05-17609. Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SR, and 747SP 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 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SR, and 747SP series airplanes, without a stretched upper deck or stretched upper deck modification. This proposed AD would require detailed and high-frequency eddy current inspections for cracks at the outboard ends of each affected tension tie and of the surrounding structure, and related investigative and corrective actions if necessary. This proposed AD results from a report of a crack in the tension tie at the body station 820 frame connection, and cracks found on the Boeing 747SR fatigue-test airplane in both the tension ties and frames at the tension tie to frame connections at body stations 800, 820, and 840. We are proposing this AD to find and fix cracks in the tension ties, which could lead to cracks in the skin and body frame and result in rapid in-flight depressurization of the airplane.

DATES:

We must receive comments on this proposed AD by October 21, 2005.

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:

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. Include the docket number “FAA-2005-22289; Directorate Identifier 2005--NM-101-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 a report indicating that, during routing maintenance on a 747-200F series airplane, one operator found a crack in the tension tie at the body station (STA) 820 frame connection. The crack was 0.125 inch long and located at a fastener hole. The manufacturer then inspected the 747SR fatigue-test airplane and found similar cracks in both the tension ties and frames at the tension ties to the frame connection. The cracks were found at STAs 800, 820, and 840 at 40,000 total flight cycles (20,000 operating cycles, 20,000 test cycles). Cracks in the frames were up to 1.25 inches long, and cracks in the tension ties were up to 0.20 inch long. Cracks in the tension ties, if not detected and corrected before they reach critical crack lengths, could lead to cracks in the skin and body frame and result in rapid in-flight depressurization of the airplane.

Other Relevant Rulemaking

On September 4, 1984, we issued AD 84-19-01, amendment 39-4913 (49 FR 35365, September 17, 1984) for Boeing Model 747 series airplanes. That AD was prompted by a report of a crack that occurred during fatigue testing. That AD requires repetitive close visual inspections for cracks of the tension tie at STA 760 for certain airplanes and at STA 780 for certain other airplanes, and repair if necessary. We issued that AD to detect cracks and prevent failure of the frame to tension tie joint structure. The airplanes in the applicability of AD 84-19-01 would also be subject to the requirements of this proposed AD.

On June 14, 1994, we issued AD 94-13-06, amendment 39-8946 (59 FR 32879, June 27, 1994), for certain Boeing Model 747 series airplanes. That AD requires inspections to detect cracking in certain fuselage upper deck tension ties, and repair or modification of any cracked tension ties. We issued that AD to prevent failure of two or more tension ties and the resultant rapid decompression of the airplane. The airplanes in the applicability of AD 94-13-06 would also be subject to the requirements of this proposed AD.

On March 24, 2004, we issued AD 2004-07-22, amendment 39-13566 (69 FR 18250, April 7, 2004), for all Boeing Model 747 series airplanes. That AD requires revising the FAA-approved maintenance or inspection program to include repetitive inspections for discrepancies of various structural significant items (SSIs); as listed in Boeing Document No. D6-35022, “Supplemental Structural Inspection Document (SSID),” Revision G, dated December 2000 (referred to after this as “the SSID”); and repair if necessary.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005. The service bulletin describes procedures for doing repetitive detailed and high-frequency eddy current (HFEC) inspections for cracks at the outboard ends of each affected tension tie and of the surrounding structure. If any cracking is found, the service bulletin describes procedures for related investigative and corrective actions. These actions include doing all applicable repairs and doing further HFEC inspections of certain fastener holes until the inspection indicates that the repair has removed all cracking. If the cracking exceeds certain limits defined in the service bulletin, or if the area cannot be repaired without exceeding certain limits, or if the discrepancy is at certain locations defined in the service bulletin, the corrective action is contacting Boeing for repair instructions.

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 the Proposed AD and the Service Bulletin.”

Certain actions in this proposed AD are alternative methods of compliance (AMOCs) for certain actions in the ADs referenced below. All provisions of the referenced ADs, including applicable post-modification inspection thresholds, remain fully applicable and must be complied with.

• Repairs of the aft tension tie channels in accordance with this proposed AD would be AMOCs to the repair requirements of paragraph A. of AD 84-19-01, and paragraphs (a)(2) and (b)(2) of AD 94-13-06.
• The inspection requirements of this proposed AD would be AMOCs for the post-modification inspection requirements of paragraph B. of AD 84-19-01, and paragraph (b) of AD 94-13-06.
• The inspection requirements of this proposed AD would be AMOCs for the corresponding requirements of paragraphs (c) and (d) of AD 2004-07-22 for the inspections of SSI item F-19A of the SSID in the area addressed by this proposed AD.

Difference Between the Proposed AD and the Service Bulletin

The service bulletin specifies that you may contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require you to repair 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.

This difference has been coordinated with the manufacturer.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.

Costs of Compliance

There are about 458 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 141 airplanes of U.S. registry. The proposed inspections would take about 8 work hours per airplane, per tension tie location. There are between 8 and 12 tension tie locations on each airplane, depending on the airplane's configuration. The average labor rate is $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is between $586,560 and $879,840, or between $4,160 and $6,240 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-2005-22289; Directorate Identifier 2005-NM-101-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 21, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SR, and 747SP series airplanes, certificated in any category; without a stretched upper deck or stretched upper deck modification; as identified in Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005.

Unsafe Condition

(d) This AD results from a report of a crack in the tension tie at the body station 820 frame connection, and cracks found on the Boeing 747SR fatigue-test airplane in both the tension ties and frames at the tension tie to frame connections at body stations 800, 820, and 840. We are issuing this AD to find and fix cracks in the tension ties, which could lead to cracks in the skin and body frame and result in rapid in-flight depressurization 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 and Corrective Actions

(f) At the applicable time in paragraph (f)(1) or (f)(2) of this AD: Do detailed and high-frequency eddy current inspections for cracks at the outboard ends of each affected tension tie and of the surrounding structure. If any cracking is found: Before further flight, do all applicable corrective and related investigative actions. Do all actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005. Where the service bulletin specifies to contact Boeing for repair instructions: Before further flight, repair the area using a method approved in accordance with paragraph (g) of this AD.

(1) For airplanes identified in the service bulletin as Group 1, 3, and 6 airplanes: Do the first inspections before the accumulation of 20,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and repeat the inspections thereafter at intervals not to exceed 4,000 flight cycles.

(2) For airplanes identified in the service bulletin as Group 2, 4, and 5 airplanes: Do the first inspections before the accumulation of 17,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.

Alternative Methods of Compliance (AMOCs)

(g)(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) 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.

(3) Certain actions required by paragraph (f) of this AD are AMOCs for certain requirements in the ADs identified in paragraphs (g)(1)(i), (g)(2)(ii), and (g)(3)(iii) of this AD. All provisions of the referenced ADs, including applicable post-modification inspection thresholds, remain fully applicable and must be complied with.

(i) Repairs of the aft tension tie channels done in accordance with this AD are AMOCs for the repair requirements of paragraph A. of AD 84-19-01, amendment 39-4913, and paragraphs (a)(2) and (b)(2) of AD 94-13-06, amendment 39-8946.

(ii) The inspection requirements of this AD are AMOCs for the post modification inspection requirements of paragraph B. of AD 84-19-01, and paragraph (b) of AD 94-13-06.

(iii) The inspection requirements of this AD are AMOCs for the inspections of structural significant item (SSI) F-19A of Boeing Supplemental Structural Inspection Document D6-35022, Revision G, dated December 2000, as required by paragraphs (c) and (d) of AD 2004-07-22, amendment 39-13566.

Issued in Renton, Washington, on August 29, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.