Definition
An FAA-approved inspection program in which the work normally done in a single annual or 100-hour inspection is broken into smaller scheduled segments performed at shorter intervals, so that over a defined cycle the entire aircraft is inspected. The program must be approved by the FAA and conducted under the requirements of 14 CFR Part 91.409(d).
Plain English
Instead of doing one big inspection of the whole aircraft once a year, the inspection is split into smaller pieces and spread out across the year. By the end of the cycle, every part has been checked, just in stages.
Context Anchor
Seen in aircraft inspection requirements, maintenance records, and discussions of alternatives to a standard annual inspection.
Derivation
Progressive comes from the Latin progressus, meaning to move forward step by step. Here it describes an inspection that moves through the aircraft in steps over time, rather than all at once.
Why Pilots Care
Reduces the time an aircraft must remain on the ground while still meeting all airworthiness inspection requirements.
Analogy
It is like cleaning and checking a house one room at a time on a set schedule, instead of doing the whole house in one long day. The important point is that every room still gets checked by the time the schedule is complete.
Intuition Check
Progressive does not mean the inspection is more advanced or better than a normal inspection. Here it means the inspection is divided into scheduled stages.
Example Sentence 1
The flight school placed its busiest training aircraft on a progressive inspection program so the airplanes could stay on the line instead of being grounded for a full annual each year.
Example Sentence 2
Under the progressive inspection program, the mechanic completed the next segment of the inspection during the scheduled 50-hour oil change.