X-15 Flight 3-65-97

Flight 191
	Crash site
Mission type	Test flight
Mission duration	10 minutes, 35 seconds
Apogee	81 kilometres (266,000 ft)
Spacecraft properties
Spacecraft	X-15 56-6672
Crew
Crew size	1
Members	Michael J. Adams
Start of mission
Launch date	15 November 1967, 18:30:07 UTC
Launch site	Balls 8, Edwards; Dropped over Delamar Dry Lake
End of mission
Destroyed	15 November 1967, 18:40:42 UTC; Broke up over Randsburg, California; 35°25′10.68″N 117°36′2.00″W / 35.4196333°N 117.6005556°W

X-15 Flight 3-65-97, also known as X-15 Flight 191 (being the 191st free flight of the X-15), was a sub-orbital spaceflight of the North American X-15 experimental spaceplane, carrying seven experiments to a peak altitude of 266,000 feet (50.4 mi; 81 km; 43.8 nmi), above NASA's definition of the start of space at 50 miles (80 km) but below the Kármán line definition at 62 miles (100 km). The flight, on November 15, 1967, ended when the aircraft broke apart minutes after launch due to technical difficulties, killing the pilot Michael J. Adams and destroying the aircraft.

Mission overview[edit]

Adams's seventh X-15 flight took place on November 15, 1967, in the number three aircraft. At 10:30 in the morning on November 15, the X-15-3 was released from the wing of NB-52B mothership at 14,000 m (45,000 ft) over Delamar Dry Lake.^[1]

Experiments and tests on this flight to 266,000 feet were:^[2]

Boost guidance experiment
Solar spectrum measurement
Ultraviolet plume detection
Micrometeorites collection
Wingtip pod deflection photography
Test of Saturn V booster insulation on X-15 reentry
Test of traversing probe in a wingtip experiment pod

While in powered flight, an electrical disturbance distracted Adams and slightly degraded the control of the aircraft; having adequate backup controls, Adams continued. At 10:33 he reached a peak altitude of 81,000 m (266,000 ft). In the NASA 1 control room, mission controller Pete Knight monitored the mission with a team of engineers.

As the X-15 climbed, Adams began a planned wing-rocking (rolling) maneuver so an on-board camera could scan the horizon. At the conclusion of the wing-rocking portion of the climb, the X-15 had begun a slow drift in heading; 40 seconds later, when the aircraft had reached its maximum altitude, it was off heading by 15 degrees to the left. As Adams came over the top, the drift briefly halted as the aircraft's nose yawed 15 degrees back to the correct attitude. Then the drift to the left began again; within 30 seconds, Adams's descending flight path was at right angles to the attitude of the aircraft. At 70,000 m (230,000 ft), while descending into the rapidly increasing density of the atmosphere, the X-15 entered a Mach 5 (5,300 km/h) spin.

In the NASA 1 control room, there was no way to monitor the heading of the aircraft, so the situation was unknown to the engineers monitoring the flight. Normal conversation continued between Knight and Adams, with Knight advising Adams that he was "a little bit high", but in "real good shape". Adams radioed that the aircraft "[seemed] squirrelly", and moments later repeatedly told Knight that he had entered a spin. The ground controllers sought to get the X-15 straightened out, but there was no recommended spin recovery technique for the X-15, and engineers knew nothing about the aircraft's supersonic spin tendencies. The chase pilots, realizing that the X-15 would never make Rogers Dry Lake, headed for the emergency lakes, Ballarat and Cuddeback, in case Adams attempted an emergency landing.

Adams held the X-15's controls against the spin, using both the flight controls and the reaction control jets in the nose and wings. He managed to recover from the spin at 36,000 m (118,000 ft) and went into an inverted Mach 4.7 (5,300 km/h)^[3] dive at an angle between 40 and 45 degrees. In theory, Adams was in a good position to roll upright, pull out of the dive and set up a landing. However, due to high gain in the adaptive control system, the X-15 went into limit-cycle oscillations with rapid pitching motion of increasing severity, still in a dive at 49,000 m (160,000 ft) per minute. As the X-15 neared 20,000 m (65,000 ft), it was diving at Mach 3.93 (4,200 km/h; 2,600 mph) and experiencing more than 15 g₀ (150 m/s²) vertically, and 8 g₀ (78 m/s²) laterally.

The aircraft broke up northeast of the small Californian settlement of Johannesburg 10 minutes and 35 seconds after launch. An Air Force pilot, who was filling in for another chase pilot, spotted the main wreckage northwest of Cuddeback Lake. The aircraft was destroyed, and Adams died.^[4]

Investigation[edit]

NASA and the Air Force convened an accident board. Chaired by NASA's Donald R. Bellman, the board took two months to prepare its report. Ground parties scoured the countryside looking for wreckage, specifically the film from the cockpit camera. The weekend after the accident, an unofficial NASA Flight Research Center (FRC) search party found the camera, but could not find the film cartridge. FRC engineer Victor W. Horton organized a search and on November 29, during the first pass over the area, Willard E. Dives found the cassette.

The accident board found that the cockpit instrumentation had been functioning properly, and concluded that Adams had lost control of the X-15 as a result of a combination of distraction, misinterpretation of his instrumentation display, and possible vertigo.^[3] The electrical disturbance early in the flight degraded the overall effectiveness of the aircraft's control system and further added to pilot workload.

The board made two major recommendations: install a telemetered heading indicator in the control room, visible to the flight controller; and medically screen X-15 pilot candidates for labyrinth (vertigo) sensitivity. As a result of the X-15's crash, the FRC added a ground-based "8 ball" attitude indicator in the control room to furnish mission controllers with real time pitch, roll, yaw, heading, angle of attack, and side-slip information.

Memorials[edit]

Adams was awarded astronaut wings posthumously.^[1] His name appears on the Space Mirror Memorial.^[5]

References[edit]

This article incorporates public domain material from X-15 - Biography: Michael Adams. National Aeronautics and Space Administration.

Citations[edit]

^ ^a ^b Thompson 1992, p. 352.
^ Thompson 1992, p. 252.
^ ^a ^b Thompson 1992, p. 263.
^ Thompson 1992, p. 252–264.
^ "Who We Honor". Astronauts Memorial Foundation. Michael J. Adams. Retrieved 2023-04-03.

Bibliography[edit]

Dennehy, Cornelius J; Orr, Jeb S; Barshi, Immanuel; Statler, Irving C (October 2014). A Comprehensive Analysis of the X-15 Flight 3-65 Accident (PDF). Langley Research Center. Hampton, Virginia: NASA. NASA/TM-2014-218538.
Godwin, Robert, ed. (2000). X-15: The NASA Mission Reports. Apogee Books. ISBN 9781896522654. OCLC 829406542. with accompanying CD
Jenkins, Dennis R (June 2000). Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane (PDF). Monographs in Aerospace History No. 18. NASA. SP-2000-4518.
Stillwell, Wendell H (1965). X-15 Research Results with a Selected Bibliography (PDF). Scientific and Technical Information Division. Washington, D.C: NASA. SP-60.
Thompson, Milton O. (1992). At the Edge of Space: The X-15 Flight Program. Washington: Smithsonian Institution Press. ISBN 1-56098-107-5. OCLC 24010699.

External links[edit]

[FOOTNOTEThompson1992352-1] Thompson 1992, p. 352.

[FOOTNOTEThompson1992252-2] Thompson 1992, p. 252.

[FOOTNOTEThompson1992263-3] Thompson 1992, p. 263.

[FOOTNOTEThompson1992252–264-4] Thompson 1992, p. 252–264.

[5] "Who We Honor". Astronauts Memorial Foundation. Michael J. Adams. Retrieved 2023-04-03.

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v t e North American X-15
Operators	NASA United States Air Force
Manufacturer	North American Aviation
Pilots	Michael Adams Neil Armstrong Scott Crossfield William Dana Joe Engle William Knight John McKay Forrest Petersen Robert Rushworth Milton Thompson Joseph Walker Robert White
Flights	List of X-15 flights Flight 35 (first flight into the mesosphere, Walker) Flight 62 (first spaceflight, White) Flight 87 (spaceflight, Rushworth) Flight 90 (spaceflight, Walker) Flight 91 (spaceflight, program altitude record, Walker) Flight 188 (program speed record, Knight) Flight 191 (spaceflight, fatality, Adams)
Related	Bell X-1 Boeing B-52 Stratofortress (Balls 8) Hypersonic speed List of X-planes Sub-orbital spaceflight

v t e Aviation accidents and incidents in the United States and U.S. territories in the 1960s
1960	National Airlines Flight 2511 Capital Airlines Flight 20 Northwest Orient Airlines Flight 710 Chicago Helicopter Airways Flight 698 World Airways Flight 830 Eastern Air Lines Flight 375 Cal Poly football team New York mid-air collision
1961	Goldsboro B-52 American Airlines Flight 1502 Yuba City B-52 United Air Lines Flight 859 Alaska Airlines Flight 779 TWA Flight 529 Northwest Orient Airlines Flight 706 Imperial Airlines Flight 201/8 Cincinnati Zantop DC-4
1962	American Airlines Flight 1 Continental Airlines Flight 11 Canadian Pacific Air Lines Flight 301 United Air Lines Flight 297 Eastern Air Lines Flight 512
1963	Elephant Mountain B-52 Northwest Orient Airlines Flight 705 Camden PA-24 Northwest Orient Airlines Flight 293 Mohawk Airlines Flight 112 Pan Am Flight 214
1964	Savage Mountain B-52 Eastern Air Lines Flight 304 Paradise Airlines Flight 901A Pacific Air Lines Flight 773 United Air Lines Flight 823 Bonanza Air Lines Flight 114 Flying Tiger Line Flight 282
1965	USAF KC-135 Wichita Eastern Air Lines Flight 663 Pan Am Flight 843 Continental Airlines Flight 12 Allegheny Airlines Flight 604 United Air Lines Flight 389 American Airlines Flight 383 United Air Lines Flight 227 Carmel mid-air (Eastern 853, TWA 42)
1966	NASA T-38 American Flyers Airline Flight 280/D Braniff International Airways Flight 250 West Coast Airlines Flight 956
1967	Lake Central Airlines Flight 527 TWA Flight 553 West Coast Airlines Flight 720 Delta Air Lines Flight 9877 Mohawk Airlines Flight 40 Piedmont Airlines Flight 22 Lake Erie skydiving disaster TWA Flight 159 X-15 Flight 3-65-97 TWA Flight 128
1968	Ozark Air Lines Flight 965 Braniff International Airways Flight 352 Los Angeles Airways Flight 841 Los Angeles Airways Flight 417 Northeast Airlines Flight 946 Japan Air Lines Flight 2 Pan Am Flight 281 Wien Consolidated Airlines Flight 55 Allegheny Airlines Flight 736 Pan Am Flight 799 North Central Airlines Flight 458 Ozark Air Lines Flight 982
1969	Allegheny Airlines Flight 737 Scandinavian Airlines System Flight 933 United Air Lines Flight 266 Hawthorne Nevada Airlines Flight 708 Prinair Flight 277 Delta Air Lines Flight 821 TWA Flight 5787 Newton Cessna 172 crash Allegheny Airlines Flight 853 Mohawk Airlines Flight 411
This list is incomplete.