05-6688. Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 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, -300, -400, and -500 series airplanes. This AD requires repetitive detailed and eddy current inspections to detect cracking of the frame web around the cutout for the doorstop intercostal strap at the aft side of the body station 291.5 frame at stringer 16R, and corrective actions if necessary. This AD is prompted by reports of fatigue cracks in the web of the body station 291.5 frame near the forward galley door. We are issuing this AD to detect and correct fatigue cracking of the aft frame and frame support structure of the forward galley door, which could result in a severed fuselage frame web, rapid decompression of the airplane, and possible loss of the forward galley door.

DATES:

This AD becomes effective May 12, 2005.

The incorporation by reference of a certain publication listed in the AD is approved by the Director of the Federal Register as of May 12, 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-2004-18997; the directorate identifier for this docket is 2004-NM-19-AD.

FOR FURTHER INFORMATION CONTACT:

Howard Hall, 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, -300, -400, and -500 series airplanes. That action, published in the Federal Register on September 3, 2004 (69 FR 53858), proposed to require repetitive detailed and eddy current inspections to detect cracking of the frame web around the cutout for the doorstop intercostal strap at the aft side of the body station 291.5 frame at stringer 16R, and corrective actions 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.

Request To Delay Issuing AD

Several commenters note that the proposed AD does not provide a terminating action for the repetitive inspections specified in the proposed AD. Two commenters suggest that a terminating action be included in either the final AD action or in the instructions of the structural inspection document. One commenter requests that the FAA delay issuing the final AD action until Boeing Alert Service Bulletin 737-53A1241, dated June 13, 2002, has been revised to include a terminating modification. (That service bulletin was referenced in the proposed AD as the appropriate source of service information for accomplishing the repetitive inspections.) One commenter states that the proposed repetitive intervals will allow enough time for accomplishment of the inspections during its fleet's heavy maintenance visits, but that it would be helpful if terminating action instructions were provided.

We agree that a terminating action for the repetitive inspections would benefit operators. The airplane manufacturer is currently developing a terminating action. Once the proposed terminating action has been submitted to us for review, and we have approved the proposed action as terminating action for the requirements of the AD, anyone may use that terminating action as an alternative method of compliance (AMOC) under the provisions of paragraph (h) of this AD. We do not agree that we should delay issuing this AD until a terminating action is developed. We have determined that an unsafe condition exists, and we do not have any technical justification for delaying the release of this AD. We have not changed this AD regarding this issue.

One commenter requests that operators be allowed to review the additional service history information referenced in the proposed AD before the FAA issues the final AD action. The commenter states that it has requested that Boeing disseminate that additional history information to all operators. The commenter notes that the initial inspection threshold specified in the proposed AD is 20 percent lower than the threshold specified in Boeing Alert Service Bulletin 737-53A1241. The commenter concludes that the additional history information had an obvious impact on the FAA's decision to include a lowered initial inspection threshold in the proposed AD.

We agree with the intent of the commenter's request. As stated in the “Differences Between the Proposed AD and Service Bulletin” section of the proposed AD, the service bulletin includes an initial inspection threshold of 50,000 total flight cycles, and the proposed AD includes an initial inspection threshold of 40,000 total flight cycles. The threshold specified in the service bulletin is based on the first two reported cracks, which were found on an airplane that had accumulated more than 54,000 total flight cycles. After the release of the service bulletin, a subsequent crack was reported on an airplane that had accumulated only 44,153 total flight cycles. In light of this additional service history, we met with Boeing and determined that a threshold of 40,000 total flight cycles was appropriate for the initial inspection. We do not agree to delay issuing this AD until operators have had the opportunity to review the additional service history referenced in the proposed AD. We do not have any technical justification for such a delay. We have not changed this AD regarding this issue.

Request To Revise Repetitive Inspection Interval

Two commenters state that the repetitive inspection interval specified in the proposed AD is not synchronized with their maintenance programs, and that doing the inspection at the interval specified in the proposed AD would be a significant burden for operators that need to remove the galley to do an inspection. We infer that the commenters are requesting that the repetitive inspection interval of “not to exceed 4,500 flight cycles,” which is specified in the proposed AD, be increased so the interval is synchronized with the commenters' maintenance programs.

We agree that it would be a significant burden if operators have to remove the galley outside of a scheduled maintenance visit in order to perform an inspection. We do not agree to revise this AD so the repetitive inspection interval is synchronized with the maintenance programs of specific operators. In developing the repetitive inspection interval for this AD we considered the manufacturer's recommendation, the degree of urgency associated with the subject unsafe condition, and the practical aspect of accomplishing the required inspection at an interval that corresponds to the normal scheduled maintenance for most affected operators. However, under the provisions of paragraph (h) of this AD, we may approve requests to adjust the repetitive interval if the request includes data that justify that a different interval would provide an acceptable level of safety. We have not changed this AD regarding this issue.

Request To Address Inspection of Areas With Existing Repairs

One commenter notes that the proposed AD does not address inspection requirements if a repair exists in the subject areas. We infer that the commenter is requesting that we revise the proposed AD to include information regarding the inspection of areas with existing repairs.

We acknowledge that special inspection procedures may be required if a previously installed repair prevents an operator from accomplishing the actions required by this AD. It is not possible to foresee all possible repair configurations and to provide an appropriate inspection. If this is the case, the operator must apply for an AMOC as provided by paragraph (h) of this AD. We have not changed this AD regarding this issue.

Request To Revise Costs of Compliance

Several commenters state that the estimated costs for compliance stated in the proposed AD are misleading. The commenters note that inspecting the subject areas may only take 2 hours per inspection cycle to accomplish, but the time for accessing and closing the inspection area may take an additional 20 hours per inspection cycle. The commenters state that these access and closing costs would be attributable to the proposed AD because the proposed compliance time would not allow for doing the proposed actions during a scheduled maintenance visit when the galley would be removed. We infer that the commenters are requesting that the estimated costs of compliance be revised to include labor hours for accessing and closing the inspection area.

We do not agree to revise the “Costs of Compliance” section of this AD. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. This AD requires repetitive detailed and eddy current inspections. We recognize that in accomplishing the requirements of any AD, operators may incur incidental costs in addition to the direct costs. However, the cost analysis in AD rulemaking actions typically does not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate.

Explanation of Change to the Proposed AD

Boeing has received a Delegation Option Authorization (DOA). We have revised this AD to delegate the authority to approve an AMOC for any replacement required by this AD to the Authorized Representative (AR) for the Boeing DOA Organization rather than the Designated Engineering Representative.

We have revised paragraph (h) of this AD to provide the option of requesting an AMOC from either the Manager, Seattle Aircraft Certification Office (ACO), FAA, or an approved AR of the Boeing DOA Organization who has been authorized by the Manager, Seattle ACO, to make such findings.

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 affects about 3,113 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 per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection, per inspection cycle	2	$65	None	$130, per inspection cycle	876	$113,880, per inspection cycle.

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):

2005-07-12 Boeing: Amendment 39-14036. Docket No. FAA-2004-18997; Directorate Identifier 2004-NM-19-AD.

Effective Date

(a) This AD becomes effective May 12, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; certificated in any category; as identified in Boeing Alert Service Bulletin 737-53A1241, dated June 13, 2002.

Unsafe Condition

(d) This AD was prompted by reports of fatigue cracks in the web of the body station 291.5 frame near the forward galley door. We are issuing this AD to detect and correct fatigue cracking of the aft frame and frame support structure of the forward galley door, which could result in a severed fuselage frame web, rapid decompression of the airplane, and possible loss of the forward galley door.

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.

Initial and Repetitive Inspections

(f) Prior to the accumulation of 40,000 total flight cycles, or within 2,250 flight cycles after the effective date of this AD, whichever occurs later: Do a detailed inspection and an eddy current inspection to detect cracking of the frame web around the cutout for the doorstop intercostal strap at the aft side of the body station 291.5 frame at stringer 16R, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1241, dated June 13, 2002. If no cracking is found, repeat the inspections thereafter at intervals not to exceed 4,500 flight cycles.

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

Corrective Action

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

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle ACO, 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 inspection required by this AD, if it is approved by an AR for the Boeing DOA who has been authorized by the Manager, Seattle ACO, to make those findings. For an inspection method to be approved, the approval must specifically refer to this AD.

Material Incorporated by Reference

(i) You must use Boeing Alert Service Bulletin 737-53A1241, dated June 13, 2002, 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 this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, go to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view the 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 March 25, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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