AD 46-40-01
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Fairchild Industries, Inc. | 24 C8 | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8A | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8B | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8D | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8DS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8E | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8ES | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8F (Army UC-61J) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8FS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24G (Army UC-61H) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24GS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24H | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24HS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24J (Army UC-61B) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24JS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24K (Army UC-61E) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24KS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8C | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R9 (Army UC-61C) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-9 (Army UC-61F) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R40 (Army UC-86) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-40 (Army UC-61G) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-41 (Army UC-61) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R46A (Army UC-61K) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-41A (Army UC-61A) | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R46 | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24 C8CS | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-40S | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24W-9S | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R46S | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R40S | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
| aircraft | Fairchild Industries, Inc. | 24R9S | Airworthiness Directives; Fairchild Model 24 Series Aircraft |
Unsafe Condition
Engine failure due to air-lock in the fuel system when fuel is fed from more than one tank at a time.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Placard the fuel tank selector valve with a caution label stating 'CAUTION. Operate on One Tank at a Time Only.'
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
immediately
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Fairchild Model 24 Series Aircraft, including models 24 C8, 24 C8A, 24 C8B, 24 C8D, 24 C8DS, 24 C8E, 24 C8ES, 24 C8F (Army UC-61J), 24 C8FS, 24G, and others as listed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Fuel Tank Selector Valve Placard
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_46-40-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-40-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Fairchild Model 24 Series Aircraft Subject: Fuel Tank Selector Valve Placard Status: Current Citation: This information is not available. Citation Publish Date: 06/17/1950 Effective Date: 12/31/1946 Make: Fairchild Industries, Inc. Model: 24 C8 | 24 C8A | 24 C8B | 24 C8D | 24 C8DS | 24 C8E | 24 C8ES | 24 C8F (Army UC-61J) | 24 C8FS | 24G...Show more Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: AIR-700: Compliance & Airworthiness Division Office of Primary Responsibility: AIR-720: Operational Safety Branch CFR Part Reference: Part 39 Comments: unable to find issue date or effective date other than in https://www.govinfo.gov/content/pkg/FR-195...Show more AIRWORTHINESS DIRECTIVES FINAL RULES: 46-40-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-40-01 SUBJECT HEADING: Airworthiness Directives; Fairchild Model 24 Series Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-40-01 FAIRCHILD: (Was Mandatory Note 4 of AD-707-2: 3 of AD-706-1: 3 of AD- 667-2; 4 of AD-600-2; 4 of AD-633-2; 4 of AD-535-2.) Applies to All Model 24 Series Aircraft. To eliminate the possibility of engine failure due to air-lock in the fuel system, the fuel tank selector valve should be placarded immediately to specify that fuel be fed from only one tank at a time. This placard should read: "CAUTION. Operate on One Tank at a Time Only." (Fairchild Service Bulletin No. 44-7-C dated February 10, 1944, covers this same subject.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_46-40-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-40-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Fairchild Model 24 Series Aircraft Subject: Fuel Tank Selector Valve Placard Status: Current Citation: This information is not available. Citation Publish Date: 06/17/1950 Effective Date: 12/31/1946 Make: Fairchild Industries, Inc. Model: 24 C8 | 24 C8A | 24 C8B | 24 C8D | 24 C8DS | 24 C8E | 24 C8ES | 24 C8F (Army UC-61J) | 24 C8FS | 24G...Show more Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: AIR-700: Compliance & Airworthiness Division Office of Primary Responsibility: AIR-720: Operational Safety Branch CFR Part Reference: Part 39 Comments: unable to find issue date or effective date other than in https://www.govinfo.gov/content/pkg/FR-195...Show more AIRWORTHINESS DIRECTIVES FINAL RULES: 46-40-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-40-01 SUBJECT HEADING: Airworthiness Directives; Fairchild Model 24 Series Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-40-01 FAIRCHILD: (Was Mandatory Note 4 of AD-707-2: 3 of AD-706-1: 3 of AD- 667-2; 4 of AD-600-2; 4 of AD-633-2; 4 of AD-535-2.) Applies to All Model 24 Series Aircraft. To eliminate the possibility of engine failure due to air-lock in the fuel system, the fuel tank selector valve should be placarded immediately to specify that fuel be fed from only one tank at a time. This placard should read: "CAUTION. Operate on One Tank at a Time Only." (Fairchild Service Bulletin No. 44-7-C dated February 10, 1944, covers this same subject.) 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.
Related Airworthiness Directives
46-40-02
final ruleAirworthiness Directives; Fairchild Models 22 and 24 Series Aircraft
Unsafe Condition: Failure of the oleo tube reinforcement could result in structural failure of the oleo tube at the piston end, leading to loss of aircraft control.
46-21-01
final ruleAirworthiness Directives; Fairchild Model 24 Series Aircraft
Unsafe Condition: Freezing of the upper and lower universal joints on the landing gear oleo shock struts.
