Airworthiness directives: Boeing,
[Federal Register: October 14, 1998 (Volume 63, Number 198)]
[Proposed Rules]
[Page 55065-55067]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14oc98-24]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-243-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 777-200 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 777-200 series airplanes. This proposal would require inspections to verify correct installation of certain fasteners located on the trailing edges of the horizontal and vertical stabilizer; replacement of the existing fasteners with new fasteners installed with wet sealant; and follow-on actions, if necessary. This proposal is prompted by reports indicating that, during manufacture of the horizontal and vertical stabilizers, certain fasteners attaching the aluminum ribs and brackets to the trailing edges on the empennage were not correctly installed with wet sealant. The actions specified by the proposed AD are intended to prevent corrosion and possible cracking of those aluminum parts, which could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane.
DATES: Comments must be received by November 30, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-243-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Stan Wood, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2772; fax (425) 227-1181.
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 shall 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice
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must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-243-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, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-243-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
The FAA has received reports indicating that, during manufacture of the horizontal and vertical stabilizers, which are made primarily of graphite composite, certain fasteners attaching the aluminum ribs and brackets to the trailing edges on the empennage were not correctly installed with wet sealant. If moisture is present this lack of sealant results in an electrolytic path between the aluminum components and composite structure that could cause corrosion of the aluminum components. Such corrosion could lead to the initiation of fatigue cracks. This condition, if not corrected, could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin 777-55A0005, Revision 1, dated June 4, 1998, which describes procedures for visual inspections to verify correct installation of certain fasteners located on the trailing edges of the horizontal and vertical stabilizer, and replacement of the existing fasteners with new fasteners installed with wet sealant, if necessary. The alert service bulletin also describes follow-on procedures for oversizing the fastener holes and applying primer prior to installation of fasteners. Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the alert service bulletin described previously.
Cost Impact
There are approximately 18 airplanes of the affected design in the worldwide fleet. The FAA estimates that 2 airplanes of U.S. registry would be affected by this proposed AD.
It would take approximately 331 work hours per airplane to accomplish the proposed inspection of the horizontal stabilizer, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $39,720, or $19,860 per airplane.
It would take approximately 206 work hours per airplane to accomplish the proposed inspection of the vertical stabilizer, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $24,720, or $12,360 per airplane.
The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.
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.
For the reasons discussed above, I certify that this proposed regulation (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) 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 is contained 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 part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
Section 39.13 is amended by adding the following new airworthiness directive:
Boeing: Docket 98-NM-243-AD.
Applicability: Model 777-200 series airplanes, line numbers 15 through 33, excluding line number 18; certificated in any category.
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 (b) 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, unless accomplished previously.
To prevent corrosion and possible cracking of the aluminum ribs and brackets of the trailing edges on the empennage, which could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane, accomplish the following:
(a) Within five years since the date of manufacture of the airplane, perform visual inspections of the specified number of fasteners installed in each zone on the aluminum ribs and brackets located on the trailing edges of the horizontal and vertical stabilizer to verify correct installation of fasteners with wet sealant, in accordance with Boeing Alert Service Bulletin 777- 55A0005, Revision 1, dated June 4, 1998. Following the inspection, oversize the holes for all removed fasteners, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin.
(1) If the fasteners are correctly installed with wet sealant, no further action is required for that zone.
(2) If the fasteners are not correctly installed with wet sealant in any zone, remove the remaining fasteners in that zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin.
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(3) If it cannot be determined that the fasteners are correctly installed with wet sealant, remove and inspect the specified number of additional fasteners in that zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin.
(i) If, after removal, all additional fasteners inspected in that zone are found to be correctly installed with wet sealant, no further action is required for that zone.
(ii) If, after removal, the fasteners in that zone are found to be incorrectly installed, remove all other fasteners in the zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin.
(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
(c) Special flight permits may be issued in accordance with Secs. 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.
Issued in Renton, Washington, on October 7, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-27481Filed10-13-98; 8:45 am]
BILLING CODE 4910-13-U
