In April 1943, Max Constant was hired by Northrop to fly the N-9M-1. Constant had worked for years as a flight instructor at Burbank Airport. Born in Bordeaux, France, in 1899 he had been a writer and director in the Hollywood movie industry until he turned to aviation. Active on the air show circuit, Constant also participated in Bendix Trophy air races in the 1930s.

On 19 May 1943, Constant took off from Muroc Army Airfield in the N-9M-1 to conduct aft center-of-gravity stability and control tests, including stalls. During a test maneuver the N-9M-1 apparently entered a right-hand, 60-degree nose-down spin. Constant attempted to recover by deploying the left-hand spin chute and lowering the flaps.

Realizing that he could not recover from the spin, Constant set the propeller brakes and released the canopy. He unfastened his safety harness, but never left the cockpit. Whether he was prevented from bailing out by lack of time or by some unknown physical circumstance was never determined. Post-accident investigation suggested that aerodynamic forces might have developed full-aft pressure on the control column, exceeding Constant's strength and trapping him in the cockpit.

The N-9M-1, with just 22.5 hours of accumulated flight time, was a complete loss. Its shattered remains were found in a gully some 12 miles west of Muroc.