AD 48-17-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-51 | Airworthiness Directives; Sikorsky Model S-51 Helicopters |
Unsafe Condition
Wear in the primary and secondary planet pinion shafts (Sikorsky P/N S-535524) may cause malfunctioning of the main rotor gearbox.
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Required Actions
Rotate the planet pinion shafts 180 degrees or replace them with new parts after 800 hours of operation. If rotated, replacement must be done after an additional 800 hours.
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Compliance Time
at each 800-hour inspection
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Affected Aircraft
Sikorsky Model S-51 Helicopters
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Federal Register Abstract
Planet Pinion Shafts Wear
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-17-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-17-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Model S-51 Helicopters Subject: Planet Pinion Shafts Wear Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sikorsky Aircraft Corporation Model: S-51 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-17-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-17-03 SUBJECT HEADING: Airworthiness Directives; Sikorsky Model S-51 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-17-03 SIKORSKY: Applies to Model S-51 Helicopters. Compliance required at each 800-hour inspection. In order to preclude any malfunctioning of the main rotor gearbox due to the normal wear which may be expected to occur in the primary and secondary planet pinion shafts (Sikorsky P/N S-535524), these parts should be rotated 180 degrees or replaced by new parts after 800 hours of operation. If rotated, replacement by new parts should be made after an additional 800 hours. (Sikorsky Aircraft Service Information Circular No. 8 Revision "B" dated January 13, 1948, covers this same subject.) AD 48-17-03 FOOTER:
Document Text
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AD Final Rules - DRS_48-17-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-17-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Model S-51 Helicopters Subject: Planet Pinion Shafts Wear Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sikorsky Aircraft Corporation Model: S-51 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-17-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-17-03 SUBJECT HEADING: Airworthiness Directives; Sikorsky Model S-51 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-17-03 SIKORSKY: Applies to Model S-51 Helicopters. Compliance required at each 800-hour inspection. In order to preclude any malfunctioning of the main rotor gearbox due to the normal wear which may be expected to occur in the primary and secondary planet pinion shafts (Sikorsky P/N S-535524), these parts should be rotated 180 degrees or replaced by new parts after 800 hours of operation. If rotated, replacement by new parts should be made after an additional 800 hours. (Sikorsky Aircraft Service Information Circular No. 8 Revision "B" dated January 13, 1948, covers this same subject.) AD 48-17-03 FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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