E6-1681. Airworthiness Directives; Boeing Model 777 Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking.

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 777 airplanes. This proposed AD would require repetitive inspections for corrosion or missing corrosion inhibiting compound of the fuselage skin under the forward and aft wing-to-body fairings for certain airplanes, or the fuselage skin under the forward wing-to-body fairings only for other airplanes; and corrective action if necessary. The proposed AD would also provide an optional preventive modification of the wing-to-body fairing panels, which would terminate the repetitive inspections. This proposed AD results from several reports indicating that significant levels of corrosion were found on the external surface of the fuselage skin under the forward and aft wing-to-body fairings. We are proposing this AD to detect and correct corrosion, and prevent subsequent fatigue cracks, on the fuselage skin under the forward and aft wing-to-body fairings, which could result in rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by March 27, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Gary Oltman, 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:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-23817; Directorate Identifier 2005-NM-176-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may 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 DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received several reports indicating that significant levels of corrosion were found on the external surface of the fuselage skin under the forward and aft wing-to-body fairings. The depth of the corrosion was up to 67 percent of the original skin thickness, and corrosion was found on some airplanes as early as four years after original delivery of the airplane. During an evaluation done by the manufacturer it was determined that water can enter the wing-to-body area through the seal and drain holes in the fairings, causing corrosion. Inadequate or missing corrosion-inhibiting compound (CIC) on the fuselage skin also contributes to early corrosion. This condition, if not corrected, could result in corrosion and subsequent fatigue cracks on the fuselage skin under the forward and aft wing-to-body fairings, and consequent rapid decompression of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 777-53A0044, dated July 28, 2005. The service bulletin describes procedures for repetitive detailed inspections for corrosion or missing CIC of the fuselage skin under the forward and aft wing-to-body fairings for Group 1 airplanes, or the fuselage skin under the forward wing-to-body fairings only for Group 2 airplanes; and corrective action if necessary. The corrective action includes performing a detailed inspection to determine the extent of the corrosion, removing any corrosion found, and applying CIC. The service bulletin also describes procedures for an optional preventive modification of the wing-to-body fairing panels. The modification involves applying sealant to certain fasteners, removing and replacing the seal, installing scuppers, and applying CIC on the fuselage skin. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between Proposed AD and Alert Service Bulletin.”

Difference Between Proposed AD and Alert Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

Costs of Compliance

There are about 385 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 140 airplanes of U.S. registry.

The proposed inspection would take about 8 work hours per airplane for Group 1 airplanes, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed inspection for U.S. operators is $520 per airplane, per inspection cycle.

The proposed inspection would take about 4 work hours per airplane for Group 2 airplanes, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed inspection for U.S. operators is $260 per airplane, 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 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
• 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-23817; Directorate Identifier 2005-NM-176-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by March 27, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 777-200, -300, and -300ER series airplanes; certificated in any category; as identified in Boeing Alert Service Bulletin 777-53A0044, dated July 28, 2005.

Unsafe Condition

(d) This AD results from several reports indicating that significant levels of corrosion were found on the external surface of the fuselage skin under the forward and aft wing-to-body fairings. We are issuing this AD to detect and correct corrosion, and prevent subsequent fatigue cracks, on the fuselage skin under the forward and aft wing-to-body fairings, which could result in rapid decompression of the airplane.

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.

Repetitive Inspections

(f) At the latest of the compliance times specified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD, as applicable: Perform a detailed inspection of the fuselage skin under the wing-to-body fairings for corrosion or missing corrosion inhibiting compound (CIC) by doing all the applicable actions specified in Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 777-53A0044, dated July 28, 2005. Repeat the inspection thereafter at intervals not to exceed 1,500 days until the requirements of paragraph (h) are accomplished.

(1) Before the accumulation of 1,500 days since the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness.

(2) Within 1,500 days after accomplishing the latest zonal or surveillance inspection before the effective date of this AD that is equivalent to the detailed inspection specified in paragraph (f) of this AD.

(3) Within 750 days after the effective date of this AD.

Corrective Action

(g) If any corrosion or missing CIC is found during any inspection required by paragraph (f) of this AD, before further flight, do a detailed inspection to determine the full extent of the corrosion; repair before further flight by doing all the applicable actions specified in Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 777-53A0044, dated July 28, 2005. Where the alert service bulletin specifies to contact Boeing for repair instructions: Repair before further flight, according to a method approved in accordance with the procedures specified in paragraph (i) of this AD.

Optional Terminating Action

(h) Accomplishing the preventive modification of the wing-to-body fairing panels in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 777-53A0044, dated July 28, 2005, terminates the repetitive inspections required by paragraph (f) of this AD for the modified area only.

Alternative Methods of Compliance (AMOCs)

(i)(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) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards 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 an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization 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.

Issued in Renton, Washington, on January 30, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.