Registration & Maintenance
Registration Letters
Every aircraft must have a registration letter showing the state it is registered in (EI for Ireland followed by a hyphen and the registration mark of three capital letters). The nationality and registration marks are to be inscribed on fireproof material prominently near the main entrance and painted or affixed to the aircraft. The precise requirements with respect to the external display of the registration mark and nationality depend on the type of aircraft.
Registered in Ireland
Aircraft may be registered in Ireland if they are owned by
- an Irish or EU citizen, with a place of business or residence in the State
- a company registered in and having a business in Ireland, whose principal place of business is in Ireland or the EU State, with at least a two thirds majority of the Board comprising EU citizens; or
- such as an individual or a company who acquired the aircraft under hire purchase.
A non-Irish citizen who resides in Ireland and operates/ trades in Ireland or a company falling outside the above criteria may register an aircraft, but not for use in aerial work or public transport and subject to such additional conditions as may be imposed.
The IAA may impose conditions of registration.
Certificates
A certificate of registration is given. It shows particulars of the registration marks, serial numbers, names and addresses of legal owners or hirers under the hire purchase agreement. The certificate is not transferable. If required by the Authority, it must be surrendered within a reasonable time. A duplicate may be issued if the original is lost or destroyed.
The following requirements apply to Irish-registered aircraft. It applies to other aircraft insofar as it is not inconsistent with the relevant airworthiness rules of the home state when they are in or over the State.
The Certificate of type approval proves the airworthiness of the particular type of aircraft. The Authority may recognise the approval of another Convention State. It may require air and ground tests necessary in order to prove the airworthiness of the design and craft. The Authority may require a certificate of approval before issuing or granting a renewal of the certificate of airworthiness.
Airworthiness & Compliance Cert
The Certificate of airworthiness will specify the category of approval in respect of the aircraft concerned. It may be approved for public transport and private or aerial work.
An aircraft must not be flown unless it has a current certificate of airworthiness or flight permit. There are exceptions in respect of experimental flights. They are themselves subject to conditions requiring certification of the aircraft and engine as fit for flight, no passengers or cargo carried, and no flying over built-up areas.
Before an issue of a certificate of airworthiness, an aircraft must be weighed by a  duly authorised person and its centre of gravity must be determined. This is used to create the weight schedule for the aircraft.
The weight schedule is to include weight when empty plus unusable fuels and other equipment listed in the weight schedule. The centre of gravity of the aircraft is to be set out.
A certificate of compliance must be produced when any repair, maintenance, modification or inspection is undertaken on an aircraft component. It may be issued by a person who is approved by the Irish Aviation Authority for such purposes.
It must be retained for two years from issue for private aircraft. In the case of public transport aircraft, it must be retained for so long as the logbook is required to be maintained for that component.
Maintenance Requirements
An aircraft registered in Ireland may not fly unless it has been maintained by an authorised engineer in accordance with an approved schedule in the case of aerial or public transport aircraft and in an approved manner in the case of private aircraft.
Irish public transport and registered aerial aircraft must maintain a technical log. It must be completed by the pilot in command after each flight. It is to contain details of takeoff and landing times, details of any defects and state that there have been no defects.
Details listed must be signed off on by an engineer prior to the next flight. The log must be maintained for at least 12 months following the last entry by the operator.
Operators of aerial public and private transport aircraft must maintain records for major aircraft components, total time in service, period since overhaul and period of last inspection. They are to be maintained for up to two years after the life of the component.
Maintenance
Irish registered aircraft must keep and maintain a flight manual. This contains all limitation conditions by the Aviation Authority. It should furnish sufficient information for the crew to enable the aircraft to operate safely.
Where a public transport aircraft suffers a defect which affects safety, it must land at the first available opportunity to do so safely. It must not fly until the defect is remedied and a certificate of compliance is issued in respect of the matter. Where a two-engine loses power, the pilot may land at a more convenient aerodrome at the earliest opportunity. The report must be submitted to the operator, which must submit it to the IAA with comments within 14 days.
Passengers may not be carried on maintenance test flights unless they are partaking in the test and their presence is authorised by the operator and pilot in command. Smoking is prohibited on-board aircraft if the certificate of airworthiness or the flight manual so provides or when smoking may endanger the aircraft.  Steps must be taken to inform passengers that smoking is prohibited.