# AD 46-40-01: Fuel Tank Selector Valve Placard - Type: Airworthiness directive - Status: Current - Products: Fairchild Industries 24 C8, 24 C8A, 24 C8B, 24 C8D, 24 C8DS, 24 C8E, 24 C8ES, 24 C8F (Army UC-61J), 24 C8FS, 24G (Army UC-61H), 24GS, 24H and 20 more - Effective: December 31, 1946 - Published: June 17, 1950 - Issued: December 31, 1946 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Registered aircraft: 188 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/5AB367C086B18D6986256A38004EA5E1.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/46-40-01 ## The airworthiness directive 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.) ## Affected data sheets (13) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A-706](https://openairdocs.org/tcds/A-706): Fairchild Personal Planes Division Fairchild Engine and Airplane Corp.; names 7 of 7 models: 24R46, 24R9S, 24R40 (Army UC-86), 24R46S, 24R9 (Army UC-61C), 24R46A (Army UC-61K), 24R40S - [TCDS A-707](https://openairdocs.org/tcds/A-707): Fairchild Personal Planes Division Fairchild Engine and Airplane Corp.; names 6 of 10 models: 24W-41 (Army UC-61), 24W-9 (Army UC-61F), 24W-9S, 24W-41A (Army UC-61A), 24W-40S, 24W-40 (Army UC-61G) - [TCDS A-535](https://openairdocs.org/tcds/A-535): Fairchild Personal Planes Division Fairchild Engine and Airplane Corp.; names 2 of 2 models: 24 C8CS, 24 C8C - [TCDS ATC 576](https://openairdocs.org/tcds/ATC%20576): Fairchild Industries Inc.; names 2 of 2 models: 24 C8D, 24 C8DS - [TCDS ATC 600](https://openairdocs.org/tcds/ATC%20600): Fairchild Industries Inc.; names 2 of 2 models: 24 C8ES, 24 C8E - [TCDS ATC 610](https://openairdocs.org/tcds/ATC%20610): Fairchild Industries Inc.; names 2 of 2 models: 24 C8F (Army UC-61J), 24 C8FS - [TCDS ATC 632](https://openairdocs.org/tcds/ATC%20632): Fairchild Industries Inc.; names 2 of 2 models: 24H, 24HS - [TCDS ATC 633](https://openairdocs.org/tcds/ATC%20633): Fairchild Industries Inc.; names 2 of 2 models: 24G (Army UC-61H), 24GS - [TCDS TC 663](https://openairdocs.org/tcds/TC%20663): Fairchild Industries Inc.; names 2 of 2 models: 24JS, 24J (Army UC-61B) - [TCDS TC 667](https://openairdocs.org/tcds/TC%20667): Fairchild Industries Inc.; names 2 of 2 models: 24KS, 24K (Army UC-61E) - [TCDS ATC 475](https://openairdocs.org/tcds/ATC%20475): Fairchild Industries Inc.; names 1 of 1 models: 24 C8 - [TCDS ATC 497](https://openairdocs.org/tcds/ATC%20497): Fairchild Industries Inc.; names 1 of 1 models: 24 C8A - [TCDS ATC 498](https://openairdocs.org/tcds/ATC%20498): Fairchild Industries Inc.; names 1 of 1 models: 24 C8B ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 188 (188 by airframe model, 0 by engine model) - Makers: Fairchild 188 Models with the most aircraft: - [Fairchild 24R-46](https://openairdocs.org/model/fairchild-24r-46): 50 aircraft (airframe model) - [Fairchild 24W-41A](https://openairdocs.org/model/fairchild-24w-41a): 18 aircraft (airframe model) - [Fairchild 24R-46A](https://openairdocs.org/model/fairchild-24r-46a): 15 aircraft (airframe model) - [Fairchild 24W-40](https://openairdocs.org/model/fairchild-24w-40): 15 aircraft (airframe model) - [Fairchild 24 C8C](https://openairdocs.org/model/fairchild-24-c8c): 14 aircraft (airframe model) - [Fairchild 24 G](https://openairdocs.org/model/fairchild-24-g): 14 aircraft (airframe model) - [Fairchild 24 H](https://openairdocs.org/model/fairchild-24-h): 9 aircraft (airframe model) - [Fairchild 24R-9](https://openairdocs.org/model/fairchild-24r-9): 9 aircraft (airframe model) - [Fairchild 24 J](https://openairdocs.org/model/fairchild-24-j): 8 aircraft (airframe model) - [Fairchild 24W-9](https://openairdocs.org/model/fairchild-24w-9): 7 aircraft (airframe model) - [Fairchild 24 C8E](https://openairdocs.org/model/fairchild-24-c8e): 6 aircraft (airframe model) - [Fairchild 24 K](https://openairdocs.org/model/fairchild-24-k): 6 aircraft (airframe model) - [Fairchild 24 C8F](https://openairdocs.org/model/fairchild-24-c8f): 5 aircraft (airframe model) - [Fairchild 24R-40](https://openairdocs.org/model/fairchild-24r-40): 5 aircraft (airframe model) - [Fairchild 24 C8A](https://openairdocs.org/model/fairchild-24-c8a): 4 aircraft (airframe model) - [Fairchild 24 C8](https://openairdocs.org/model/fairchild-24-c8): 1 aircraft (airframe model) - [Fairchild 24 C8D](https://openairdocs.org/model/fairchild-24-c8d): 1 aircraft (airframe model) - [Fairchild 24R-46S](https://openairdocs.org/model/fairchild-24r-46s): 1 aircraft (airframe model) All 18 models: https://openairdocs.org/ad/46-40-01/models.md Every aircraft: https://openairdocs.org/ad/46-40-01/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.