AD 2008-22-21

The FAA adopts a new airworthiness directive (AD) to supersede AD 78-08-09, which applies to certain Allied Ag Cat Productions, Inc. (formerly Grumman-American) (Allied Ag Cat) Models G-164, G-164A, and G-164B airplanes. AD 78-08-09 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. Since we issued AD 78-08-09, the rudder main tubular spar failed on a later production airplane. Consequently, this AD retains the actions required in AD 78-08-09 and expands the applicability to include all G-164 series airplanes. We are issuing this AD to detect and correct corrosion in the rudder main tubular spar, which could result in failure of the weld to the main spar tube. This failure could lead to loss of directional control.

Final rule.

2008-22-21 Allied Ag Cat Productions, Inc.: Amendment 39-15718; Docket No. FAA-2008-0854; Directorate Identifier 2008-CE-050-AD.

Effective Date

(a) This AD becomes effective on December 19, 2008.

Affected ADs

(b) This AD supersedes AD 78-08-09, Amendment 39-3191.

Applicability

(c) This AD applies to the following airplane models, all serial numbers, that are certificated in any category:

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.

Unsafe Condition

(d) This AD results from a report of the rudder main tubular spar failing on a later production airplane. We are issuing this AD to detect and correct corrosion in the rudder main tubular spar, which could result in failure of the weld to the main spar tube. This failure could lead to loss of directional control.

Compliance

(e) To address this problem, you must do the following, 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.
(i) For airplanes previously affected by AD 78-08-09: Initially inspect within the next 60 months after the last inspection required in AD 78-08-09 or within the next 30 days after December 19, 2008 (the effective date of this AD), whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 60 calendar months.
(ii) For airplanes not previously affected by AD 78-08-09: Initially inspect within the next 30 days after the effective date of this AD. Repetitively inspect thereafter at intervals not to exceed 60 calendar months.
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 (e)(1) of this AD, repair in accordance with Advisory Circular 43.13-1B or equivalent, 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. Following Advisory Circular 43.13-1B or equivalent and/or an
FAA-approved procedure. The appropriate maintenance manual contains these procedures.
(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 any inspection required in paragraph (e)(1) of this AD and after any repair or replacementrequired in paragraph (e)(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 any inspection required in paragraph (e)(1) of this AD and after any repair or replacement required in paragraph (e)(2) of this AD.
Following an
FAA-approved procedure. The appropriate maintenance manual contains these procedures.
(5) Only install a rudder that has been inspected as specified in paragraph (e)(1) of this AD, is free of corrosion, and has had the corrosion protection applied and sealed as specified in paragraph (e)(3) of this AD.
As of the next 30 days after December 19, 2008 (the effective date of this AD.
Not applicable.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Fort Worth Airplane Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Andy McAnaul, Aerospace Engineer, ASW-150, FAA San Antonio MIDO-43, 10100 Reunion Place, Suite 650, San Antonio, Texas 78216, phone: (210) 308-3365; fax: (210) 308-3370. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.
(g) AMOCs approved for AD 78-08-09 are not approved for this AD.

Material Incorporated by Reference

(h) You must use Grumman American Aviation Corporation Ag-Cat Service Bulletin No. 61, dated June 6, 1977, and 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, to do the actions required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2)For service information identified in this AD, contact Allied Ag Cat Productions, Inc., 301 West Walnut Street, P.O. Box 482, Walnut Ridge, Arkansas 72479; telephone: (870) 886-2418.
(3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202- 741-6030, or go to: http://www.archives.gov/federal_register/code_ of_federal_regulations/ibr_locations.html.

Discussion

On August 1, 2008, we issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Allied Ag Cat Models G-164, G-164A, and G-164B airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on August 7, 2008 (73 FR 45900). The NPRM proposed to supersede AD 78-08-09 with a new AD that would retain the actions required in AD 78-08-09 and expand the applicability to include all G-164 series airplanes.

Comments

We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:

Comment Issue No. 1: AD Is Supported

Ronald I. Gustin, Craig T. Fountain, and Ken J. Kuther all state that they support the AD action as proposed in the NPRM.
Ronald Gustin states that of the 13 Ag Cat airplanes inspected by mechanics at Gustin Aviation, which was prompted by the NPRM, 4 airplanes had severe corrosion of the rudder main spar tube that required repair; 2 airplanes had light rust; and 7 airplanes were corrosion free. Craig T. Fountain and Ken J. Kuther, who collectively own four of the airplanes inspected by Gustin Aviation, confirm the reported corrosion found and also support the proposed AD action.
The commenters support the NPRM.
We are not changing the final rule AD action based on these comments.

Comment Issue No. 2: Extend Comment Period

Bryan D. Hauschild states that he is planning to recover the rudder on his airplane during the off-season, which is November through March. He states that at that time he would be able to get a good look at the area in question.
Mr. Hauschild requests to extend the comment period for the NPRM so that his airplane is not pulled from its seasonal service at this time.
We do not agree with the commenter. We believe that the fleet servicehistory and severity of corrosion reported on Ag Cat rudders requires AD action. Extending the comment period in order to delay the effective date of this AD would create an unacceptable safety risk.
We are not changing the final rule AD action based on this comment.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections:
Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.

Costs of Compliance

We estimate that this AD affects 2,700 airplanes in the U.S. registry.
We estimate the following costs to do the inspections:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on U.S. Operators
4 work-hours X $80 per hour = $320
Not applicable
$320
$864,000

We have no way of determining the cost of repairs, parts replacement, or the number of airplanes that may require repair or parts replacement based on the result of the proposed inspections.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, section 44701, "General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.
For the reasons discussed above, I certify that this AD:
1. Is not a "significant regulatory action'' under Executive Order 12866;
2. Is not a "significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this AD (and other information as included in the Regulatory Evaluation) and placed it in the ADDocket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "Docket No. FAA-2008-0854; Directorate Identifier 2008-CE-050-AD'' in your request.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 78-08-09, Amendment 39-3191, and adding the following new AD: