US-FAA14 CFR 121.603
Facilities and services: Supplemental operations
Read the official ruleOfficial FAA regulation text (public domain)
(a) Before beginning a flight, each pilot in command shall obtain all available current reports or information on airport conditions and irregularities of navigation facilities that may affect the safety of the flight. (b) During a flight, the pilot in command shall obtain any additional available information of meteorological conditions and irregularities of facilities and services that may affect the safety of the flight.
Verbatim text of a US Federal Aviation Regulation (public domain), reproduced for reference — not legal advice and not for navigation. A plain-English explainer may be added later; always rely on the current official rule linked above.