An inspection of a Minnesota National Guard helicopter failed to detect that a part was not installed properly, leading to the Dec. 5, 2019, UH-60L Black Hawk crash that killed three crew members outside of St. Cloud.

The Minnesota National Guard on Wednesday, Aug. 5, released a summary of a military investigation board into the accident, according to a news release from the Minnesota National Guard.

The accident occurred during a routine maintenance flight.

Chief Warrant Officer 2 Charles P. Nord, 30, of Detroit Lakes; Chief Warrant Officer 2 James A. Rogers Jr., 28, of Madelia, and Sgt. Kort M. Plantenberg, 28 of St. Cloud were killed in the crash.

The investigation found that on Dec. 5, 2019, a crew of three Minnesota National Guard members a maintenance test pilot, a pilot and an aircraft mechanic conducted a maintenance test flight to verify the proper installation of the aircraft’s hydromechanical unit, according to the release. The crew was conducting a maximum power check on the No. 1 engine in an area southwest of the St. Cloud Regional Airport. The No. 1 engine failed during the check and the No. 2 engine was in the idle setting, causing a condition where both engines were out. The crew was not able to recover and the helicopter crashed into the ground at high speed.

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The UH-60 Black Hawk helicopter lost contact with the Guard shortly after its 2 p.m. takeoff from the Army Aviation Support Facility at the St. Cloud airport. It crashed southwest of the city, near Marty, Minn., approximately 15 minutes later, according to a previous report from the Stearns County Sheriff's Office.

According to the release, the investigation identified several factors that contributed to the accident:

  • The No. 1 engine failed due to an incorrect installation of the hydromechanical unit, or HMU.
  • The inspection of the HMU installation was not completed in accordance with the published installation procedure.
  • The maintenance test pilot failed to respond to a critical situation during a maintenance maneuver.
  • The pilot on the controls failed to use autorotation for its descent and landing.
  • Leaders did not adequately assess the technical inspector’s ability to perform his duties while pending administrative actions
  • In accordance with Army regulation and the Minnesota Army Aviation Standard Operating Procedures, the aircraft mechanic should not have been on the flight because he did not have a valid purpose for being on the flight

According to the release, the investigation recommends the Minnesota National Guard take these actions to prevent an accident like this from happening again:

  • Consider administrative action for the mechanic who installed the HMU.
  • Consider administrative action for the inspector who inspected the maintenance work. (As of January 2020, the inspector is no longer employed with the Minnesota National Guard).
  • Additional training for maintenance test pilots regarding the conduct of maintenance test flights.
  • Additional training for all Minnesota National Guard pilots in responding to emergency procedures.
  • Review of the written and unwritten policies regarding maintenance test flights.

The Minnesota National Guard’s investigation is in addition to a safety investigation conducted by the U.S. Army Combat Readiness Center at Fort Rucker, according to the release. The safety investigation results provide recommendations to prevent future accidents and are not releasable to the public. The aviation community uses the results of safety investigations for safety and accident prevention purposes.