I write tech manuals for a living, but we don't do things nowadays the way they did back in the Olden Days.
Back in the '40's, the thinking apparently was that a little levity would keep the reader's attention, or drive a point home. Or sometimes there was just some white space to fill, maybe. But scattered here and there through the PV-2 flight manual, you'll find these little cartoons.
I have seen some things in other publications--like Naval Aviation News, specifically the old "Grampaw Pettibone" panels--that are kind of reminiscent of some of these. It may actually be the same artist, whose name escapes me at the moment.
I'm wondering if such cartoons (examples below) are common among other types, or maybe they're only in Navy manuals, or only Lockheed manuals.
Anyhow, check these out, and enjoy. Don't be like Dilbert!
Encouragement to read the book: (with some bleed-thru from the backing page)
Weight and balance, always important:
Preflight, anyone?
What's that white arc for, again?
I haven't found this sort of thing in the maintenance manuals, only in the pilot's handbook. What that says about the difference between mechs and zoomies, I'll leave for others to interpret ...