Airworthiness Directives; American Champion Aircraft Corporation Model 8GCBC Airplanes

[Federal Register Volume 62, Number 187 (Friday, September 26, 1997)] [Proposed Rules] [Pages 50527-50529] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-25607]

======================================================================== Proposed Rules Federal Register ________________________________________________________________________ This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules. ========================================================================

Federal Register / Vol. 62, No. 187 / Friday, September 26, 1997 / Proposed Rules

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-37-AD] RIN 2120-AA64

Airworthiness Directives; American Champion Aircraft Corporation Model 8GCBC Airplanes

agency: Federal Aviation Administration, DOT.

action: Notice of proposed rulemaking (NPRM).

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summary: This document proposes to supersede Airworthiness Directive (AD) 87-18-09, which currently requires inspecting (one-time) the sides of the front and rear wood spars for compression cracks on certain American Champion Aircraft Corporation (ACAC) Model 8GCBC airplanes, and repairing or replacing any wood spar with compression cracks. The proposed AD would require installing inspection holes on the top and bottom wing surfaces, repetitively inspecting the front and rear wood spars for damage, repairing or replacing any damaged wood spar, and installing inspection covers. Damage is defined as cracks; compression cracks; longitudinal cracks through the bolt holes, spacer holes, or nail holes; or loose or missing rib nails. The proposed AD results from in-flight wing structural failure on one of the affected airplanes that was in compliance with the one-time inspection requirement of AD 87-18- 09. The actions specified by the proposed AD are intended to prevent damage in the wood spar wing from going undetected, which could result in in-flight structural failure of the wing with consequent loss of control of the airplane.

dates: Comments must be received on or before November 28, 1997.

addresses: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-CE-37-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Comments may be inspected at this location between 8 a.m. and 4 p.m., Monday and Friday, holidays excepted. Service information that applies to the proposed AD may be obtained from American Champion Aircraft Corporation, P.O. Box 37, 32032 Washington Avenue, Highway D, Rochester, Wisconsin 53167. This information also may be examined at the Rules Docket at the address above.

for further information contact: Mr. William Rohder, Aerospace Engineer, FAA, Chicago Aircraft Certification Office, 2300 E. Devon Avenue, Des Plaines, Illinois 60018; telephone (847) 294-7697; facsimile (847) 294-7834.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket No. 97-CE-37-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-CE-37-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Discussion

AD 87-18-09, Amendment 39-5725, currently requires inspecting (one- time) the sides of the front and rear wood spars for compression cracks on American Champion Aircraft Corporation (ACAC) Model 8GCBC airplanes, repairing or replacing any wood spar with compression cracks, and re- inspecting immediately after any incident involving wing damage. AD 87- 18-09 was the result of three accidents involving ACAC Model 8GCBC airplanes where compression cracks in the wood spar caused in-flight structural failure of the wing. Wood compression cracks are failures of wood fibers on a plane perpendicular to the wood fiber longitudinal axis. Repetitive high stress can initiate these compression cracks on the top or bottom surface of the wing spar adjacent to doubler plate glue lines and rib nail holes. These high stress conditions can occur during crop dusting, banner and glider tow operations, turbulence, and rough field or float operations. Compression cracks can also initiate if the wing contacts the ground. Compression cracks can initiate at either the top or bottom surface of the spar depending on the bending loads (either upward or downward) at impact.

Actions Since Issuance of Previous Rule

In-flight structural failure of the wing recently occurred on an ACAC Model 8GCBC airplane that was initially inspected as required by AD 87-18-09. A possible contributing factor of this accident was an undetected compression crack on the right wing front spar. Review of data acquired from inspections of several ACAC Model 8GCBC airplanes indicate that wood spar compression cracks can occur without previous wing damage. The data indicates that detection of a compression crack on the sides of the spar is unlikely, unless the crack is in an advanced state of propagation. Based

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on this data, the FAA believes that repetitive inspections are necessary.

Relevant Service Information

The FAA has reviewed and approved the technical contents of ACAC Service Letter 406, dated March 28, 1994, and ACAC Service Letter 417, dated August 14, 1997. ACAC Service Letter 406 includes procedures for conducting a detailed visual inspection of both the front and rear wood wing spars for cracks; compression cracks; longitudinal cracks through the bolt holes, spacer holes, or nail holes; and loose or missing rib nails (referred to as damage hereon). ACAC Service Letter 417 includes procedures for installing inspection holes and surface covers and assuring that all applicable lower surface drain holes are installed.

The FAA's Determination

After examining the circumstances and reviewing all available information related to the incidents and accidents described above, including the referenced service information, the FAA has determined that AD action should be taken to prevent damage in the wood spar from going undetected, which could result in in-flight structural failure of the wing with consequent loss of control of the airplane.

Explanation of the Provisions of the Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop in other ACAC Model 8GCBC airplanes of the same type design, the FAA is proposing an AD to supersede AD 87-18-09. The proposed AD would require installing inspection holes on the top and bottom wing surfaces, repetitively inspecting the front and rear wood spars for damage, repairing or replacing any damaged wood spar, and installing surface covers. Accomplishment of the proposed actions would be as follows:

--Installations: in accordance with ACAC Service Letter 417, dated August 14, 1997; --Inspections: in accordance with ACAC Service Letter 406, dated March 28, 1994; and --Spar Repair and Replacement, as applicable: in accordance with Advisory Circular (AC) 43-13, Acceptable Methods, Techniques and Practices; or other data that the FAA has approved for spar repair and replacement

Difference Between This Proposed AD and ACAC Service Letter 406

ACAC Service Letter 406, dated March 28, 1994, specifies the same inspections as are proposed in this notice of proposed rulemaking (NPRM). The differences between the service letter and NPRM are:

--The service letter specifies the proposed action within the next 30 days or 10 flight hours and at each 100 hour/annual inspection thereafter. The FAA has determined that a more realistic compliance and enforceable compliance time would be to require the proposed action within 3 calendar months after the effective date of the AD, and thereafter at intervals not to exceed 12 calendar months or 500 hours time-in-service (TIS), whichever occurs first; and --The service letter applies to all ACAC 7 and 8 series airplanes, whereas the NPRM applies only to ACAC Model 8GCBC airplanes. The FAA is currently reviewing the service history of all of the ACAC airplane models specified in ACAC Service Letter 406. Based on this review, the FAA may initiate additional rulemaking action in the future on the airplane models other than the Model 8GCBC airplanes. This potential action may propose the same actions as the proposed AD with either the same or different compliance times, or may propose entirely different actions altogether.

Compliance Time of the Proposed AD

The compliance time of the proposed AD is presented in calendar time and hours TIS. Although the unsafe condition specified in the proposed AD is a result of airplane operation, operators of the affected airplanes utilize their airplanes in different ways. For example, an operator may utilize his/her airplane 50 hours TIS in a year while utilizing the aircraft in no or very little crop dusting operations, banner and glider tow operations, or rough field or float operations. This airplane operator would obviously experience less of a chance of high crack propagation than the airplane operator that utilizes his/her airplane 300 hours TIS in a year regularly in heavy crop dusting operations, banner and glider tow operations, or rough field or float operations. However, this airplane could have pre- existing and undetected wood spar damage that occurred during previous operations. In this situation, the damage to the wood spar would propagate at a level that depends on the operational exposure of the airplane and severity of the wood spar damage. To assure that compression cracks do not go undetected on the wood spars of the affected airplanes, the FAA has determined that an initial 3 calendar month compliance time should be used. Repetitive actions would be accomplished every 12 calendar months or 500 hours TIS, whichever occurs first.

Cost Impact

The FAA estimates that 261 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 6 workhours (Installations: 5 workhours; Initial Inspection: 1 workhour) per airplane to accomplish the proposed action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $292 per airplane, provided that each airplane would only need 11 additional standard inspection hole covers per wing (total of 22 additional standard covers per airplane). If the airplane would require the installation of more inspection covers (i.e., a result of previous non- factory wing recover work), the cost could be slightly higher. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $170,172 or $652 per airplane. This cost figure is based on the presumption that no affected airplane owner/operator has accomplished the installations or the initial inspection. The FAA has no knowledge of any owner/operator of the affected airplanes that has already accomplished the installations and initial inspection. The cost figure also does not account for repetitive inspections. The FAA has no way of determining the number of repetitive inspections each owner/operator of the affected airplanes will incur over the life of his/her airplane. However, each proposed repetitive inspection would cost substantially less than the initial inspection because of the cost of the initial proposed inspection hole and cover installations. The inspection covers allow easy access for the inspection of the wood spars, and the proposed compliance time would enable the owners/ operators of the affected airplanes to accomplish the repetitive inspections at regularly scheduled annual inspections.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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For the reasons discussed above, I certify that this action (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action has been placed in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 of the Federal Aviation Regulations 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. Section 39.13 is amended by removing Airworthiness Directive (AD) 87-18-09, Amendment 39-5725, and by adding a new AD to read as follows:

American Champion Aircraft Company: Docket No. 97-CE-37-AD; Supersedes AD 87-18-09, Amendment 39-5725.

Applicability: Model 8GCBC airplanes, all serial numbers, certificated in any category, that are equipped with wood wing spars.

Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, repaired, or reconfigured in the area subject to the requirements of this AD. For airplanes that have been modified, altered, repaired, or reconfigured 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 (e) 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 as indicated in the body of this AD, unless already accomplished. To prevent damage in the wood spar wing from going undetected, which could result in in-flight structural failure of the wing with consequent loss of control of the airplane, accomplish the following: (a) Within the next 3 calendar months after the effective date of this AD, accomplish the following: (1) Install inspection holes in the top and bottom surface of each wing in accordance with American Champion Aircraft Corporation (ACAC) Service Letter 417, dated August 14, 1997. Assure that all drainage holes are installed as depicted in this service letter, and install drainage holes as necessary. (2) Inspected (detailed visual) both the front and rear wood wing spars for cracks; compression cracks; longitudinal cracks through the bolt holes, spacer holes, or nail holes; and loose or missing rib nails (referred to as damage hereon). Accomplish these inspections in accordance with ACAC Service Letter 406, dated March 28, 1994. (3) If any spar damage is found, prior to further flight, accomplish the following: (i) Repair or replace the wood wing spar in accordance with Advisory Circular (AC) 43-13, Acceptable Methods, Techniques and Practices; or other data that is approved by the FAA for wing spar repair or replacement. (ii) If the wing is recovered, accomplish the installations required by paragraph (a)(1) of this AD, as applicable. (4) Install inspection hole covers on the top and bottom surface of the wing in accordance with ACAC Service Letter 417, dated August 14, 1997. (b) Within 12 calendar months or 500 hours TIS (whichever occurs first) after accomplishing all actions required by paragraph (a), all subparagraphs included, of this AD, and thereafter at intervals not to exceed 12 calendar months or 500 hours TIS, whichever occurs first, accomplish the inspection, repair, replacement, and installation required by paragraphs (a)(2), (a)(3) as applicable; including its subparagraphs; and (a)(4) of this AD.

Note 2: The affected airplanes are not certificated for acrobatic maneuvers. AD 87-18-09 required a placard prohibiting acrobatic maneuvers in addition to the existing operational placard. The FAA encourages owners/operators of the affected airplanes to keep this placard installed on their airplanes.

(c) If any of the affected airplanes are involved in an incident involving wing damage after the effective date of this AD, prior to further flight, accomplish the inspection, repair, replacement, and installation required by paragraphs (a)(2), (a)(3), as applicable; including its subparagraphs; and (a)(4) of this AD. (d) 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. (e) 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. (1) The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Chicago ACO. (2) Alternative methods of compliance approved in accordance with AD 87-18-09 (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.

(f) All persons affected by this directive may obtain copies of the documents referred to herein upon request to American Champion Aircraft Corporation, P.O. Box 37, 32032 Washington Avenue, Highway D, Rochester, Wisconsin 53167; or may examine these documents at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. (g) This amendment supersedes AD 87-18-09, Amendment 39-5725.

Issued in Kansas City, Missouri, on September 22, 1997. Henry A. Armstrong, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-25607 Filed 9-25-97; 8:45 am] BILLING CODE 4910-13-M