Le Chaud Lapin writes:

For example, as I mentioned earlier, I am reading Jeppesens Private
Pilot manual, and there are clearly errors in concept the manual
(energy being created by engine, for example), even though Jeppensen
probably has access to as many Ph.D. laureates as they want.

Describe the errors in a letter and send it to them. Good technical
publishers are always willing to accept corrections.