Proposed Rules. Notice of proposed rulemaking (NPRM)

Agency: Federal Aviation Administration (FAA), DOT
Action: Notice of proposed rulemaking (NPRM)
Citation: FR Doc. 2014-16942 · RIN 2120-AA64 · Docket No. FAA-2014-0450; Directorate Identifier 2013-NM-250-AD · 14 CFR 39

Summary

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. This proposed AD was prompted by reports of cracks emanating from the aft-most barrel nut holes of the left and right upper rear spar caps of the horizontal stabilizer. This proposed AD would require repetitive high frequency eddy current (ETHF) inspections for cracks in the areas around the two aft-most barrel nut holes of the upper rear spar caps, and corrective action if necessary; and repetitive ETHF inspections for cracks in the areas around the two aft-most barrel nut holes of any repaired or replaced upper rear spar cap, and corrective actions if necessary. We are proposing this AD to detect and correct such cracks, which could propagate until the upper rear spar cap severs, and result in failure of the horizontal stabilizer upper center or aft skin panel and adversely affect the structural integrity of the airplane.

Dates

We must receive comments on this proposed AD by September 2, 2014.

Supplementary Information

Comments Invited We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2014-0450; Directorate Identifier 2013-NM-250-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments. We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD. Discussion We have received reports of cracks emanating from the aft-most barrel nut holes of the left and right upper rear spar caps of the horizontal stabilizer. One airplane had accumulated 40,144 total flight hours and 32,253 total landing cycles, while another airplane had accumulated 58,296 total flight hours and 43,512 total landing cycles. Investigations have determined that the cracks were caused by fatigue. In both cases, the cracks originated inside of the barrel nut holes, and radiated vertically and in the aft direction from the barrel nut holes. This condition, if not corrected, could result in cracks in the horizontal stabilizer, which could propagate until it severs the upper rear spar cap, and result in failure of the horizontal stabilizer upper center or aft skin panel and adversely affect the structural integrity of the airplane. Relevant Service Information We reviewed Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. For information on the procedures and compliance times, see this service information at http://www.regulations.gov by searching for Docket No. FAA-2014-0450. FAA's Determination We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. Proposed AD Requirements This proposed AD would require accomplishing repetitive high frequency eddy current (ETHF) inspections for cracks of the areas around the aft-most barrel nut holes of the upper rear spar caps, and corrective actions if necessary; and repetitive ETHF inspections for cracks at the two aft-most barrel nut holes of the repaired or replaced upper rear spar cap, and corrective actions if necessary. The phrase “corrective actions” is used in this proposed AD. “Corrective actions” are actions that correct or address any condition found. Corrective actions in an AD could include, for example, repairs. Difference Between This Proposed AD and the Service Information Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, specifies post-repair inspections of the upper rear spar cap of the aft flange that has been splice-repaired, which may be used in support of compliance with Section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). However, this NPRM does not propose to require those post-repair inspections. This difference has been coordinated with Boeing. Costs of Compliance We estimate that this proposed AD affects 52 airplanes of U.S. registry. We estimate the following costs to comply with this proposed AD: Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators Inspection 9 work-hours X $85 per hour = $765 per inspection cycle $1,410 $2,175 per inspection cycle Up to $113,100 per inspection cycle. We estimate the following costs to do any necessary repairs and replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of aircraft that might need these repairs and replacements: On-condition Costs Action Labor cost Parts cost Cost per product Repair (per side) 368 work-hours X $85 per hour = $31,280 Up to $90,129 Up to $121,409. Replacement 368 work-hours X $85 per hour = $31,280 $81,764 $113,044. 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 determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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. For the reasons discussed above, I certify 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), (3) Will not affect intrastate aviation in Alaska, and (4) 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. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Proposed Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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): The Boeing Company: Docket No. FAA-2014-0450; Directorate Identifier 2013 NM-250-AD. (a) Comments Due Date We must receive comments by September 2, 2014. (b) Affected ADs None. (c) Applicability This AD applies to all The Boeing Company Model MD-90-30 airplanes, certificated in any category. (d) Subject Air Transport Association (ATA) of America Code Stabilizers, 55. (e) Unsafe Condition This AD was prompted by reports of cracks emanating from the aft-most barrel nut holes of the left and right upper rear spar caps of the horizontal stabilizer. We are issuing this AD to detect and correct cracks in the horizontal stabilizer, which could propagate until the upper rear spar cap severs, and result in failure of the horizontal stabilizer upper center or aft skin panel and adversely affect the structural integrity of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Inspection At the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, except as provided by paragraph (i) of this AD: Do a high frequency eddy current inspection (ETHF) for cracks in the areas around the two aft-most barrel nut holes of the upper rear spar cap; and do all applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Thereafter, repeat the ETHF inspection at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Do all corrective actions before further flight. (h) Post-Repair/Replacement Actions For airplanes on which a splice repair or replacement was done as specified in Boeing Alert Service Bulletin MD90-55A017: At the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, do an ETHF inspection for cracks at the two aft-most barrel nut holes of any repaired or replaced upper rear spar cap, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Thereafter, repeat the ETHF inspection at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. If any cracking is found, before further flight, do the repair or replacement, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. (i) Post-Repair Inspections The post-repair inspections of the upper rear spar cap of the aft flange that has been splice-repaired specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, are not required by this AD. Note 1 to paragraph (h) of this AD: The damage tolerance inspections (post-repair inspections of the upper rear spar cap aft flange) specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, may be used in support of compliance with Section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, are not required by this AD. (j) Exception to the Service Information Where Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD. (k) Alternative Methods of Compliance (AMOCs) (1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in paragraph (l)(1) of this AD. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Los Angeles ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD. (l) Related Information (1) For more information about this AD, contact George Garrido, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5357; fax: 562-627-5210; email: george.garrido@faa.gov. (2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800 0019, Long Beach, CA 90846-0001; telephone 206-544-5000, extension 2; fax 206-766-5683; Internet https://www.myboeingfleet.com. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. Issued in Renton, Washington, on July 11, 2014. Michael Kaszycki, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2014-16942 Filed 7-17-14; 8:45 am]