04-13223. Airworthiness Directives; Short Brothers Model SD3 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 series airplanes. This proposal would require testing for stiffness of the aft pintle pin bushing of the main landing gear (MLG), and inspecting and measuring the aft pintle pin bushings of the MLG for damage, and for out-of-limit dimensions of the bushing bore. This proposal would also require corrective action if necessary. This action is necessary to detect and correct corrosion and deterioration of the aft pintle pin bushings of the MLG. Corrosion and deterioration of the bushings, if not detected and corrected, could result in the MLG not extending fully during landing, with consequent damage to the airplane structure. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by July 14, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-178-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-178-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 or 2000 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.

FOR FURTHER INFORMATION CONTACT:

Todd Thompson, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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 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.

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 Number 2003-NM-178-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. 2003-NM-178-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 series airplanes. The CAA advises that the main landing gear (MLG) on one Short Brothers Model SD3-30 series airplane failed to extend fully and lock. This failure resulted from deterioration and corrosion of the aft pintle pin bushings of the MLG. In addition, the CAA reports that there continues to be a high frequency of problems with the MLG, which may be associated with deterioration of the aft pintle pin bushings. Deterioration and corrosion of the aft pintle pin bushings of the MLG, if not corrected, could result in the MLG not extending fully during landing, with consequent damage to the airplane structure.

The subject area on Short Brothers Model SD3-30 series airplanes is almost identical to that on the other Short Brothers Model SD3 series airplanes. Therefore, all Shorts Model SD3 series airplanes may be subject to the unsafe condition revealed on Model SD3-30 series airplanes.

Explanation of Relevant Service Information

Short Brothers has issued the following service bulletins:

• For Model SD3-30 series airplanes: Service Bulletin SD330-32-122, dated April 30, 2003;
• For Model SD3 SHERPA series airplanes: Service Bulletin SD3 SHERPA-32-3, dated April 30, 2003;
• For Model SD3-60 SHERPA series airplanes: Service Bulletin SD360 SHERPA-32-2, dated April 30, 2003; and
• For Model SD3-60 series airplanes: Service Bulletin SD360-32-36, Revision 1, dated May 26, 2003. This service bulletin references Short Brothers Service Bulletin SD360-32-03, dated November 1983, as an additional source of service information for replacement of certain bushings, if necessary.

These service bulletins describe the following procedures related to the aft pintle pin bushings of the MLG:

• Doing friction tests for stiffness of the aft pintle pin bushings, and sending results of the tests to the manufacturer;
• Performing a detailed inspection for defects (corrosion or deterioration) of the bushings;
• Measuring the bore diameter, in three locations, of each of the three bushings to determine if the dimensions are outside specified limits;
• Taking corrective action if there is any defect in a bushing or if the bore dimension is outside specified limits (the corrective action is replacing the bushing with a new improved bushing having a new part number, and refitting the bushing); and
• Doing other significant actions such as refitting new bushings and any bushings that were removed during inspection, but not replaced; and doing a functional test of the MLG extension and retraction function.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. The CAA classified these service bulletins as mandatory and issued British airworthiness directives 001-04-2003 (for Model SD3-30 series airplanes), 002-04-2003 (for Model SD3-60 series airplanes), 004-04-2003 (for Model SD3 SHERPA series airplanes), and 003-04-2003 (for Model SD3-60 SHERPA series airplanes), 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 us informed of the situation described above. We have 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, except as discussed below.

Difference Between the Proposed Rule and the Service Bulletins

Operators should note that, although the service bulletins describe procedures for sending certain information and items to the manufacturer (i.e., results of the friction tests, unserviceable bushings, and photographs of serviceable bushings), this proposed rule does not include that requirement.

Interim Action

We consider this proposed AD interim action. If final action is later identified, we may consider further rulemaking then.

Cost Impact

We estimate that 108 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 30 work hours per airplane to accomplish the proposed test, inspection, and measurement, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $210,600, or $1,950 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. 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.

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

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

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

§ 39.13

[Amended]

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

Short Brothers PLC: Docket 2003-NM-178-AD.

Applicability: All Short Brothers Model SD3 series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct corrosion and deterioration of the aft pintle pin bushings of the main landing gear (MLG), which could result in the MLG not extending fully during landing, with consequent damage to the airplane structure, accomplish the following:

Service Bulletin Reference

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For Model SD3-30 series airplanes: Short Brothers Service Bulletin SD330-32-122, dated April 30, 2003.

(2) For Model SD3 SHERPA series airplanes: Short Brothers Service Bulletin SD3 SHERPA-32-3, dated April 30, 2003.

(3) For Model SD3-60 SHERPA series airplanes: Short Brothers Service Bulletin SD360 SHERPA-32-2, dated April 30, 2003.

(4) For Model SD3-60 series airplanes: Short Brothers Service Bulletin SD3-60-32-36, Revision 1, dated May 26, 2003.

Note 1:

Short Brothers Service Bulletin SD3-60-32-36 references Short Brothers Service Bulletin SD360-32-03, dated November 1983, as an additional source of service information for replacement of certain bushings, if necessary.

Tests, Inspection, Measurements, and Corrective Action

(b) Within 24 months after the effective date of this AD: Do a friction test for stiffness of the aft pintle pin bushings of the MLG, and a detailed inspection for any defect of the bushings of the aft pintle pin of the MLG; and measure the bore diameter of the bushings (if a defect is found, this paragraph requires that the bushing be replaced; therefore, it is not necessary to do the bore diameter measurement on that bushing). Do all applicable corrective actions and other specified actions prior to further flight. Do all actions per the applicable service bulletin.

Note 2:

For the purposes of this AD, a detailed 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.”

No Reporting Requirement

(c) Although the service bulletins specify to send certain items to Short Brothers for evaluation (i.e., results of the friction tests, unserviceable bushings, and photographs of serviceable bushings), this AD does not require that action.

Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, ANM-116, FAA, Transport Airplane Directorate, is authorized to approve alternative methods of compliance for this AD.

Note 3:

The subject of this AD is addressed in British airworthiness directives 001-04-2003 (for Model SD3-30 series airplanes), 002-04-2003 (for Model SD3-60 series airplanes), 004-04-2003 (for Model SD3 SHERPA series airplanes), and 003-04-2003 (for Model SD3-60 SHERPA series airplanes).

Issued in Renton, Washington, on June 3, 2004.

Franklin Tiangsing,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.