.
Scott Crossfield wrote:
Two minutes after launch I reached 50,000 feet and pushed over in level flight. Then I dropped the nose slightly for a speed run, meanwhile maneuvering the ship through a series of turns and rolls, conscious of a deep rumbling noise of the rocket and a great rush of wind on the fuselage. It was obvious the black bird was in her element at supersonic speeds. She responded beautifully. I stared in fascination at the Mach meter which climbed from 1.5 Mach to 1.8 Mach and then effortlessly to my top speed for this flight of 2.3 Mach or about 1,500 miles and hour. Then, because I was under orders not to take the X-15 wide open, I shut off three of the rocket barrels. As I slowed down, I recalled the agony at Edwards many years before when we had worked for months pushing, calculating, polishing and who knows what else to achieve Mach 2 in the Skyrocket. Now with the X-15 we had reached that speed in three minutes on our first powered flight and I had to throttle back.
—Always Another Dawn, The Story Of A Rocket Test Pilot, by A. Scott Crossfield with Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960. Chapter 39 at Pages 362.
The X-15 dropped 2,000 feet (610 meters) while Scott Crossfield ignited the two XLR-11 engines and then started “going uphill.” During the 224.3 seconds burn duration, the X-15 reached Mach 2.11 (1,393 miles per hour, 2,242 kilometers per hour) and climbed to 52,300 feet (15,941 meters), both slightly higher than planned.
Problems developed when the rocket engine’s turbo pump case failed, and fire broke out in the hydrogen peroxide compartment, engine compartment and in the ventral fin. Crossfield safely landed on Rogers Dry Lake at Edwards Air Force Base. The duration of the flight was 9 minutes, 11.1 seconds. Damage to the rocket plane was extensive but was quickly repaired. 56-6670 flew again 17 October 1959.
Over the next nine years the three X-15s would make 199 flights, setting speed and altitude records nearly every time they flew, and expanding NASA’s understanding of flight in the hypersonic range. The first two X-15s, 56-6670 and 56-6671, survived the program. 670 is at the Smithsonian Institution National Air and Space museum and 671 is at the National Museum of the United States Air Force.
8 September 1954: Scott Crossfield, a NACA Aeronautical Research Pilot at the High Speed Flight Station, Edwards Air Force Base, California, took the North American Aviation F-100A-5-NA Super Sabre, 52-5778, on its first NACA test flight—and his first flight in an F-100.
Tests of the prototype and early production Super Sabres revealed directional stability problems, a very dangerous inertia coupling characteristic that could cause the aircraft to go violently out of control (and which would result in the death of North American’s chief test pilot, George Welch, in just another three weeks). The highly swept wings could stall at high angles of attack, causing the airplane to pitch up in the deadly “Sabre dance”. NACA wanted to explore the causes of these aerodynamic problems and design solutions.
During the flight there was an engine fire warning and Crossfield shut down the Pratt & Whitney J57-P-7 turbojet engine. The F-100A had no flaps and North American’s own test pilots did not think a “dead stick” landing was possible due the very high landing speed required.
Scott Crossfield tells the story in his autobiography:
. . . As a matter of fact, North American tests pilots were then flipping coins to see who would bring an F-100 in dead-stick to fulfill a requirement of the Air Force acceptance tests. I was not concerned. Dead-stick landings in low L-over-D[Lift-over-Drag]airplanes were my specialty. Every test pilot develops a strong point. I was certain that my talent lay in dead-stick landings.
With the engine idling and generating no energy to the plane’s systems, I was running out of hydraulic pressure to operate the controls. Following the handbook instructions, I pulled a lever which extended a miniature “windmill” into the slipstream. This “windmill” churned, building up pressure in the hydraulic lines. Unknown to me, there was a major leak in the line. The windmill was not helping, but hurting me. It was pumping hydraulic fluid overboard as fast as it could turn.
I called Edwards tower and declared an emergency. All airborne planes in the vicinity of the base were warned away from the lake area. I held the ailing F-100 on course, dropping swiftly, following the glide path that I used for the dead-stick Skyrocket.[Douglas D-558-II Skyrocket] I flared out and touched down smoothly. It was one of the best landings I have ever made, in fact. Seconds later, while the F-100 was rolling out, the remaining bit of hydraulic pressure in the control lines drained out and the controls froze.
I then proceeded to violate a cardinal rule of aviation: never try tricks with a compromised airplane. The F-100 was still rolling at a fast clip, coming up fast on the NACA ramp, when I made my poor decision. I had already achieved the exceptional, now I would end it with a flourish, a spectacular wind-up. I would snake the stricken F-100 right up the ramp and bring it to a stop immediately in front of the NACA hangar. This trick, which I had performed so often in the Skyrocket, was a fine touch. After the first successful dead-stick landing in an F-100, it would be fitting.
According to the F-100 handbook, the hydraulic brake system—a separate hydraulic system from the controls—was good for three “cycles,” engine out. This means three pumps on the brake, and that proved exactly right. The F-100 was moving at about fifteen miles an hour when I turned up the ramp. I hit the brakes once, twice, three times. The plane slowed, but not quite enough. I was still inching ahead ponderously, like a diesel locomotive. I hit the brakes a fourth time—and my foot went clear to the floorboards. The hydraulic fluid was exhausted. The F-100 rolled on, straight between the yawning hangar doors!
The good Lord was watching over me—partially anyhow. The NACA hangar was then crowded with expensive research tools—the Skyrocket, all the X-1 series, the X-3, X-4 and X-5. Yet somehow, my plane, refusing to halt, squeezed by them all and bored steadily on toward the side wall of the hangar.
The nose of the F-100 crunched through the corrugated aluminum, punching out an eight-inch steel I-beam. I was lucky. Had the nose bopped three feet to the left or right, the results could have been catastrophic. Hitting to the right, I would have set off the hangar fire-deluge system, flooding the hangar with 50,000 barrels of water and ruining all the expensive airplanes. Hitting to the left, I would have dislodged a 25-ton hangar-door counterweight, bringing it down on the F-100 cockpit, and doubtless ruining Crossfield.
Chuck Yeager never let me forget the incident. He drew many laughs at congregations of pilots by opening his talk: “Well, the sonic wall was mine. The hangar wall was Crossfield’s.” That’s the way it was at Edwards. Hero one minute, bum the next. That I was the first pilot to land an F-100 dead-stick successfully, and memorized elaborate and complete instrument data on the engine failure besides, was soon forgotten.
The F-100 is a tough bird. Within a month NACA’s plane was flying again, with Crossfield back at the helm. In the next few weeks I flew forty-five grueling flights in the airplane, pushing it to the limits, precisely defining the roll coupling. (On one flight the coupling was so severe that it cracked a vertebra in my neck.) These data confirmed, in actual flight, the need for a new F-100 tail, which North American was planning to install on later models of the airplane.
Every night after landing, I taxied the F-100 slowly to the NACA ramp. At the bottom, placed there on orders of Walt Williams, there was a large new sign, symbolic of the new atmosphere at Edwards. It said:
PLEASE COME TO A COMPLETE STOP BEFORE TAXIING UP RAMP
—Always Another Dawn, The Story Of A Rocket Test Pilot, by A. Scott Crossfield with Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960. Chapter 20 at Pages 196–199.
8 June 1959: At Edwards Air Force Base, California, North American Aviation’s Chief Engineering Test Pilot, A. Scott Crossfield, made the first flight of the X-15A hypersonic research rocketplane.
56-6670 was the first of three X-15s built for the U.S. Air Force and NASA. It was airdropped from a Boeing B-52 Stratofortress, NB-52A-1-BO 52-003, at 37,550 feet (11,445 meters) over Rosamond Dry Lake at 08:38:40 a.m, Pacific Time.
This was an unpowered glide flight to check the flying characteristics and aircraft systems, so there were no propellants or oxidizers aboard other than hydrogen peroxide which powered the pumps and generators.
The aircraft reached 0.79 Mach (522 miles per hour, 840 kilometers per hour) during the 4 minute, 56.6 second flight.
In his autobiography, Scott Crossfield described the first flight:
“Three” . . . “Two” . . . “One” . . .
Inside the streamlined pylon, a hydraulic ram disengaged the three heavy shackles from the upper fuselage of the X-15. They were so arranged that all released simultaneously, and if one failed they all failed. The impact of the release was clearly audible in the X-15 cockpit. I heard a loud “kerchunk.”
The X-15 hung in its familiar place beneath the pylon for a split second. Then the nose dipped sharply down and to the right more rapidly than I had anticipated. The B-52, so long my constant companion, was gone. The X-15 and I were alone in the air and flying 500 miles an hour. In less than five minutes I would be on the ground. . . .
There was much to do in the first hundred seconds of flight. First I had to get the “feel” of the airplane, to make certain it was trimmed out for landing just as any pilot trims an airplane after take-off or . . . when dwindling fuel shifts the center of gravity. Then I had to pull the nose up, with and without flaps, to feel out the stall characteristics, so that I would know how she might behave at touchdown speeds . . . My altimeter unwound dizzily: from 24,000 to 13,000 feet in less than forty seconds. . . .
The desert was coming up fast. At 600 feet altitude I flared out. . . .
In the next second without warning the nose of the X-15 pitched up sharply. It was a maneuver that had not been predicted by the computers, an uncharted area which the X-15 was designed to explore. I was frankly caught off guard. Quickly I applied corrective elevator control.
The nose went down sharply. But instead of leveling out, it tucked down. I applied reverse control. The nose came up but much too far. Now the nose was rising and falling like a skiff in a heavy sea. Although I was putting in maximum control I could not subdue the motions. The X-15 was porpoising wildly, sinking toward the desert at 200 miles an hour. I would have to land at the bottom of an oscillation, timed perfectly; otherwise, I knew, I would break the bird. I lowered the flaps and the gear. . . .
. . . With the next dip I had one last chance and flared again to ease the descent. At that moment the rear skids caught on the desert floor and the nose slammed over, cushioned by the nose wheel. The X-15 skidded 5,000 feet across the lake, throwing up an enormous rooster tail of dust. . . .
—Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960, Chapter 37 at Pages 338–342.
Before the drop, it was discovered that the aircraft’s Stability Augmentation System was inoperative in pitch mode. During the flight it was found that the hydraulic-assisted flight control system was responding too slowly to Crossfield’s inputs. Engineers analyzed the problem and increased the hydraulic system pressure. The problem never recurred.
Scott Crossfield was the most experienced rocketplane pilot with 82 rocketplane flights before the X-15 program. “. . . he was intimately involved in the design of the aircraft and contributed immensely to the success of the design.”
—At The Edge Of Space, by Milton O. Thompson, Smithsonian Institution Press, 1992, Introduction, at Page 3.
North American Aviation X-15A 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. It is in the collection of National Air and Space Museum at Washington, D.C.