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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-NM-374-AD; Amendment 39-11957; AD 2000-22-11] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule. 

# SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires modification of the canted pressure deck drain system in the wheel well of the main landing gear (MLG). This amendment is prompted by reports of ice accumulation on the aileron control cables and on the MLG door and door seal during flight, due to fluid entering the canted pressure deck area, leaking into the MLG wheel well, and freezing. The actions specified by this AD are intended to prevent such ice accumulation, which could render one of the aileron control systems and/or the MLG doors inoperative, resulting in reduced controllability of the airplane. 

# DATES:

Effective December 13, 2000. 

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of December 13, 2000. 

# ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

# FOR FURTHER INFORMATION CONTACT:

James G. Rehrl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2783; fax (425) 227-1181. 

# SUPPLEMENTARY INFORMATION:

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 767 series airplanes was published in the                     **Federal Register**                     on February 4, 2000 (65 FR 5455). That action proposed to require modification of the canted pressure deck drain system in the wheel well of the main landing gear (MLG).                 

## Comments 

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. 

## Support for the Proposed AD 

One commenter supports the proposed AD. 

## Request To Accept Alternative Methods of Compliance 

One commenter, the airplane manufacturer, requests that the FAA revise the proposed AD to reference certain other service bulletins as acceptable methods of compliance with the proposed AD, in lieu of accomplishment of Boeing Service Bulletin 767-51A0020, Revision 1, dated July 22, 1999. (Paragraph (a) of the proposed AD cites Revision 1 as the appropriate source of service information for the actions specified in that paragraph.) The commenter states that accomplishment of Boeing Service Bulletin 767-53-0059, dated November 12, 1992 (which describes a one-time pressure check of the seals of the canted pressure deck), along with either Boeing Service Bulletin 767-51-0014, dated August 2, 1990 (which describes relocation of the vent holes for the pressure-operated drain lines), or Boeing Service Bulletin 767-51-0019, dated June 27, 1996 (which describes relocation of drain outlets from the MLG wheel wells to the heat shields of the ram air outlets), will prevent ice accumulation on the aileron control cables and the MLG door and seal as effectively as incorporation of Boeing Service Bulletin 767-51A0020. 

The FAA partially concurs with the commenter's request. The FAA concurs that accomplishment of Boeing Service Bulletin 767-53-0059 and Boeing Service Bulletin 767-51-0014 or 767-51-0019 would adequately prevent ice accumulation on the aileron control cables. The FAA also finds that accomplishment of Boeing Service Bulletins 767-53-0059 and 767-51-0019 adequately prevents ice accumulation on the main landing gear door and seal. However, the FAA finds that accomplishment of Boeing Service Bulletins 767-53-0059 and 767-51-0014 does not adequately prevent ice accumulation on the MLG door and seal. Therefore, the FAA finds that accomplishment of Boeing Service Bulletins 767-53-0059 and 767-51-0019, but not Boeing Service Bulletin 767-51-0014, is acceptable for compliance with the requirements of paragraph (a) of this AD. A new “Note 3” has been added to this AD (and renumbered subsequent notes accordingly) to state the acceptable means of compliance. 

The same commenter requests that the FAA revise paragraph (a) of the proposed AD to allow accomplishment of the modification in accordance with the original issue of Boeing Alert Service Bulletin 767-51A0020, dated November 19, 1998, or Revision 1. The commenter notes that airplanes modified per the original issue do not require additional work because Revision 1 only clarifies certain work instructions. 

The FAA concurs with the intent of the commenter's request, but notes that “Note 2” of the proposed AD already states that modification in accordance with the original issue of the service bulletin prior to the effective date of this AD is acceptable for compliance with paragraph (a) of this AD. Therefore, no change to the final rule is necessary in this regard. 

## Request To Extend Compliance Time 

                    Three commenters request that the FAA extend the compliance time for the proposed modification beyond 24 months. One commenter requests that the FAA extend the compliance time to 36 months to allow for delivery of                           ( print page 66924)                        necessary parts. Another commenter requests that the FAA extend the compliance time to 60 months to allow for accomplishment of the modification during a major maintenance visit, such as a “D”-check. The commenter that requests extension of the compliance time to 60 months justifies its request based on the fact that there have been very few in-service problems related to freezing of the aileron control cables on Model 767 series airplanes, and on design changes that have been made related to potential ice accumulation on the aileron control cables.                 

The FAA concurs with the first commenter's request to extend the compliance time from 24 months to 36 months. This extension will allow a 12-month lead time for affected operators to obtain the parts necessary for the modification. The FAA finds that such an extension will not adversely affect safety, and this determination is based in part on the justifications cited by the second commenter. However, the FAA finds that extension of the compliance time to 60 months, as requested by the second commenter, would not ensure accomplishment of the modification required by this AD on all affected airplanes in a timely manner. Paragraph (a) of this final rule has been revised accordingly. 

Another commenter requests extension of the compliance time to 48 months to allow time for accomplishment of another service bulletin that the commenter notes may be required to be accomplished concurrently with the modification in this AD (see the “Request to Clarify Requirements” section of this document, below). The FAA does not concur with this commenter's request to extend the compliance time for this AD to 48 months. As explained below, the service bulletin with which the commenter is concerned is not required by this AD; thus, no extension of the compliance time is necessary in this regard. 

## Request To Clarify Requirements 

                    Two commenters question whether Boeing Service Bulletin 767-53-0059, dated November 12, 1992, must be incorporated concurrently with the proposed modification. The commenters note that Section 1.B. (“Concurrent Requirements”) of Boeing Service Bulletin 767-51A0020, Revision 1, states that accomplishment of Boeing Service Bulletin 767-53-0059 is required for certain airplanes, but Section 1.D. (“Description”), Note 4, of Boeing Service Bulletin 767-51A0020, Revision 1, states that accomplishment of Boeing Service Bulletin 767-53-0059 is                     *recommended*                    for those airplanes. The commenters request that the FAA revise the proposed AD to clarify whether Boeing Service Bulletin 767-53-0059 is required.                

The FAA concurs that clarification is indeed necessary. The FAA has determined that accomplishment of Boeing Service Bulletin 767-53-0059 is not required by this AD because the modification in accordance with Boeing Service Bulletin 767-51A0020 corrects the conditions addressed by Boeing Service Bulletin 767-53-0059. Because the proposed rule did not directly reference Boeing Service Bulletin 767-53-0059, the FAA finds that no change to the final rule is necessary in this regard. However, operators should note that, as stated previously, accomplishment of Boeing Service Bulletins 767-53-0059 and 767-51-0019 is acceptable for compliance with this AD, in lieu of accomplishment of Boeing Service Bulletin 767-51A0020. 

## Conclusion 

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. 

## Cost Impact 

There are approximately 716 Model 767 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 278 airplanes of U.S. registry will be affected by this AD, that it will take approximately 15 work hours per airplane to accomplish the required modification, and that the average labor rate is $60 per work hour. Required parts will cost approximately $6,623 per airplane. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $2,091,394, or $7,523 per airplane. 

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this 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 adopted herein will 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 final rule does not have federalism implications under Executive Order 13132. 

                    For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption                     **ADDRESSES.**

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - Safety

## Adoption of the Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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: 

**2000-22-11 Boeing:**                            Amendment 39-11957. Docket 99-NM-374-AD.                         

*Applicability:*                             Model 767 series airplanes, line numbers 1 through 723 inclusive, certificated in any category.                         

# Note 1:

                                This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an                                       ( print page 66925)                                    alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.                            

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

To prevent ice accumulation on the aileron control cables and/or main landing gear (MLG) door and door seal during flight, which could render one of the aileron control systems and/or the MLG doors inoperative, resulting in reduced controllability of the airplane, accomplish the following: 

## Modification 

(a) Within 36 months after the effective date of this AD: Modify the canted pressure deck drain system in the wheel well of the MLG, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 767-51A0020, Revision 1, dated July 22, 1999. 

# Note 2:

Modification of the canted pressure deck drain system accomplished prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 767-51A0020, dated November 19, 1998, is considered acceptable for compliance with the modification specified in this AD.

# Note 3:

Accomplishment of the actions specified in both Boeing Service Bulletins 767-53-0059, dated November 12, 1992, and 767-51-0019, dated June 27, 1996, is acceptable for compliance with paragraph (a) of this AD. 

## Alternative Methods of Compliance 

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. 

# Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

## Special Flight Permits 

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. 

## Incorporation by Reference 

(d) The actions shall be done in accordance with Boeing Service Bulletin 767-51A0020, Revision 1, dated July 22, 1999. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

## Effective Date 

(e) This amendment becomes effective on December 13, 2000. 

Issued in Renton, Washington, on October 27, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-28089 Filed 11-7-00; 8:45 am] 

BILLING CODE 4910-13-P