Within the privilege described in 145.A.75(c) a Part-145 maintenance organisation may perform line maintenance activity in other-than-approved locations, provided it is considered as ‘occasional’. There is no formal definition of ‘occasional’ in the regulation, AMC and GM, but the need for line maintenance in such case should be understood as arising from special occasion, not frequent, regular or recurrent. The repetitive use of this privilege at the same location should not be foreseen.
Subject to the approval by the Competent Authority, the maintenance organisation should develop in the MOE (e.g. Chapter 2.24 Reference to Specific Maintenance Procedures) the procedures to be followed in such a case: how to assess whether the maintenance can be performed, availability of tools/equipment/material/components/maintenance data, staff, adequacy of the facilities, environmental conditions, quality system etc. In particular, it should describe the maximum duration of such line maintenance activity at that location.