Humans, dogs, bats, etc. are neurologically wired to prevent deafening
themselve from their own loud vocalilizations. Some bats can vocalize at
up to 120 db (luckily in frequencies that we don't hear). When you yell,
a reflex mechanism is activated that relaxes the muscles that tension
the eardrums. This effectively reduces the sensitivity of your hearing
and protects your inner ears. This mechanism is wired into the nerves
that govern vocalization and so this mechanism only works for your own
vocalizations. That's why a dog won't go deaf from it's own barking but
will go deaf from exposure to outside noise.


Exposure to prolonged engine and propeller noise definitely will cause
hearing loss in humans, just as prolonged exposure to rock and roll will.
Dogs, however, can and do create noise that is just as loud and prolonged
without any apparent hearing loss on their part, despite the fact that
humans exposed to dogs' barking can lose their hearing.