AMC1 145.A.45(d) Maintenance data

CAA ORS9 Decision No. 38

The referenced procedure should address the need for a practical demonstration by the maintenance personnel proposing the change to the compliance monitoring personnel, of the modified maintenance instruction. Depending on the nature of the maintenance instruction modification, a risk assessment may be required to demonstrate that an equivalent or improved maintenance standard is reached. When satisfied, the compliance monitoring personnel should approve the modified maintenance instruction, and ensure that the author of the maintenance instruction i.e., the originating design organisation is informed of the modified maintenance instruction. The procedure should include a paper/electronic traceability of the complete process from start to finish, and ensure that the relevant maintenance instruction clearly identifies the modification. Modified maintenance instructions should only be used in the following circumstances:

1. Where the original intent of the maintenance instruction can be carried out in a more practical or more efficient manner.

2. Where the original intent of the maintenance instruction cannot be achieved by when following the maintenance instructions. For example, where a component cannot be replaced following the original maintenance instructions.

3. For the use of alternative tools / equipment.

Important Note: Critical Design Configuration Control Limitations (CDCCL) are airworthiness limitations. Any modification of the maintenance instructions linked to CDCCL constitutes a change to a (restricted) type certificate that should be approved in accordance with Part-21.