05-17461. Airworthiness Directives; Boeing Model 737-100, -200, -200C, and -300 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, -200C, and -300 series airplanes. This AD requires repetitive detailed inspections to detect discrepancies of the retaining pin lugs on the support fitting of the main landing gear (MLG) beam, and rework of the support fitting, or replacement of the fitting if necessary. This AD is prompted by reports of discrepancies of the lugs. We are issuing this AD to prevent separation of the support beam of the MLG from the rear spar, which could cause cracking of the MLG support fitting and a consequent leak in the wing fuel tank or collapse of the MLG.

DATES:

This AD becomes effective October 11, 2005.

The incorporation by reference of certain publications listed in the AD is approved by the Director of the Federal Register as of October 11, 2005.

ADDRESSES:

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

Docket: The AD docket contains the proposed AD, comments, and any final disposition. You can examine the 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 U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Washington, DC. This docket number is FAA-2004-18877; the directorate identifier for this docket is 2002-NM-340-AD.

FOR FURTHER INFORMATION CONTACT:

Robert C. Hardwick, 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:

The FAA proposed to amend 14 CFR part 39 with an AD for certain Boeing Model 737-100, -200, -200C, and -300 series airplanes. That action, published in the Federal Register on August 17, 2004 (69 FR 51017), proposed to require repetitive detailed inspections to detect discrepancies of the retaining pin lugs on the support fitting of the main landing gear (MLG) beam, and rework of the support fitting or replacement of the fitting if necessary.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD.

Agreement With the Proposed AD

One commenter, the manufacturer, agrees with the proposed AD.

Conditional Agreement With the Proposed AD

One commenter, an operator, agrees with the proposed AD provided that there are adequate parts available if the discrepant condition is found.

The FAA agrees that adequate availability of parts is necessary. We have received no information from the manufacturer concerning a possible delay in availability of parts. In the event there is a delay in the availability of parts, an operator may request approval for an alternative method of compliance as specified in paragraph (k)(1) of this AD.

Request for Clarification of Paragraph (g) of the Proposed AD

One commenter, an operator, requests additional information and clarification regarding the reference in paragraph (g)(2) of the proposed AD to replacing the fittings in accordance with the Accomplishment Instructions, Part III—Fitting Replacement, of Boeing Service Bulletin 737-57-1216, Revision 2, dated May 6, 1999. The commenter notes that, in certain situations, those Accomplishment Instructions instruct the operator to install a self-locking nut to secure the support pin of the MLG support beam. However, the commenter advises that installing a self-locking nut would be in conflict with AD 2002-02-08 (67 FR 6372, February 12, 2002).

We agree that clarification of paragraph (g)(2) of the AD is necessary in order to prevent a conflict between the requirements of this AD and AD 2002-02-08. Therefore, we have added further information to paragraph (g)(2) of the AD to specify that, if operators choose to accomplish the corrective action specified in paragraph (g)(2) of the AD, replacing the fitting in accordance with the Accomplishment Instructions, Part III—Fitting Replacement, of Boeing Service Bulletin 737-57-1216, Revision 2, dated May 6, 1999, must also include replacing the retaining bolt, self-locking nut, and associated hardware of the support beam for the MLG with a new bolt, castellated nut, and new hardware; in accordance with Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001.

Request for Credit for Accomplishing Certain Service Bulletins

One commenter, an operator, requests that the original issue, dated December 17, 1992, and Revision 1, dated September 23, 1993, of Boeing Service Bulletin 737-57-1216 be approved as acceptable for terminating the requirements of the proposed AD. The commenter states that the original issue and Revision 1 provide procedures for replacing the fitting that are essentially the same as those in Revision 2, which is cited as the appropriate service information in paragraph (g)(2) of the proposed AD.

We agree with the commenter for the reason stated and have revised paragraph (g)(2) of the AD accordingly.

Request To Clarify Paragraph (j) of the Proposed AD

One commenter, an operator, requests that the fittings acceptable for installation be stated in a more definite manner than “a new lug.” The commenter suggests that paragraph (j) of the proposed AD be revised to specify a part number or serial number, rather than just “a new lug.” The commenter also requests that the inspection and rework instructions of paragraph (j) of the proposed AD be more specific.

We agree that clarifying the intent of the words “new lug” is necessary. Although the inspection requirements of this AD are intended to detect cracking of “the retaining pin lugs of the support fitting of the MLG, or elongation of a bolt hole in a lug,” the corrective actions of paragraph (g) of this AD require reworking or replacing the fittings. We specify reworking or replacing the fittings, rather than the lugs, since the lugs are not available as individual replacement parts. The intent and purpose of paragraph (j) of this AD is to specify that any lug must be inspected and the fitting reworked or replaced, as applicable, except for those fittings that previously have been reworked or replaced, in accordance with paragraph (g) of this AD. We have revised paragraph (j) of the AD accordingly. We do not, however, agree that the inspection and rework instructions of paragraph (j) of the AD need to be more specific. The requirements of paragraph (j) of the AD indicate multiple actions that are clearly encompassed by stating “in accordance with this AD,” rather than to specify each action that has already been stated in previous paragraphs of the AD.

Changes to Delegation Authority

Boeing has received a Delegation Option Authorization (DOA). We have revised this final rule to delegate the authority to approve an alternative method of compliance for any repair required by this AD to the Authorized Representative for the Boeing DOA Organization rather than the Designated Engineering Representative (DER).

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

There are about 1,670 airplanes worldwide of the affected design and 668 airplanes of U.S. registry. The required actions take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the required actions for U.S. operators is $86,840, or $130 per airplane, per inspection cycle.

The rework, if accomplished, will take about 24 work hours per airplane to accomplish at an average labor rate of $65 per work hour. Required parts will cost about $1,006 per airplane. Based on these figures, the cost impact of the rework provided by this AD is estimated to be $2,566 per airplane.

The replacement of the support fitting of the MLG beam, if accomplished, will take about 128 work hours per airplane to accomplish at an average labor rate of $65 per work hour. Required parts will cost between $4,540 and $5,271 per airplane. Based on these figures, the cost impact of the replacement provided by this AD is estimated to be between $12,860 and $13,591 per airplane.

The replacement of the support fitting and installation of a special bushing of the MLG beam (for Group 9 and Group 10 airplanes), if accomplished, will take about 144 work hours per airplane to accomplish at an average labor rate of $65 per work hour. Required parts will cost about $5,081 per airplane. Based on these figures, the cost impact of this replacement and installation is estimated to be $14,441 per airplane.

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. 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

2005-18-08 Boeing: Amendment 39-14248. Docket No. FAA-2004-18877; Directorate Identifier 2002-NM-340-AD.

Effective Date

(a) This AD becomes effective October 11, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-100, -200, -200C, and -300 series airplanes, certificated in any category; line numbers 1 through 1670 inclusive.

Unsafe Condition

(d) This AD was prompted by reports of discrepancies of the lugs on the support fitting of the main landing gear (MLG) beam. We are issuing this AD to prevent separation of the support beam of the MLG from the rear spar, which could cause cracking of the MLG support fitting and a consequent leak in the wing fuel tank or collapse of the MLG.

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.

Inspection

(f) Prior to the accumulation of 15,000 total flight cycles, or within 3,000 flight cycles after the effective date of this AD, whichever occurs later: Perform a detailed inspection to detect cracking of the retaining pin lugs of the support fitting of the MLG beam, or elongation of a bolt hole in a lug, in accordance with the Accomplishment Instructions, Part I: Inspection, of Boeing Special Attention Service Bulletin 737-57-1267, dated August 8, 2002. If no cracked lug or elongated bolt hole is found, repeat the inspection thereafter at intervals not to exceed 12,000 flight cycles, until the actions specified in paragraph (h) of this AD are accomplished.

Note 1:

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 mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required.”

Corrective Action

(g) If any cracked lug or elongated bolt hole is found during any inspection required by paragraph (f) of this AD, before further flight, do paragraph (g)(1) or (g)(2) of this AD.

(1) Rework the fitting in accordance with the Accomplishment Instructions, Part II: Rework, of Boeing Special Attention Service Bulletin 737-57-1267, dated August 8, 2002.

(2) Replace the fitting in accordance with the Accomplishment Instructions, Part III—Fitting Replacement, of Boeing Service Bulletin 737-57-1216, Revision 2, dated May 6, 1999, and install a retaining bolt, castellated nut, and cotter pin in accordance with Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001. Replacing the fitting in accordance with the Accomplishment Instructions, Part III—Fitting Replacement, of Boeing Service Bulletin 737-57-1216, dated December 17, 1992, or Revision 1, dated September 23, 1993; and replacing the retaining bolt, self-locking nut, and associated hardware of the support beam for the MLG with a new bolt, castellated nut, and new hardware; in accordance with Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001; prior to the effective date of this AD are acceptable methods of compliance with the requirements of this paragraph.

Optional Terminating Action

(h) Reworking or replacing the fitting in accordance with paragraph (g)(1) or (g)(2) of this AD constitutes terminating action for the inspections required by paragraph (f) of this AD.

Repair

(i) If any cracking is found during any inspection required by this AD, and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by an Authorized Representative (AR) for the Boeing DOA Organization who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.

Parts Installation

(j) As of the effective date of this AD: With the exception of a new support fitting of the MLG; (i.e., a fitting that has been reworked or replaced as required by paragraph (g) of this AD), all retaining pin lugs of the support fitting, and bolt holes of the lugs must be inspected in accordance with this AD before being installed on any airplane.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Seattle 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 corrective actions per data meeting the type certification basis of the airplane approved by a Boeing DOA Organization AR 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 reference this AD.

Material Incorporated by Reference

(l) You must use Boeing Special Attention Service Bulletin 737-57-1267, dated August 8, 2002; Boeing Service Bulletin 737-57-1216, Revision 2, dated May 6, 1999; and Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001; as applicable, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view an AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to 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/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on August 24, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.