CheckAero compiles data from public government files to help aircraft owners and ham radio operators track their registrations. This glossary defines the abbreviations and regulatory terms you will meet in these records.
Agencies and rules
FAA
Federal Aviation Administration, the US government agency for civil aviation. Aircraft registration records and Type Certificate Data Sheets come from the FAA.
FCC
Federal Communications Commission. The FCC regulates radio communications, including amateur radio licenses. FCC records appear on ham radio license pages.
CFR
Code of Federal Regulations, the codification of the rules issued by federal agencies. Aviation rules are in 14 CFR; telecommunications rules, including amateur radio, are in 47 CFR.
Aircraft registration
N-number
Also called the tail number or registration number: the US aircraft registration mark. It is the letter N followed by one to five characters; the first is a digit 1-9, up to two letters may come at the end, and the letters I and O are not used. Every aircraft record is found by its N-number.
AC Form 8050-1
Aircraft Registration Application, used to apply for a registration.
AC Form 8050-1B
Aircraft Registration Renewal Application, used to renew an existing registration in the six months before it expires. See the renewal guide.
LLC
Limited liability company. If the registrant is an LLC, a corporation or a government body, the owner name is shown on the aircraft record page; names of individual owners are not.
Grace period
A period after an expiration date during which renewal is still possible. An aircraft registration has no grace period. An amateur radio license has a two-year grace period, during which the station may not transmit until it is renewed.
Aircraft certification and tracking
Mode S code
A unique 24-bit code assigned to every US-registered aircraft for its Mode S transponder. CheckAero shows it in hexadecimal (6 characters, for example A12239) and octal, and you can search by the hex code.
TCDS
Type Certificate Data Sheet, the FAA document that lists the approved models, engines, limits and serial numbers covered by a type certificate. It is linked on model pages and aircraft records.
TC holder
The company that holds the type certificate for an aircraft model.
DRS
FAA Dynamic Regulatory System, where the FAA publishes TCDS and other documents. CheckAero links to the TCDS documents there.
FSDO
Flight Standards District Office, the local FAA office for airmen certification (pilots, mechanics), airworthiness certificates, special flight permits, accident reporting, low-flying aircraft complaints and illegal charter reports. See the FSDO directory.
Ham radio licensing
ULS
FCC Universal Licensing System, the system used to file amateur radio license applications and renewals. Its public access files are the source of the ham radio records on CheckAero.
FRN
FCC Registration Number. It is needed to file in the ULS.
Operator class
The license class of an amateur radio operator. Active licenses show Technician, General or Amateur Extra; older classes still seen on some licenses are Novice, Advanced and Technician Plus. The class is shown on the ham radio record page.