• Airworthiness Directives (ADs) are issued to address unsafe conditions on aeronautical products, parts and appliances.
    Aircraft on the UK register are required to comply with all applicable ADs.

    An Alternative Method of Compliance (AMOC) to an AD may be approved by the CAA if requested and appropriately substantiated.

    An AMOC to an AD is a different way of meeting the intent of an AD.

    Applicants seeking AMOC to an AD approval need to ensure and demonstrate that an equivalent level of safety is achieved compared to the compliance with the original AD.

    An AMOC to an AD linked to a minor or major change or an STC will be approved after the related change is approved.
    If an AD is superseded, all AMOCs related to the AD are automatically invalidated. In these cases, a new application is required to ascertain that compliance with the new AD is achieved.
    A new application is not required when an AD is revised.


    Anyone may apply for the CAA approval of an AMOC to an AD.

    How to apply

    An application is made using CAA Form SRG1781.

    Approval process

    x   Submit application on CAA Form SRG1781 
      x Check eligibility of Applicant and completeness of information submitted
    x   Provide substantiation for the AMOC to AD application and demonstrate equivalent level of safety compared to compliance with original AD
      x Perform technical investigation and determine AMOC to AD provide equivalent level of safety compared to compliance with original AD
      x Issue AMOC to AD approval certificate