Airworthiness Directive · Amendment 39-16616 · Stabilizers
Allied Ag Cat Productions, Inc. Models G-164, G-164A, G-164B, G-164B With 73″ Wing Gap, G-164B-15T, G-164B-34T, G-164B-20T, G-164C, G-164D, and G-164D With 73″ Wing Gap Airplanes
This AD applies to the following Allied Ag Cat Productions, Inc. model airplanes, all serial numbers, that are certificated in any category:
| G-164 | G-164A | G-164B | G-164B with 73″ wing gap. |
| G-164B-15T | G-164B-20T | G-164B-34T | G-164C. |
| G-164D | G-164D with 73″ wing gap |
We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires repetitively inspecting the interior and the exterior of the main tubular spar of the rudder assembly for corrosion, taking necessary corrective action if corrosion is found, and applying corrosion protection. This AD retains the requirements of the previous AD and changes the compliance time for certain products listed above. This AD was prompted by our determination that the compliance time specified for Models G-164, G- 164A, and G-164B airplanes does not adequately address the unsafe condition. We are issuing this AD to detect and correct corrosion in the rudder main tubular spar, which could result in failure of the rudder main spar tube. This failure could lead to loss of directional control.
Comply with this AD within the compliance times specified, unless already done.
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Drill an access hole and do a visual inspection using a borescope of the lower end internal cavity of the rudder main spar tube for corrosion and do a visual inspection of the exterior of the rudder main spar tube for corrosion | Initially inspect within the next 30 days after March 17, 2011 (the effective date of this AD), unless already done within the previous 60 months. Repetitively inspect thereafter at intervals not to exceed 60 months from the last inspection | Following Steps 1 through 3 of Grumman American Aviation Corporation Ag-Cat Service Bulletin No. 61, dated June 6, 1977. |
| (2) If corrosion is found during any inspection required in paragraph (f)(1) of this AD, repair in accordance with Chapter 4 of FAA Advisory Circular 43.13-1B, Chg 1, dated September 27, 2001, or replace the damaged part(s) | Before further flight after any inspection in which corrosion is found | As specified in Steps 5 and 6 of Grumman American Aviation Corporation Ag-Cat Service Bulletin No. 61, dated June 6, 1977, and following Chapter 4 of FAA Advisory Circular 43.13-1B, Chg 1, dated September 27, 2001, which can be found at http://rgl.faa.gov/. |
| (3) After each inspection, repair, or replacement required in this AD, corrosion protect the spar tube internal cavity by filling with warm, raw linseed oil, Paralketone, or CRC3 (LPS Heavy Duty Rust Inhibitor Type 3), or suitable equivalent protector for alloy steel, and allow to drain. Seal access hole with Scotch caulking compound, a suitable silicone based sealant, or equivalent | Before further flight after each inspection required in paragraph (f)(1) of this AD and after each repair or replacement required in paragraph (f)(2) of this AD | As specified in Step 4 of Grumman American Aviation Corporation Ag-Cat Service Bulletin No. 61, dated June 6, 1977. |
| (4) Verify rigging check of the rudder | Before further flight after each inspection required in paragraph (f)(1) of this AD and after each repair or replacement required in paragraph (f)(2) of this AD | Following Ag-Cat Maintenance Manual pages 6-14 through 6-16, copyright 1978; or Ag-Cat G-164D Maintenance Manual pages 6-24 and 6-29, copyright 1995, as applicable. |
| (5) Only install a rudder that has been inspected as specified in paragraph (f)(1) of this AD, is found free of corrosion, has had the corrosion protection applied, and has been sealed as specified in paragraph (f)(3) of this AD | As of 30 days after March 17, 2011 (the effective date of this AD) | Not applicable. |
