E6-903. Airworthiness Directives; Boeing Model 727, 727C, 727-100, 727-100C, and 727-200 Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing transport category airplanes. This proposed AD would require determining if the terminal fittings of the spars of the wings are made of 7079 aluminum alloy material. For any positive finding, the proposed AD would require doing repetitive inspections for cracks and corrosion of all exposed surfaces of the terminal fitting bores; doing repetitive inspections for cracks, corrosion, and other surface defects, of all exposed surfaces, including the flanges, of the terminal fitting; applying corrosion inhibiting compound to the terminal fittings; and repairing or replacing any cracked, corroded, or defective part with a new part. This proposed AD also provides for an optional terminating action for the repetitive inspections. This proposed AD results from reports of cracking of the terminal fittings of the spars of the wings. We are proposing this AD to detect and correct stress-corrosion cracking of the terminal fittings, which could result in the failure of one of the terminal fitting connections. Such a failure, combined with a similar failure of one of the other three terminal fittings, could result in the inability of the airplane structure to carry fail-safe loads, which could result in loss of structural integrity of the wing attachment points.

DATES:

We must receive comments on this proposed AD by March 13, 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:

Daniel F. Kutz, 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-2006-23672; Directorate Identifier 2005-NM-237-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 reports of cracking of the terminal fittings of the front and rear spars of the wings. The affected terminal fittings were made from a 7079-T6 aluminum forging. This material is known to be susceptible to stress-corrosion cracking. This condition, if not detected and corrected, could result in the failure of one of the terminal fitting connections. Such a failure, combined with a similar failure of one of the other three terminal fittings, could result in the inability of the airplane structure to carry fail-safe loads, which could result in loss of structural integrity of the wing attachment points.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 727-57A0185, Revision 1, dated November 3, 2005. The service bulletin describes procedures for determining if the terminal fittings of the front and rear spars of the wings are made of 7079 aluminum alloy material by either inspecting the forging number or doing a conductivity test. For any case where the terminal fitting is determined to be made of 7079 aluminum alloy material or where the material cannot be determined, the service bulletin describes procedures for doing repetitive fluorescent dye penetrant inspections for cracks and corrosion of all exposed surfaces of the terminal fitting bores; doing repetitive detailed inspections for cracks, corrosion, and other surface defects, of all exposed surfaces, including the flanges, of the terminal fitting; applying corrosion inhibiting compound to the terminal fittings; and repairing any cracked, corroded, or defective part or contacting Boeing if necessary.

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 “Differences Between the Proposed AD and Service Bulletin.” In addition, the proposed AD would provide for an optional terminating action for the repetitive inspections. The proposed AD also would require sending the initial inspection results to Boeing.

Differences Between the Proposed AD and 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.

In paragraph 1.E., the service bulletins states, “Contact Boeing for replacement of the fitting with a fitting not made from 7079 aluminum alloy. Replacement of the fitting is considered terminating action for that fitting only.” However, the Accomplishment Instructions of the service bulletin do not contain any procedures for accomplishing this replacement. Therefore, this proposed AD specifies that the optional replacement be done in accordance with a method approved by the Manager, Seattle Aircraft Certification Office.

Interim Action

This proposed AD is considered to be interim action. The inspection reports that are required by this AD will enable the manufacturer to obtain better insight into the extent of the cracking and corrosion of the terminal fittings of the front and rear spars of the wings in the fleet, and to develop additional action if necessary to address the unsafe condition. If additional action is identified, we may consider further rulemaking.

Costs of Compliance

There are about 302 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 157 airplanes of U.S. registry. The proposed determination of forging number/material identification would take about 4 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $40,820, or $260 per airplane.

Accomplishing the fluorescent dye penetrant and detailed inspections, if required, will take about 16 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, we estimate the cost of the inspections to be $1,040 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-2006-23672; Directorate Identifier 2005-NM-237-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by March 13, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 727, 727C, 727-100, 727-100C, and 727-200 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 727-57A0185, Revision 1, dated November 3, 2005.

Unsafe Condition

(d) This AD results from reports of cracking of the terminal fittings of the front and rear spars of the wings. We are issuing this AD to detect and correct stress-corrosion cracking of the terminal fittings, which could result in the failure of one of the terminal fitting connections. Such a failure, combined with a similar failure of one of the other three terminal fittings, could result in the inability of the airplane structure to carry fail-safe loads, which could result in loss of structural integrity of the wing attachment points.

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.

Determination of Type of Terminal Fittings, Repetitive Inspections, and Corrective Actions

(f) Within 24 months after the effective date of this AD, determine if the terminal fittings of the front and rear spars of the wings are made of 7079 aluminum alloy material by either inspecting the forging number or doing a conductivity test, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0185, Revision 1, dated November 3, 2005.

(1) If the forging number is that identified in Table 1 of this AD, or if the terminal fitting material is not made of 7079 aluminum alloy: No further action is required by this AD for that terminal fitting only.

Table 1.—Forging Numbers Not Made of 7079 Aluminum Alloy

Forging No. of terminal fittings	Location
(i) 65-16214-3	Rear spar of left wing.
(ii) 65-16213-3	Front spar of left wing.
(iii) 65-16214-4	Rear spar of right wing.
(iv) 65-16213-4	Front spar of right wing.

(2) If any forging number other than those identified in Table 1 of this AD is found, or if any forging material is made of 7079 aluminum alloy, or if the material cannot be determined: Within 24 months after the effective date of this AD, do the inspections specified in Table 2 of this AD and apply corrosion inhibiting compound (CIC) to the terminal fittings, and before further flight, repair or replace any cracked, corroded, or defective part found during the inspections. Repeat the inspections thereafter at intervals not to exceed 60 months for the first two repeat intervals, and then thereafter at intervals not to exceed 30 months. Do the inspections, application of CIC, and repair in accordance with the service bulletin, except as provided by paragraphs (h) and (i) of this AD. Do the replacement in accordance with paragraph (g) of this AD.

Table 2.—Inspections

Do—	For—	Of—
(i) A fluorescent dye penetrant inspection	Cracks and corrosion	All exposed surfaces of the terminal fitting bores.
(ii) A detailed inspection	Cracks, corrosion, and other surface defects	All exposed surfaces, including the flanges, of the terminal fitting.

Optional Terminating Action

(g) Replacement of any terminal fitting of the front and rear spars of the wings with a new terminal fitting not made of 7079 aluminum alloy, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, ends the repetitive inspections required by paragraph (f)(2) of this AD for that terminal fitting only. For the replacement to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.

Exception to Service Information

(h) Where the service bulletin specifies to contact Boeing for appropriate action:

Before further flight, repair the cracked, corroded, or defective part using a method approved in accordance with the procedures specified in paragraph (l) of this AD, or replace in accordance with paragraph (g) of this AD.

(i) Although the note in paragraph 3.B.7. of the service bulletin specifies procedures for a fluorescent dye penetrant inspection of the body fitting bore and repair if necessary, those procedures are not required by this AD.

Parts Installation

(j) As of the effective date of this AD, no person may install any terminal fitting having forging number 65-16213-1/-2 or 65-16214-1/-2, or install any terminal fitting material made of 7079 aluminum alloy, on any airplane.

Reporting

(k) Submit a report of the findings (both positive and negative) of the initial inspection required by paragraph (f)(2) of this AD to Boeing Commercial Airplane Group, Attention: Manager, Airline Support, P.O. Box 3707, Seattle, WA 98124-2207, at the applicable time specified in paragraph (k)(1) or (k)(2) of this AD. The report must include the operator's name, inspection results, a detailed description of any discrepancies found, the airplane serial number, and the number of flight cycles and flight hours on the airplane. Under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If the inspection was done after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was accomplished prior to the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

(l)(1) The Manager, Seattle ACO, FAA, 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, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on January 17, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.