SERVICE BULLETIN Propellers Blade Angle Adjustment HC-SB-61-236
Piper PA-24 Comanche 260 · Service Bulletins
Overview
This Service Bulletin from Hartzell Propeller Inc. addresses the adjustment of the blade angle for HC-C3YR-1RF/F7590 model propellers installed on Piper PA-24 Comanche 260 aircraft. Issued on May 12, 1998, it highlights the need to increase the low pitch blade angle from 10.5° to 13.8° to prevent potential engine overspeed during certain failure conditions. The bulletin outlines compliance requirements, adjustment procedures, and necessary documentation for maintenance personnel. Compliance is recommended during the next 100-hour or annual inspection, ensuring safety and performance standards are maintained for affected aircraft.
- The low pitch blade angle for affected propellers must be adjusted from 10.5° to 13.8°.
- Compliance is recommended during the next 100-hour or annual inspection, within 12 months of the bulletin's issue date.
- Maximum engine RPM after adjustment should be between 2650 and 2700 RPM.
- Adjustment procedure includes specific steps for loosening and tightening components, requiring a certified mechanic.
- Documentation of compliance must be recorded in the aircraft logbook.
Document
Source
Originally published by hartzellprop.com. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type
- Service Bulletins
- Year
- 1998
- Pages
- 3
- File size
- 38 KB
- Publisher
- hartzellprop.com
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In this document
Effectivity
The Service Bulletin applies specifically to HC-C3YR-1RF/F7590 model propellers installed on Piper PA-24-260 Comanche 260 aircraft under STC SA288CH. Propellers manufactured between May 1995 and April 1998, prior to serial number DY3940A, are affected.
Reason
The bulletin addresses a potential issue where the original low pitch blade angle of 10.5° could lead to engine overspeed in the event of governor failure or oil pressure loss. The adjustment to 13.8° is necessary to mitigate this risk.
Compliance
It is recommended that compliance with this bulletin be performed at the next 100-hour or annual inspection, not exceeding 12 calendar months from the bulletin's issue date.
Accomplishment Instructions
The adjustment procedure involves removing the spinner dome, loosening the low pitch stop jam nut, and turning the low pitch stop screw in 2-1/3 turns to achieve the new blade angle. A static test run of the engine must follow to ensure the maximum RPM is within the specified range of 2650 to 2700 RPM.
Manpower
The expected time to comply with this bulletin is less than one hour, making it a relatively quick adjustment for maintenance personnel.
Safety notes
- Failure to comply with the adjustment may lead to engine overspeed, posing safety risks during flight.
Full document text
HARTZELL PROPELLER INC. SERVICE BULLETIN Propellers Blade Angle Adjustment HC-SB-61-236 Page 1 of 3 May 12, 1998 1. Planning Information A. Effectivity This Service Bulletin applies to HC-C3YR-1RF/F7590 model propellers installed on Piper PA24-260 Comanche 260 aircraft under Supplemental Type Certificate Number SA288CH. The propellers were manufactured between May, 1995 and April 1998 prior to serial number DY3940A. HC-C3YR-1RF/F7590 model propellers with serial numbers greater than DY3940A are not affected by this bulletin. B. Concurrent Requirements None. C. Reason (1) The original STC specified a low pitch blade angle setting of 10.5°. This blade angle has been determined to be lower than desired and could cause engine overspeed in the unlikely case of governor failure or oil pressure loss, during rapid application of power. (2) The condition is limited to the propellers listed in the Effectivity section of this document. (3) Compliance with this bulletin is required to reduce the chance of engine overspeed. (4) Owners of the affected aircraft will receive a new Airplane Flight Manual and Supplement. D. Description This Service Bulletin establishes a new low pitch blade angle of 13.8° for HC-C3YR-1RF/F7590 propellers installed under STC SA288CH and provides a procedure for maintenance personnel to adjust the blade angle in the field. E. Compliance Compliance with this bulletin is recommended at next 100 hour or annual inspection, not to exceed 12 calendar months time from the date of this bulletin. F. Approval FAA approval has been obtained on technical data in this publication that affects type design. HARTZELL PROPELLER INC. SERVICE BULLETIN Propellers Blade Angle Adjustment May 12, 1998 HC-SB-61-236 Page 2 of 3 G. Manpower Compliance with this bulletin is expected to require less than one hour. H. Weight and Balance Not Affected. I. Electrical Load Data Not Affected. J. References Hartzell Manual 113( ), Compact Non-Feathering Propeller Overhaul Manual Hartzell Manual 115( ), Compact Propeller Owner's Manual and Logbook Hartzell Manual 133( ), Aluminum Blade Overhaul Manual K. Other Publications Affected Hartzell February 1998 Application Guide 2. Material Information None required 3. Accomplishment Instructions NOTE: At the discretion of the propeller owner, the low pitch blade angle may be reset with a blade protractor on wing by a propeller repair facility. Hartzell Manual 133C, Table 307 must be referenced due to the convex contour of the blade face at the reference station. A. Resetting of the low pitch blade angle on-wing must be performed by a certified aircraft mechanic or propeller repair facility. (1) Remove spinner dome. (2) Loosen low pitch stop jam nut (see Figure 1) (3) Turn the low pitch stop screw in 2-1/3 turns. This will increase the low pitch angle from 10.5° to 13.8°. (4) Tighten jam nut and torque to 15 ft/lbs (+/-10%). HARTZELL PROPELLER INC. SERVICE BULLETIN Propellers Blade Angle Adjustment HC-SB-61-236 Page 3 of 3 May 12, 1998 B. Perform static test run of engine (1) With propeller and engine controls set for takeoff, check maximum RPM of engine. Maximum RPM should be between 2650 and 2700 RPM. If engine RPM is too low, the low pitch stop may have been adjusted at an earlier time. (a) If engine RPM requires adjustment, each turn out of low pitch stop will increase engine RPM by approximately 200 RPM. (b) Adjustments should be made in small increments to set maximum static RPM to 2650 - 2700. (2) Reinstall spinner dome. (3) Make a log book entry recording compliance with this bulletin. C. Propeller repair facilities are encouraged to make a notation of the 13.8° low pitch blade angle change to page 31 of the Propeller Blade Angle section of the Hartzell 1998 Application Guide for the PA-24-260 (STC-SA288CH). 4. Appendix For Hartzell service literature and revisions, contact: Hartzell Propeller Inc. Telephone: 937.778.4299 Product Support Technical Publications Fax: 937.778.4365 One Propeller Place Piqua, Ohio 45356 U.S.A. SPINNER DOME CYLINDER LOW PITCH STOP JAM NUT LOW PITCH STOP Figure 1 Low Pitch Stop Location