Rules of the Air Article 39
Wherever time is utilized in the application of data link communications, it shall be accurate to within 1 second of UTC.
中文原文 飛航規則第39條
於資料鏈結通信中應用時間時，應準確至世界協調時間一秒鐘內。
English translation for reference only; the Chinese text prevails. Not legal advice.