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Proposed Rule

Airworthiness Directives; Short Brothers Model SD3 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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Federal Aviation Administration, DOT.


Notice of proposed rulemaking (NPRM).


This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Short Brothers Model SD3 series airplanes. This proposal would require a one-time inspection of the installation of the bearing housings of the elevator torque shaft assembly, and corrective action if necessary. This action is necessary to prevent failure of the elevator torque shaft, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.


Comments must be received by November 5, 2001.


Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-229-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: Comments sent via fax or the Internet must contain “Docket No. 2001-NM-229-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

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.

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Todd Thompson, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1175; fax (425) 227-1149.

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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 action may be changed in light of the comments received.

Submit comments using the following format:

  • Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
  • For each issue, state what specific change to the proposed AD is being requested.
  • Include justification (e.g., reasons or data) for each request. Start Printed Page 50585

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 filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket 2001-NM-229-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 2001-NM-229-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.


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 series airplanes. The CAA advises that an operator reported freeplay of the bearing housings of the elevator torque shaft assembly at frame station 74 due to incorrect installation of the bearing housings of the elevator torque shaft. This condition, if not corrected, could result in failure of the elevator torque shaft and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

Shorts has issued the following service bulletins, and the CAA has issued the following British airworthiness directives:

Model/seriesShort Brothers service bulletinDate of service bulletinCorresponding British airworthiness directive
SD3-60 SherpaSD360 SHERPA-27-6May 22, 2001003-05-2001
SD3 SherpaSD3 SHERPA-27-5May 22, 2001008-05-2001
SD360SD360-27-31May 22, 2001009-05-2001
SD330SD330-27-39May 22, 2001007-05-2001

The service bulletins describe procedures for a one-time inspection of the elevator torque shaft to ensure that the bearing housings are securely mounted, without any obvious or apparent movement relative to the mounting structure. The CAA classified the service bulletins as mandatory and issued the above-referenced British airworthiness directives to ensure 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 applicable service bulletin described previously.

The service bulletins recommend that operators submit reports of inspection results to the manufacturer. While ADs do not typically require a report, the inspection results will enable the manufacturer to determine the prevalence of the corrosion in the affected fleet. Therefore, Note 3 has been included in this proposed AD to advise operators accordingly.

Cost Impact

The FAA estimates that 75 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 2 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 $9,000, or $120 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 proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Start Printed Page 50586Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

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1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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

Short Brothers PLC: Docket 2001-NM-229-AD.

Applicability: All Model SD3 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 (c) 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 failure of the elevator torque shaft, which could result in reduced controllability of the airplane, accomplish the following:


(a) Within 60 days after the effective date of this AD: Perform a detailed visual inspection of the bearing housings of the elevator torque shaft assembly to detect discrepancies (including movement of the housings relative to the mounting structure), in accordance with the applicable service bulletin listed in the following table:

Table 1.—Service Bulletins

For modelInspect in accordance with Short Brothers service bulletinDated
(1) SD3-60 Sherpa series airplanesSD360 SHERPA-27-6May 22, 2001.
(2) SD3 Sherpa series airplanesSD3 SHERPA-27-5May 22, 2001.
(3) SD360 series airplanesSD360-27-31May 22, 2001.
(4) SD330 series airplanesSD330-27-39May 22, 2001.

Note 2:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Corrective Action

(b) If any discrepancy is found during the inspection required by paragraph (a) of this AD: Prior to further flight, replace any affected part with a new part, in accordance with the applicable service bulletin listed in Table 1 of this AD.

Note 3:

The service bulletins listed in Table 1 of this AD recommend that operators submit a report of their inspection findings to the manufacturer. Although operators may submit such a report, this AD does not require it.

Alternative Methods of Compliance

(c) 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, Transport Airplane Directorate, FAA. 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 4:

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

(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.

Note 5:

The subject of this AD is addressed in British airworthiness directives 003-05-2001, 008-05-2001, 009-05-2001, and 007-05-2001.

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Issued in Renton, Washington, on September 28, 2001.

Charles Huber,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 01-24874 Filed 10-3-01; 8:45 am]