# AD 78-08-09: Rudder Assembly - Type: Airworthiness directive - Status: Historical - Products: Allied Ag Cat Productions G-164, G-164A, G-164B, G-164B-15T, G-164B-20T, G-164B-34T and G-164B (with 73 inch wing gap) - Effective: April 21, 1978 - Superseded by: [AD 2008-22-21](https://openairdocs.org/ad/2008-22-21) - Product type: Aircraft, Small airplane - Amendment: 39-3191 - Registered aircraft: 536 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/69CDF1001B1D24DB86256A5400709C8D.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/78-08-09 ## The airworthiness directive 78-08-09 GRUMMAN AMERICAN: Amendment 39-3191. Applies to Models G-164 (S/N 1 thru 400), G-164A (S/N 401 thru 1674), and G-164B (S/N 1B thru 79B) airplanes certified in all categories. Compliance required as indicated. To prevent collection of water in the bottom of the rudder main tubular spar (P/N A1203- 11) of the rudder assembly and the resulting corrosion, accomplish the following: 1. Within the next 50 hours in service after the effective date of this AD, unless already accomplished, perform the inspection and corrosion protection specified in Steps (1) thru (6) of Grumman American Service Bulletin No. 61 dated June 6, 1977, or equivalent. 2. Within the next 300 hours in service after compliance with paragraph (1) of this AD, and within every 300 hours in service thereafter, visually inspect the exterior of the main tubular spar for corrosion. If corrosion is noted, comply with Steps (5) and (6) of the bulletin or equivalent. 3. If repairs are required in (1)and (2) of this AD, they shall be in accordance with Advisory Circular 43.13-1A, Paragraph 74, Figure 2.7 or equivalent. 4. Upon request, with substantiating data submitted through an FAA Maintenance Inspector, the compliance times specified in this AD may be adjusted by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. 5. Equivalent methods of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. This amendment is effective April 21, 1978. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 1A16](https://openairdocs.org/tcds/1A16): Allied Ag Cat Productions Inc.; names 6 of 10 models: G-164B, G-164, G-164B-20T, G-164A, G-164B-34T, G-164B-15T ## 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: 536 (536 by airframe model, 0 by engine model) - Makers: Grumman Acft ENG Cor-Schweizer 307, Grumman 117, Schweizer 62, Gulfstream-Schweizer A/C 33, Grumman American Avn. 12, Ag-Cat 5 Models with the most aircraft: - [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b): 157 aircraft (airframe model) - [Grumman Acft ENG Cor-Schweizer G-164A](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164a): 150 aircraft (airframe model) - [Grumman G-164A](https://openairdocs.org/model/grumman-g-164a): 63 aircraft (airframe model) - [Schweizer G-164B](https://openairdocs.org/model/schweizer-g-164b): 56 aircraft (airframe model) - [Grumman G-164](https://openairdocs.org/model/grumman-g-164): 52 aircraft (airframe model) - [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B](https://openairdocs.org/model/gulfstream-schweizer-a-c-gulfstream-am-g-164b): 33 aircraft (airframe model) - [Grumman American Avn. G-164B](https://openairdocs.org/model/grumman-american-avn-g-164b): 6 aircraft (airframe model) - [Ag-Cat G-164B](https://openairdocs.org/model/ag-cat-g-164b): 5 aircraft (airframe model) - [Grumman American Avn. G-164](https://openairdocs.org/model/grumman-american-avn-g-164): 3 aircraft (airframe model) - [Grumman American Avn. G-164A](https://openairdocs.org/model/grumman-american-avn-g-164a): 3 aircraft (airframe model) - [Schweizer G-164B-20T](https://openairdocs.org/model/schweizer-g-164b-20t): 3 aircraft (airframe model) - [Grumman G-164B](https://openairdocs.org/model/grumman-g-164b): 2 aircraft (airframe model) - [Schweizer G164B-34T](https://openairdocs.org/model/schweizer-g164b-34t): 2 aircraft (airframe model) - [Schweizer G164A](https://openairdocs.org/model/schweizer-g164a): 1 aircraft (airframe model) All 15 models: https://openairdocs.org/ad/78-08-09/models.md Every aircraft: https://openairdocs.org/ad/78-08-09/aircraft.md ## Related documents - [AD 2008-22-21](https://openairdocs.org/ad/2008-22-21) (historical): Main tubular spar · Allied Ag Cat Productions G-164, G-164A, G-164B and 7 more. Effective Dec 19, 2008. Supersedes this AD - [AC 43.13-1B CHG 1 Ed Update](https://openairdocs.org/ac/43.13-1): Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair. Cited as AC 43.13-1A in the AD's requirements ## NTSB investigations that cite this AD (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB LAX08LA083](https://openairdocs.org/ntsb/LAX08LA083), Mar 22, 2008: Gulfstream-Schweizer G-164B (N8148K), Genesee, ID, substantial damage. Probable cause: The in-flight failure of the rudder attachment point due to severe corrosion, which made directional control of the airplane not possible during landing. --- 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.