AD 96-18-02

This amendment supersedes Airworthiness Directive (AD) 96-03-11, which currently requires the following on American Champion Aircraft Corporation (American Champion) Models 8KCAB, 8GCBC, 7GCBC, and 7ECA airplanes that are equipped with metal spar wings: inspecting (one-time) the wing front strut attach fittings for cracks, scratches, or surface deformities; replacing any wing front strut attach fitting with cracks, scratches, or surface deformities; and reporting the inspection results to the Federal Aviation Administration (FAA). This action results from reports submitted as a requirement of the existing AD that reference 24 fittings with cracks, scratches, or surface deformities on 7 different airplanes, and the FAA's determination that improved wing front strut attach fittings (developed by American Champion) are not susceptible to cracks, scratches, or surface deformities. This action requires installing removable inspection hole covers for the wing front strut attachfittings, and replacing the wing front strut attach fittings with fittings of improved design. The action also provides the provision of repetitively inspecting the wing front strut attach fittings (provided no cracks, scratches, or surface deformities are found) if parts have been ordered but are not available. The actions specified by this AD are intended to prevent structural failure of a wing caused by cracked wing front strut attach fittings, which, if not detected and corrected, could result in loss of control of the airplane.

Final rule; request for comments.

96-18-02 AMERICAN CHAMPION AIRCRAFT CORPORATION: Amendment 39-9726; Docket No. 96-CE-36-AD. Supersedes AD 96-03-11, Amendment 39-9508.

Applicability: The following airplane models and serial numbers, certificated in any category, that are equipped with metal spar wings:

- Model 8KCAB airplanes, serial numbers 643-90 through 768-96;

- Model 8KCAB airplanes, all serial numbers, that are equipped with metal spar wings, wing assembly part number (P/N) 7-1521 (installed in accordance with American Champion Service Kit 403);

- Model 8GCBC airplanes, serial numbers 361-91 through 377-96;

- Model 8GCBC airplanes, all serial numbers, that are equipped with metal spar wings, wing assembly part number 7-1542;

- Model 7GCBC airplanes, serial numbers 1200-94 through 1215-96;

- Model 7GCBC airplanes, all serial numbers, that are equipped with metal spar wings, wing assembly part number 7-1545;

- Model 7ECA airplanes, serial numbers 1355-95 through1358-96; and

- Models 7ECA, 7GCAA, and 7KCAB airplanes, all serial numbers, that are equipped with metal spar wings, wing assembly part number 7-1567.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required within the next 20 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

To prevent structural failure of a wing assembly caused by cracked wing front strut attach fittings, which, if not detected and corrected, could result in loss of control of the airplane, accomplish the following:

(a) Install removable inspection hole openings for the wing front strut attach fittings in accordance with one of the following, as applicable:

(1) American Champion Service Letter (SL) 410, dated May 6, 1996, for Model 8KCAB airplanes that have complied with American Champion SL 408, dated January 24, 1996;

(2) American Champion SL 411, dated May 6, 1996, for Model 8KCAB airplanes that have not complied with American Champion SL 408, dated January 24, 1996;

(3) American Champion SL 412, dated May 6, 1996, for Models 7ECA, 7GCAA, 7GCBC, and 8GCBC airplanes that have complied with American Champion SL 409, Revision A, dated April 22, 1996; and

(4) American Champion SL 413, dated May 6, 1996, for Models 7ECA, 7GCAA, 7GCBC, and 8GCBC airplanes that have not complied with American Champion SL 409, Revision A, dated April 22, 1996.

NOTE 2: American Champion SL 408 and American Champion SL 409, when complied with, incorporate permanent inspection holes for access to the wing front strut attach fittings, P/N 3-1632-1 and P/N 3-1632-2; and P/N 3-1646L and 3-1646R, respectively.

(b) Replace the wing front strut attach fittings with P/N 3-1691 (Model 8KCAB) or P/N 3-1692 (Models 8GCBC, 7ECA, 7GCAA, 7GCBC, and 7KCAB) wing front strut attach fittings, as applicable. Accomplishment of these actions is required in accordance with the instructions in American Champion SL 414, Revision A, dated June 25, 1996; or American Champion SL 415, Revision A, dated June 25, 1996, as applicable.

(c) If the improved design wing front strut attach fittings referenced in paragraph (b) have been ordered from the manufacturer, but are not available, repetitively inspect the wing front strut attach fittings for cracks, scratches, or surface deformities at intervals not to exceed 20 hours TIS in accordance with the instructions in American Champion SL 408, dated January 24, 1996, or American Champion SL 409, Revision A, dated April 22, 1996, as applicable. Figure 3 of these service letters depicts the crosshatched areas of the fittings that must be inspected. These service letters also specify both a visual inspection and the choice of either a dye penetrant, Zyglo test, ultrasonic, or x-ray inspection.

(d) The repetitive inspections allowed in paragraph (c) of this AD may be continued until one of the following occurs at which time the replacement required by paragraph (b) of this AD must be accomplished prior to further flight:

(1) Cracks, scratches, or surface deformities are found on a wing front strut attach fitting;

(2) Parts become available from the American Champion Aircraft Corporation; or

(3) Six repetitive inspection intervals are accomplished (120 hours TIS).

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) An alternative method of compliance or adjustment of the initial or repetitive compliance time that provides an equivalent level of safety may be approved by the Manager, Chicago Aircraft Certification Office (ACO), 2300 E. Devon Avenue, Des Plaines, Illinois 60018. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Chicago ACO. Alternative methods of compliance approved in accordance with AD 96-03-11 (superseded by this action), are not considered approved as alternative methods of compliance for this AD.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Chicago ACO.

(g) The incorporation of certain documents referenced in this AD is as follows:

(1) The installations required by this AD shall be done in accordance with American Champion Service Letter 410, dated May 6, 1996; American Champion Service Letter 411, dated May 6, 1996; American Champion Service Letter 412, dated May 6, 1996; or American Champion Service Letter 413, dated May 6, 1996, as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The replacements required by this AD shall be accomplished in accordance with American Champion Service Letter 414, Revision A, dated June 25, 1996; or American Champion Service Letter 415, Revision A, dated June 25, 1996, as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(3) The inspections (if parts are not available) required by this AD shall be accomplished in accordance with American Champion Service Letter 408, dated January 24, 1996, or American Champion Service Letter 409, Revision A, dated April 22, 1996.

(i) The incorporation by reference of American Champion Service Letter 408 reference was previously approved as of February 26, 1996 (61 FR 5501, February 13, 1996) by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(ii) The incorporation by reference of American Champion Service Letter 409 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(4) Copies may be obtained from the American Champion Aircraft Corporation, 32032 Washington Avenue, Rochester, Wisconsin 53167. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment (39-9726) supersedes AD 96-03-11, Amendment 39-9598.

(i) This amendment becomes effective on September 20, 1996.

Events Leading to This Action
On January 31, 1996, the FAA issued AD 96-03-11, Amendment 39-9598 (61 FR 5501, February 13, 1996), to require the following on American Champion Models 8KCAB, 8GCBC, 7GCBC, and 7ECA airplanes that are equipped with metal spar wings:

- inspecting (one-time) the wing front strut attach fittings for cracks, scratches, or surface deformities;

- replacing any wing front strut attach fitting with cracks, scratches, or surface deformities; and

- reporting the inspection results to the FAA.

AD 96-03-11 resulted from an investigation of an American Champion Model 8KCAB airplane accident that revealed fatigue cracking of the wing front strut attach fittings. The design of the wing and fuselage structure of this airplane is such that the outboard ends of the wing fittings for each primary strut are bolted to the web of the wing's front spar. One fitting is on the forward side of the web and one is on the aft side of the web. The fittings then transition to a wider area where the strut is attached with a bolt. On the airplane involved in the accident that resulted in AD 96-03-11, the forward fitting fractured through the transition area (approximately in the center of the fitting length), causing the fitting to separate. This wing front strut attach fitting transition area contains an aft leg that is assembled against the forward face of the wing spar web and a forward leg.

Investigation of the fitting from the accident aircraft revealed that small, sharp scratches in the forward edge of the shorter portion of the aft leg contributed to the fatigue cracking in the wing fitting. Metallurgical examination of the fitting indicated that these fatigue cracks formed in scratches and surface deformities that resulted during the manufacturing process, and existed prior to the accident.

After that accident and prior to issuing AD 96-03-11, the FAA and American Champion inspected anotherModel 8KCAB airplane and found fatigue cracks on two of the four wing front strut attach fittings. These fatigue cracks also originated from scratches and surface deformities in the wing front strut attach fitting. In addition, an evaluation of new uninstalled wing front strut attach fittings revealed these scratches and surface deformities. American Champion Models 8GCBC, 7GCBC, and 7ECA airplanes incorporate this same design fitting, and thus were included in the Applicability section of AD 96-03-11.

The results of the inspections required by AD 96-03-11 revealed 24 wing front strut attach fittings with cracks, scratches, or surface deformities. These cracked and scratched fittings were from 7 different affected airplanes that had between 103 to 666 total hours time-in-service.

Improved Design Parts and Service Information
American Champion has designed improved wing front strut attach fittings, part number (P/N) 3-1691 and P/N 3-1692, which, when manufactured according to design specifications, will not contain the surface deformities and scratches found on the existing design fittings. After extensive analysis, these fittings have proven to not have the cracking susceptibility of those currently in service. The following presents service information that American Champion has issued that relates to this issue:

o American Champion Service Letter (SL) 408, dated January 24, 1996, and American Champion SL 409, Revision A, dated April 22, 1996, which specify procedures for accessing and inspecting wing front strut attach fittings, part number (P/N) 3-1632-1 and P/N 3-1632-2; and P/N 3-1646L and 3-1646R, respectively.

o American Champion SL 410, dated May 6, 1996, which includes procedures for installing removable inspection hole covers for the wing front strut attach fittings on Model 8KCAB airplanes that have complied with American Champion SL 408;

o American Champion SL 411, dated May 6, 1996, which includes procedures for installing removable inspection hole covers for the wing front strut attach fittings on Model 8KCAB airplanes that have not complied with American Champion SL 408;

o American Champion SL 412, dated May 6, 1996, which specifies procedures for installing removable inspection hole covers for the wing front strut attach fittings on Models 7ECA, 7GCAA, 7GCBC, and 8GCBC airplanes that have complied with American Champion SL 409;

o American Champion SL 413, dated May 6, 1996, which specifies procedures for installing removable inspection hole covers for wing front strut attach fittings on Models 7ECA, 7GCAA, 7GCBC, and 8GCBC airplanes that have not complied with American Champion SL 409.

o American Champion SL 414, Revision A, dated June 25, 1996, which specifies procedures for replacing the wing front strut attach fittings on Model 8KCAB airplanes with improved wing front strut attach fittings, P/N 3-1691, and also includes procedures for inspecting the wing front strut attachfittings on these airplanes; and

o American Champion SL 415, Revision A, dated June 25, 1996, which specifies procedures for replacing the wing front strut attach fittings on Models 8GCBC, 7ECA, 7GCAA, 7GCBC, and 7KCAB airplanes with improved wing front strut attach fittings, P/N 3-1692, and also includes procedures for inspecting the wing front strut attach fittings on these airplanes.

FAA's Determination
After examining the circumstances and reviewing all available information related to the events described above, the FAA has determined that (1) the wing front strut attach fittings on American Champion Models 8KCAB, 8GCBC, 7ECA, 7GCAA, 7GCBC, and 7KCAB airplanes should incorporate P/N 3-1691 and 3-1692, as applicable; and (2) AD action should be taken in order to prevent structural failure of a wing caused by cracked wing front strut attach fittings, which, if not detected and corrected, could result in loss of control of the airplane.

In addition, based on resultsof an in-depth analysis of the existing wing front strut attach fittings, the FAA has determined that if the fittings were not replaced with the improved design fittings, repetitive inspections would need to be performed at intervals not to exceed 20 hours TIS. Allowing repetitive inspections of these airplanes over a long period of time goes against FAA policy, which states that if a modification exists for critical structure that could eliminate or reduce the number of short-term inspections, the modification should be incorporated. The FAA makes short-term allowances on this policy to account for parts availability provided analysis shows that an acceptable level of safety can be maintained through a short-term repetitive inspection program.

The Provisions of the Required AD Action
Since an unsafe condition has been identified that is likely to exist or develop in other American Champion Models 8GCBC, 7ECA, 7GCAA, 7GCBC, and 7KCAB airplanes of the same type design, this ADsupersedes AD 96-03-11 with a new AD that requires installing removable inspection hole covers for the wing front strut attach fittings, and replacing the wing front strut attach fittings with P/N 3-1691 (Model 8KCAB) or P/N 3-1692 (Models 8GCBC, 7ECA, 7GCAA, 7GCBC, and 7KCAB) wing front strut attach fittings, as applicable. The FAA is including a provision of repetitively inspecting the wing front strut attach fittings (provided no cracks, scratches, or surface deformities are found) if parts have been ordered but are not available. Accomplishment of these actions is in accordance with the service information previously referenced.

Since a situation exists (structural failure of the wing caused by a cracked wing front strut attach fitting) that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting immediate flight safety and, thus, was not preceded by notice and opportunity to comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 96-CE-36-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to 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 USC 106(g), 40113, 44701.

Section 39.13 - [AMENDED]
2. Section 39.13 is amended by removing AD 96-03-11, Amendment 39-9598 (61 FR 5501, February 13, 1996), and by adding a new airworthiness directive (AD) to read as follows: