05-23956. Airworthiness Directives; Boeing Model 757-200 and -300 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 757-200 and -300 series airplanes. This proposed AD would require installing clamps on certain end caps of the overhead distribution ducts, and doing other specified and related investigative actions as necessary. This proposed AD results from finding that the end caps of the overhead distribution ducts for the air conditioning system were not bonded to the ducts with an adhesive. We are proposing this AD to detect and correct loosened end caps, which could change the air flow balance in the airplane. During a smoke event in the cargo or main electronics compartments, the incorrect balance of air flow could change the smoke clearance air capacity and result in smoke and toxic fumes penetrating the flight deck and main cabin.

DATES:

We must receive comments on this proposed AD by January 27, 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:

Barbara Mudrovich, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, 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-2005-23282; Directorate Identifier 2005-NM-210-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 the airplane manufacturer found that the end caps of the overhead distribution ducts of the air conditioning system were not bonded to the ducts with an adhesive. The parts manufacturer determined from a records check that none of the overhead duct assemblies had end caps bonded to the ducts. Instead, the overhead duct assemblies had been delivered with plastic tie straps to hold the end caps onto the ducts. In some cases, the airplane manufacturer's mechanics removed the plastic tie straps from the end caps because the tie straps are not specified on the overhead duct assembly drawing. The bead on the end of ducts alone will not keep the end caps from loosening. A loosened end cap could change the air flow balance in the airplane. This condition, if not corrected, could change the smoke clearance air capacity during a smoke event in the cargo compartment or main electronics compartments and result in smoke and toxic fumes penetrating the flight deck and main cabin.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletins 757-21-0106 (for Model 757-200 series airplanes) and 757-21-0107 (for Model 757-300 series airplanes), both dated March 24, 2005. Boeing Special Attention Service Bulletin 757-21-0106 describes procedures for installing clamps on the end caps of the overhead distribution ducts at stations 864.9, 866.6, and 875. Boeing Special Attention Service Bulletin 757-21-0107 describes procedures for installing clamps on the end caps of the overhead distribution ducts at stations 864.88 and 875. The service bulletins also describe procedures for doing other specified and related investigative actions if necessary. The other specified actions include the following:

• Removing any tie straps, if installed, from the end caps of the overhead distribution ducts.
• Pushing each end cap against the end of the overhead duct all the way around.
• Torquing the clamps.

The related investigative actions include the following:

• Visually inspecting the end caps to ensure that each end cap has been pushed against the overhead duct all the way around.
• Ensuring that there is no air leakage from the end caps of the overhead ducts in the flight and passenger compartments in accordance with certain chapters of the Boeing 757 Airplane Maintenance Manual.

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.

Clarification of Compliance Time

The service bulletins specify installing the clamps in 36 months or less, or 12,000 flight hours or less from the release date of the service bulletin. However, the proposed AD would require installing the clamps within 12,000 total flight hours or within 36 months after the effective date of this AD, whichever is first.

Clarification of Inspection Terminology

Figure 1 of both service bulletins specifies to inspect the end caps “visually.” This proposed AD, however, would require doing a general visual inspection of the end caps. Paragraph 3.A. of the service bulletin includes the definition for a general visual inspection.

Costs of Compliance

There are about 63 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 37 airplanes of U.S. registry. The proposed actions would take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Required parts would cost between $20 and $40 per airplane, depending on airplane configuration. Based on these figures, the estimated cost of the proposed AD for U.S. operators is between $3,145 and $3,885, or between $85 and $105 per airplane, depending on 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-2005-23282; Directorate Identifier 2005-NM-210-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 27, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to airplanes identified in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category.

(1) Boeing Model 757-200 series airplanes, having certain variable numbers as identified in Boeing Special Attention Service Bulletin 757-21-0106, dated March 24, 2005.

(2) Boeing Model 757-300 series airplanes, having certain variable numbers as identified in Boeing Special Attention Service Bulletin 757-21-0107, dated March 24, 2005.

Unsafe Condition

(d) This AD results from finding that the end caps of the overhead distribution ducts for the air conditioning system were not bonded to the ducts with an adhesive. We are issuing this AD to detect and correct loosened end caps, which could change the air flow balance in the airplane. During a smoke event in the cargo or main electronics compartments, the incorrect balance of air flow could change the smoke clearance air capacity and result in smoke and toxic fumes penetrating the flight deck and main cabin.

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 References

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

(1) For Model 757-200 series airplanes: Boeing Special Attention Service Bulletin 757-21-0106, dated March 24, 2005; and

(2) For Model 757-300 series airplanes: Boeing Special Attention Service Bulletin 757-21-0107, dated March 24, 2005.

Install Clamps

(g) Within 12,000 flight hours or 36 months after the effective date of this AD, whichever is first: Install clamps on the end caps of the overhead distribution ducts of the air conditioning system at stations 864.88, 864.9, 866.6, and 875, as applicable, and before further flight do any other specified and related investigative actions as applicable, by doing all of the applicable actions specified in the applicable service bulletin.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office, 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.

Issued in Renton, Washington, on December 6, 2005.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.