AD-53-03-01
Hartzell Propeller RPM Placard


Category: navion, Hartzell, propeller, placard

Applicability: All model B aircraft equipped with Hartzell HC-12 x 20-8C19333C-0 propellers.

Supersedes: n/a

Compliance: Not later than March 15, 1953

Procedure: Vibration tests conducted subsequent to the initial tests of the Hartzell HC-12 x 20-8C19333C-O propeller installed on the Lycoming GO- 435 engine revealed vibration characteristics of a hazardous nature. Therefore, to prevent possible blade cracks and/or failures, the existing r.p.m. restriction placard should be revised as follows:

"Avoid continuous ground operation between 1675 and 2150 engine r.p.m."

Notes: none


AD-53-03-01