2010-7944. Airworthiness Directives; The Boeing Company Model 737-300, -400, and -500 Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Model 737-300, -400, and -500 series airplanes. The existing AD currently requires inspecting to determine if certain carriage spindles are installed, repetitive inspections for corrosion and indications of corrosion on affected carriage spindles, and if necessary, related investigative and corrective actions. The existing AD also provides an optional terminating action. This proposed AD would mandate the optional terminating action, which would eliminate the need for the repetitive inspections. The proposed AD results from reports of corrosion found on carriage spindles that are located on the outboard trailing edge flaps. We are proposing this AD to detect and correct corrosion of the carriage spindle, which could result in fracture. Fracture of both the inboard and outboard carriage spindles, in the forward ends through the large diameters, on a flap, could adversely affect the airplane's continued safe flight and landing.

DATES:

We must receive comments on this proposed AD by May 24, 2010.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. 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;​; 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 proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0379; Directorate Identifier 2009-NM-210-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

On October 26, 2009, we issued AD 2009-23-10, Amendment 39-16084 (74 FR 57564, November 9, 2009), for all Model 737-300, -400, and -500 series airplanes. That AD requires inspecting to determine if certain carriage spindles are installed, repetitive inspections for corrosion and indications of corrosion on affected carriage spindles, and if necessary, related investigative and corrective actions. That AD also provides an optional terminating action. That AD resulted from reports of corrosion found on carriage spindles that are located on the outboard trailing edge flaps. We issued that AD to detect and correct corrosion of the carriage spindle, which could result in fracture. Fracture of both the inboard and outboard carriage spindles, in the forward ends through the large diameters, on a flap, could adversely affect the airplane's continued safe flight and landing.

Actions Since Existing AD Was Issued

The preamble to AD 2009-23-10 explains that we consider the requirements “interim action” and were considering further rulemaking. We now have determined that further rulemaking is indeed necessary, and this proposed AD follows from that determination.

Boeing Commercial Airplanes has received an Organization Designation Authorization (ODA), which replaces their previous designation as a Delegation Option Authorization (DOA) holder. We have revised paragraph (l)(3) of this AD to delegate the authority to approve an alternative method of compliance for any repair required by this AD to the Boeing Commercial Airplanes ODA.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 2009-23-10 and would retain the requirements of the existing AD. This proposed AD would also mandate the optional terminating action, which would eliminate the need for the repetitive inspections.

Costs of Compliance

There are about 482 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 150 airplanes of U.S. registry.

The inspection that is required by AD 2009-23-10 and retained in this proposed AD takes about 2 work hours per airplane, at an average labor rate of $85 per work hour. Based on these figures, the estimated cost of the currently required inspection is $170 per airplane, per inspection cycle.

The replacement of each affected carriage spindle that is proposed in this AD would take about 17 work hours per spindle (4 spindles per airplane), at an average labor rate of $85 per work hour. Required parts cost would be provided under warranty. Based on these figures, the estimated cost of the replacement specified in this proposed AD for U.S. operators is up to $5,780, or $1,445 per carriage spindle or up to $867,000.

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 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 that the 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); 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 proposed 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

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 removing Amendment 39-16084 (74 FR 57564, November 9, 2009) and adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0379; Directorate Identifier 2009-N-210-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by May 24, 2010.

Affected ADs

(b) This AD supersedes AD 2009-23-10, Amendment 39-16084.

Applicability

(c) This AD applies to all The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category.

Subject

(d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

(e) This AD results from reports of corrosion found on carriage spindles that are located on the outboard trailing edge flaps. The Federal Aviation Administration is issuing this AD to detect and correct corrosion of the carriage spindle, which could result in fracture. Fracture of both the inboard and outboard carriage spindles, in the forward ends through the large diameters, on a flap, could adversely affect the airplane's continued safe flight and landing.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

RESTATEMENT OF REQUIREMENTS OF AD 2008-15-05, AMENDMENT 39-15617: Inspection To Determine Affected Carriage Spindle

(g) For all airplanes: Within 30 days after August 5, 2008 (the effective date of AD 2008-15-05), inspect the carriage sub-assembly to determine whether an affected carriage spindle with a high velocity oxy-fuel (HVOF) thermal coating is installed, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008. A review of airplane maintenance records is acceptable in lieu of this inspection if the part number and/or serial number of the carriage can be conclusively determined from that review. If no affected carriage spindle is installed, no further action is required by this paragraph.

Repetitive Inspections, Related Investigative Actions, and Corrective Action

(h) For airplanes on which any affected carriage spindle was determined to be installed in accordance with Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008, as of August 5, 2008; and the spindle is identified in Table 2 of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009: At the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD, do a detailed inspection (or, as an option for the forward end of the spindle only, a borescope inspection technique may be used) of the spindle for corrosion and potential indications of corrosion of the carriage spindle, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008; or Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009. Do all applicable related investigative and corrective actions before further flight. Repeat the detailed inspection (or, as an option for the forward end of the spindle only, the borescope inspection) and certain related investigative actions (i.e., the gap-check or optional non-destructive test (NDT) ultrasonic inspection) at the applicable compliance times specified in paragraph 1.E. of Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008; or Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009.

(1) Within 30 days after August 5, 2008.

(2) Within 90 days after the installation of a new HVOF-coated spindle.

Note 1:

Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008; and Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009; reference Boeing Alert Service Bulletin 737-57A1277, Revision 1, dated November 25, 2003; for further guidance on accomplishing the related investigative actions.

RESTATEMENT OF REQUIREMENTS OF AD 2009-23-10, AMENDMENT 39-16084: Repetitive Inspections, Related Investigative Actions, and Corrective Action for Certain Airplanes

(i) For airplanes on which a carriage spindle having a serial number identified in Table 3 of Appendix A of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009, is installed: At the latest of the times specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD, as applicable, do a detailed inspection (or, as an option for the forward end of the spindle only, a borescope inspection technique may be used) of the spindle for corrosion and potential indications of corrosion of the carriage spindle, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009. Do all applicable related investigative and corrective actions before further flight. Repeat the detailed inspection (or, as an option for the forward end of the spindle only, the borescope inspection) and related investigative actions (i.e., the gap-check or optional NDT ultrasonic inspection) at the applicable compliance times specified in paragraph 1.E. of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009.

(1) Within 30 days after November 24, 2009 (the effective date of AD 2009-23-10).

(2) Within 90 days after the installation of a new HVOF-coated spindle identified in Table 3 of Appendix A of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009.

(3) Within 90 days after doing an inspection in accordance with Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008.

Parts Installation

(j) As of August 5, 2008, an HVOF-coated spindle without an `R' suffix on the serial number may be installed on an airplane provided the actions required by paragraph (h) or (i) of this AD, as applicable, are done on that spindle.

NEW REQUIREMENTS OF THIS AD: Terminating Action

(k) Within 48 months after the effective date of this AD: Replace any HVOF-coated carriage spindle having a serial number identified in Table 2 or 3 of Appendix A of Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009, with a non-HVOF coated carriage spindle, or with a serviceable HVOF-coated carriage spindle with an `R' suffix on the serial number, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008; or Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 2009. Replacing all affected carriage spindles terminates the repetitive inspections required by this AD.

Alternative Methods of Compliance (AMOCs)

(l)(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. Send information to ATTN: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]. Or, e-mail information to [e-mail].

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(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 Delegation 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.

Issued in Renton, Washington, on April 1, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.