Every 100 hours, it was the same-old, same-old. I could barely keep my eyes open while doing yet another 100-hour inspection on the same trainer I had just inspected a month ago and the month before that and on and on. Each time I did the inspection, I had to play a game where I figured that if I looked hard enough, I’d find something wrong. But in the dozens of times I inspected those airplanes, I never found a broken wing bolt or spar or other major structural damage.

What I did find was that I spent 90 percent of my time looking in inspection holes and checking those bolts and spars and by the time I was nearly done and ready to fix all the discrepancies (squawks) that were on my list, the front desk was desperate for the airplane to get back on the line so it could resume making money.

This seemed to me to be completely backward. Why don’t we mechanics spend more time fixing and less time inspecting? What is ultimately better for the airplane and the customer? An inspected airplane with some minor corrosion spots that need to get fixed and some placarded broken equipment or fixing all those minor items before they become major and inspecting the really important parts?

What I’m getting at is that in aviation, too much of what we do is prescribed by rules that at the time they were written appeared to be a good idea. And we keep doing the same thing over and over again because everyone else down the years thinks that it is a good idea. But no one ever questions whether it makes sense or is supportable by evidence instead of feel-goodness.

Aircraft inspection is a good case in point. Many interval-based inspections have hourly or calendar time limits. But what are these limits based on? Most, I suggest, are based on previous time limits. When a manufacturer certifies a new aircraft, it starts with inspection times that are conservative and based on previously approved time limits.

For light aircraft, the FAA is obsessed with the 100-hour limitation. The agency made a regulation (which is near-impossible to change) that aircraft operated for hire or where the instructor provides the aircraft for the student, it must go through what is essentially an annual inspection every 100 hours. What this means is that almost every flight school operating under FAA regulations grounds each aircraft every 100 hours of operation for at least a day or two to undergo a redundant and wasteful inspection.

The problem with the 100-hour is that it is intrusive, requiring a lot of work to open up the aircraft for inspection and leaving many opportunities for mechanics to forget something and cause more harm than good. Also in the more-harm department, the time spent inspecting items that don’t need to be inspected could better be used to fix broken stuff and remedy squawks. Too often I have seen airplanes returned to the flight line with broken seatbelts, missing panel equipment, inoperative lights, corrosion that keeps getting put off, and more.

There are efforts to improve this situation, and aircraft manufacturers aren’t blind to this problem. Most use the Maintenance Steering Group (MSG-3) process to continually evaluate the need for certain maintenance processes and extend (or in some necessary cases shorten) maintenance intervals. Even with light airplanes, companies such as Textron Aviation have created a phased maintenance program for high-use airplanes (although few flight schools use this in my experience).

But I believe we can do better at eliminating unnecessary maintenance and inspection. We have gazillions of bytes of data about modern aircraft. Are the manufacturers really diving deeply into that data to see where maintenance intervals could be extended? I suspect they’re too busy supporting their fleets, designing new upgrades, and working certification issues and don’t have time for looking too closely at maintenance interval opportunities.

Flight schools could create their own sensible maintenance programs that don’t involve 100-hour inspections, focusing on the areas that truly need attention, spending more time fixing, and gaining more availability.

Working this problem would have a huge benefit, freeing up a significant amount of maintenance hours that right now are being wasted as eyes-glazed-over mechanics struggle to inspect yet again those wing bolts that aren’t going anywhere anytime soon.