FAA has issued airworthiness directive 2019-22-02 for all Boeing 747-200Bs, 747-200Cs, 747-200Fs, 747-300s, 747-400s, 747-400Ds, 747-400Fs, 747-8Fs and 747-8s, requiring, for the captain's and first officer's seats, repetitive horizontal actuator identifications, repetitive checks of the horizontal movement system, a detailed inspection of this system for certain airplanes, and applicable on-condition actions, and inspection to determine the part number and, if applicable, the serial number of the captain's and first officer's seats, and applicable on-condition actions, effective January 16, 2020.