AD 2001-13-12

[Federal Register Volume 66, Number 126 (Friday, June 29, 2001)]
[Rules and Regulations]
[Pages 34526-34530]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-16049]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-313-AD; Amendment 39-12292; AD 2001-13-12]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 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 series airplanes. This AD 
requires repetitive inspections to detect cracks and corrosion around 
the lower bearing of the actuator attach fittings of the inboard and 
outboard flaps. This AD also requires repetitive overhauls for certain 
actuator attach fittings or repetitive replacement of the fittings with 
new fittings, as applicable, which terminates the repetitive 
inspections. This AD also provides for replacement of actuator attach 
fittings with improved fittings, which terminates all requirements of 
this AD. This amendment is prompted by reports of cracks on the lower 
bearing journal of the inboard actuator attach fittings of the outboard 
trailing edge flaps due to stress corrosion. The actions specified by 
this AD are intended to detect and correct cracking on the actuator 
attach fittings of the trailing edge flaps, which could result in 
abnormal operation or retraction of a trailing edge flap, and 
consequent reduced controllability of the airplane.

DATES: Effective August 3, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 3, 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 all Boeing Model 747-100, -200, -
300, -400, and 747SR series airplanes was published in the Federal 
Register on April 24, 2000 (65 FR 21675). That action proposed to 
require repetitive inspections to detect cracks and corrosion around 
the lower bearing of the actuator attach fittings of the inboard and 
outboard flaps. That action also proposed to require repetitive 
overhauls for certain attach fittings or repetitive replacement of the 
attach fittings with new attach fittings, as applicable, which would 
constitute terminating action for certain repetitive actions.

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.

Limit Applicability of AD

    One commenter, the airplane manufacturer, requests that the FAA 
limit the applicability of the proposed rule to airplanes having line 
numbers up to and including 1265. The commenter states that new, 
improved actuator attach fittings will be installed during production 
on airplanes starting at line number 1266. The commenter explains that 
the new, improved actuator attach fittings in certain positions (i.e., 
actuator attach fittings number 2 and 7) have an increased cross-
sectional area that reduces stress levels and, consequently, the 
possibility of stress corrosion cracking. Attach fittings in all other 
locations will have increased bushing interference, and BMS 5-26 
sealant will be applied to the new fittings to prevent general 
corrosion.
    The FAA concurs with the intent of the commenter's request to limit 
the applicability of this AD. However, since they submitted their 
comment, the airplane manufacturer has advised the FAA that new 
fittings have been incorporated on airplanes starting with line number 
1264. This coincides with the effectivity listing of a new service 
bulletin related to this AD, Boeing Service Bulletin 747-57A2310, 
Revision 2, dated February 22, 2001 (which is described in the next 
section of this final rule). Therefore, the FAA has revised and 
clarified the applicability of this AD to apply only to Model 747 
series airplanes listed in Boeing Service Bulletin 747-57A2310, 
Revision 2. (Operators may note that, while the applicability of this 
AD has been reduced, the estimated number of affected airplanes has 
been increased in the ``Cost Impact'' section of the preamble. The new 
estimate includes airplanes delivered after the preparation of the 
proposed rule.)

Reference New Terminating Action

    One commenter notes that, in the preamble of the proposed AD, the 
FAA identifies the proposed AD as interim action, and states that, once 
a modification is developed, approved, and available, the FAA may 
consider additional rulemaking. The commenter states that it is very 
interested in this terminating modification. The commenter requests 
that, if release of the modification is imminent, the FAA delay release 
of this AD until the airplane manufacturer has developed the 
terminating modification. If the release is not imminent, the commenter 
requests that the FAA make the modification available as an alternative 
method of compliance (AMOC) to this AD or issue a superseding AD to 
include the terminating action as soon as possible.
    The FAA partially concurs with the commenter's request. The FAA 
does not agree that issuance of the final rule should intentionally be 
delayed pending development of a terminating modification. The 
commenter provides no technical justification for such a delay.
    However, since the issuance of the proposed AD, the FAA has 
reviewed and approved Boeing Service Bulletin 747-57A2310, Revision 2. 
(The proposed AD references Boeing Service Bulletin 747-57A2310, 
Revision 1, dated November 23, 1999, as an appropriate source of 
service

[[Page 34527]]

information for certain proposed actions.) Among other actions, 
Revision 2 of the service bulletin includes procedures for a new 
terminating action. The new terminating action involves rework of the 
numbers 1, 3, 4, 5, 6, and 8 actuator attach fittings on both the 
inboard and outboard flaps, or replacement of the attach fittings with 
improved attach fittings; and replacement of the number 2 and 7 attach 
fittings of the trailing edge flap actuators with new, improved attach 
fittings (of a new design).
    The FAA has determined that, if accomplished, this terminating 
action would adequately address the unsafe condition. Therefore, the 
FAA has added subparagraphs to paragraph (e) of this final rule, 
including paragraph (e)(2) which provides the terminating action 
specified in Revision 2 of the service bulletin as an option that ends 
the requirements of this AD. Additionally, the FAA finds that Revision 
2 is also an acceptable source of service information for the 
inspections required by paragraph (c) of this AD. Thus, paragraph (c) 
of this final rule has also been revised to reference Revision 2 of the 
service bulletin, in addition to Revision 1, as an acceptable source of 
service information.

Clarify References in Paragraphs (a) and (b)

    One commenter requests that the FAA revise paragraphs (a) and (b) 
of the proposed rule to state, ``Accomplish the actions in paragraphs 
(c), (d), or (e) of this AD * * *'' instead of referring to paragraph 
(c) only. The commenter provides no justification for its request.
    The FAA concurs with the commenter's request because adding 
references to paragraphs (d) and (e) will clarify the complete range of 
actions available to operators. Paragraphs (a) and (b) of this final 
rule have been revised accordingly.

Provide for Previous Overhaul of Actuator Fittings

    One commenter requests that the FAA provide for actuator attach 
fittings of the inboard flaps that have been overhauled in accordance 
with a revision of Boeing 747 Overhaul Manual (OHM) 57-52-35 that is 
dated prior to June 10, 1999. The commenter specifically requests that, 
for airplanes previously overhauled, the FAA revise the compliance 
times in paragraph (a) of the proposed AD to 8 years or 8,000 flight 
cycles after overhaul of the actuator attach fittings for the inboard 
flaps. The commenter notes that this compliance time would agree with 
the compliance time for the actuator attach fittings of the outboard 
flaps, which are more critical.
    The FAA concurs with the commenters request, and has revised 
paragraph (a) of this final rule to apply to:
    <bullet> Actuator attach fittings on the outboard flaps that have 
NOT been overhauled in accordance with revisions of OHM 57-52-55 dated 
prior to June 1, 1999, or replaced with a new fitting; and
    <bullet> Actuator attach fittings on the inboard flaps that have 
NOT been overhauled in accordance with revisions of OHM 57-52-35, dated 
prior to June 10, 1999, or replaced with a new fitting.
    Also, the FAA has revised paragraph (b) of this final rule to apply 
to:
    <bullet> Actuator attach fittings on the outboard flaps that HAVE 
been overhauled in accordance with revisions of OHM 57-52-55 dated 
prior to June 1, 1999, or replaced with a new fitting; and
    <bullet> Actuator attach fittings on the inboard flaps that HAVE 
been overhauled in accordance with revisions of OHM 57-52-35, dated 
prior to June 10, 1999, or replaced with a new fitting.

Allow Use of Later Revisions of OHM

    One commenter requests that the FAA revise paragraph (d) of the 
proposed rule to specify overhaul of the actuator attach fittings for 
the flaps in accordance with Boeing OHM 57-52-55, Temporary Revision 
57-7, dated June 1, 1999, or Temporary Revision 57-9, dated May 14, 
2000; and Boeing OHM 57-52-35, Temporary Revision 57-8, dated June 10, 
1999, Temporary Revision 57-10, dated May 8, 2000, or Full Revision 57-
10, dated July 1, 2000. The commenter also requests that the FAA refer 
to Boeing OHM 57-52-35, Temporary Revision 57-10, or Full Revision 57-
10, in Note 4 of the proposed rule. The commenter states that these 
later revisions of the OHM chapters describe the same actions as those 
revisions referred to in the proposed rule but provide additional 
repair information.
    Similarly, a second commenter requests that the FAA revise 
paragraph (d) of the proposed rule to specify overhaul of the actuator 
attach fittings in accordance with Boeing OHM 57-52-55, Temporary 
Revision 57-7, dated June 1, 1999, or later, and Boeing OHM 57-52-35, 
Temporary Revision 57-8, dated June 10, 1999, or later. The commenter 
states that this would allow use of the latest revision of the OHM when 
overhauling the fittings.
    The FAA partially concurs with the commenters' requests. The FAA 
has reviewed the specific revisions referenced by the first commenter 
and finds them acceptable. The FAA has also reviewed Boeing OHM 57-52-
55, Full Revision 57-9, dated July 1, 2000, and finds it acceptable. 
However, rather than revising paragraph (d) to cite all of these 
revisions, the FAA finds that paragraph (d) of this AD may be revised 
to refer to the accomplishment instructions of Boeing Service Bulletin 
747-57A2310, Revision 1, dated November 23, 1999, or Revision 2, dated 
February 22, 2001, as acceptable sources of service information for the 
accomplishment of the overhaul required by that paragraph. The FAA 
finds that this change will clarify the requirements of paragraph (d) 
of this AD, and make it easier for operators to comply with that 
paragraph. The FAA has revised paragraph (d) accordingly. In addition, 
for the actuator attach fittings on the inboard flaps, the FAA has 
revised Note 4 of this AD to refer to specific OHM revisions referenced 
by the first commenter and reviewed and accepted by the FAA.

Allow Approval of Repairs By Designated Engineer Representative 
(DER)

    One commenter requests that the FAA revise the ``Alternative 
Methods of Compliance'' paragraph--paragraph (f) in the proposed rule--
to allow repairs of corrosion or cracking that is outside the limits 
specified in the OHM in accordance with a method approved by a Boeing 
DER, in lieu of requiring replacement of the actuator attach fittings 
before further flight. The commenter states that this allowance is 
necessary to prevent unnecessary delays or grounding of airplanes if 
operators find conditions outside the rework limits in the OHM.
    The FAA partially concurs with the commenter's request. The FAA 
does not concur with the commenter's request to revise the 
``Alternative Methods of Compliance'' paragraph to allow the Boeing DER 
to approve repairs. However, the FAA finds that a new paragraph may be 
added to provide for repair of actuator attach fittings, in lieu of 
replacement. Therefore, the FAA has added paragraph (f) to this final 
rule (and reordered subsequent paragraphs accordingly), to allow for 
repair of the actuator attach fittings on the inboard and outboard 
flaps in accordance with a method approved by the FAA or data approved 
by a Boeing Company DER who has been authorized to make such findings.

Revise Cost Impact Estimate

    One commenter requests that the FAA revise the estimate of the cost 
impact in the proposed rule. The commenter states that the estimate of 
5 work hours

[[Page 34528]]

per airplane for overhaul of the actuator attach fittings is extremely 
low. The commenter notes that the procedures for each actuator attach 
fitting include cleaning, removing sleeves, machining, performing non-
destructive tests, and manufacturing and installing new sleeves. The 
commenter also submits estimates from several vendors as well as their 
own estimate of 192 work hours per airplane.
    The FAA partially concurs with the commenter's request. The FAA 
does not concur that the commenter's estimate of 192 work hours is 
appropriate for use in this AD. The cost impact information in AD 
actions includes only the ``direct'' costs of the specific actions 
required by the AD. The FAA recognizes that, in accomplishing the 
requirements of any AD, operators may incur ``incidental'' costs in 
addition to the ``direct'' costs. The cost analysis in AD rulemaking 
actions, however, typically does not include incidental costs, such as 
the time required to gain access and close up; planning time; or time 
necessitated by other administrative actions. Because incidental costs 
may vary significantly from operator to operator, they are almost 
impossible to calculate.
    However, the FAA does concur that the estimated number of work 
hours can be adjusted somewhat. The estimate of 5 work hours included 
only the time necessary specifically for the overhaul, based on the 
data included in the manufacturer's service bulletin. The FAA finds it 
appropriate to include the estimate of work hours needed for removal, 
inspection, and re-installation, as well as overhaul, of the subject 
parts. Based on the data provided in the airplane manufacturer's 
service bulletin, the FAA estimates the number of work hours for these 
actions to be 37 work hours per airplane. Similarly, the FAA finds that 
the cost estimate for replacement of the actuators should include time 
for the inspection that is included in the procedures for the 
replacement. Thus, the number of work hours for the replacement has 
been increased from 2 to 4 work hours per airplane. The FAA has revised 
the cost impact estimate in this final rule accordingly.

Reduce Compliance Time for Actions on Attach Fittings on Outboard 
Flap

    One commenter, an operator, requests that the FAA reduce the 
proposed initial compliance time for actions on the actuator attach 
fittings on the outboard flap that have been overhauled per OHM 57-52-
55. The commenter requests a compliance time of 6 years or 6,000 flight 
cycles, whichever occurs first, after the attach fitting was 
overhauled, for the accomplishment of paragraph (c), (d), or (e) of 
this AD. The commenter states that the earlier of 6 years or 6,000 
flight cycles is its ``hard time'' interval between overhauls.
    The FAA does not concur. The compliance time of 8 years or 8,000 
flight cycles, whichever occurs first, is based on when cracking of 
actuator attach fittings has been found, and the manufacturer's 
recommendation in the service bulletin. However, an operator may choose 
to accomplish the actions in this AD prior to the 8-year-or-8,000-
flight-cycle threshold. No change to the final rule 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 1,111 Model 747 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 237 
airplanes of U.S. registry will be affected by this AD.
    It will take approximately 2 work hours per airplane to accomplish 
the required inspection, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of this inspection on U.S. 
operators is estimated to be $28,440, or $120 per airplane, per 
inspection cycle.
    The overhaul of actuator attach fittings, which is offered as one 
alternative for compliance with this AD action, will take approximately 
37 work hours per airplane to accomplish, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this 
overhaul is estimated to be $2,220 per airplane, per overhaul cycle.
    In lieu of the overhaul, this AD provides for a replacement of 
actuator attach fittings, which would take approximately 4 work hours 
per airplane to accomplish, at an average labor rate of $60 per work 
hour. Required parts will cost approximately $6,623 (for the four 
attach fittings on the outboard flaps) and $7,566 (for the four attach 
fittings on the inboard flaps). Based on these figures, the cost impact 
of this replacement is estimated to be $14,429, per airplane, per 
replacement cycle.
    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.
    Should an operator elect to accomplish the optional replacement 
with improved attach fittings, which terminates the requirements of 
this AD, it would take approximately 16 work hours to accomplish, at an 
average labor rate of $60 per work hour. The cost of required parts 
would be approximately $15,322 per airplane. Based on these figures, 
the cost impact of the optional terminating action would be $16,282 per 
airplane.

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:

[[Page 34529]]

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:

2001-13-12  Boeing: Amendment 39-12292. Docket 99-NM-313-AD.

    Applicability: Model 747 series airplanes, as listed in Boeing 
Service Bulletin 747-57A2310, Revision 2, dated February 22, 2001; 
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 (g) 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 detect and correct cracking on the actuator attach fittings 
of the trailing edge flaps, which could result in abnormal operation 
or retraction of a trailing edge flap, and consequent reduced 
controllability of the airplane, accomplish the following:

Actuator Attach Fittings That Have Not Been Overhauled or Replaced

    (a) For actuator attach fittings on the outboard flaps that have 
NOT been overhauled in accordance with revisions of Boeing 747 
Overhaul Manual (OHM) 57-52-55 dated prior to June 1, 1999, or 
replaced with a new fitting, prior to the effective date of this AD; 
and for actuator attach fittings on the inboard flap actuators that 
have NOT been overhauled in accordance with revisions of OHM 57-52-
35, dated prior to June 1, 1999, or replaced with a new fitting, 
prior to the effective date of this AD: Accomplish the actions in 
paragraph (c), (d), or (e) of this AD at the later of the times 
specified in paragraphs (a)(1) and (a)(2) of this AD.
    (1) Prior to the accumulation of 8 years since date of 
manufacture or 8,000 total flight cycles, whichever occurs first.
    (2) Within 6 months after the effective date of this AD.

Actuator Attach Fittings That Have Been Overhauled or Replaced

    (b) For actuator attach fittings on the outboard flaps that HAVE 
been overhauled in accordance with revisions of OHM 57-52-55 dated 
prior to June 1, 1999, or replaced with a new fitting, prior to the 
effective date of this AD; and for actuator attach fittings on the 
inboard flap actuators that HAVE been overhauled in accordance with 
revisions of OHM 57-52-35 dated prior to June 1, 1999, or replaced 
with a new fitting, prior to the effective date of this AD: 
Accomplish the actions in paragraph (c), (d), or (e) of this AD at 
the later of the times specified in paragraphs (b)(1) and (b)(2) of 
this AD.
    (1) Within 8 years or 8,000 total flight cycles after the attach 
fitting was overhauled or replaced, whichever occurs first.
    (2) Within 6 months after the effective date of this AD.

Inspections and Corrective Action

    (c) Perform a detailed visual inspection to detect corrosion 
around the lower bearing journal on the actuator attach fittings on 
the inboard and outboard flaps, and perform an ultrasonic inspection 
to detect cracks around the lower bearing journal of the actuator 
attach fittings on the outboard flaps, in accordance with Boeing 
Service Bulletin 747-57A2310, Revision 1, dated November 23, 1999; 
or Revision 2, dated February 22, 2001.

    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.''


    Note 3: Inspections and replacements accomplished in accordance 
with Boeing Alert Service Bulletin 747-57A2310, dated June 17, 1999, 
are acceptable for compliance with the requirements of paragraph (c) 
of this AD.

    (1) If no corrosion or cracks are detected, repeat the 
inspections required by paragraph (c) of this AD at intervals not to 
exceed 18 months. Within 5 years after the initial inspections 
required by paragraph (c) of this AD, accomplish the actions 
specified in paragraph (d) or (e) of this AD.
    (2) If any corrosion is detected, prior to further flight, 
remove the corrosion by accomplishing the actions of either 
paragraph (c)(2)(i) or (c)(2)(ii) of this AD.
    (i) If corrosion is within the limits of the Boeing 747 OHM: 
Prior to further flight, accomplish the actions specified in 
paragraph (d) or (e) of this AD.
    (ii) If corrosion is not within the limits of the Boeing 747 
OHM: Prior to further flight, accomplish the actions specified in 
paragraph (e) or (f) of this AD.
    (3) If any crack is detected: Prior to further flight, 
accomplish the actions specified in paragraph (e) or (f) of this AD.

Overhaul

    (d) Overhaul the actuator attach fittings on the outboard flaps 
in accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-57A2310, Revision 1, dated November 23, 1999; or 
Revision 2, dated February 22, 2001. Repeat the overhaul of 
actuators on the outboard flaps as specified in Part 2 of the Work 
Instructions of the service bulletin thereafter at intervals not to 
exceed 8 years or 8,000 flight cycles, whichever occurs first. 
Accomplishment of the overhaul of the actuator attach fittings on 
the outboard flaps constitutes terminating action for the repetitive 
inspection requirements of paragraph (c)(1) of this AD. Overhaul the 
actuator attach fittings on the inboard flaps in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 747-57A2310, 
Revision 1, dated November 23, 1999; or Revision 2, dated February 
22, 2001. Accomplishment of the overhaul of the actuator attach 
fittings on the inboard flaps constitutes terminating action for the 
requirements of this AD for the actuator attach fittings on the 
inboard flaps.

Replacement

    (e) Replace the actuator attach fittings on the inboard and 
outboard flaps in accordance with paragraph (e)(1) or (e)(2) of this 
AD.
    (1) Replace the actuator attach fittings on the inboard and 
outboard flaps with new attach fittings in accordance with ``Part 
3--Replacement'' of Boeing Service Bulletin 747-57A2310, Revision 1, 
dated November 23, 1999; or Revision 2, dated February 22, 2001. 
Accomplishment of this replacement constitutes terminating action 
for the repetitive inspections required by paragraph (c) of this AD 
for the replaced fitting. Within 8 years or 8,000 flight cycles 
following accomplishment of the replacement, whichever occurs first, 
repeat this replacement or accomplish the overhaul specified in 
paragraph (d) of this AD.
    (2) Replace the actuator attach fittings on the inboard and 
outboard flaps with improved attach fittings in accordance with 
``Part 4--Terminating Action'' of Boeing Service Bulletin 747-
57A2310, Revision 2, dated February 22, 2001. If accomplished, this 
replacement with improved fittings terminates the requirements of 
this AD for the replaced fitting.

    Note 4: Replacement of the actuator attach fittings on the 
inboard flaps with fittings that have been overhauled in accordance 
with Boeing OHM 57-52-35, Temporary Revision 57-8, dated June 10, 
1999; Temporary Revision 57-10, dated May 8, 2000; or Full Revision 
57-10, dated July 1, 2000; constitutes terminating action for the 
requirements of this AD for the actuator attach fittings on the 
inboard flaps.

Repair

    (f) During any inspection done in accordance with paragraph (c) 
of this AD, if corrosion is found that is outside the limits 
specified in the Boeing 747 OHM, or if any crack is detected: In 
lieu of replacement of the actuator attach fittings in accordance 
with paragraph (e) of this AD, repair the actuator attach fittings 
on the inboard and outboard flaps in accordance with 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,

[[Page 34530]]

Seattle ACO, as required by this paragraph, the Manager's approval 
letter must specifically reference this AD.

Alternative Methods of Compliance

    (g) 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 5: 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

    (h) 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

    (i) Except as provided by paragraph (f) of this AD, the actions 
shall be done in accordance with Boeing Service Bulletin 747-
57A2310, Revision 1, dated November 23, 1999; or Boeing Service 
Bulletin 747-57A2310, Revision 2, dated February 22, 2001; as 
applicable. 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

    (j) This amendment becomes effective on August 3, 2001.

    Issued in Renton, Washington, on June 20, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-16049 Filed 6-28-01; 8:45 am]
BILLING CODE 4910-13-P