The German Federal Bureau of Aircraft Accident Investigation (BFU) notified the NTSB of an incident involving a Boeing 747-422, registration N121UA, which took place on July 18, 2017, in Frankfurt, Germany.
Under the provisions of ICAO Annex 13, the NTSB appointed a U.S. Accredited Representative to support the investigation led by the BFU, acting as the State of Manufacturer and Design.