OSIP
 

Hi,
From CASA website : OSIP Overhaul and Special Inspections Periods
OSIP : Overhaul and Special Inspections Periods.
Thank you google.
Never heard about this before or do not remember or maybe with another name...
Sometimes abbreviations and acronyms are really useless and are making things difficult to understand for nothing...

OSIP Overhaul and Special Inspections Periods

From some FAA documents :
OSIP : Office of Surveillance Inspection Program ...

back to CASA ...
 

items, i.e components and systems subject to some form of time control expressed in flight hours, engine or flight cycles and/or calendar time, that are out of phase with the scheduled checks should be catalogued in an Overhaul and Special Inspection Period (OSIP) list. The list must include repetitive and life limiting Airworthiness Directives (ADs), Certification Maintenance Requirements (CMRs) and Airworthiness Limitations (ALs). The items, with their applicable maintenance task/s, eg, inspection, lubrication, overhaul, test, retire, etc and the intervals at which these occur should be set down in the OSIP.

Hope that clarifies ...
MM.