05-19871. Airworthiness Directives; Boeing Model 737-100, -200, and -200C Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-100, -200, and -200C series airplanes. This AD requires a one-time detailed inspection for cracking of the lugs of the inboard attach fittings of the wing leading edge slat tracks at slat numbers 2 and 5; prior or concurrent actions for certain airplanes; repetitive high-frequency eddy current (HFEC) inspections for cracking of the lug surfaces of those inboard attach fittings if necessary; and replacement of the attach fittings with new, improved fittings. This AD results from reports of damage to the lugs of certain inboard attach fittings of the leading edge slat tracks. We are issuing this AD to prevent a lifted slat, which, if the airplane performs any non-normal maneuver during takeoff or landing at very high angles of attack, could lead to the loss of the slat and reduced control of the airplane.

DATES:

This AD becomes effective November 9, 2005.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of November 9, 2005.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Boeing Model 737-100, -200, and -200C series airplanes. That NPRM was published in the Federal Register on May 9, 2005 (70 FR 24335). That NPRM proposed to require a one-time detailed inspection for cracking of the lugs of the inboard attach fittings of the wing leading edge slat tracks at slat numbers 2 and 5; prior or concurrent actions for certain airplanes; repetitive high-frequency eddy current (HFEC) inspections for cracking of the lug surfaces of those inboard attach fittings if necessary; and replacement of the attach fittings with new, improved fittings.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Support for the NPRM

One commenter, the manufacturer, concurs with the content of the NPRM.

Request To Disallow Use of Aluminum Attach Fittings

One commenter requests that we revise the NPRM to prohibit replacing aluminum attach fittings with new aluminum fittings after the effective date of the AD. The commenter provides no justification for this request.

We do not agree with this request. The manufacturer recommends that, unless cracked, an aluminum attach fitting need not be replaced until 120 months or 30,000 flight cycles, whichever comes first, after the effective date of the AD. We have determined that the manufacturer recommendation is sound and that the repetitive inspections of the aluminum fittings required by the AD are sufficient to maintain safety until the aluminum fittings are removed from service. We have not changed the AD in this regard.

Explanation of Change Made to This AD

We have revised the “Alternative Methods of Compliance (AMOCs)” paragraph in this AD to clarify the delegation authority for Authorized Representatives for the Boeing Commercial Airplanes Delegation Option Authorization.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

We have carefully reviewed the available data, including the comments that have been submitted, 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 neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

This AD will affect about 909 airplanes worldwide. 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	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Detailed inspection	1	$65	None	$65	522	$33,930.
HFEC inspection	4	65	None	$260, per inspection cycle	522	$135,720, per inspection cycle.
Replace fitting	2	65	$1,674	$1,804	522	$941,688.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. 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.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA 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 rulemaking action.

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 and placed it in the AD docket. 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

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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2005-20-16 Boeing: Amendment 39-14310. Docket No. FAA-2005-21138; Directorate Identifier 2004-NM-131-AD.

Effective Date

(a) This AD becomes effective November 9, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-100, -200, and -200C series airplanes; line numbers 1 through 1585 inclusive; certificated in any category.

Unsafe Condition

(d) This AD was prompted by reports of damage to the lugs of certain inboard attach fittings of the leading edge slat tracks. We are issuing this AD to prevent a lifted slat, which, if the airplane performs any non-normal maneuver during takeoff or landing at very high angles of attack, could lead to the loss of the slat and reduced control of the airplane.

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 Boeing Special Attention Service Bulletin 737-57-1273, Revision 2, dated October 30, 2003; unless otherwise specified in this AD.

Inspections

(g) Prior to the accumulation of 7,000 total flight cycles or within 12 months after the effective date of this AD, whichever occurs later, perform a one-time detailed inspection for cracking and damage of the inboard attach fittings at slats 2 and 5 of the wing leading edge in accordance with the service bulletin.

Note 1:

For the purposes of this AD, a detailed inspection is “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.”

(1) If any crack or damage is found, replace the cracked inboard attach fitting in accordance with paragraph (h) of this AD.

(2) If no crack or damage is found, within 4,500 flight cycles or 18 months after the detailed inspection required by paragraph (g) of this AD, whichever occurs first, perform a high-frequency eddy current (HFEC) inspection for cracking of the lugs of the inboard attach fittings in accordance with the service bulletin. If no crack is found, repeat the HFEC inspection at intervals not to exceed 4,500 flight cycles.

Replacement of Fittings

(h) Replace the aluminum inboard attach fittings with new, improved steel fittings at the applicable compliance time in paragraph (h)(1) or (h)(2) of this AD in accordance with the service bulletin. Replacement of any aluminum fitting with a new, improved steel fitting terminates the one-time detailed inspection and the repetitive HFEC inspections required by paragraph (g) of this AD for that fitting.

(1) If any crack or damage is found during any inspection required by paragraphs (g) or (i) of this AD, before further flight.

(2) If no crack or damage is found during any inspection required by paragraph (g) or (i) of this AD, within 30,000 flight cycles or within 120 months after the effective date of this AD, whichever occurs first.

Concurrent Service Bulletin

(i) For airplanes listed in Group 2 of the service bulletin: Prior to or during the one-time detailed inspection for cracking or damage required by paragraph (g) of this AD or during replacement of the fitting required by paragraph (h) of this AD, whichever occurs first, perform a detailed inspection on slats 2 and 5 for interference of the slat tab support clips with the slat track attach fittings and trim the support clips to eliminate any interference with the attach fittings as applicable; in accordance with Figure 3 of the Accomplishment Instructions of Boeing Service Bulletin 737-57-1080, Revision 3, dated September 24, 1992; and replace any cracked or damaged aluminum attach fitting with a new, improved steel fitting in accordance with paragraph (h) of this AD.

Actions Accomplished Per Previous Issue of Service Bulletin

(j) Actions accomplished before the effective date of this AD in accordance with Boeing Service Bulletin 737-57-1080, dated September 10, 1973; Revision 1, dated February 25, 1983; or Revision 2, dated August 24, 1989; are considered acceptable for compliance with the corresponding actions specified in paragraph (i) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplane Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(3) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Material Incorporated by Reference

(l) You must use Boeing Special Attention Service Bulletin 737-57-1273, Revision 2, dated October 30, 2003; and Boeing Service Bulletin 737-57-1080, Revision 3, dated September 24, 1992; as applicable; to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on September 26, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.