Height of nationality and registration marks

BACKGROUND

Title 14 CFR part 45, Identification and Registration Marking, covers the identification of aircraft, engines, propellers, and certain replacement and modification parts, as well as the nationality and registration marking required on U.S.-registered aircraft. The nationality and registration marks are commonly called the N-number on U.S.-registered aircraft. Their size can vary with the year the aircraft was built and with whether or not the aircraft has been repainted, but the most common size is at least 12 inches in height. Small aircraft built at least 30 years ago, replicas of these, and experimental exhibition or amateur-built aircraft may use letters at least 2 inches in height, and only a few aircraft are authorized to display markings of at least 3 inches. This marking regulation applies to both original and recurrent airworthiness, so the marks must remain correct throughout the life of the aircraft and not only when it is first certificated.

STUDY TIP

Learn the three marking heights together with the narrow categories that earn the smaller sizes, because the exceptions are what the exam tests. Remember that the size depends on the year the aircraft was built and on whether it has been repainted.

KEY POINTS

• The most common required height for nationality and registration marks is at least 12 inches.
• Letters at least 2 inches high are limited to small aircraft built at least 30 years ago, replicas, and experimental exhibition or amateur-built aircraft.
• Only a few aircraft are authorized to display markings of at least 3 inches.

SOURCES

• FAA-H-8083-30B ch02 "14 CFR Part 45—Identification and Registration Marking"