Airworthiness directives: Short Brothers,

[Federal Register: June 23, 1999 (Volume 64, Number 120)]

[Proposed Rules]

[Page 33439-33441]

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

[DOCID:fr23jn99-28]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-137-AD]

RIN 2120-AA64

Airworthiness Directives; Short Brothers Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60 SHERPA 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 all Short Brothers Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60 SHERPA series airplanes. This proposal would require a one-time borescope inspection to detect corrosion of the shear decks and ribs of the left and right stub wings, follow-on corrective actions, if necessary; and drilling of new drain holes in the lower shear decks. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent corrosion of the stub wing shear decks and ribs, which could result in cracking or failure of the stub wing structure.

DATES: Comments must be received by July 23, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-137-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 Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

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:

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.

[[Page 33440]]

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 must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-137-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-137-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, notified the FAA that an unsafe condition may exist on all Short Brothers Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60 SHERPA series airplanes. The CAA advises that corrosion has been found in the area of the upper and lower shear decks, and on the outer and inner ribs of the left and right stub wings. The corrosion is believed to have been caused by the ingress of water and debris into the area from the main landing gear wheels, and lack of follow-on maintenance in ensuring that the area is dry and clean. Corrosion of the stub wing shear decks and ribs, if not corrected, could result in cracking or failure of the stub wing structure.

Explanation of Relevant Service Information

Shorts has issued the following service bulletins, all dated November 27, 1998:

‹bullet› SD330-53-68 (for Model SD3-30 series airplanes);

‹bullet› SD360-53-43, Revision 1 (for Model SD3-60 series airplanes);

‹bullet› SD3 Sherpa-53-4 (for Model SD3 SHERPA series airplanes); and

‹bullet› SD360-Sherpa-53-4 (for Model SD3-60 SHERPA series airplanes).

These service bulletins describe procedures for a one-time borescope inspection to detect corrosion of the shear decks and ribs of the left and right stub wings, in the areas of the inner and outer ribs, front and rear web plates, strut support bracket, and upper and lower shear decks; and corrective actions, if necessary. The corrective actions include additional inspections for corrosion in other areas; removal of corrosion within acceptable limits; replacement of certain components with new components; and, follow-on repetitive inspections if corrosion is found. The service bulletins also describe procedures for drilling of new drain holes in the lower shear decks. Additionally, the service bulletins specify that operators are to report the results of the initial inspection to the manufacturer.

Accomplishment of the actions specified in these service bulletins is intended to adequately address the identified unsafe condition. The CAA classified these service bulletins as mandatory and issued British airworthiness directives 006-11-97, 006-11-98, 007-11-98, and 008-11-98 in order to assure the continued airworthiness of these airplanes in the United Kingdom.

FAA's Conclusions

These airplane models are manufactured in the United Kingdom and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service bulletins described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletins

Operators should note that, although the service bulletins specify that the manufacturer may be contacted for disposition of certain corrosion conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by either the FAA, or the CAA (or its delegated agent). In light of the type of repair that would be required to address the identified unsafe condition, and in consonance with existing bilateral airworthiness agreements, the FAA has determined that, for this proposed AD, a repair approved by either the FAA or the CAA would be acceptable for compliance with this proposed AD.

Cost Impact

The FAA estimates that 112 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 100 work hours per airplane to accomplish the proposed inspection, and that the average labor rate is $60 per work hour.

Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $672,000, or $6,000 per airplane.

The cost impact figure discussed above is 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.

[[Page 33441]]

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

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:

   Short Brothers PLC: Docket 98-NM-137-AD.

   Applicability: All Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60 SHERPA series airplanes, 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 (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, unless accomplished previously.

   To prevent corrosion of the stub wing shear decks and ribs, which could result in cracking or failure of the stub wing structure, accomplish the following:

   Inspection and Corrective Actions

   (a) Within 6 months after the effective date of this AD, perform a borescope inspection in the areas of the stub wing shear decks and ribs to detect corrosion, and drill new drain holes in the lower shear decks, in accordance with Part A of the Accomplishment Instructions of the applicable Shorts Service Bulletin specified below, all dated November 27, 1998 (hereinafter referred to as the applicable service bulletin):

   ‹bullet› SD330-53-68 (for Model SD3-30 series airplanes);

   ‹bullet› SD360-53-43, Revision 1 (for Model SD3-60 series airplanes);

   ‹bullet› SD3 Sherpa-53-4 (for Model SD3 SHERPA series airplanes); and

   ‹bullet› SD360-Sherpa-53-4 (for Model SD3-60 SHERPA series airplanes).

   Note 2: In the case where no corrosion is detected during the inspection described in Part A of the Accomplishment Instructions of the applicable service bulletin, the service bulletin specifies accomplishment of follow-on repetitive inspections of this area as specified in Short Brothers Aircraft Maintenance Programme, Chapter 5-26-57.

   (b) Except as provided by paragraph (c) of this AD: If any corrosion is detected during the inspection required by paragraph (a) of this AD, prior to further flight, accomplish corrective actions (i.e., additional inspections, removal of corrosion, replacement of components), as applicable, in accordance with Part B of the Accomplishment Instructions of the applicable service bulletin. Thereafter, repeat the inspection required by paragraph (a) of this AD at intervals not to exceed 12 months.

   (c) If any corrosion condition is found for which the applicable service bulletin specifies that Short Brothers is to be contacted for an appropriate repair action: Prior to further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, or the Civil Aviation Authority (CAA) of the United Kingdom (or its delegated agent).

   Reporting Requirement

   (d) Within 10 days after accomplishment of the initial inspection required by paragraph (a) of this AD, or within 30 days after the effective date of this AD, whichever occurs later, submit a report of the inspection findings (positive or negative) to: Team Leader, Service Engineering-Aerospace Customer Support Short Brothers plc, Belfast, N. Ireland. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

   Alternative Methods of Compliance

   (e) 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.

   Special Flight Permits

   (f) 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.

   Note 4: The subject of this AD is addressed in British airworthiness directives 006-11-97, 006-11-98, 007-11-98, and 008- 11-98.

   Issued in Renton, Washington, on June 17, 1999. Vi L. Lipski, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-15930Filed6-22-99; 8:45 am]

   BILLING CODE 4910-13-U