[Federal Register Volume 66, Number 124 (Wednesday, June 27, 2001)]
[Rules and Regulations]
[Pages 34094-34096]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-15933]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-NM-250-AD; Amendment 39-12286; AD 2001-13-06]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-100, -200, -300, and
747SP 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 747-100, -200, -300, and 747SP
series airplanes; that requires certain inspections to find missing and
alloy-steel taperlock fasteners (bolts) in the diagonal brace underwing
fittings; and corrective actions, if necessary. For airplanes with
missing or alloy-steel fasteners, this AD also mandates replacement of
certain fasteners with new fasteners, which constitutes terminating
action for the repetitive inspections. This action is necessary to
prevent loss of the underwing fitting load path due to missing or
damaged alloy-steel taperlock fasteners, which could result in
separation of the engine and strut from the airplane. This action is
intended to address the identified unsafe condition.
DATES: Effective August 1, 2001.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 1, 2001.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. 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 Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Tamara L. Anderson, Aerospace
Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2771; fax (425) 227-1181.
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 747-100, -
200, -300, and 747SP series airplanes was published in the Federal
Register on January 23, 2001 (66 FR 7433). That action proposed to
require certain inspections to find missing and alloy-steel taperlock
fasteners (bolts) in the diagonal brace underwing fittings; and
corrective actions, if necessary. For airplanes with missing or alloy-
steel fasteners, that action also proposed to mandate replacement of
certain fasteners with new fasteners, which would constitute
terminating action for the repetitive inspections.
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.
Support for the Proposal
One commenter supports the proposed rule.
Request To Clarify Potential Damage Conditions
One commenter, the airplane manufacturer, requests that the FAA
revise language in the preamble and paragraph (b)(1) of the proposed
AD, which specifies, ``an open-hole high frequency eddy current (HFEC)
inspection to detect cracks at the bolt hole locations * * *.'' The
commenter requests that these sections refer to corrosion and damage in
addition to cracking. The commenter states that corrosion is often
present in bolt holes where cracked alloy steel bolts have been
removed, and that fastener holes may be damaged during removal of
bolts.
The FAA concurs with the commenter's request to reference all
conditions that may be found during the open-hole HFEC inspection, and
has revised paragraph (b)(1) to specify ``an open-hole [HFEC]
inspection to detect cracks, corrosion, or damage at the bolt hole
locations of the aft 10 taperlock fasteners in the diagonal brace
underwing fitting.'' Paragraphs (b)(3) and (c) have also been revised
to acknowledge that conditions other than cracking may be present. The
FAA finds that these changes will not result in any additional burden
for operators because the open-hole HFEC inspection is used to indicate
whether there is a discrepancy, regardless of whether the discrepancy
is a crack, corrosion, or other damage. The section of the preamble
which the commenter asked to be changed is not restated in this final
rule; thus, no change is necessary in this regard.
Request To Estimate Cost of Corrective Action
Two commenters request that the FAA revise the cost impact
information included in the proposed AD to include an estimate of the
cost for replacement of alloy-steel fasteners. One of the commenters
also requests that the FAA estimate the number of airplanes on which
this replacement may be necessary. The commenters note that, based on
inspections accomplished thus far, it is highly probable that many
operators will find alloy-steel fasteners installed on their airplanes.
One of the commenters specifically requests that the FAA use the work
hour estimate of 448 work hours per airplane that is provided in Boeing
Alert Service Bulletin 747-57A2312, dated June 15, 2000.
The FAA concurs with the commenters' requests, though we note that
the cost impact estimate included in ADs is typically limited only to
the cost of actions actually required by the rule. The cost estimate
does not typically consider the costs of ``on-condition'' actions, such
as repairing a crack if one is detected during a required inspection
(``repair, if necessary''). Such ``on-condition'' repair actions would
be required to be accomplished--regardless of AD requirements--in order
to correct an unsafe condition identified in an airplane and to ensure
operation of that airplane in an airworthy condition, as required by
the Federal Aviation Regulations.
In this case, however, the FAA acknowledges that many operators
will probably find alloy-steel fasteners installed; thus, we agree that
it is acceptable to provide an estimate of the costs associated with
replacement of alloy steel fasteners. Accordingly, the FAA has added an
estimate of the cost of the replacement of alloy steel fasteners to the
``Cost Impact'' section of this final rule. The FAA is unable to
accommodate the commenter's request to estimate the number of airplanes
that will actually require bolt replacement, but has instead estimated
the total cost if all U.S.-registered airplanes subject to this AD must
accomplish the bolt replacement. Operators will note that
[[Page 34095]]
the estimated cost is based on a work hour estimate of 135 hours per
airplane, which differs from the estimate of 448 work hours suggested
by the commenter. The commenter's figure of 448 work hours includes
time for gaining access and closing up, which the FAA considers
incidental costs. Incidental costs are not typically included in the
cost estimate in AD actions because these costs may vary significantly
from operator to operator, making them almost impossible to calculate.
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 363 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 60 airplanes of U.S. registry
will be affected by this AD.
It will take approximately 2 work hours per airplane to accomplish
the required visual and magnetic inspections, at an average labor rate
of $60 per work hour. Based on these figures, the cost impact of these
inspections on U.S. operators is estimated to be $7,200, or $120 per
airplane.
Should an operator be required to accomplish the fastener
replacement, it will take approximately 135 work hours per airplane, at
an average labor rate of $60 per work hour. Required parts will cost
approximately $1,600 per airplane. Based on these figures, the cost
impact of such replacement is estimated to be $9,700 per airplane.
Should all airplanes on the U.S. Register that are subject to this AD
be required to accomplish this replacement, the FAA estimates that the
cost impact of this replacement on U.S. operators would be $582,000.
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.
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
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
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:
2001-13-06 Boeing: Amendment 39-12286. Docket 2000-NM-250-AD.
Applicability: Model 747-100, -200, -300, and 747SP series
airplanes, equipped with titanium diagonal brace underwing fittings;
as listed in Boeing Alert Service Bulletin 747-57A2312, dated June
15, 2000; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (e) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent loss of the underwing fitting load path due to
missing or damaged taperlock fasteners, which could result in
separation of the engine and strut from the airplane, accomplish the
following:
Repetitive Inspections
(a) Within 12 months after the effective date of this AD: Do a
one-time detailed visual inspection of the diagonal brace underwing
fitting at the Number 1 and Number 4 engine pylons to find missing
taperlock fasteners (bolts), and a magnetic inspection to find
alloy-steel fasteners per Part 1 of the Accomplishment Instructions
of Boeing Alert Service Bulletin 747-57A2312, dated June 15, 2000.
Note 2: For the purposes of this AD, a detailed visual
inspection is defined as: ``An intensive visual examination of a
specific structural area, system, installation, or assembly to
detect damage, failure, or irregularity. Available lighting is
normally supplemented with a direct source of good lighting at
intensity deemed appropriate by the inspector. Inspection aids such
as mirror, magnifying lenses, etc., may be used. Surface cleaning
and elaborate access procedures may be required.''
(1) If no alloy-steel fasteners are found and no fasteners are
missing, no further action is required by this AD.
(2) If any alloy-steel fasteners are found or any fasteners are
missing, before further flight, do an ultrasonic inspection of the
alloy-steel fasteners to find damage per Part 2 of the
Accomplishment Instructions of the service bulletin.
(i) If no damaged alloy-steel fasteners are found, and no
fasteners are missing: Repeat the ultrasonic inspection thereafter
at intervals not to exceed 18 months until accomplishment of the
terminating action required by paragraph (b) of this AD.
(ii) If any damaged alloy-steel fasteners are found, or any
fasteners are missing: Before further flight, do an ultrasonic
inspection of all 10 aft fasteners (including non-alloy steel) per
Part 2 of the Accomplishment Instructions of the service bulletin.
Before further flight, replace damaged and missing fasteners with
new fasteners per Part 3 of the Accomplishment Instructions of the
service bulletin, except as provided by paragraph (c) of this AD.
Thereafter, repeat the inspection of the remaining alloy-steel
fasteners at intervals not to exceed 18 months until accomplishment
of the terminating action required by paragraph (b) of this AD.
[[Page 34096]]
Terminating Action
(b) Within 48 months after the effective date of this AD: Do the
actions required by paragraphs (b)(1) and (b)(2), or (b)(3) of this
AD, per Boeing Alert Service Bulletin 747-57A2312, dated June 15,
2000. Accomplishment of the actions specified in this paragraph
constitutes terminating action for the repetitive inspection
requirements of this AD.
(1) Perform an open-hole high frequency eddy current (HFEC)
inspection to detect cracks, corrosion, or damage at the bolt hole
locations of the aft 10 taperlock fasteners in the diagonal brace
underwing fitting at the Number 1 and Number 4 engine pylons per
Part 3 of the Accomplishment Instructions of the service bulletin.
If any cracking is detected, before further flight, perform
applicable corrective actions per the service bulletin, except as
provided by paragraph (c) of this AD.
(2) Before further flight: Replace all 10 aft taperlock
fasteners with new, improved fasteners per Part 3 of the
Accomplishment Instructions of the service bulletin.
(3) Do an ultrasonic inspection to find damaged fasteners per
Part 2 of the Accomplishment Instructions of the service bulletin.
Before further flight, replace all damaged non-alloy steel and all
alloy-steel fasteners with new fasteners per Part 3 of the
Accomplishment Instructions of the service bulletin. Do an open-hole
HFEC inspection before installation of the new fasteners; if any
cracking, corrosion, or damage is found, before further flight,
perform applicable corrective actions per the service bulletin,
except as provided by paragraph (c) of this AD.
Corrective Actions
(c) If any cracking, corrosion, or damage of the bolt hole that
exceeds the limits specified in the service bulletin is found, or if
any non-alloy steel bolt is found to be damaged, during any
inspection required by this AD, and the bulletin specifies to
contact Boeing for appropriate action: Before further flight, repair
per a method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA; or per data meeting the type certification basis
of the airplane approved by a Boeing Company Designated Engineering
Representative who has been authorized by the Manager, Seattle ACO,
to make such findings. For a repair method to be approved by the
Manager, Seattle ACO, as required by this paragraph, the Manager's
approval letter must specifically reference this AD.
Spares
(d) As of the effective date of this AD, no person shall install
on any airplane, a fastener, part number BACB30PE( ) * ( ); or any
other fastener made of 4340, 8740, PH13-8 Mo or H-11 steel, in the
locations specified in this AD.
Alternative Methods of Compliance
(e) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle ACO. Operators shall submit
their requests through an appropriate FAA Principal Maintenance
Inspector, who may add comments and then send it to the Manager,
Seattle ACO.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Special Flight Permits
(f) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Incorporation by Reference
(g) Except as provided by paragraph (c) of this AD, the actions
shall be done in accordance with Boeing Alert Service Bulletin 747-
57A2312, dated June 15, 2000. 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 Airplane Group, 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
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
Effective Date
(h) This amendment becomes effective on August 1, 2001.
Issued in Renton, Washington, on June 19, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 01-15933 Filed 6-26-01; 8:45 am]
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