INVALIDATION OF CERTIFICATE OF AIRWORTHINESS
Listed below are the four major reasons why a Certificate of Airworthiness could become invalid. There may be other specific reasons, but the majority will come under one or other of these categories.
1. If the aircraft or such of its equipment necessary for airworthiness is overhauled, repaired or modified in a manner not approved by the C.A.A.
2. If any part of the aircraft or equipment is removed or replaced in a manner or with material not approved.
3. Until completion of any inspection classified by the C.A.A. as mandatory.
4. Until completion of an inspection required by an approved maintenance schedule.
The inspections and modifications referred to above are those required for the purpose of ascertaining and ensuring that an aircraft remains airworthy.