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Proposed Rule

Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes; and Model 757-200 and -200CB Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

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 certain Boeing Model 737-300, -400, and -500 series airplanes; and Model 757-200 and -200CB series airplanes. This proposal would require inspection of the applicable body station frames for open body station frames and related investigative/corrective actions; and installation of lanyard hook brackets and lanyard assemblies under the air conditioning overhead ducts, as applicable. This action is necessary to prevent loosened or disconnected overhead ducts from causing ceiling panels to drop below the minimum height of the evacuation zone for the passenger cabin, which could result in inadequate height for safe exit in the event of an emergency evacuation. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by June 25, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-221-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-221-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, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Keith Ladderud, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6435; fax (425) 917-6590.

End Further Info End Preamble Start Supplemental Information

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 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-221-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-221-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA received a report that the manufacturer has received numerous reports of leaking air conditioning (AC) overhead ducts (indicating cracking of the ducts) on Boeing Model 737 and 757 series airplanes. Two of those reports stated that fallen overhead ducts had caused ceiling panels to fall into the passenger cabin. Loosened or disconnected overhead ducts could fall, causing the ceiling panels to drop below the minimum height of the evacuation zone for the passenger cabin, since the inboard edge of the ceiling panels are attached to the diffusion fitting of the AC overhead duct. As regulated by the FAA, the minimum height of the evacuation zone for the passenger cabin is 73 inches. However, review of the ceiling panel configurations and reports from in-service airplanes show that ceiling panels may drop to 63 inches or less. This condition, if not corrected, Start Printed Page 26055could result in inadequate height for safe exit in the event of an emergency evacuation.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Special Attention Service Bulletin 737-21-1131, Revision 2, dated April 18, 2002 (for Model 737-300, -400, and -500 series airplanes). This service bulletin describes procedures for a general visual inspection at body station frames 420 through 887, as applicable, for open body station frames and related investigative/corrective actions; and installation of lanyard hook brackets and lanyard assemblies under the AC overhead ducts. (For Model 737-300, -400, and -500 series airplanes, an open body station frame is a body station frame that does not have an overhead life raft or video monitor installed under the frame between stringers 3L and 3R.) The related investigative action includes a general visual inspection of the open body station frames between stringers 2L and 2R to determine if AC overhead duct supports are installed and to determine if open body station frames have sound damping angles. The corrective actions include installing lanyard support brackets on the body station frames, if the open body station frames do not have sound damping angles; removing part of the sound damping angles and installing lanyard support brackets, if the open body station frames have sound damping angles; and reworking the adjacent insulation blankets and installing the insulation blankets on the body station frames.

We have also reviewed and approved Boeing Special Attention Service Bulletin 757-21-0088, dated April 18, 2002 (for Model 757-200 and -200CB series airplanes). This service bulletin describes procedures for a general visual inspection at body station frames 418 through 1480, as applicable, for open body station frames and corrective actions. (For Model 757-200 and -200CB series airplanes, an open body station frame is a body station frame that does not have a center overhead video monitor, center overhead stowage bin, or lowered ceiling panel installed under the frame between stringers 3L and 3R.) The corrective actions include installing lanyard support brackets adjacent to stringers 2L and 2R; installing insulation capstrip blankets and tapes around the lanyard support brackets; and installing lanyard hook brackets and lanyards.

Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

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.

Difference Between Proposed Rule and Service Bulletins

Operators should note that, although the service bulletins do not recommend a compliance time for accomplishing the proposed actions, we have determined that a compliance time is needed to ensure an adequate level of safety for the affected fleet. In developing an appropriate compliance time for this AD, we considered the degree of urgency associated with the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the proposed actions (27 to 28 hours). In light of all of these factors, we find that a 60-month compliance time represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 2,187 airplanes of the affected design in the worldwide fleet. The FAA estimates that 984 airplanes of U.S. registry would be affected by this proposed AD. The following table shows the estimated cost impact for airplanes affected by this AD. The average labor rate is $65 per work hour. The estimated maximum total cost for all airplanes affected by this proposed AD is $10,607,648.

Table—Cost Impact

ModelU.S. registered airplanesWork hours per airplaneLabor cost per airplaneParts cost per airplaneTotal cost
737-300, -400, and 500 series airplanes66528 (Identify the body frames; install support brackets; rework and install insulation; install lanyard and hook brackets)$1,820$6,925 to $9,650 (Depending on overhead duct installation configuration)$5,815,425 to $7,627,550 (Depending on overhead duct installation configuration), or $8,745 to $11,470 per airplane.
757-200 and -200CB series airplanes31927 (Examine station frame, install bracket, lanyard, and insulation)$1,755$7,587$2,980,098, or $9,342 per airplane.

The cost impact figures discussed above are 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. Start Printed Page 26056A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

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

Boeing: Docket 2003-NM-221-AD.

Applicability: This AD applies to the airplanes listed in Table 1 of this AD, certificated in any category:

Table 1.—Applicability

Boeing modelAs listed in
Model 737-300, -400, and -500 series airplanesBoeing Special Attention Service Bulletin 737-21-1131, Revision 2, dated April 18, 2002.
Model 757-200 and -200CB series airplanesBoeing Special Attention Service Bulletin 757-21-0088, dated April 18, 2002.

Compliance: Required as indicated, unless accomplished previously.

To prevent loosened or disconnected overhead ducts from causing ceiling panels to drop below the minimum height of the evacuation zone for the passenger cabin, which could result in inadequate height for safe exit in the event of an emergency evacuation, accomplish the following:

Service Bulletin References

(a) The term “service bulletin,” as used in this AD, means the applicable service bulletins listed in Table 1 of this AD.

Inspection and Related Investigative/Corrective Actions

(b) For Model 737-300, -400, and -500 series airplanes, do the actions required in paragraphs (b)(1) and (b)(2) of this AD at the specified compliance times, in accordance with the Accomplishment Instructions of the service bulletin.

(1) Within 60 months after the effective date of this AD, do a general visual inspection at the applicable body station frames for open body station frames; and, before further flight, do all the related investigative/corrective actions, as applicable; by accomplishing all of the actions in paragraph 3.B. of the service bulletin.

Note 1:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

(2) Within 60 months after the effective date of this AD, do the actions required in paragraph (b)(2)(i) or (b)(2)(ii) of this AD, as applicable.

(i) For Groups 1 and 3 airplanes identified in the service bulletin: Install the lanyard hook brackets and each lanyard assembly under the air conditioning (AC) overhead ducts in accordance with paragraph 3.C. of the service bulletin.

(ii) For Group 2 airplanes identified in the service bulletin: Install the lanyard hook brackets and the lanyard assemblies under the AC overhead ducts by accomplishing all of the actions in paragraph 3.D. of the service bulletin.

(c) For Model 757-200 and -200CB series airplanes: Within 60 months after the effective date of this AD, do a general visual inspection of the applicable body station frames for open body station frames; and, before further flight, do all the corrective actions, as applicable; by accomplishing all of the actions in the Accomplishment Instructions of the service bulletin.

Credit for Actions Accomplished per Previous Service Bulletins

(d) Actions accomplished before the effective date of this AD per Boeing Special Attention Service Bulletin 737-21-1131, original release, dated December 20, 2001; or Revision 1, dated January 25, 2002; are acceptable for compliance with the requirements of paragraph (b) of this AD.

Alternative Methods of Compliance

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

Start Signature

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

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 04-10695 Filed 5-10-04; 8:45 am]

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