E6-7016. Airworthiness Directives; Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR 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 Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR series airplanes. This proposed AD would require doing repetitive inspections of engine struts 1 through 4, as applicable, for heat discoloration, cracking, buckling, or wrinkling. This proposed AD also would require a conductivity test to detect the extent of the heat damage and an inspection to detect cracking of the heat-discolored, buckled, or wrinkled area; and repair; if necessary. This proposed AD results from reports of heat damage and cracking of the skin and internal structure adjacent to and aft of the precooler exhaust vent on several engine struts. We are proposing this AD to detect and correct cracking, buckling, wrinkling, or heat damage of the skin and internal structure of the engine struts, which could result in extensive damage to the engine struts and consequent possible separation of an engine from the airplane during flight.

DATES:

We must receive comments on this proposed AD by June 23, 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.
• Governmentwide 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:

Ivan Li, 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-2006-24695; Directorate Identifier 2006-NM-035-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 heat damage and cracking of the skin and internal structure adjacent to and aft of the precooler exhaust vent on 14 engine struts on in-service airplanes. These airplanes had the terminating modification specified in Boeing Service Bulletin 747-54-2163 incorporated, which installed external titanium doublers and internal frame reinforcement to originally address high-temperature air from the precooler exhaust vent of the engine struts. However, the reported damage has occurred in unmodified areas, as well as modified areas. High-temperature air from the precooler exhaust vent could heat up and potentially anneal (reducing the strength) the skin and internal structure of the engine struts, which could result in cracking, buckling, wrinkling, or heat damage of the skin and internal structure of the engine struts. Such cracking, buckling, wrinkling, or heat damage, if not detected and corrected, could result in extensive damage to the engine strut and consequent possible separation of an engine from the airplane during flight.

Other Relevant Rulemaking

We have previously issued AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28, 1995), applicable to certain Boeing Model 747 series airplanes. That AD requires modifications of the nacelle strut and wing structure, inspections and checks to detect discrepancies, and correction of discrepancies. The actions required by that AD must be done in accordance with Boeing Alert Service Bulletin 747-54A2158, dated November 30, 1994. That service bulletin refers to several service bulletins as additional sources of service information for doing the actions required by AD 95-13-07. One of those additional sources is Boeing Service Bulletin 747-54-2163.

We have determined that the actions specified in Boeing Service Bulletin 747-54-2163 continue to prevent failure of the strut and subsequent loss of the engine. Therefore, this proposed AD would not affect the requirements of AD 95-13-07.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 747-54-2223, dated January 26, 2006. The service bulletin describes the following procedures:

• Doing repetitive detailed inspections of engine struts 1 through 4, as applicable, for heat discoloration, cracking, buckling, or wrinkling;
• Doing a conductivity test to detect the extent of the heat damage and a penetrant inspection or high frequency eddy current (HFEC) inspection to detect cracking of the heat-discolored, buckled, or wrinkled area, if necessary;
• Contacting Boeing for repair instructions if necessary.

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 “Differences Between the Proposed AD and Service Bulletin.”

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.

Costs of Compliance

There are about 112 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 33 airplanes of U.S. registry. The proposed detailed inspections would take about 4 or 8 work hours per airplane (depending on the airplane configuration), at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $10,560 or $21,120, or $320 or $640 per airplane, per inspection cycle (depending on the airplane configuration).

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-2006-24695; Directorate Identifier 2006-NM-035-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by June 23, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 747-54-2223, dated January 26, 2006.

Unsafe Condition

(d) This AD results from reports of heat damage and cracking of the skin and internal structure adjacent to and aft of the precooler exhaust vent on several engine struts on in-service airplanes. We are issuing this AD to detect and correct cracking, buckling, wrinkling, or heat damage of the skin and internal structure of the engine struts, which could result in extensive damage to the engine struts and consequent possible separation of an engine from the airplane during flight.

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.

Service Bulletin

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-54-2223, dated January 26, 2006.

Repetitive Detailed Inspections

(g) Within 18 months after the effective date of this AD, do a detailed inspection of engine struts 1 through 4, as applicable, for heat discoloration, cracking, buckling, or wrinkling, in accordance with the service bulletin. Repeat the detailed inspection thereafter at intervals not to exceed 18 months.

Corrective Actions

(h) If any heat discoloration, buckling, or wrinkling is found during any detailed inspection required by paragraph (g) of this AD, before further flight, do a conductivity test to detect the extent of the heat damage and a penetrant inspection or high frequency eddy current inspection to detect cracking of the heat-discolored, buckled, or wrinkled area, in accordance with the service bulletin.

(1) If the conductivity test results are within the limits specified in the service bulletin and no cracking is detected, before further flight, repair any buckled or wrinkled area using a method approved in accordance with the procedures specified in paragraph (j) of this AD. Heat discoloration does not need to be repaired if the conductivity test results of the heat-discolored area are within the specified limits in the service bulletin.

(2) If the conductivity test results are outside the limits specified in the service bulletin or if any cracking is detected, before further flight, repair any cracking, heat discoloration, or buckled or wrinkled area using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

(i) If any cracking is found during any detailed inspection required by paragraph (g) of this AD, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office (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 April 28, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.