Airworthiness directives: British Aerospace,

[Federal Register: July 16, 1998 (Volume 63, Number 136)]

[Rules and Regulations]

[Page 38289-38290]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr16jy98-7]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-02-AD; Amendment 39-10659; AD 98-15-08]

RIN 2120-AA64

Airworthiness Directives; British Aerospace Model BAe 146 and Model Avro 146-RJ Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes, that requires repetitive detailed visual inspections of the top wing skins for stress corrosion cracks, damage, or missing surface protective finish of the metallic surfaces; and repair, if necessary. This amendment is prompted by reports of stress corrosion cracks found on the top wing skin during routine inspection on three airplanes. The actions specified by this AD are intended to detect and correct such cracking, which could result in reduced structural integrity of the wing.

DATES: Effective August 20, 1998.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of August 20, 1998.

ADDRESSES: The service information referenced in this AD may be obtained from AI(R) American Support, Inc., 13850 Mclearen Road, Herndon, Virginia 20171. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes was published in the Federal Register on June 17, 1997 (62 FR 32701). That action proposed to require repetitive detailed visual inspections of the top wing skins for stress corrosion cracks, damage, or missing surface protective finish of the metallic surfaces, and repair, if necessary.

Consideration of Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received.

Components Made of 7150-T651 Aluminum Material

The commenter supports the proposed AD. However, the commenter expresses a concern that other airplane components made from the same material could pose a similar problem. As a result, the commenter requests the FAA to accomplish the following actions:

--Identify any other aircraft components made from the same material. --Review the inspection criteria and frequency for those applications. --Ensure that a failure of the material will be detected prior to the failure posing a risk to continued flight safety.

The FAA acknowledges the concerns of the commenter. Based on additional information from the manufacturer, the FAA has determined that the problem is limited to a discrepant production lot of 7150-T651 aluminum material that was produced with the incorrect thickness for the wing skins. In addition, the FAA has determined that no other components made of this aluminum material are affected. In light of this information, the FAA finds that it is unnecessary to take any additional action, and that the actions required by this AD are adequate in order to ensure the continued safety of the fleet.

Explanation of New Service Information

Since the issuance of the proposed AD, the manufacturer issued British Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19, 1997, which replaces British Aerospace Service Bulletin SB.57-49, dated June 4, 1996. Revision 1 reduces the effectivity specified in the previous service bulletin to those airplanes on which 7150-T651 aluminum material from a discrepant production lot was used for the top wing skins. The discrepant material was manufactured with an inappropriate thickness, which causes the wings to be susceptible to early stress corrosion cracking on the top wing skin, and which could result in reduced structural integrity of the airplane wing. However, since the discovery of this problem, subsequent 7150-T651 aluminum material used for the top wing skins has been machined to the appropriate thickness and, as a result, is not susceptible to early stress corrosion cracking. In all other respects, Revision 1 of the service bulletin is essentially the same as the original issue of the service bulletin.

The FAA has reduced the applicability of this final rule to those airplanes having wing skins made from 7150-T651 aluminum material, as specified in British Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19, 1997. In addition, the FAA has revised paragraph (a) of the final rule to require accomplishment of those actions in accordance with either the original service bulletin or Revision 1.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air

[[Page 38290]]

safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

The FAA estimates that 12 British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,880, or $240 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the 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 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.

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) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

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 U.S.C. 106(g), 40113, 44701.

    Sec. 39.13 [Amended]

  2. Section 39.13 is amended by adding the following new airworthiness directive:

    98-15-08 British Aerospace Regional Aircraft (Formerly British Aerospace Regional Aircraft Limited, Avro International Aerospace Division; British Aerospace, PLC; British Aerospace Commercial Aircraft Limited): Amendment 39-10659. Docket 97-NM-02-AD.

    Applicability: Model BAe 146 and Model Avro 146-RJ series airplanes, as listed in British Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19, 1997, and having wing skins made from 7150-T651 aluminum; 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 detect and correct stress corrosion cracking in the wing skin, which could result in reduced structural integrity of the wing, accomplish the following:

    (a) Within 4 months after the effective date of this AD; and thereafter at intervals not to exceed 4,000 landings or 2 years, whichever occurs first: Perform a detailed visual inspection of the top wing skins to detect stress corrosion cracking, and any damaged or missing surface protective finish that exposes the metallic surfaces, in accordance with British Aerospace Service Bulletin SB.57-49, dated June 4, 1996, or Revision 1, dated June 19, 1997.

    (1) If any damaged or missing surface protective finish is detected, and no cracking or corrosion is detected, prior to further flight, reapply the protective finish in accordance with the service bulletin. Repeat the detailed visual inspection, thereafter, at intervals not to exceed 4,000 landings or 2 years, whichever occurs first.

    (2) If any cracking is detected, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate.

    Note 2: During the detailed visual inspections of the top wing skins, pay particular attention to the edge of cutouts, skin edges, and attachment bolt holes.

    (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, International Branch, ANM-116. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

    Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

    (c) 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.

    (d) Except as provided by paragraph (a)(2) of this AD, the inspections and repairs shall be done in accordance with British Aerospace Service Bulletin SB.57-49, dated June 4, 1996; or British Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19, 1997. 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. Copies may be obtained from AI(R) American Support, Inc., 13850 Mclearen Road, Herndon, Virginia 20171. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

    Note 4: The subject of this AD is addressed in British airworthiness directive 005-06-96, dated June 4, 1996.

    (e) This amendment becomes effective on August 20, 1998.

    Issued in Renton, Washington, on July 8, 1998. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

    [FR Doc. 98-18770Filed7-15-98; 8:45 am]

    BILLING CODE 4910-13-U

VLEX uses login cookies to provide you with a better browsing experience. If you click on 'Accept' or continue browsing this site we consider that you accept our cookie policy. ACCEPT