Within the privilege described in 145.A.75(c) an aircraft maintenance organisation (AMO) 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 this privilege should be used to support an operator with which the AMO is already in contractual relation, when this operator needs line maintenance service for a short period at a new location due to a special occasion or particular reason (e.g. one-time flights, short term contracts/flight destination, flight schedule changes, special event at a particular location such as European athletics championship in Berlin, 6-12 August 2018, etc.).
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 generic 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, record keeping, need to report these cases to the competent authority, etc. In addition, the procedure should include the criteria (e.g. maximum service duration without gap in the continuity; limitation in the repetition of the need* at one given location) to classify the activity as ‘occasional line maintenance’.
* In principle, the repetitive use of this privilege at the same location should not be considered, and for repetitive needs, an approved line station should normally be established at that location.