[Federal Register Volume 69, Number 91 (Tuesday, May 11, 2004)]
[Proposed Rules]
[Pages 26054-26056]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-10695]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-221-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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: 
[email protected]. 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.

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.

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,

[[Page 26055]]

could 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
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                                    U.S.
            Model                registered     Work hours per  Labor cost per   Parts cost per     Total cost
                                  airplanes        airplane        airplane         airplane
----------------------------------------------------------------------------------------------------------------
737-300, -400, and 500 series             665  28 (Identify             $1,820  $6,925 to        $5,815,425 to
 airplanes.                                     the body                         $9,650           $7,627,550
                                                frames;                          (Depending on    (Depending on
                                                install                          overhead duct    overhead duct
                                                support                          installation     installation
                                                brackets;                        configuration).  configuration)
                                                rework and                                        , or $8,745 to
                                                install                                           $11,470 per
                                                insulation;                                       airplane.
                                                install
                                                lanyard and
                                                hook brackets).
757-200 and -200CB series                 319  27 (Examine              $1,755  $7,587.........  $2,980,098, or
 airplanes.                                     station frame,                                    $9,342 per
                                                install                                           airplane.
                                                bracket,
                                                lanyard, and
                                                insulation).
----------------------------------------------------------------------------------------------------------------

    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.

[[Page 26056]]

A copy of it may be obtained by contacting the Rules Docket at the 
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.


Sec.  39.13  [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 model                         As listed in
------------------------------------------------------------------------
Model 737-300, -400, and -500 series     Boeing Special Attention
 airplanes.                               Service Bulletin 737-21-1131,
                                          Revision 2, dated April 18,
                                          2002.
Model 757-200 and -200CB series          Boeing Special Attention
 airplanes.                               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.

    Issued in Renton, Washington, on April 29, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-10695 Filed 5-10-04; 8:45 am]
BILLING CODE 4910-13-P