AD 56-16-03
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | HRS-1/CH-19 | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | HRS-3/H-19B | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | S-51 | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | S-55 | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | S-55B | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
| aircraft | Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation | S-55C | Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters |
Unsafe Condition
Fine cuts on the spar beneath the edges of the pockets of main rotor blades, resulting from repairs to blade pockets, which act as serious stress raisers and may reduce blade service life.
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Required Actions
Inspect main rotor blades for fine cuts beneath pocket edges following Sikorsky Service Information Circulars No. 676 (S-51) and 1410-669 (S-55). Refinish serviceable blades, rework salvagable blades, and return blades with cuts on the back or excessive service hours to the manufacturer for evaluation.
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Compliance Time
Inspections required as soon as practicable but prior to 500 hours service since manufacture/rebuilding (for blades with less than 500 hours) or not later than August 15, 1956 (for blades with 500+ hours).
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Affected Aircraft
Sikorsky Models S-55 (S14-10-2000-1, -2, -3, -4, -5 blades, serial 100-3700) and S-51 (S10-10-2065 series blades, serial 100-3700).
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Main Rotor Blade Inspection
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_56-16-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-16-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters Subject: Main Rotor Blade Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation Model: HRS-1/CH-19 | HRS-3/H-19B | S-51 | S-55 | S-55B | S-55C 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: 56-16-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-16-03 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-16-03 SIKORSKY: Applies to All Model S-55 Helicopters With S14-10-2000-1, -2, - 3, -4, and -5 Main Rotor Blades Bearing Serial Numbers 100-3700 Inclusive, and All Model S-51 Helicopters With S10-10-2065 Series Main Rotor Blades Bearing Serial Numbers 100-3700 Inclusive. Compliance required as indicated. Main rotor blades of the S10-10-2065 Series on the S-51 and of the S14-10-2000-1, -2, - 3, -4 and -5 Series on the S-55 have been found with fine cuts on the spar beneath the edges of the pockets. These cuts are believed to be a result of repairs to blade pockets and constitute serious stress raisers which may materially affect the service life of the blades. Inspections are to be accomplished as indicated below. The necessary preparations for inspections, the inspections, the finishing of serviceable blades and the rework of salvable blades are to be in accordance with the procedures recommended in Sikorsky Service Information Circular No. 676 for the S-51 and 1410-669 for the S-55. 1. All blades with less than 500 hours service since manufacture or complete rebuilding prior to May 1953, should be inspected as soon as practicable but prior to the accumulation of 500 hours. 2. All blades with 500 hours or more service since manufacture or complete rebuilding prior to May 1953, should be inspected as soon as practicable but not later than August 15, 1956. 3. Blades found to have no cuts may be returned to service after refinishing. 4. S-55 blades with less than 1,200 hours service and S-51 blades with less than 1,000 hours service and found to have cuts on the top or bottom may be salvaged. 5. Blades found to have cuts on the back are to be returned to the manufacturer for evaluation. 6. S-55 blades with 1,200 hours or more service and S-51 blades with 1,000 hours or more service and found to have cuts on the top, bottom or back are to be returned to the manufacturer for evaluation. FOOTER:
Document Text
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AD Final Rules - DRS_56-16-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 56-16-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters Subject: Main Rotor Blade Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Orlando Helicopter Airways, Inc. | Sikorsky Aircraft Corporation Model: HRS-1/CH-19 | HRS-3/H-19B | S-51 | S-55 | S-55B | S-55C 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: 56-16-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 56-16-03 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-55 and S-51 Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 56-16-03 SIKORSKY: Applies to All Model S-55 Helicopters With S14-10-2000-1, -2, - 3, -4, and -5 Main Rotor Blades Bearing Serial Numbers 100-3700 Inclusive, and All Model S-51 Helicopters With S10-10-2065 Series Main Rotor Blades Bearing Serial Numbers 100-3700 Inclusive. Compliance required as indicated. Main rotor blades of the S10-10-2065 Series on the S-51 and of the S14-10-2000-1, -2, - 3, -4 and -5 Series on the S-55 have been found with fine cuts on the spar beneath the edges of the pockets. These cuts are believed to be a result of repairs to blade pockets and constitute serious stress raisers which may materially affect the service life of the blades. Inspections are to be accomplished as indicated below. The necessary preparations for inspections, the inspections, the finishing of serviceable blades and the rework of salvable blades are to be in accordance with the procedures recommended in Sikorsky Service Information Circular No. 676 for the S-51 and 1410-669 for the S-55. 1. All blades with less than 500 hours service since manufacture or complete rebuilding prior to May 1953, should be inspected as soon as practicable but prior to the accumulation of 500 hours. 2. All blades with 500 hours or more service since manufacture or complete rebuilding prior to May 1953, should be inspected as soon as practicable but not later than August 15, 1956. 3. Blades found to have no cuts may be returned to service after refinishing. 4. S-55 blades with less than 1,200 hours service and S-51 blades with less than 1,000 hours service and found to have cuts on the top or bottom may be salvaged. 5. Blades found to have cuts on the back are to be returned to the manufacturer for evaluation. 6. S-55 blades with 1,200 hours or more service and S-51 blades with 1,000 hours or more service and found to have cuts on the top, bottom or back are to be returned to the manufacturer for evaluation. FOOTER:
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Retrieved: Apr 8, 2026
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