Can't catch a break with you, can I?
![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
The express point of this language is to signal lack of certainty. How can one learn if one is sure?
I get tired of non-mechanics telling pilots how to maintain or fix their airplanes, or what's wrong with them. There is far too much assumptive knowledge floating around, based on assumptions, of course, that often have no basis in reality, and it just piles up and misleads too many people. If there's a lack of certainty, the uncertain person should not be making diagnoses or prognostications.
We often see it when someone complains that their engine won't crank properly, for example. About 90% of the posters will suggest replacing the battery. That's expensive, and with these old airplanes, it usually will not fix the problem. There are so many factors that can cause poor cranking, and unless the mechanic takes a few minutes to make some measurements, he'll just end up, for example, replacing the battery, then the starter, then the starter contactor, then the alternator, then the regulator, then the cables, and finally find that the $40 master contactor was shot. And we wonder why flying is so expensive.
We also see it when someone complains that his engine hesitates or stumbles. 95% of the posters will blame water in the carb, or obstructed screens or lines, or something else fuel-related. And yet, 90% of engine performance problems are electrical problems, specifically ignition, and specifically magnetos or plugs in the vast majority of cases. It's why we have one carb or fuel servo, and two magnetos and two sets of plugs. Because people don't understand ignition, both the operation of the magneto and the physics of spark ignition, they think that if the magnetos are running fine at runup, everything is OK. They don't know that a weak spark will not ignite a lean mixture reliably, sometimes eve a rich mixture, nor at high cylinder pressures, and both normally occur during acceleration. It can happen as the throttle is closing, too.