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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2003-NM-109-AD] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 767 series airplanes. This proposal would require repetitive detailed inspections of the aft pressure bulkhead for indications of “oil cans” and previous “oil can” repairs, and corrective actions, if necessary. An “oil can” is an area on a pressure dome web that moves when pushed from the forward side. This action is necessary to detect and correct the propagation of fatigue cracks in the vicinity of “oil cans” on the web of the aft pressure bulkhead, which could result in rapid decompression of the passenger cabin, possible damage or interference with the airplane control systems that pass through the bulkhead, and consequent loss of control of the airplane. This action is intended to address the identified unsafe condition. 

# DATES:

Comments must be received by March 22, 2004. 

# ADDRESSES:

                        Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-109-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address:                         *9-anm-nprmcomment@faa.gov*. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-109-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.                     

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplanes, PO Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. 

# FOR FURTHER INFORMATION CONTACT:

Suzanne Masterson, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6441; fax (425) 917-6590. 

# SUPPLEMENTARY INFORMATION:

 

## Comments Invited 

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received. 

Submit comments using the following format:
    - Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
    - For each issue, state what specific change to the proposed AD is being requested.
    - Include justification ( e.g. , reasons or data) for each request.                 

                    Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments                           ( print page 5772)                        submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.                 

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-109-AD.” The postcard will be date stamped and returned to the commenter. 

## Availability of NPRMs 

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-109-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

The FAA has received a report indicating that a 2.1-inch crack in the web of the aft pressure bulkhead at the perimeter of an “oil can” was found on a Model 747 series airplane. An “oil can” is an area on a pressure dome web that moves when pushed from the forward side. The cause of the crack in the web is fatigue. This condition, if not detected and corrected, could lead to the propagation of fatigue cracks in the vicinity of “oil cans” on the web of the aft pressure bulkhead, which could result in rapid decompression of the passenger cabin, possible damage or interference with the airplane control systems that pass through the bulkhead, and consequent loss of control of the airplane. 

The aft pressure bulkhead on Model 767 series airplanes is almost identical to that on the affected Model 747 series airplanes. Therefore, those Model 767 series airplanes may be subject to the unsafe condition revealed on the Model 747 series airplanes. 

## Other Related Rulemaking 

The FAA may consider further rulemaking to address the unsafe condition identified on Model 747 series airplanes. 

## Explanation of Relevant Service Information 

The FAA has reviewed and approved Boeing Alert Service Bulletin 767-53A0105, dated April 10, 2003; and Boeing Alert Service Bulletin 767-53A0106, dated April 10, 2003; which describe procedures for performing repetitive detailed inspections of the aft pressure bulkhead for indications of “oil cans” and previous “oil can” repairs, and corrective actions, if necessary. The corrective actions include performing a detailed inspection of the web around any “oil can” repair for cracks and smaller “oil cans” and repairing cracks; and performing repetitive high frequency eddy current inspections of the web around the periphery of the “oil can” indication for cracks and repairing cracks. Repair of all “oil cans” eliminates the need for the repetitive high frequency eddy current inspections. 

## Explanation of Requirements of Proposed Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below. 

## Differences Between Proposed Rule and Service Bulletins 

Operators should note that, although the service bulletins specify that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished per a method approved by the FAA, or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings. 

## Clarification of Actions in Service Bulletins 

Operators should note that paragraph 1.b. of “Part 3—Inspection of ‘Oil Cans,’ ” of the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0106, dated April 10, 2003, states, “ * * * limits shown in 767-200, 767-300, or 767-300F Structural Repair Manual (SRM) 53-80-08, Figure 102.” However, the service bulletin applies to Model 767-400ER series airplanes, and thus the reference should be to 767-400 SRM 53-80-08, Figure 102, as specified in the previous paragraph 1.a. of the service bulletin. 

Operators should note that “Part 2—Inspection of Previous ‘Oil Can’ Repairs” of the Accomplishment Instructions of both service bulletins states, “Do the inspections shown in Part 2 again at the time shown in Figure 1.” However, Figure 1 of the service bulletins specifies that the inspection in “Part 1—Access and Inspection” is to be repeated. We have determined that the correct reference is Part 1. Therefore this proposed AD would require repetitive inspection per Part 1. 

## Interim Action 

This is considered to be interim action. The FAA may consider further rulemaking to reduce thresholds if cracks are reported earlier than the predicted fatigue life. 

## Cost Impact 

There are approximately 890 airplanes of the affected design in the worldwide fleet. The FAA estimates that 398 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 14 work hours per airplane to accomplish the proposed detailed inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $362,180, or $910 per airplane, per inspection cycle. 

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. 

## Regulatory Impact 

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132. 

                    For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the                           ( print page 5773)                        location provided under the caption                     **ADDRESSES**                    .                

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## The Proposed Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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 

2. Section 39.13 is amended by adding the following new airworthiness directive:

**Boeing:**                                 Docket 2003-NM-109-AD.                            

*Applicability:*                                 All Model 767 series airplanes, certificated in any category.                             

*Compliance:*                                 Required as indicated, unless accomplished previously.                             

To detect and correct the propagation of fatigue cracks in the vicinity of “oil cans” on the web of the aft pressure bulkhead, which could result in rapid decompression of the passenger cabin, possible damage or interference with the airplane control systems that pass through the bulkhead, and consequent loss of control of the airplane, accomplish the following: 

## Service Bulletin References 

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For Model 767-200, -300, and -300F series airplanes: Boeing Alert Service Bulletin 767-53A0105, dated April 10, 2003; and 

(2) For Model 767-400ER series airplanes: Boeing Alert Service Bulletin 767-53A0106, dated April 10, 2003. 

## Initial and Repetitive Inspections 

(b) Perform a detailed inspection of the aft pressure bulkhead for indications of “oil cans” and previous “oil can” repairs, in accordance with the service bulletin, at the applicable time specified in paragraph (b)(1) or (b)(2) of this AD. Repeat the detailed inspection thereafter at intervals not to exceed 6,000 flight cycles. 

# Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.” 

(1) For Model 767-200 and -300 series airplanes: Prior to the accumulation of 50,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later. 

(2) For Model 767-300F and -400ER series airplanes: Prior to the accumulation of 40,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later. 

## Indication of Previous “Oil Can” Repairs 

(c) If any previous “oil can” repair is found during any detailed inspection required by paragraph (b) of this AD: Before further flight, do a detailed inspection of the web around any “oil can” repair for cracks or smaller “oil cans,” in accordance with the service bulletin. 

(1) If any crack is found, before further flight, repair in accordance with the service bulletin. Where the service bulletin specifies to contact Boeing for repair, before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD. 

(2) If any “oil can” is found, before further flight, perform the surface high frequency eddy current (HFEC) inspection specified in paragraph (d) of this AD. 

## Indication of “Oil Can”

(d) If any indication of an “oil can” is found during any detailed inspection specified in paragraph (b) or (c) of this AD: Before further flight, perform a surface HFEC inspection of the web around the periphery and in the center of the “oil can” indication for cracks, at all “oil cans,” and perform a detailed inspection of the web for cracks, in accordance with the service bulletin. Alternative inspection specified in the service bulletin is acceptable for this AD. 

(1) If no crack is found and the “oil can” meets the allowable limits specified in the service bulletin, do the action in either paragraph (d)(1)(i) or (d)(1)(ii) of this AD. 

(i) Repeat the surface HFEC inspection specified in paragraph (d) of this AD thereafter at intervals not to exceed 3,000 flight cycles. 

(ii) Before further flight, repair the “oil can” in accordance with the service bulletin. Repair of all “oil cans” is considered a terminating action for the repetitive HFEC inspections required by paragraph (d)(1)(i) of this AD. However, continue to repeat the detailed inspection required by paragraph (b) of this AD. 

(2) If no crack is found and the “oil can” does not meet the specified allowable limits specified in the service bulletin: Before further flight, repair the “oil can” in accordance with the service bulletin. If, following the repair, any “oil can” remains that meets the allowable limits specified in the service bulletin, do the action required by either paragraph (d)(1)(i) or (d)(1)(ii) of this AD. 

(3) If any crack is found, before further flight, repair in accordance with the service bulletin. Where the service bulletin specifies to contact Boeing for appropriate action, before further flight, repair per a method approved by the Manager, ACO, FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD. 

## Alternative Methods of Compliance 

(e) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, FAA, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on January 29, 2004.

Kalene C. Yanamura, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 04-2472 Filed 2-5-04; 8:45 am] 

BILLING CODE 4910-13-P