Information and guidance associated with the Approval of Modifications and Repairs for CAA Regulated Aircraft
Approval must be sought when performing a modification or repair on a CAA regulated aircraft or importing a CAA regulated aircraft fitted with modifications.
Failure to do so will invalidate the Certificate of Airworthiness or Permit to Fly.
The length and cost of the approval investigation is determined by the complexity of the modification and how accurate and comprehensive the information submitted by the applicant is.
Applying for the Approval of a Minor Modification
Applications for the approval of minor modifications to non-EASA aircraft, together with the appropriate fee, should be directed to the CAA Applications and Approvals, Floor 2E , Aviation House, Gatwick, RH6 0YR.
Details of charges can be found in the CAA Scheme of Charges - Airworthiness, Noise Certification and Aircraft and Aircraft Engine Emissions.
Approval may be limited to a specific aircraft or it may be applicable to a range or type/series of aircraft. Any associated conditions or limitations will be stated on the approval.
The CAA has provided the following documents to assist applicants when preparing applications for Minor Changes to:
Application should be accompanied by an initial payment equal to the cost of three hours investigation. If the investigation time exceeds three hours, the additional costs will be invoiced to the applicant.
Details of the hourly rates are listed in the CAA Scheme of Charges - Airworthiness, Noise Certification and Aircraft and Aircraft Engine Emissions.
Where the investigation specifies that a CAA Supplemental Type Certificate (STC) is required, approval will be granted largely upon the basis of the STC Definition Document submitted by the applicant.
CAP 562 - "Civil Aircraft Airworthiness Information and Procedures" section 11-44 provides further details.
The CAA may request any further information or ask to conduct any inspection required in order to be satisfied with respect to compliance. Once satisfied that compliance has been demonstrated to the CAA, the STC will be issued.
Where the application does not state that a CAA STC is required, the major modification approval procedures will be based upon Airworthiness Approval Notes (AANs).
An AAN will be produced detailing the modifications and the requirements with which they must comply.
The AAN will record the evidence supplied by the applicant to demonstrate that the modifications comply with the set requirements.
Once completed and signed, the AAN is the statement of approval by the CAA.
Records are kept of all AANs. Most can be viewed using the CAA AAN Database.
The procedures for the approval of repairs are essentially the same as those for modifications.