AD 50-12-01
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hamilton Standard | Teledyne Continental Motors | Propeller Blades | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| aircraft | Hamilton Standard | Teledyne Continental Motors | W670-16 | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| aircraft | Hamilton Standard | Teledyne Continental Motors | W670-6A | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| aircraft | Hamilton Standard | Teledyne Continental Motors | W670-6N | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| appliance | Hamilton Standard | Teledyne Continental Motors | Propeller Blades | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| appliance | Hamilton Standard | Teledyne Continental Motors | W670-16 | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| appliance | Hamilton Standard | Teledyne Continental Motors | W670-6A | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
| appliance | Hamilton Standard | Teledyne Continental Motors | W670-6N | HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 |
Unsafe Condition
Propeller blade shank fatigue failures as a result of noncompliance with a mandatory engine operation restriction.
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Required Actions
Check and correctly mark the engine tachometer with a red arc above 1,900 r.p.m., install a placard to avoid engine operation above 1,900 r.p.m. except during takeoff, and check and index the propeller position to the zero degree position.
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Compliance Time
not later than April 15, 1950
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Affected Aircraft
Hamilton Standard Ground Adjustable Propellers with blades Model 11C1 installed on aircraft equipped with Continental Engines Models W-670-6A, W-670-6N, or W-670-16.
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Federal Register Abstract
Propeller Blade
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_50-12-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 50-12-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 Subject: Propeller Blade Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hamilton Standard | Teledyne Continental Motors Model: Propeller Blades | W670-16 | W670-6A | W670-6N Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 50-12-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 50-12-01 SUBJECT HEADING: HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 50-12-01 HAMILTON STANDARD: Applies to All Aircraft Equipped With Continental Engines, Models W-670-6A (R-670-3, -5), W-670-6N (R-670-4), W-670-16 (R-670-8, -11, - 11A) and Hamilton Standard Ground Adjustable Propellers Having Blades, Model 11C1 (Navy 4350, 4350F, 4350F1). Compliance required not later than April 15, 1950. To minimize the possibility of propeller blade shank fatigue failures as a result of noncompliance with a mandatory engine operation restriction, the following precautionary measures should be taken: (1) Check the marking on the engine tachometer and correctly mark it, if necessary, with a red arc which covers the entire r.p.m. range above the higher side of the 1,900 r.p.m. graduation. (2) Install placard in aircraft to read: "Avoid all engine operation above 1,900 r.p.m. except during takeoff". (3) Check position of the propeller and correctly index, if necessary, in the zero degree position (blades in line with crankthrow). FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_50-12-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 50-12-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 Subject: Propeller Blade Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hamilton Standard | Teledyne Continental Motors Model: Propeller Blades | W670-16 | W670-6A | W670-6N Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 50-12-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 50-12-01 SUBJECT HEADING: HAMILTON STANDARD Ground Adjustable Propellers Having Blades, Model 11C1 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 50-12-01 HAMILTON STANDARD: Applies to All Aircraft Equipped With Continental Engines, Models W-670-6A (R-670-3, -5), W-670-6N (R-670-4), W-670-16 (R-670-8, -11, - 11A) and Hamilton Standard Ground Adjustable Propellers Having Blades, Model 11C1 (Navy 4350, 4350F, 4350F1). Compliance required not later than April 15, 1950. To minimize the possibility of propeller blade shank fatigue failures as a result of noncompliance with a mandatory engine operation restriction, the following precautionary measures should be taken: (1) Check the marking on the engine tachometer and correctly mark it, if necessary, with a red arc which covers the entire r.p.m. range above the higher side of the 1,900 r.p.m. graduation. (2) Install placard in aircraft to read: "Avoid all engine operation above 1,900 r.p.m. except during takeoff". (3) Check position of the propeller and correctly index, if necessary, in the zero degree position (blades in line with crankthrow). FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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