SERVICE BULLETIN #R-12A
Beechcraft 23 Musketeer · Service Bulletins
Overview
This document is a service bulletin issued by Sensenich Propeller Manufacturing Company, specifically addressing issues related to corrosion in fixed-pitch metal propellers used on Beechcraft Musketeer aircraft. The bulletin outlines the necessary actions for propeller owners, including the removal of mid-blade decals and inspection for corrosion pits and cracks. It is directed towards FAA-approved propeller repair stations, Sensenich distributors, and Beech Musketeer owners. The compliance date for the actions specified in the bulletin is within the next twenty hours of operation, emphasizing the urgency of addressing potential safety issues.
- Propeller models affected include all Sensenich fixed-pitch metal propellers with water-soluble mid-blade decals, including M74DC and M74DM.
- Compliance is required within the next twenty hours of operation.
- Inspection for corrosion pits must be done with a magnifying glass of at least 3 power.
- If corrosion pits deeper than 0.015 inches are found, the propeller must be replaced before further flight.
- Decals must be removed using paint remover; scraping or sanding is prohibited.
Document
Source
Originally published by www.sensenich.com. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type
- Service Bulletins
- Year
- 1967
- Pages
- 2
- File size
- 75 KB
- Publisher
- www.sensenich.com
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- Pilot's Operating Handbook / AFM
- Checklist
- Maintenance Manual
- Parts Catalog (IPC)
- Systems & Wiring
- Service Bulletins
- Type Certificate (TCDS)
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In this document
Propeller Models Affected
The service bulletin applies to all Sensenich fixed-pitch metal propellers with water-soluble mid-blade decals, specifically including models M74DC and M74DM that carry Beech mid-blade decals. It excludes propellers that have already been serviced or replaced in accordance with previous Sensenich bulletins and FAA airworthiness directives.
Compliance Requirements
Owners are required to comply with the bulletin not later than the next twenty hours of operation. This includes the removal of mid-blade decals and a thorough inspection of the mid-blade area for corrosion pits and cracks.
Inspection and Maintenance Procedures
The mid-blade area must be inspected using a magnifying glass of at least 3 power. If cracks or corrosion pits deeper than 0.015 inches are found, the propeller must be replaced before further flight. If corrosion pits are present, they must be removed within the next twenty hours of operation using specified sanding and cleaning methods.
Decal Removal Process
Decals must be removed by soaking with paint remover and rubbing off with a rag. Scraping or sanding is not permitted. The area must then be sanded, polished, cleaned, and inspected for remaining pits.
Reconditioning Options
Owners have the option to return their propellers to the factory for reconditioning or exchange for a factory reconditioned propeller.
Safety notes
- Corrosion pits deeper than 0.015 inches require propeller replacement before further flight.
- Water-soluble decals must not be re-installed after removal.
Full document text
Visit Our Web Site at http://www.sensenich.com S E N S E N I C H P R O P E L L E R M A N U F A C T U R I N G C O M P A N Y , I N C . AREA CODE 717 PHONE - 569-0435 FAX - 560-3725 14 CITATION LANE LITITZ, PA 17543 SERVICE BULLETIN #R-12A FEBRUARY 6, 1967 TO: FAA APPROVED PROPELLER REPAIR STATIONS, SENSENICH DISTRIBUTORS; BEECH MUSKETEER OWNERS PROPELLER MODELS AFFECTED: ALL SENSENICH FIXED-PITCH METAL PROPELLERS WITH WATER- SOLUBLE MID-BLADE DECALS INCLUDING MODELS M74DC AND M74DM WITH BEECH MID-BLADE DECALS, BUT EXCLUDING THOSE PROPELLERS WHICH HAVE ALREADY BEEN SERVICED OR REPLACED IN ACCORDANCE WITH SENSENICH BULLETINS R-11 AND R-12 AND FEDERAL AVIATION AGENCY AIRWORTHINESS DIRECTIVES 66-11-3 AND 66-23-2. COMPLIANCE DATE: NOT LATER THAN THE NEXT TWENTY HOURS OF OPERATION SUBJECT: REMOVAL OF MID-BLADE DECALS AND INSPECTION OF MID- BLADE AREA FOR CORROSION PITS AND CRACKS Sensenich Propeller Bulletin Number R-11 dated March 1,1966 and FAA Airworthiness Directive 66-11-3 dealt with the problem of corrosion pits found in the area of the mid-blade propeller decal. Instances of corrosion pits under and in the immediate area of the mid-blade decal have been discovered in M74DC and M74DM propellers carrying Beech decals and other models of Sensenich fixed-pitch metal propellers with Sensenich decals attached by a water-soluble adhesive. The Sensenich decals can be identified by their black border (sketch #1). Later Sensenich epoxy-adhesive decals (with a narrow gold border outside the black, sketch #2 ) are satisfactory. Water-soluble decals must not be re- installed. These decals must be removed by soaking with paint remover and rubbing off with a rag; they must not be scraped or sanded off. The mid-blade area must be thoroughly inspected with a glass of at least 3 power. If a crack or corrosion pits deeper than .015 inch are found, the propeller must be replaced before further flight. If corrosion pits (tiny black dots) are discovered, they must be removed within the next twenty hours of operation. They can be removed in the following manner: 1. Sand the area with 220 grit wet-or-dry abrasive paper and polish with 320 grit or finer. 2. Clean the area thoroughly and apply a dye penetrant. 3. Inspect with a low-power glass; it is very important that the bottom of the pits be completely removed. If the pits re-appear, repeat the operations. 4. When the pits are completely removed, spray the area with a clear lacquer. Visit Our Web Site at http://www.sensenich.com Owners who wish to do so may return their propellers to the factory for reconditioning or exchange for a factory reconditioned propeller.