The data contained in OSD FC documents are identified as either ‘mandatory’ or ‘non-mandatory’ elements. While mandatory elements have the status of a rule, non-mandatory elements have the status of Acceptable Means of Compliance (AMC).
In order to provide some flexibility to users, non-mandatory elements typically address such items as training devices, training duration, previous experience, or currency. In line with the general principles for AMCs, these elements are non-binding provisions established as a means of compliance with the Aircrew Requirements.
Users may choose Alternative Means of Compliance (AltMoC) to use alternatives to the OSD-FC non-mandatory parts by following the dedicated process for AltMoCs described in the implementing rules for aircrew licensing and air operations. Further details on the AltMoC process can be found on EASA's website.