NASA Test Flight Ends in Ejection Following Frozen Pitot Tube (1995)

On January 19, 1995, the first X-31 Enhanced Fighter Maneuverability Demonstrator was lost during a test flight near Edwards Air Force Base in California. German research pilot Karl-Heinz Lang ejected safely before the aircraft crashed in the desert.

The X-31 was an experimental aircraft developed to investigate advanced maneuverability, including flight at high angles of attack and the use of thrust-vectoring technology. NASA states that only two X-31 aircraft were built and that the first aircraft was lost in the January 19, 1995 accident.

During the flight, ice accumulated in the nose-mounted data probe. NASA's account explains that the probe was not heated and that the ice reduced the internal diameter of the probe. This produced incorrect data for the aircraft's flight computers.

The incorrect data eventually contributed to an uncontrollable aircraft. Lang ejected before the X-31 struck the ground. NASA records that he survived the ejection, while the aircraft was destroyed in the crash.

The loss was especially significant because the X-31 was a research program intended to demonstrate advanced control concepts. The accident exposed how a relatively small measurement-system problem could undermine the flight-control information required by a highly maneuverable experimental aircraft.

NASA's historical account states that the second X-31 survived and remains preserved in Germany. The January 19 accident therefore ended the first aircraft's test career but did not end the technological legacy of the X-31 program.

Accident Facts

Recorded line: “The skies above Edwards Air Force Base in California were clear.”

Sources

NASA, “X-31 Enhanced Fighter Maneuverability Demonstrator.”

Center for Land Use Interpretation, X-31 January 19, 1995 historical accident record.

the associated record: “NASA Test Flight Ends in Ejection Following Frozen Pitot Tube (1995).”

https://www.youtube.com/watch?v=w9yipoXPzbg