X-15 Flight 191 - All About All

X-15 Flight 191

Crew

• Michael J. Adams

Mission Parameters

• Mass: unknown kg fueled; unknown kg burnout
• Maximum Altitude: 266,000 feet (50.38 miles)
• Range: unknown
• Burn Time: 83.2 seconds
• Mach: 5.20
• Launch Vehicle: NB-52B Bomber #008

Mission Highlights

Adams' seventh X-15 flight took place on 15 November 1967 in the number three aircraft. The X-15-3 would also make the most tragic flight of the program. At 10:30 in the morning on 15 November, the X-15-3 dropped away from underneath the wing of an NB-52B at 45,000 feet over Delamar Dry Lake.

While in powered flight, an electrical disturbance distracted Adams and slightly degraded the control of the aircraft; having adequate backup controls, Adams continued on. At 10:33 he reached a peak altitude of 266,000 feet. 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. As Adams came over the top, the drift briefly halted, with the airplane yawed 15 degrees to the right. Then the drift began again; within 30 seconds, Adams was descending at right angles to the flight path. At 230,000 feet, encountering rapidly changing air pressure, the X-15 entered a Mach 5 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 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 controls. He managed to recover from the spin at 118,000 feet and went into an inverted Mach 4.7 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 technical problems with the aircraft, the X-15 began a rapid pitching motion of increasing severity, still in a dive at 160,000 feet per minute. As the X-15 neared 65,000 feet, it was diving at Mach 3.93 and experiencing more than 15-g vertically, and 8-g laterally.

The aircraft broke up northeast of the town 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 was killed.

Reference

• X-15 The NASA Mission Reports - by Robert Godwin - ISBN 1896522-65-3

NASA reports (PDF format)

• Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000068530_2000075022.pdf)
• X-15 research results with a selected bibliography (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650010561_1965010561.pdf)

External Links

• The Crash Site of the X-15A-3 (http://www.check-six.com/Crash_Sites/X-15A_crash_site.htm)