A juvenile male lost control of his remote controlled airplane, injuring onlookers in San Jose, on Monterey Highway, Bat. Chief Mike Jarski confirmed.
The 911 call came over shortly before 2pm, Sunday.
Another RC plane operator, male, about 40 years old, was hit and received lacerations from the propeller, above the knee, which will require surgery.
Another juvenile bystander was clipped by the strut but was not hospitalized.
Normally operators are supposed to work with a spotter before launching the plane, but this operator did not have one.
No one has been cited at this time.