MSG3 LOGIC
Most modern aircraft are maintained in accordance with the above mentioned maintenance programme. In simple terms most items are maintained on condition. However items that are identified as Structurally or Functionaly Significant maintained to a hard time based on hours, cycles or time.
Most of the structure is maintained using the zonal maintenance concept.
The maintenance programme is written by the operator based on information from the manufacture. This takes in account of how the operator uses the airframe. Inspection and maintenance times can be varied depending on defects etc.
Although the B707 airframe was built before the MSG LOGIC came into being it can be applied to older airframes. The original MSG LOGIC 1 came in with the B747. By using MSG LOGIC heavy maintenance checks on a B747 required a fraction of the man hours compared with the B707 using maintenance based on hard time principles.
I am sure the AIR FORCE have applied MSG LOGIC to the Senrty Fleet and will apply it to the Rivet Joint aircraft. Although both are derived from the B707 the advantage of the MSG system is it's flexibility.
Selecting airframes with enough hours / cycles to cover the planned flying and life of the project would rate higher than trying to "zero life" the airframe.
Applying MSG LOGIC and an ageing aircraft maintance programme will mean the age of the airframe is not a major issue.