On April 22, 2019, a Northrop N-9MB aircraft crashed in Norco, California, United States, killing the pilot.

[3] The pilot had been performing a test flight at low altitude following the completion of the aircraft's annual inspection.

[1]: 1 Ground witnesses—including at least one qualified pilot—saw the aircraft flying straight and level at what sounded like a normal cruise power setting when it pitched up into a climb, banked to the left, and then "abruptly" rolled to the right.

[1]: 3 Radar data obtained by the National Transportation Safety Board (NTSB) did not reveal the aircraft's altitude when it departed from level flight.

[3] The aircraft crashed in an outpatient housing yard of the prison complex, and had touched down right wingtip first, as evidenced by a ground scar consistent with the green plastic right wing navigation light lens.

[1]: 8–9 Post-crash toxicological testing found traces of ethanol and pseudoephedrine or ephedrine in the pilot's body, but the NTSB concluded that the concentrations were too small to be a contributing factor, and ruled out alcohol intoxication.