AD 2004-25-13

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Short Brothers Model SD3-60 and SD3-SHERPA series airplanes. That AD currently requires a one-time inspection to detect cracks and/or corrosion of the gland nut on the shock absorber of the main landing gear (MLG), and follow-on actions. That AD also requires repair or replacement of any cracked/corroded gland nut with a new nut. This new AD adds airplanes to the applicability; adds repetitive inspections and corrective actions; and provides an optional action that ends the repetitive inspections. This AD is prompted by reports of cracked aluminum alloy gland nuts that had been inspected previously using the existing AD. We are issuing this AD to prevent failure of the aluminum alloy gland nut on the MLG shock absorber, which could cause the MLG to collapse.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The FAA amends 39.13 by removing amendment 39-9797 (61 FR 57311, November 6, 1996) and adding the following new airworthiness directive (AD):

2004-25-13 Short Brothers PLC: Amendment 39-13901. Docket No. FAA-2004-18661; Directorate Identifier 2003-NM-273-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective January 20, 2005.

Affected ADs

(b) This AD supersedes AD 96-22-09, amendment 39-9797.

Applicability

(c) This AD applies to Short Brothers Model SD3-60, SD3-SHERPA, and SD3-60 SHERPA series airplanes; certificated in any category; that are equipped with aluminum alloy gland nuts, part number (P/N) 200920604, on the main landing gear (MLG) shock absorber.

Unsafe Condition

(d) This AD was prompted by reports of cracked aluminum alloy gland nuts on the MLG shock absorber that had been previously inspected using AD 96-22-09. We are issuing this AD to prevent failure of the aluminum alloy gland nut on the MLG shock absorber, which could cause the MLG to collapse.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Service Bulletin Reference

(f) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of the applicable service bulletin or service bulletins listed in the following paragraphs:

(1) For the requirements specified in paragraphs (g) and (h) of this AD, which are restated from AD 96-22-09, use the applicable service bulletins in Table 1 of this AD.

Table 1.-Shorts Service Bulletins for Restated Requirements

Model
Service bulletin
Revision
Date
SD3-SHERPA series airplanes
SD3 SHERPA-32-2
Original
September 22, 1995.
SD3-SHERPA series airplanes
SD3 SHERPA-32-2
1
June 30, 2003.
SD3-60 series airplanes
SD360-32-34
Original
September 22, 1995.
SD3-60 series airplanes
SD360-32-34
1
June 30, 2003.

(2) For the new requirements specified in paragraphs (i) and (j) of this AD, use the applicable service bulletin in Table 2 of this AD.

Table 2.-Shorts Service Bulletins for New Requirements

Model
Service bulletin
Revision
Date
SD3-SHERPA series airplanes
SD3 SHERPA-32-2
1
June 30, 2003.
SD3-60 SHERPA series airplanes
SD360 SHERPA-32-1
Original
June 30, 2003.
SD3-60 series airplanes
SD360-32-34
1
June 30, 2003.

Note 1: The Messier-Dowty service bulletins listed in Table 3 of this AD are additional sources of service information for certain actions in the Shorts service bulletins.

Table 3.-Additional Sources of Service InformationThis Messier-Dowty service bulletin-
Is an additional source of service information for these shorts service bulletins-
32-78SD, dated July 19, 1995
SD3 SHERPA-32-2, dated September 22, 1995; and SD360-32-34, dated September 22, 1995.
32-78SD, Revision 1, dated December 9, 2002
SD360 SHERPA-32-1, dated June 30, 2003; and SD360-32-34, Revision 1, dated June 30, 2003.
32-80SD, dated August 31, 2000
SD360 SHERPA-32-1, dated June 30, 2003; SD3 SHERPA-32-2, Revision 1, dated June 30, 2003; and SD360-32-34, Revision 1, dated June 30, 2003.

Restatement of the Requirements of AD 96-22-09

(g) For Model SD3-60 series airplanes and Model SD3-SHERPA series airplanes: Within 90 days after December 11, 1996 (the effective date AD 96-22-09), perform a one-time visual and fluorescent dye penetrant inspection to detect cracks and/or corrosion of the gland nut on the shock absorber of the MLG, in accordance with the applicable service bulletin.

(1) If no crack and/or corrosion is detected, no further action is required by paragraph (g) of this AD.

(2) If no crack is detected, but corrosion is detected that is within the limits specified in the service bulletin, prior to further flight, repair the gland nut in accordance with the applicable service bulletin.

(3) If any crack is detected, or if any corrosion is detected that is outside the limits specified in the applicable service bulletin, prior to further flight, replace the gland nut with a new gland nut, in accordance with the applicable service bulletin.

(h) Following accomplishment of paragraph (g) of this AD, prior to further flight, apply grease to the threads of the cylinder, and apply sealant to the inner radius of the gland nut, in accordance with the applicable service bulletin.

New Requirements of This AD

Detailed Inspection and Corrective Action

(i) For all airplanes: Within 4 months after the effective date of this AD, do a detailed inspection of the P/N 200920604 gland nut on the MLG shock absorber for corrosion and/or cracking, and do any applicable corrective action before further flight, in accordance with the applicable service bulletin. Repeat the inspection at intervals not to exceed 12 months.

Note 2: For the purposes of this AD, a detailed inspection is: "An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required."

Optional Terminating Action

(j) Replacing the aluminum alloy gland nut, P/N 200920604, with a new steel gland nut, P/N 200920639, in accordance with the applicable service bulletin, terminates the requirements of this AD.

Alternative Methods of Compliance (AMOCs)

(k) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Related Information

(l) British airworthiness directive 008-06-2003 also addresses the subject of this AD.

Material Incorporated by Reference

(m) You must use the service information that is specified in Table 4 of this AD to perform the actions that are required by this AD, unless the AD specifies otherwise. For copies of the service information, contact Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. For information on the availability of this material at the National Archives and Records Administration (NARA), call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. You may view the AD docket at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC.

Table 4.-Material Incorporated by Reference

Shorts service bulletin
Revision level
Date
SD3 SHERPA-32-2
Original
September 22, 1995.
SD3 SHERPA-32-2
1
June 30, 2003.
SD360 SHERPA-32-1
Original
June 30, 2003.
SD360-32-34
Original
September 22, 1995.
SD360-32-34
1
June 30, 2003.

(1) The incorporation by reference of the service information listed in Table 5 of this AD is approved by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

Table 5.-Material Newly Incorporated by Reference

Shorts service bulletin
Revision level
Date
SD3 SHERPA-32-2
1
June 30, 2003.
SD360 SHERPA-32-1
Original
June 30, 2003.
SD360-32-34
1
June 30, 2003.

(2) The incorporation by reference of the service information listed in Table 6 of this AD was approved previously by the Director of the Federal Register as of December 11, 1996 (61 FR 57311, November 6, 1996).

Table 6.-Material Previously Incorporated by Reference

Shorts service bulletin
Revision level
Date
SD3 SHERPA-32-2
Original
September 22, 1995.
SD360-32-34
Original
September 22, 1995.

The FAA proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with an AD to supersede AD 96-22-09, amendment 39-9797 (61 FR 57311, November 6, 1996). The existing AD applies to certain Short Brothers Model SD3-60 and SD3-SHERPA series airplanes. The proposed AD was published in the Federal Register on July 22, 2004 (69 FR 43779). The proposed AD continued to require a one-time inspection to detect cracks and/or corrosion of the gland nut on the shock absorber of the main landing gear (MLG), and follow-on actions. The proposed AD also continued to require repair or replacement of any cracked/corroded gland nut with a new nut. The proposed AD added airplanes to the applicability; added repetitive inspections and corrective actions; and provided an optional action that would end the repetitive inspections.

Comments

We provided the public the opportunity to participate in the development of this AD. No comments have been submitted on the proposed AD or on the determination of the cost to the public.

Editorial Changes to AD

Minor editorial changes have been incorporated into this AD. These include changes in the following areas:

Summary section, accurately identifying the airplanes affected by the AD being superseded.

Note 2 of the body, updating text for the definition of a detailed inspection.

Table 3, correcting the dates of certain service bulletins and correcting the service bulletin reference for certain other service bulletins.

Changing all service bulletin references from "Short Brothers" service bulletin(s) to "Shorts" service bulletin(s). This change was made to comply with the Office of the Federal Register's guidelines for material incorporated by reference.

Paragraph (l), correcting the document number of the British airworthiness directive.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this AD.

Estimated Costs

Action
Work hours
Average labor rate per hour
Parts
Cost per airplane
Number of U.S.-registered airplanes
Fleet cost
Inspections required by AD 96 -22-09
5
$65
N/A
$325
58
$18,850
Proposed inspections (per inspection cycle)
5
65
N/A
325
85
26,625

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. Subtitle I, Section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the agency's authority.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A,Subpart III, Section 44701, "General requirements." Under that section, the FAA is charged with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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.

For the reasons discussed above, I certify that this AD:

(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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.