Нетипово, про пізнавальне.
Pilot's flight operating instructions for Army model P-39Q-1 airplane
www.wwiiaircraftperformance.org/P-39/P-39Q-1_Op...
This publication shall not be carried in aircraft on combat missions or when there is a reasonable chance of its falling into the hands of the enemy.
(...) Its transmission or the revelation of its contents to an unathorized person is prohibited by law.