HARTZELL SERVICE LETTER
61U
OVERHAUL LIMITS CATEGORY 1 PROPELLERS
RECIPROCATING ENGINES
PUBLISHED MARCH 20, 1998

Y Shank (Compact Propellers ( )HC-( )(2,3,4)Y( )-( ) () ( See Note 1)

 Propeller Model & Application Flt Hrs/Calendar Mos.
 Agricultural Aircraft ( See Note 2) 2000 Hr/36 Mos.
Acrobatic Aircraft ( See Note 3) 1000 Hr/Note 1
Franklin Engine Applications 1500 Hr/Note 1
All Other Two Blade Applications Note 4/Note 1
All Other Three and Four Blade Applications Note 5/ Note 1

R,Z,W,P Shank Propellers HC-( )2,3) (R,Z,W,P)( )-( )

 Propeller Model & Application Flt Hrs/Calendar Mos.
 Agricultural Aircraft ( See Note 2) 2000Hr/36Mo
Acrobatic Aircraft ( See Note 3) 1000Hr/60Mo
Jacobs R-755 Engine Applications 1000Hr/60Mo
All Others 1000Hr/60Mo

X & V Shank Propellers ( ) HC ( )2,3) (X,V) ( )-( ) See Note 6

 Propeller Model & Application Flt Hrs./Calendar Mos
Agricultural Aircraft (See Note 2) 1000Hr/36Mo
Acrobatic Aircraft ( See Note 3) 1000Hr/60Mo
All Others 1000Hr/60Mo

Modified V Shank Propellers ( )HC-( )2,3)MV( )-( ) (See Note 6)

 Propeller Model & Application Flt Hrs/Calendar Mos
 Agricultural Aircraft ( See Note 2) 2000Hr/36Mo
Acrobatic Aircraft ( See Note 3) 1000Hr/60Mo
All Others 2000Hr/60Mo

Note 1. Y shank propellers manufacturered or overhauled since October 1991 are required to have the hub internal surfact painted for additional corrosion protection. Overhaul calendar limit for these propellers is 72 months. Calendar limit remains 60 months for propellers manufacturered or overhauled prior to October 1991 until internal painting has been applied during overhaul.

Note 2. Agricultural aircraft are defined as aircraft used as aerial applicators which expose the propeller to a relatively severe chemical/corrosive environment. Once used on an agricultural aircraft, the 36 month overhaul limit is to be maintained even if propeller is later installed on other category airplanes.

Note 3. Acrobatic aircraft are defined as certified acrobatic category aircraft or other aircraft routinely exposed to acrobatic use.

Note 4. Two blade, Y shank propellers made after April 1997 use an improved hub "fillet radius" and are identified with a suffix letter "B" in the serial number. Overhaul limit for these propellers is 2400 hours. Overhaul limit for earlier models is 2000 hours of operation.

Note 5. Three blade, Y shank propellers made after 1983 use a different grease fitting location and are identified with a suffix letter "A" in the serial number. Overhaul limit for these propellers is 2400 hours. Overhaul limit for pre-1983 models is 2000 hours of operation. Overhaul limit for four blade, Y shank propellers is 2400 hours of operation.

Note 6. HC-(1,D)2X20-(7,8) and HC-(1,D)2(M)V20-(7,8) Hartzell Hydro-Selective propellers require replacement of rubber diaphram (P/N B119-2) at intervals not to exceed 24 months or 250 hours of operation whichever occurs first.

GOVERNORS

Hartzell propeller Governors are to be overhauled at the same time as engine overhaul, but not to exceed 2000 Hours of operation. ( There is no calendar limit applicable to governors.)


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