2014-29190. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by reports of fatigue cracking in the skin assembly and bear strap of the aft lower corner of the forward airstair stowage doorway. This AD requires repetitive inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; post-repair and post-modification inspections for certain airplanes; and related investigative and corrective actions, if necessary. This AD also provides optional terminating actions for certain inspections. We are issuing this AD to detect and correct fatigue cracking, which could result in rapid loss of cabin pressure.

DATES:

This AD is effective January 20, 2015.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of January 20, 2015.

ADDRESSES:

For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone [phone], extension 1; fax [phone]; 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.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2014-0257; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (phone: [phone]) is Docket Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Alan Pohl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on May 1, 2014 (79 FR 24628). The NPRM was prompted by reports of fatigue cracking in certain areas. The NPRM proposed to require repetitive inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; post-repair and post-modification inspections for certain airplanes; and related investigative and corrective actions, if necessary. The NPRM also proposed to provide optional terminating actions for certain inspections. We are issuing this AD to detect and correct fatigue cracking, which could result in rapid loss of cabin pressure.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM (79 FR 24628, May 1, 2014) and the FAA's response to each comment.

Effect of Winglets on AD

Aviation Partners Boeing and UPS stated that the installation of winglets per Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/​Regulatory_​and_​Guidance_​Library/​rgstc.nsf/​0/​ebd1cec7b301293e86257cb30045557a/​$FILE/​ST01219SE.pdf) does not affect the accomplishment of the manufacturer's service instructions.

We agree with the commenters' statement. We have redesignated paragraph (c) of the NPRM (79 FR 24628, May 1, 2014) as (c)(1) in this AD and added new paragraph (c)(2) to this AD to state that the installation of winglets as specified in STC ST01219SE (http://rgl.faa.gov/​Regulatory_​and_​Guidance_​Library/​rgstc.nsf/​0/​ebd1cec7b301293e86257cb30045557a/​$FILE/​ST01219SE.pdf) does not affect accomplishment of the requirements of this AD, and for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of section 39.17 of the Federal Aviation Regulations (14 CFR 39.17).

Request To Revise Paragraph (m) of the NPRM (79 FR 24628, May 1, 2014)

Southwest Airlines (SWA) stated that the NPRM (79 FR 24628, May 1, 2014), does not address terminating the initial inspection if a repair was previously installed using Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014. SWA requested that we revise the text of paragraph (m)(3) of the NPRM, to state that repairs or modifications using Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, terminates both the initial and repetitive inspections required by paragraph (j) of this AD. SWA also requested that repairs previously approved by a Boeing authorized representative via an FAA 8100-9 form are terminating action to both the initial and repetitive inspection requirements required by paragraph (j) of the NPRM.

We agree with the request because it was not intended that a separate initial inspection would be performed on airplanes that have the repair previously installed. We have deleted the word “repetitive” from paragraphs (m)(1) through (m)(3) of this AD to clarify that accomplishing the actions in those paragraphs terminates certain initial and repetitive inspections. We have also added paragraph (m)(4) to this final rule, which specifies that the accomplishment of a repair of the aft lower corner of the forward airstair stowage doorway that was previously approved using FAA Form 8100-9, terminates the inspections required by paragraph (j) of this AD.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and minor editorial changes. We have determined that these minor changes:

• Αre consistent with the intent that was proposed in the NPRM (79 FR 24628, May 1, 2014) for correcting the unsafe condition; and
• Do not add any additional burden upon the public than was already proposed in the NPRM (79 FR 24628, May 1, 2014).

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Costs of Compliance

We estimate that this AD affects 132 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Inspection	5 work-hours × $85 per hour = $425 per inspection cycle	None	$425 per inspection cycle	$56,100 per inspection cycle.

We have received no definitive data that would enable us to provide cost estimates for any on-condition actions specified in this AD.

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

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),

(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

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):

2014-25-09 The Boeing Company: Amendment 39-18051; Docket No. FAA-2014-0257; Directorate Identifier 2014-NM-012-AD.

(a) Effective Date

This AD is effective January 20, 2015.

(b) Affected ADs

None.

(c) Applicability

(1) This AD applies to The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014.

(2) Installation of Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/​Regulatory_​and_​Guidance_​Library/​rgstc.nsf/​0/​ebd1cec7b301293e86257cb30045557a/​$FILE/​ST01219SE.pdf) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by reports of fatigue cracking in the skin assembly and bear strap of the aft lower corner of the forward airstair stowage doorway. We are issuing this AD to detect and correct fatigue cracking, which could result in rapid loss of cabin pressure.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Inspections and Corrective Actions for Group 1 and Group 2 Airplanes That Do Not Have a Certain Repair or Preventative Modification Installed

For Group 1 and Group 2 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, on which no repair or preventative modification has been done as specified in any of the service information identified in paragraphs (g)(1) through (g)(4) of this AD: At the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(1) of this AD, do high frequency eddy current and detailed inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections at the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, until the applicable terminating action specified in paragraph (m) of this AD is done.

(1) Boeing Service Bulletin 737-53-1058, dated April 4, 1980.

(2) Boeing Service Bulletin 737-53-1058, Revision 1, dated March 5, 1987.

(3) Boeing Service Bulletin 737-53-1058, Revision 2, dated December 7, 1989.

(4) Boeing Service Bulletin 737-53-1058, Revision 3, dated March 11, 1993.

(h) Inspections and Corrective Actions for Group 1 and Group 2 Airplanes That Have a Certain Repair Installed

For Group 1 and Group 2 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, on which a repair has been installed as specified in Boeing Service Bulletin 737-53-1058, dated April 4, 1980: Within the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(1) of this AD, do a high frequency eddy current inspection for cracking of the bear strap of the forward airstair stowage doorway, and do low frequency eddy current and detailed inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections at the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, until the applicable terminating action specified in paragraph (m) of this AD is done.

(i) Inspections and Corrective Actions for Group 1 and Group 2 Airplanes That Have a Certain Preventative Modification Installed

For Group 1 and Group 2 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, on which a preventative modification has been installed as specified in any of the service information identified in paragraphs (i)(1) through (i)(4) of this AD: Within the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(1) of this AD, do a high frequency eddy current inspection for cracking of the bear strap of the forward airstair stowage doorway, a low frequency eddy current inspection for cracking of the skin assembly and bear strap of the forward airstair stowage doorway, and detailed inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; and do all related investigative and applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections at the applicable times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, until the applicable terminating action specified in paragraph (m) of this AD is done.

(1) Boeing Service Bulletin 737-53-1058, dated April 4, 1980.

(2) Boeing Service Bulletin 737-53-1058, Revision 1, dated March 5, 1987.

(3) Boeing Service Bulletin 737-53-1058, Revision 2, dated December 7, 1989.

(4) Boeing Service Bulletin 737-53-1058, Revision 3, dated March 11, 1993.

(j) Inspections and Corrective Actions for Group 3 Through Group 5 Airplanes

For Group 3 through Group 5 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014: At the applicable times specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(1) of this AD, do a high frequency eddy current inspection for cracking of the bear strap of the forward airstair stowage doorway, a low frequency eddy current inspection for cracking of the skin assembly and bear strap of the forward airstair stowage doorway, and detailed inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; and do all related investigative and applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections at the applicable times specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, until the applicable terminating action specified in paragraph (m) of this AD is done.

(k) Inspections and Corrective Actions for Group 6 Airplanes

For Group 6 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014: Within 120 days after the effective date of this AD, inspect and repair any cracking using a method approved in accordance with the procedures specified in paragraph (q) of this AD.

(l) Post-Repair and Post-Modification Inspections for Group 1 and Group 2 Airplanes

For Group 1 and Group 2 airplanes on which any repair has been done as specified in any of the service information identified in paragraphs (l)(1) through (l)(3) of this AD, or on which any repair or modification has been done as specified in the service information identified in paragraph (l)(4) of this AD: At the applicable times specified in Table 3 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, except as required by paragraph (o)(1) of this AD, do a high frequency eddy current inspection for cracking in the bear strap and skin assembly and a general visual inspection for cracking in the frame of the forward airstair stowage doorway; or do low frequency eddy current inspections for cracking of the skin assembly and bear strap of the forward airstair stowage doorway; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014. Options provided in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, for accomplishing the inspections are acceptable for compliance with the corresponding requirements of this paragraph provided that the inspections are done at the applicable times specified in paragraph 1.E., “Compliance,” of the Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014. If any cracking is found, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (q) of this AD. Repeat the inspections at the applicable times specified in Table 3 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014.

(1) Boeing Service Bulletin 737-53-1058, Revision 1, dated March 5, 1987.

(2) Boeing Service Bulletin 737-53-1058, Revision 2, dated December 7, 1989.

(3) Boeing Service Bulletin 737-53-1058, Revision 3, dated March 11, 1993.

(4) Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014.

(m) Optional Terminating Actions

(1) For Group 1 and Group 2 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014: Accomplishment of a repair for cracking of the skin assembly and bear strap of the forward airstair stowage doorway before the effective date of this AD, using any service information specified in paragraphs (m)(1)(i) through (m)(1)(iv) of this AD, terminates the inspections required by paragraphs (g), (h), and (i) of this AD.

(i) Boeing Service Bulletin 737-53-1058, Revision 1, dated March 5, 1987.

(ii) Boeing Service Bulletin 737-53-1058, Revision 2, dated December 7, 1989.

(iii) Boeing Service Bulletin 737-53-1058, Revision 3, dated March 11, 1993.

(iv) Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014.

(2) For Group 1 and Group 2 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014: Accomplishment of a preventative modification for cracking of the skin assembly and bear strap of the forward airstair stowage doorway before the effective date of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, terminates the inspections required by paragraphs (g), (h), and (i) of this AD.

(3) For Group 3 through Group 5 airplanes identified in Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014: Repairing or modifying the forward airstair stowage doorway, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, terminates the inspections required by paragraph (j) of this AD.

(4) Accomplishment, prior to the effective date of this AD, of a repair of the aft lower corner of the forward airstair stowage doorway that was approved by Boeing Commercial Airplanes Organization Designation Authorization (ODA) using FAA Form 8100-9, terminates the inspections required by paragraph (j) of this AD.

(n) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraphs (g), (h), and (i) of this AD, if those actions were performed before the effective date of this AD using any service information specified in paragraphs (n)(i) through (n)(iii) of this AD.

(i) Boeing Service Bulletin 737-53-1058, Revision 1, dated March 5, 1987.

(ii) Boeing Service Bulletin 737-53-1058, Revision 2, dated December 7, 1989.

(iii) Boeing Service Bulletin 737-53-1058, Revision 3, dated March 11, 1993.

(o) Exceptions to the Service Information

(1) Where Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, specifies a compliance time “after the Revision 4 date of this service bulletin,” this AD requires compliance within the specified compliance time “after the effective date of this AD.”

(2) Where Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD.

(p) Post-Repair and Post-Modification Inspections for Group 3 Through Group 5 Airplanes Not Required

The post-repair and post-modification inspections specified in Table 4 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, are not required by this AD.

Note 1 to paragraph (p) of this AD:

The post-repair and post-modification inspections specified in Table 4 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014, 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)).

(q) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle 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 (r)(1) of this AD. Information may be emailed to: [e-mail].

(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, 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.

(r) Related Information

(1) For more information about this AD, contact Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: [phone]; fax: [phone]; email: [e-mail].

(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (s)(3) and (s)(4) of this AD.

(s) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) Boeing Service Bulletin 737-53-1058, Revision 4, dated January 9, 2014.

(ii) Reserved.

(3) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone [phone], extension 1; fax [phone]; Internet https://www.myboeingfleet.com.

(4) You may view this service information at 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.

(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on December 5, 2014.

Michael J. Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.