Propeller Owner’s Manual
147
INSPECTION AND CHECK
61-00-47
Page 5-33
Rev. 17 Sep/20
5. Special Inspections
(Rev. 1)
CAUTION:
INSTRUCTIONS AND PROCEDURES IN
THIS SECTION MAY INVOLVE PROPELLER
CRITICAL PARTS. REFER TO THE
INTRODUCTION CHAPTER OF THIS
MANUAL FOR INFORMATION ABOUT
PROPELLER CRITICAL PARTS. REFER TO
THE ILLUSTRATED PARTS LIST CHAPTER
OF THE APPLICABLE OVERHAUL MANUAL(S)
FOR THE IDENTIFICATION OF SPECIFIC
PROPELLER CRITICAL PARTS.
A. Overspeed/Overtorque
(1) An overspeed has occurred when the propeller RPM has
exceeded the maximum RPM stated in the applicable
Aircraft Type Certificate Data Sheet. An overtorque
condition occurs when the engine load exceeds the
limits established by the engine, propeller, or airframe
manufacturer. The duration of time at overspeed/
overtorque for a single event determines the corrective
action that must be taken to make sure no damage to
the propeller has occurred.
(2) The criteria for determining the required action after an
overspeed are based on many factors. The additional
centrifugal forces that occur during overspeed are
not the only concern. Some applications have sharp
increases in vibratory stresses at RPMs above the
maximum rated for the airframe/engine/propeller
combination.
(a) When a propeller installed on a turbine engine has
an overspeed event, refer to the Turbine Engine
Overspeed Limits (Refer to Figure 5-6) to determine
the corrective action to be taken.
(b) When a propeller installed on a turbine engine has
an overtorque event, refer to the Turbine Engine
Overtorque Limits (Refer to Figure 5-7) to determine
the corrective action to be taken.
