HC-SL-61-48A - Propeller-Diaphragm Inspection - Revision 3 Issued December 7, 2022

Sep 15, 2026

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Hartzell Propeller Inc. Service Letter HC-SL-61-48A transmits Revision 3 dated December 07, 2022, updating visual inspection requirements for the B-119 diaphragm used in affected propeller models. The publication addresses fatigue failures attributed to rubber deterioration from long-term exposure to weather, describes safety warnings, and reissues the document in full. It establishes continued airworthiness instructions, including repetitive visual inspections every six months and diaphragm replacement every 24 months, with specified compliance steps and references.

LanguageEnglish

CategoryLetters

FormatPDF

Pages6

Reading Time2 min

AccessFree to download

Planning Information

Effectivity

Concurrent Requirements

Reason

Description

Compliance

Approval

Manpower

Material Information

Material Necessary for Each Propeller/Component

Accomplishment Instructions

Visual Inspection

HARTZELL PROPELLER INC. SERVICE LETTER TRANSMITTAL SHEET HC-SL-61-48A Propeller-Diaphragm Inspection December 07, 2022 This page transmits Revision 3 to Service Letter HC-SL-61-48A • Original Issue, dated Apr 20/67 • Revision A, dated Oct 14/88 • Revision 1, dated Sep 17/07 • Revision 2, dated Apr 15/14 • Revision 3, dated Dec 07/22 Propeller assemblies that have previously complied with the diaphragm inspections and replacement required in previous revisions of this Service Letter are affected. Changes are shown by a change bar in the left margin of the revised pages. Revision 3 is issued to change the following in the Service Letter: - Revise the section, "Visual Inspection" This Service Letter is reissued in its entirety. HARTZELL PROPELLER INC. SERVICE LETTER TRANSMITTAL SHEET HC-SL-61-48A Propeller-Diaphragm Inspection (Blank Page) HARTZELL PROPELLER INC. SERVICE LETTER HC-SL-61-48A Propeller-Diaphragm Inspection 1. Planning Information A. Effectivity (1) Hartzell Propeller Inc. hydro-selective propeller models HC-(1,D)(2,3)(X,V, MV)20-(7,8) using the B-119-( ) diaphragm are affected by this Service Letter. WARNING: DO NOT USE OBSOLETE OR OUTDATED INFORMATION. PERFORM ALL INSPECTIONS OR WORK IN ACCORDANCE WITH THE MOSTRECENT REVISION OF THIS SERVICE LETTER. INFORMATION CONTAINED IN THIS SERVICE LETTER MAY BE SIGNIFICANTLY CHANGED FROM EARLIER REVISIONS. FAILURE TO COMPLY WITH THIS SERVICE LETTER OR THE USE OF OBSOLETE INFORMATION MAY CREATE AN UNSAFE CONDITION THAT MAY RESULT IN DEATH, SERIOUS BODILY INJURY, AND/OR SUBSTANTIAL PROPERTY DAMAGE. REFER TO THE SERVICE LETTER INDEX FOR THE MOSTRECENT REVISION LEVEL OF THIS SERVICE LETTER. B. Concurrent Requirements (1) Additional service documents may apply to the components/propellers affected by this Service Letter. Compliance with additional service documents may be necessary in conjunction with the completion of the Accomplishment Instructions in this Service Letter. Refer to the Hartzell Propeller Inc. website at [www.hartzellprop.com for a cross-reference of service documents](www.hartzellprop.com for a cross-reference of service documents). C. Reason (1) There have been fatigue failures of the B-119-( ) diaphragm that is used to actuate the pitch change mechanism. The failures are apparently due to high calendar times. The diaphragm ruptured and resulted in loss of engine oil. The loss of engine oil caused the blades to move to high pitch. (2) The cause of the failures were attributed to deterioration of the rubber caused by extensive exposure to weather and atmosphere. (3) This Service Letter was originally issued to require an initial and repetitive visual inspection of the B-119-( ) diaphragm. Apr 20/67 HC-SL-61-48A Revision 3, Dec 07/22 Page 1 of 4 © 1967, 1988, 2007, 2014 , 2022-Hartzell Propeller Inc. -All rights reserved HARTZELL PROPELLER INC. SERVICE LETTER HC-SL-61-48A Propeller-Diaphragm Inspection D. Description (1) This Service Letter provides Instructions for Continued Airworthiness (ICA) . (2) This Service Letter requires repetitive visual inspections of the B-119-( ) diaphragm. (3) This Service Letter requires replacement of the B-119-( ) diaphragm every 24 months. E. Compliance (1) Repetitive Visual Inspections (a) Every six months, visually inspect the B-119-( ) diaphragm in accordance with the Accomplishment Instructions in this Service Letter. 1 Perform the repetitive visual inspections for up to, but not more than 24 months from the date of the most recent diaphragm installation. (2) Diaphragm Replacement (a) Every 24 months, replace the B-119-( ) diaphragm in accordance with Hartzell Propeller Inc. Owner's Manual 140 (61-00-40), revision 3 or later. (3) After replacing the diaphragm, repeat the cycle of repetitive visual inspectionsin accordance with this Service Letter. F. Approval (1) FAA acceptance has been obtained on technical data in

FAQs

What changes does Revision 3 make to Service Letter HC-SL-61-48A?

Revision 3 updates the section titled "Visual Inspection" and reissues the service letter in its entirety.

What is the inspection interval required for the B-119 diaphragm?

The B-119 diaphragm must receive repetitive visual inspections every six months, performed in accordance with the accomplishment instructions.

When is the diaphragm required to be replaced?

The B-119 diaphragm must be replaced every 24 months, following the applicable Hartzell Propeller manual revision level.

Sep 15, 2026

Uploaded by Đào