Regulations of Aircraft Registration Article 8-1

An aircraft shall carry an identification plate inscribed with its nationality or common mark and registration mark, and secured to the aircraft in a prominent position near the main entrance. If an aircraft does not possess the main entrance structure, the identification plate shall be affixed to the prominent position of the aircraft exterior.The identification plate shall be made of fireproof metal or other fireproof material of suitable physical properties.
中文原文 航空器登記規則第8-1條
航空器應備有標示航空器國籍或共用標誌及登記號碼之識別牌,並固定於主艙門附近顯著之處。
無主艙門結構之航空器,應固定於航空器外部顯著之處。
前項規定之識別牌應以防火金屬或其他防火材料製成。

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