AD 46-23-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Noorduyn Aviation Ltd. | Army UC-64 | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft |
| aircraft | Noorduyn Aviation Ltd. | Army UC-64A | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft |
| aircraft | Noorduyn Aviation Ltd. | Army UC-64B | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft |
Unsafe Condition
Defective or deteriorated wood in the horizontal stabilizer ribs due to lack of drain holes, leading to water accumulation and structural damage.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the trailing edge of the horizontal stabilizer for drain holes. If drain holes are absent, remove fabric to inspect ribs, replace defective wood, and drill 1/16-inch diameter drain holes spaced to drain all pockets.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
At next periodic inspection.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Noorduyn Models Army UC-64, -64A, and -64B Aircraft.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Horizontal Stabilizer Drain Holes
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_46-23-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-23-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft Subject: Horizontal Stabilizer Drain Holes Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Noorduyn Aviation Ltd. Model: Army UC-64 | Army UC-64A | Army UC-64B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 46-23-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-23-05 SUBJECT HEADING: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-23-05 NOORDUYN: (Was Mandatory Note 1 of AD-2-578-1.) Applies to Army UC- 64, -64A, and -64B Aircraft. Required at next periodic inspection. Inspect the trailing edge of the horizontal stabilizer to determine whether or not drain holes are present in the metal trailing edge cover. If the holes are not present, it will be necessary to remove enough fabric to permit inspection of the ribs. Defective or deteriorated wood must be replaced and drain holes, approximately 1/16-inch diameter, spaced to drain all pockets must be drilled. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_46-23-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-23-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft Subject: Horizontal Stabilizer Drain Holes Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Noorduyn Aviation Ltd. Model: Army UC-64 | Army UC-64A | Army UC-64B Product Type: Aircraft Product Subtype: Small 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: 46-23-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-23-05 SUBJECT HEADING: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-23-05 NOORDUYN: (Was Mandatory Note 1 of AD-2-578-1.) Applies to Army UC- 64, -64A, and -64B Aircraft. Required at next periodic inspection. Inspect the trailing edge of the horizontal stabilizer to determine whether or not drain holes are present in the metal trailing edge cover. If the holes are not present, it will be necessary to remove enough fabric to permit inspection of the ribs. Defective or deteriorated wood must be replaced and drain holes, approximately 1/16-inch diameter, spaced to drain all pockets must be drilled. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
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