AD 47-10-37
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Aircraft Corporation | 49-46 | LOCKHEED Model 49 |
Unsafe Condition
Loosening of the inboard pair of bolts in the outboard fulcrum and the outboard pair of bolts in the inboard fulcrum of each main landing gear, which could lead to reduced clamping force and potential failure of the landing gear structure.
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Required Actions
Periodically check the tightness of specified landing gear fulcrum bolts at intervals not exceeding 500 flight hours using a torque wrench. Maintain a continuous record of torque readings. If any bolt loosens to approximately 900 inch-pounds, remove all 16 fulcrum bolts, countersink fitting holes to 0.064 x 45 degrees, replace bolts, and tighten to 2,300-2,500 inch-pounds. Discontinue 500-hour inspections after corrective action.
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Compliance Time
before further flight
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Affected Aircraft
Lockheed Aircraft Corporation Model 49 serial numbers up to and including 2071.
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Federal Register Abstract
Landing Gear Fulcrum Bolts
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_47-10-37.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-10-37 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49 Subject: Landing Gear Fulcrum Bolts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 49-46 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-10-37 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-10-37 SUBJECT HEADING: LOCKHEED Model 49 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-10-37 LOCKHEED: (Was Service Note 8 of AD-763-3.) Applies to All Model 49 Serials Up to and Including 2071. At periods not to exceed 500 hours, check the tightness of the inboard pair of bolts in the outboard fulcrum and the outboard pair of bolts in the inboard fulcrum of each main landing gear, using a torque wrench. A continuous record should be kept to show whether these bolts become more loose with time; therefore, these bolts should not be tightened during the periodic inspections. When any of these 8 bolts loosen to a torque wrench reading of approximately 900 inch-pounds, all fulcrum bolts (16 per airplane) should be removed, the fitting holes countersunk 0.064 x 45 degrees to accommodate the bolt head fillets, the bolts replaced and tightened to a torque wrench reading of 2,300-2,500 inch-pounds. The 500-hour inspection may then be discontinued. (Lockheed Service Bulletin 49/SB-51, revised March 3, 1947, covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_47-10-37.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-10-37 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49 Subject: Landing Gear Fulcrum Bolts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 49-46 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-10-37 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-10-37 SUBJECT HEADING: LOCKHEED Model 49 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-10-37 LOCKHEED: (Was Service Note 8 of AD-763-3.) Applies to All Model 49 Serials Up to and Including 2071. At periods not to exceed 500 hours, check the tightness of the inboard pair of bolts in the outboard fulcrum and the outboard pair of bolts in the inboard fulcrum of each main landing gear, using a torque wrench. A continuous record should be kept to show whether these bolts become more loose with time; therefore, these bolts should not be tightened during the periodic inspections. When any of these 8 bolts loosen to a torque wrench reading of approximately 900 inch-pounds, all fulcrum bolts (16 per airplane) should be removed, the fitting holes countersunk 0.064 x 45 degrees to accommodate the bolt head fillets, the bolts replaced and tightened to a torque wrench reading of 2,300-2,500 inch-pounds. The 500-hour inspection may then be discontinued. (Lockheed Service Bulletin 49/SB-51, revised March 3, 1947, covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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