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How do I determine what propeller model I have?

Your Hartzell basic propeller model is impression stamped on the propeller hub. The blade model designation should be ink stamped on the camber side of the blade or indicated on a thermal decal located on the propeller cylinder/piston under the spinner. Additionally, blades are permanently identified internally with impression stamps on the blade butt. The complete propeller model is composed of both the basic propeller model and the blade model.  It should be recorded near the front of your propeller log book. A slash mark separates the basic propeller model and blade model designations.

How do I determine my propeller’s serial number?

The propeller serial number is impression stamped on the hub.  Generally, you will find it begins with a two letter prefix followed by a series of numbers.  The prefix denotes the basic propeller model and the numbers indicate the sequence of production.

Where do I get Service Bulletin Information and does it cost anything?

Most commonly requested service documents are available for free download in the Reference Library on this site. Those who regularly work with Hartzell propellers should maintain a complete set of Hartzell Service Documents.All active Hartzell Service Documents are included on the Hartzell Technical Documents Library on CD ROM. To purchase the Hartzell Technical Documents Library on CD ROM, contact our New Parts Sales Dept. at

Do I have any airworthiness directives that affect my propeller?

You will need to know your propeller model and serial number to determine if it is affected by an airworthiness directive. Review a summary of all airworthiness directives that are applicable to Hartzell propellers.

Can I use an alternate material (paint, filler, glue, sealer, grease, etc.) instead of the specified material?

No, only materials approved by Hartzell are acceptable for use on our products.
The materials that Hartzell specifies are selected based on extensive testing and evaluation to determine that they adequately perform their desired function while not having any adverse affects to other components or materials used on the propeller. The testing and evaluation has to determine whether the material will function as desired throughout the entire operating environment and envelope of the subject propeller. On a certified product, such as a propeller, the use of the approved materials is required by the FAA.

My propeller is not operating properly (surging, leaking grease or oil, vibrating). What should I do?

For troubleshooting of common problems refer to the Testing and Troubleshooting chapter of your Hartzell Owner’s Manual or contact Product Support.

What do I need to do to maintain my propeller?

General maintenance consist of dressing out nicks, touching up paint, lubricating the propeller and periodically inspecting for corrosion. See your Owner’s Manual or contact Hartzell Propeller Product Support for more information. In addition to these general maintenance activities, Hartzell recommends that your propeller be overhauled at specific intervals as specified in Hartzell Service Letter HC-SL-61-( ).

What is the recommended time-between-overhaul (TBO) for Hartzell propellers?

Hartzell Service Letter HC-SL-61-61Y is designed to answer questions dealing with propeller and governor overhauls, TBO extensions, calendar limits and long term storage. To determine when your propeller is due for overhaul you will need to know your propeller model number (example HC-C2YK-1BF). Within the service letter locate your propeller model and all pertinent notes HC-SL-61-( ).

Why do I have to overhaul my propeller after 5 or 6 years when it has limited time since last overhaul and the aircraft has been stored in a heated hangar?

Propellers are one of the most highly stressed components on an aircraft.  The overhaul limits published in Service Letter HC-SL-61-( ) are intended to protect your safety, and maximize cost effective operation of your propeller investment.  Hartzell propellers are designed for high reliability and a long service life.  However, like any mechanical device, they require periodic maintenance and inspection to ensure a long life and safe operation.  Even propellers with low operating hours or those stored within a heated hangar are susceptible to degradation over calendar time due to corrosion, internal seal aging, and breakdown of internal lubricants.  While components within a propeller are generally protected from the environment by plating or paint, over time these protective surfaces will degrade, leaving unprotected metal components susceptible to corrosion.  Very often, this degradation is not visible externally, and can only be detected during a complete propeller disassembly and overhaul and at a certified propeller repair facility.Overhaul limits published in Service Letter HC-SL-61-( ) are designed with these limitations in mind, and following Hartzell published overhaul limits will ensure that any problems developing within the propeller are found early, usually while still easily repairable.  Neglecting the propeller by operating it beyond Service Letter HC-SL-61-( ) limits can result in minor problems developing into much larger issues, leading to reduced reliability, propeller malfunction, expensive component replacement, and potentially unsafe operating conditions.

Where can I get my propeller serviced?

Hartzell has developed a network of Recommended Service Facilities that are located throughout the world. This network is the result of Hartzell having established relationships with the highest quality repair stations in a given geographic location. These repair stations are routinely audited by Hartzell to assure that they not only meet the regulatory requirements of their aviation authorities, but also the exceptional standards required by Hartzell.In addition to the network of Recommended Service Facilities; the Hartzell Service Center is the only factory owned and operated propeller repair station. Hartzell Service Center has been in operation, servicing only Hartzell propellers, for over thirty-five years. Located within the factory in Piqua, Ohio, the Hartzell Service Center has direct access to all the engineering and manufacturing resources used in the original manufacturing of your propeller. The ability to focus on one propeller brand and to draw on this abundance of resources assures that your propeller overhaul or repair is completed to the highest of standards.

How and when do I grease my propeller?

The procedures and intervals for lubricating (greasing) your propeller are based on the type of propeller you are operating, aluminum hub or steel hub, and whether the propeller is installed on a reciprocating or turbine engine application. Specific guidance for greasing your propeller can be found in the applicable Hartzell Owner’s Manual.

What grease should I use to lubricate my propeller?

Beginning January 6, 2020, NYCO GN3058 is the preferred grease for Hartzell propellers.   As of this date, all new production Hartzell propellers will ship with NYCO GN3058 grease.   Prior to this change, Aeroshell 6 “all purpose” grease was used on all Hartzell new production propellers  manufactured since 1989.  (Exception:  propellers installed on the Piaggio P180 and the Grob Egrett.)

A label is normally applied to the propeller to indicate the type of grease used.  The same grease type must be used during re-lubrication unless the propeller has been disassembled and the old grease removed. NYCO GN3058 is not compatible with any of the approved Aeroshell greases. Do not mix different greases within a propeller.

Complete details can be found in Hartzell Service Letter HC-SL-61-366.

Refer to your propeller’s owner’s manual for other approved lubricants. Specific guidance for greasing your propeller can be found in the applicable Hartzell Owner’s Manual.

Can I repair cracks/damage to my spinner?

Refer to Hartzell Manual 127 for approved repairs or modifications to Hartzell metal spinners.

Hartzell Propeller