[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]
BILLING CODE 4910-13-P