[Federal Register: March 28, 2007 (Volume 72, Number 59)]
[Rules and Regulations]
[Page 14395-14397]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28mr07-2]
[[Page 14395]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-19755; Directorate Identifier 2004-NM-23-AD;
Amendment 39-15003; AD 2007-07-03]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Boeing Model 747 airplanes. This AD requires repetitive tests
to detect hot air leaking from the trim air diffuser ducts or sidewall
riser duct assemblies (collectively referred to in this AD as
``TADDs''), related investigative actions, and corrective actions if
necessary. This AD also provides an optional terminating action for the
repetitive tests. This AD results from reports of sealant deteriorating
on the outside of the center wing fuel tank and analysis that sealant
may deteriorate inside the tank due to excess heat from leaking TADDs.
We are issuing this AD to prevent leakage of fuel or fuel vapors into
areas where ignition sources may be present, which could result in a
fire or explosion.
DATES: This AD becomes effective May 2, 2007.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in the AD as of May 2, 2007.
ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov
or in person at the Docket Management Facility, U.S.
Department of Transportation, 400 Seventh Street, SW., Nassif Building,
Room PL-401, Washington, DC.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for service information identified in this AD.
FOR FURTHER INFORMATION CONTACT: Dan Kinney, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6499; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
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 (800) 647-5227) is located on the
plaza level of the Nassif Building at the street address stated in the
ADDRESSES section.
Discussion
The FAA issued a supplemental notice of proposed rulemaking (NPRM)
to amend 14 CFR part 39 to include an AD that would apply to certain
Boeing Model 747 airplanes. That supplemental NPRM was published in the
Federal Register on September 26, 2006 (71 FR 56064). That supplemental
NPRM proposed to require repetitive tests to detect hot air leaking
from the trim air diffuser ducts or sidewall riser duct assemblies
(collectively referred to in the AD as ``TADDs''), related
investigative actions, and corrective actions if necessary. That
supplemental NPRM also provided an optional terminating action for the
repetitive tests.
Comments
We provided the public the opportunity to participate in the
development of this AD. We have considered the comments received.
Supportive Comment
Boeing has reviewed the supplemental NPRM and concurs with the
content.
Request To Delay Corrective Actions
Lufthansa German Airlines asks that, if any hot air leak is found
during any test required by paragraph (f) of the supplemental NPRM, we
give relief for the corrective actions specified in paragraphs (g) and
(h) of the supplemental NPRM. It suggests we do this by allowing
deactivation of the zone trim air modulation valve of the affected
TADDs for at least ten days. Lufthansa states that this would allow a
delay in performing the inspection and corrective actions until after
that extension ends; this delay would permit the operator to better
plan the actions required if any hot air leak is found during the
repetitive tests required by paragraph (f).
We do not agree with the commenter. The zone trim air modulation
valves are located downstream of the potential leakage area; therefore,
deactivating them would not prevent hot air leakage from the TADDs. We
have made no change to the AD in this regard.
Clarification of Test Requirements Specified in Paragraph (f)
Lufthansa asks for clarification of the test requirements specified
in paragraph (f) of the supplemental NPRM. Lufthansa states that the
repetitive tests specified in paragraph (f) are to be done in
accordance with Boeing Service Bulletin 747-21A2418, Revision 4, dated
November 17, 2005. Lufthansa adds that Note 2 of the supplemental NPRM
refers to Chapters 21-61-20 and 21-61-21 of the Boeing 747 Airplane
Maintenance Manual as an additional source of service information for
the test and inspections of the TADDs. Lufthansa notes that those
chapters describe the temperature measurement procedure for the
repetitive hot air leak inspection and specify temperature measurements
of all TADDs after thirty seconds, one minute, two minutes, and then
every two minutes, for a duration of twenty minutes. Lufthansa states
that it is not clear whether the temperature measurements must be
performed simultaneously on all ducts, or sequentially with one or more
ducts at a time; however, the description suggests performing the
measurements simultaneously on all ducts. Lufthansa adds that
performing the temperature measurements sequentially with one or more
ducts would ease the measurement procedure. Lufthansa notes that it
does not understand why the temperature has to be measured on all TADDs
every two minutes for a duration of twenty minutes, mainly because the
airplane maintenance manual for Model 747-200 Combi airplanes has only
baseline and 10-minute measurements and there is no requirement for
additional measurements. Lufthansa asks that the intervals be reduced
to 1- and 10-minute intervals, with the possibility of performing each
measurement sequentially.
We acknowledge and agree with the commenter's concern and provide
clarification. The temperature measurement procedure identified by the
commenter does specify performing the measurements simultaneously on
all ducts. If the procedure were done sequentially, before making each
measurement, the initial conditions of the airplane would have to be
re-established, and the time required for that would be prohibitive.
Measuring the temperatures frequently allows detection of the highest
achieved temperature, given that the temperature may not increase
steadily. In addition, Model 747-200 Combi airplane configurations are
different; therefore, different procedures are used for those
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airplanes and those procedures cannot be used for the other airplane
models specified in this AD. However, according to the provisions of
paragraph (l) of this AD, we may approve requests for another method
which accomplishes the intent of the maintenance manual tasks if the
request includes data which prove that method would provide an
acceptable level of safety. We have made no change to the AD in this
regard.
Conclusion
We have carefully reviewed the available data, including the
comments received, and determined that air safety and the public
interest require adopting the AD as proposed in the supplemental NPRM.
Costs of Compliance
There are about 1,081 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs for
U.S. operators to comply with this AD.
Estimated Costs
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Number of U.S.-
Action Work hours Average labor Cost per registered Fleet cost
rate per hour airplane airplanes
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Hot air leak test............ 3 $80 $240, per test 216 $51,840, per
cycle. test cycle.
General visual inspection.... 5 $80 $400, per 216 $86,400, per
inspection inspection
cycle. cycle.
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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 AD will not have federalism
implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that this AD:
(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.
We prepared a regulatory evaluation of the estimated costs to
comply with this 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, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 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. The Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
2007-07-03 Boeing: Amendment 39-15003. Docket No. FAA-2004-19755;
Directorate Identifier 2004-NM-23-AD.
Effective Date
(a) This AD becomes effective May 2, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-
400F, 747SR, and 747SP series airplanes; certificated in any
category; line numbers 1 through 1316 inclusive.
Unsafe Condition
(d) This AD results from reports of sealant deteriorating on the
outside of the center wing fuel tank and analysis that sealant may
deteriorate inside the tank due to excess heat from leaking trim air
diffuser ducts or sidewall riser duct assemblies (collectively
referred to in this AD as ``TADDs''). We are issuing this AD to
prevent leakage of fuel or fuel vapors into areas where ignition
sources may be present, which could result in a fire or explosion.
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.
Repetitive Tests and Inspections
(f) Do the actions in Table 1 of this AD at the times specified
in Table 1 of this AD, in accordance with the Accomplishment
Instructions of Boeing Service Bulletin 747-21A2418, Revision 4,
dated November 17, 2005. When the compliance times for a hot air
leak test and a general visual inspection coincide, the hot air leak
test is not required at that time, but is required within 1,200
flight hours (i.e., one repeat interval) after the general visual
inspection.
[[Page 14397]]
Table 1.--Compliance Times
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Initially at the later of-- Then repeat within this interval until
Do this action-- paragraph (j) is done--
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(1) Repetitive test to detect hot air Prior to the accumulation 1,200 flight hours.
leaking from TADDs.. of 21,200 total flight
hours, or within 1,200
flight hours after the
effective date of this AD.
(2) General visual inspection for Prior to the accumulation 12,000 flight hours.
damage or discrepancies of the TADDs. of 32,000 total flight
hours, or within 12,000
flight hours after the
effective date of this
AD, except as provided by
paragraph (g) of this AD.
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Note 1: For the purposes of this AD, a general visual inspection
is: ``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
ensure visual access to all 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.''
Note 2: Boeing Service Bulletin 747-21A2418, Revision 4, refers
to Chapters 21-61-20 and 21-61-21 of the Boeing 747 Airplane
Maintenance Manual as an additional source for service information
for the test and inspections of the TADDs.
(g) If any hot air leak is found during any test required by
paragraph (f) of this AD: Before further flight, do the general
visual inspection for damage or discrepancies of the TADDs, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 747-21A2418, Revision 4, dated November 17, 2005.
Corrective Actions
(h) If any damage or discrepancy is found during any general
visual inspection for damage required by paragraph (f) or (g) of
this AD: Do the actions in paragraphs (h)(1), (h)(2), (h)(3), and
(h)(4) of this AD, as applicable. Do all of these actions in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 747-21A2418, Revision 4, dated November 17, 2005.
(1) Before further flight: Perform a general visual inspection
for damage of the primary and secondary fuel barriers of the center
wing tank; structure adjacent to the discrepant TADD; and cables,
cable pulleys, and raised cable seals in the over-wing area. If no
damage is found on the side of the airplane where the damaged or
discrepant TADD is found, inspecting the other side of the airplane
is not required.
(2) Before further flight: Repair all damage or discrepancies
found.
(3) Before further flight: Replace any damaged TADD with a new
TADD having the same part number or a new or serviceable, improved
TADD having a part number listed in the ``New TADD Part Number'' or
``New Sidewall Riser Duct Assy Part Number'' column, as applicable,
of the tables in Section 2.C.2. of the service bulletin.
(4) Repeat the test and inspection required by paragraph (f) of
this AD at the times specified in Table 1 of this AD, except as
provided by paragraphs (i) and (j) of this AD.
(i) For any original-material TADD that is replaced with a new
TADD having the same part number as the TADD being replaced: Within
21,200 flight hours after the TADD is replaced, do the test to
detect hot air leaking from the replaced TADD, and within 32,000
flight hours after the TADD is replaced, do the general visual
inspection for damage, as specified in paragraph (f) of this AD.
Thereafter, repeat the test and inspection at the repetitive
intervals specified in Table 1 of this AD, except when the times for
a hot air leak test and a general visual inspection coincide, the
leak test is not required.
Optional Terminating Action
(j) Replacing existing TADDs with new or serviceable, improved
TADDs terminates repetitive test and inspection requirements as
specified in paragraphs (j)(1), (j)(2), and (j)(3) of this AD. New
or serviceable, improved TADDs are those having a part number listed
in the ``New TADD Part Number'' or ``New Sidewall Riser Duct Assy
Part Number'' column, as applicable, of the tables in Section 2.C.2.
of Boeing Service Bulletin 747-21A2418, Revision 3, dated December
21, 2004; or Revision 4, dated November 17, 2005.
(1) The repetitive general visual inspections required by
paragraph (f)(2) of this AD are terminated for each TADD that is
replaced with a new or serviceable, improved TADD.
(2) Replacing all TADDs on one side of the airplane with new or
serviceable, improved TADDs terminates all repetitive tests required
by paragraph (f)(1) of this AD and all repetitive inspections
required by paragraph (f)(2) of this AD only for the side of the
airplane on which the improved TADDs are installed.
(3) Replacing all TADDs on both sides of the airplane with new
or serviceable, improved TADDs terminates all repetitive tests
required by paragraph (f)(1) of this AD and all repetitive
inspections required by paragraph (f)(2) of this AD.
Previously Accomplished Actions
(k) Actions done before the effective date of this AD in
accordance with Boeing Alert Service Bulletin 747-21A2418, dated
November 14, 2002; Revision 1, dated October 16, 2003; Revision 2,
dated March 4, 2004; or Boeing Service Bulletin 747-21A2418,
Revision 3, dated December 21, 2004; are acceptable for compliance
with the corresponding actions required by this AD.
Alternative Methods of Compliance (AMOCs)
(l)(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 Sec.
39.19 on any airplane to which the AMOC applies, notify the
appropriate principal inspector in the FAA Flight Standards
Certificate Holding District Office.
Material Incorporated by Reference
(m) You must use Boeing Service Bulletin 747-21A2418, Revision
4, dated November 17, 2005, to perform the actions that are required
by this AD, unless the AD specifies otherwise. The Director of the
Federal Register approved the incorporation by reference of this
document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for a copy of this service information. You
may review copies 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/cfr/ibr-locations.html.
Issued in Renton, Washington, on March 20, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-5557 Filed 3-27-07; 8:45 am]
BILLING CODE 4910-13-P