[Federal Register: February 2, 2005 (Volume 70, Number 21)]
[Rules and Regulations]
[Page 5366-5370]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02fe05-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2003-NM-221-AD; Amendment 39-13958; AD 2005-03-02]
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: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 737-300, -400, and -500 series
airplanes; and Model 757-200 and -200CB series airplanes, that requires
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: Effective March 9, 2005.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 9, 2005.
ADDRESSES: The service information referenced in this AD 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. 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 National Archives
and Records Administration (NARA). For information on the availability
of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html
.
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: 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 737-300, -
400, and -500 series airplanes; and Model 757-200 and -200CB series
airplanes was published in the Federal Register on May 11, 2004 (69 FR
26054). That action proposed to 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.
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.
Request for an Optional Terminating Action
Two commenters request that we add Boeing Service Letter 757-SL-21-
057-A, including Attachments I and II, dated March 24, 2004, as an
alternative method of compliance (AMOC) for the installation of
lanyards on Boeing Model 757 series airplanes. As justification, one
commenter states that the duct manufacturer has created replacement
overhead ducts with nearly 50 percent greater ultimate strength than
the ducts delivered on the affected airplanes. The commenter also
asserts that, because of the reduced duct dimensions and air loads,
there has not been any tension failure of ducts forward of station 550
or aft of station 1389 on Model 757-200 series airplanes.
The other commenter states that the new, improved overhead ducts
[[Page 5368]]
eliminate the need to install lanyards, since they are more robust and
resistant to de-coupling, delamination, moisture ingress, and breakaway
at attach points. The commenter also points out that the FAA has
approved these ducts through the parts manufacturer approval process.
We agree with the commenters. Since issuance of the proposed AD, we
have reviewed Boeing Service Letter 757-SL-21-057-A, including
Attachments I and II, dated March 24, 2004. For certain Model 757
series airplanes, the Boeing service letter describes procedures for
replacing the original design foam ducts with new, improved foam ducts.
We find that this optional replacement adequately addresses the unsafe
condition in this AD on certain Model 757-200 and -200CB series
airplanes. The optional replacement would eliminate the need for the
general visual inspection and corrective actions, if applicable,
required by paragraph (c) of this AD. Therefore, we have inserted a new
paragraph (d) into this final rule and relettered the subsequent
paragraphs accordingly.
Request To Extend Compliance Time
One commenter requests that we extend the compliance time for
installing lanyards from 60 months to at least 63 months, so affected
operators can perform the installation during a scheduled heavy
maintenance interval. The commenter states the 60-month interval does
not correspond with any maintenance interval for Boeing Model 757
series airplanes or with the Maintenance Review Board (MRB) heavy
maintenance visit (4C), which is scheduled at a 72-month interval. The
commenter also asserts that airplane downtime would be significant if
the proposed installation is scheduled outside of a heavy maintenance
visit. As justification for the request, the commenter says that
failure of the ducts is evident by the appearance of the ceiling
panels, which could be discovered and corrected during the MRB zonal
inspection of the main cabin that occurs every 18 months (at 1C). In
its experience, the commenter believes this interval is sufficient. The
commenter also states ``* * * a 63-month compliance time would leave
one interval at no more than (allowing for prior yield loss) 12 months
which would be less than the 1C interval.''
We agree with the commenter's request to extend the compliance
time. We intended to require the inspection and installation of
lanyards at intervals that would coincide with regularly scheduled
maintenance visits for the majority of the affected fleet, when the
airplanes would be located at a base where special equipment and
trained personnel would be readily available, if necessary. Based on
the information supplied by the commenters, we now recognize that 72
months corresponds more closely to the interval representative of most
of the affected operators' normal maintenance schedules. We have
revised paragraphs (b)(1), (b)(2), and (c) of the final rule to require
a compliance time of 72 months. We do not consider that this extension
will adversely affect safety.
Request To Withdraw Proposed AD
One commenter objects to requiring an AD to address the unsafe
condition in Boeing Special Attention Service Bulletin 737-21-1131,
Revision 2, dated April 18, 2002, because of the large expense of
complying with the proposed AD. For its 67 affected airplanes, the
commenter states that it would cost $1,500,000, and that the
manufacturer would not offer any reimbursement for this expense. The
commenter also states that the price of the modification kit increased
40 percent after issuance of the proposed AD. We infer that the
commenter is asking us to withdraw the proposed AD.
We do not agree with the inferred request, since the installation
of lanyards 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. This condition could
result in inadequate height for safe exit in the event of an emergency
evacuation. While we acknowledge the concern of the commenter, we
cannot control the cost of the manufacturer's modification kit or get
involved in any discussion related to reimbursement from the
manufacturer. The cost impact of this AD is based on the best data
available provided to us by the manufacturer. No change to this AD is
necessary in this regard.
Request To Allow Repetitive Inspections and Optional Terminating Action
Two commenters request that, as an alternate method of compliance,
we allow repetitive inspections of the overhead ducts and replacement
of deteriorating ducts before they fail. One commenter requests
specifically that the repetitive inspections are done at every C-check,
and that the replacement is done in accordance with Boeing Service
Letter 757-SL-21-057-A, including Attachments I and II, dated March 24,
2004. The commenter states that this service letter provides procedures
for installing improved overhead ducts, which substantially increases
the structural support for the ducts and ceiling panels. The commenter
provides no justification for the repetitive inspections.
The other commenter believes that regular inspections of the
overhead ducts for air leakage and the addition of repetitive
inspections of the duct holding clamps/brackets and ceiling supports to
the regular inspection of the overhead duct assembly by borescope
method would sufficiently address the unsafe condition in the proposed
AD. The commenter asserts that these inspections would allow early and
proper action to prevent the unsafe condition. The commenter states
that its proposed AMOC is adequate, since it has never discovered the
unsafe condition addressed by the proposed AD on any of its own or its
customer's affected airplanes.
We do not agree with the commenters' request to allow repetitive
inspections of the overhead ducts. However, as stated in our response
to a previous comment, we agree that replacement of the overhead ducts
in accordance with Boeing Service Letter 757-SL-21-057-A adequately
addresses the unsafe condition in this AD for certain Model 757-200 and
-200CB series airplanes and eliminates the need for the actions
required by paragraph (c) of this AD.
We have investigated the potential for repetitive inspections of
the overhead ducts, either by borescope or other methods, as an
alternative to installing lanyards and have determined that an
inspection program is impracticable due to the nature of the duct
design and failure mode. It has been shown that, over time, the
overhead ducts will deteriorate. In addition, operators have reported
overhead ducts with air leakage, moisture ingress, delamination, broken
isolator mounts, and support mounts that have pulled through the duct.
Furthermore, the manufacturer has told us that it cannot identify the
specific damage to the air ducts, which would indicate where failure
(the ceiling panels dropping into the passenger evacuation zone) is
imminent.
While there have been very few reported instances where the
overhead duct failed and consequently allowed the panels to fall into
the passenger cabin, such a failure has been encountered. This failure
has been linked to a deficiency in the design of the affected airplanes
and could cause the inboard edge of the ceiling panel to be in the
passenger evacuation zone. This situation will impede egress in the
event of an emergency evacuation.
[[Page 5369]]
Request To Revise Cost Impact
One commenter questions our estimate of 27 work hours for
installing lanyards in the proposed AD, where the service bulletin
estimates 39 work hours, which includes time to gain access to the
area. The commenter states that installing the attach brackets for the
lanyards involves significant problems in gaining access and working in
a confined space. The commenter also states that a review of the work
required for its fleet of Model 757 series airplanes indicated that the
estimate in the service bulletin is already very conservative. We infer
that the commenter requests that we revise the Cost Impact for this AD.
We do not agree with the inferred request because the purpose of
the Cost Impact section is only to estimate the costs of compliance
with the AD. As stated in this and the proposed AD, 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. Therefore, no change to
this AD is necessary in this regard.
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 2,187 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 984 airplanes of U.S.
registry will be affected by this 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 AD is $10,607,648.
Table.--Cost Impact
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U.S. Labor cost
Model registered Work hours per per Parts cost per Total cost
airplanes airplane airplane airplane
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737-300, -400, and -500 series 665 28 (Identify the $1,820 $6,925 to $9,650 $5,815,425 to
airplanes. body frames, (Depending on $7,627,550
install support overhead duct (Depending on
brackets; rework installation overhead duct
and install configuration). installation
insulation; configuration),
install lanyard or $8,745 to
and hook $11,470 per
brackets). airplane.
757-200 and -200CB series 319 27 (Examine 1,755 7,587............ $2,980,098, or
airplanes. station frame, $9,342 per
install bracket, airplane.
lanyard, and
insulation).
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The cost impact figures discussed above are 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.
Authority for This Rulemaking
The FAA's authority to issue rules regarding aviation safety is
found in Title 49 of the United States Code. 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.
This rulemaking is promulgated 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 AD.
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
0
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
0
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]
0
2. Section 39.13 is amended by adding the following new airworthiness
directive:
2005-03-02 Boeing: Amendment 39-13958. Docket 2003-NM-221-AD.
[[Page 5370]]
Applicability: This AD applies to the airplanes listed in Table
1 of this AD, certificated in any category:
Table 1.--Applicability
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Boeing model As listed in
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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 airplanes. Boeing Special Attention
Service Bulletin 757-21-
0088, dated April 18, 2002.
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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 72 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 72 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 72
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.
Optional Terminating Action
(d) For Model 757-200 and -200CB series airplanes: Accomplishing
the replacement of the original design foam ducts with Saint-Gobain
design foam ducts by doing all of the actions in Attachments I and
II of Boeing Service Letter 757-SL-21-057-A, dated March 24, 2004,
terminates the actions required by paragraph (c) of this AD.
Credit for Actions Accomplished Per Previous Service Bulletins
(e) 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
(f) 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.
Incorporation by Reference
(g) Unless otherwise specified by this AD, the actions shall be
done in accordance with Boeing Special Attention Service Bulletin
737-21-1131, Revision 2, dated April 18, 2002; and Boeing Special
Attention Service Bulletin 757-21-0088, dated April 18, 2002; as
applicable. The optional terminating action, if accomplished, shall
be done in accordance with Boeing Service Letter 757-SL-21-057-A,
including Attachements I and II, dated March 24, 2004. 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 Airplanes, 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 National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html
.
Effective Date
(h) This amendment becomes effective on March 9, 2005.
Issued in Renton, Washington, on January 18, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-1722 Filed 2-1-05; 8:45 am]
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