Progressive Inspections (2 of 2) -- A brief look at what happens in progressives

What might happen in a progressive inspection program? I don't have access to any current progressive inspection program documents, but thanks to discussions with friends who are airframe and power plant mechanics who have worked on progressive inspections, I have an idea of how progressives work.

In a typical FAA approved progressive program, the progressive is based on three or four operations that recycle after a certain number of hours. So lets say there is an approved progressive program , e.g. for a hypothetical single-engine fixed wing aircraft, has four operations occurring at 50 hour intervals, recycling after 200 hours (of flight time). Further, the progressive inspections must be completed within a twelve month period.

Lets say that the last twelve month period started on January 31, 2010 and the aircraft has only flown 140 hours to date with progressive inspection operations one and two already completed. Operations three and four must be completed by January 31, 2011.

There will be a list of specific items that have to be inspected in each operation. Each operation is likely to focus on detailed inspections of one or two components with routine inspections of the other components. For example operation # 1 may  have detailed inspection items for the landing gear and wings with routine inspection items for the rest of the aircraft (cabin, fuselage, engine, propeller, and empennage).

In my discussion of progressive inspections, I would be remiss if I did not mention that the FAA regulations mention that life-limited parts have to be replaced before the end of their life. I suspect, that life-limited parts will be replaced during progressive inspections. I also suspect that the replacement of life-limited parts is an important component of maintenance and inspection programs in the tanker business, whether they be progressive inspections or some other type of FAA approved inspection program.

As I have learned more about how progressive inspections work, I appreciate that the world of aircraft maintenance and inspections, including but not limited to progressives) is often complicated. A progressive inspection program in the tanker business is going to be much more involved and a lot more time consuming than a progressive for a fixed-wing single engine aircraft with non-retractable landing gear. Nothing is simple in the tanker business.

This ends my two-part series on progressive inspections. Perhaps I'll revisit progressives again in later articles. For now, I am moving on. In my next article, I'll write a little about maintenance and inspection logs.