The FAA UAS Integration Office issued an email to the industry outlining the requirement for all commercial UAS to bear an aircraft registration number when applying for a COA:
UAS, other than those owned by the Armed Forces, intended to operate under a new COA must be registered and marked prior to COA application. The aircraft registration number (N-number) must be entered into the “Aircraft Registration” field, of the System Description section in COA on-line.
Additionally, UAS, other than those owned by the Armed Forces, currently operating under an existing COA must be registered and marked within 90 days of the date of this email. COA holders will confirm their aircraft have been registered by entering the registration number, (N-number) in the Monthly Operational Report, in the block labeled, “Describe any other Operational / Coordination Issued”. Failure to comply with the registration requirements within the prescribed timeframe may result in a suspension of the COA.
UAS must be marked with their U.S. nationality and registration marks (N-Number) in accordance with 14 CFR Part 45. The marks must be painted on the aircraft or affixed by any other means ensuring a similar degree of permanence (§45.21(c) (1), General).
Most full scale UAS are able to comply with the marking requirements, including size and location of the N-Number on the aircraft. Sub-scale or small UAS, or UAS of an un-conventional shape such as a multi-rotor (quad-copter, octo-copter, etc.) or ducted fan may not be able to comply with Part 45 or the guidance in AC 45-2D because of size or space limitations on the aircraft. In these cases, 14 CFR, §45.22(d) allows the UAS owner or operator to propose an alternative marking procedure to the FAA. Alternate marking approvals may be issued to public aircraft by FAA UAS Integration Office (AFS-80). If alternative markings were required, a copy of the Alternative Marking approval letter should be attached to application in the “Aircraft Registration” field.
Complete details for registering your UAS and reserving an N-number are provided online at www.faa.gov.