Final answer:
The necessary procedure for certifying an amendment to an aircraft's weight and balance report is the signing of a maintenance release by an appropriately rated AME. This is a crucial step in maintaining the aircraft's airworthiness by ensuring changes are documented and certified.
Step-by-step explanation:
The procedure necessary for certifying an amendment to an aircraft's weight and balance report is the signing of a maintenance release by an appropriately rated Aircraft Maintenance Engineer (AME). This process ensures that any changes made to the aircraft's weight and balance are accounted for and properly documented. It is a way of maintaining aircraft airworthiness and is a regulatory requirement. An AME has the authority to inspect and certify aircraft maintenance work, which includes changes to the weight and balance report. Once the AME is satisfied that the work has been completed correctly and safely, they will sign a maintenance release, which effectively certifies the amendment to the aircraft's documentation.