Regulations Governing Aircraft Radio Stations Article 13

Prior to the implementation of the Act, those that have obtained a radio station license in accordance with the Administrative Regulations on Civil Aircraft Radio Stations authorized by the Telecommunications Law, and need to continue operating the radio station after the expiration of the radio station licenses, shall apply for license renewal in accordance with Article 5 or 7 within two months from three months prior to the expiration of the existing license.
中文原文 航空器無線電臺管理辦法第13條
本法施行前依電信法授權訂定之民用航空器無線電臺管理辦法取得電臺執照,且於電臺執照之有效期限屆滿後仍需繼續使用電臺者,應於電臺執照屆期前三個月起二個月內,依第五條或第七條規定申請換發電臺執照。

English translation for reference only; the Chinese text prevails. Not legal advice.