Airworthiness Directives; Boeing Model 747 Series Airplanes

[Federal Register Volume 66, Number 227 (Monday, November 26, 2001)]
[Rules and Regulations]
[Pages 58913-58915]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-29187]



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Federal Register / Vol. 66, No. 227 / Monday, November 26, 2001 / 
Rules and Regulations

[[Page 58913]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-02-AD; Amendment 39-12514; AD 2001-23-15]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 747 series airplanes, that 
currently requires repetitive detailed visual inspections to find 
discrepancies of the installation of the midspar fuse pins of the 
inboard and outboard struts, and follow-on actions, if necessary. That 
AD also provides for an optional terminating modification for the 
repetitive inspections. This amendment continues to require repetitive 
detailed visual inspections to find discrepancies of the installation 
of the midspar fuse pins of the inboard and outboard struts, and 
follow-on actions, if necessary. This amendment mandates accomplishment 
of the previously optional terminating modification. The actions 
specified by this AD are intended to find and fix discrepancies of the 
installation of the midspar fuse pins, which could result in loss of 
the secondary retention capability of the fuse pins, migration of the 
fuse pins, and consequent loss of the strut and engine from the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Effective December 31, 2001.
    The incorporation by reference of Boeing Service Bulletin 747-
54A2206, Revision 2, dated May 17, 2001, as listed in the regulations, 
is approved by the Director of the Federal Register, as of December 31, 
2001.
    The incorporation by reference of Boeing Service Bulletin 747-
54A2206, Revision 1, dated February 22, 2001, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of March 21, 2001 (66 FR 13424, March 6, 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 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: Existing airworthiness directive AD 2001-05-
05, amendment 39-12141 (66 FR 13424), applicable to certain Boeing 
Model 747 series airplanes, was published in the Federal Register on 
March 6, 2001 as a final rule with request for comments. This AD 
requires repetitive detailed visual inspections to find discrepancies 
of the installation of the midspar fuse pins of the inboard and 
outboard struts, and follow-on actions, if necessary. This AD also 
provides for an optional terminating modification for the repetitive 
inspections. The rule became effective on March 21, 2001.
    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) by superseding AD 2001-05-05 was published in the Federal 
Register on April 26, 2001 (66 FR 20950). The action proposed to 
continue to require repetitive detailed visual inspections to find 
discrepancies of the installation of the midspar fuse pins of the 
inboard and outboard struts, and follow-on actions, if necessary. The 
action also proposed to mandate accomplishment of the previously 
optional terminating modification.

Actions Since the Issuance of the NPRM

    Since the issuance of the NPRM, the FAA has reviewed and approved 
Boeing Service Bulletin 747-54A2206, Revision 2, dated May 17, 2001. 
Revision 2 describes procedures for use of an alternate replacement 
nut, in addition to the replacement nut specified in Revision 1, dated 
February 22, 2001.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this rule. The FAA received comments regarding both AD 
2001-05-05 and the proposed rule having Docket Number 2001-NM-02-AD. 
These comments and our response are presented below.

I. Comments to AD 2001-05-05

Request for Use of an Alternate Replacement Nut

    One commenter requests that the FAA provide for use of an alternate 
replacement for the primary retention nut having part number (P/N) 
BACN10JC24CD, which is listed in Boeing Service Bulletin 747-54A2206, 
Revision 1, dated February 22, 2001. The commenter states that the 
replacement nuts specified in AD 2001-05-05 are not readily available 
from the manufacturer.
    The FAA concurs, and has changed this final rule accordingly by 
approving Boeing Service Bulletin 747-54A2206, Revision 2, dated May 
17, 2001, which provides for use of an alternate replacement nut.

Request for Increase of Repetitive Inspection Interval

    Another commenter asks that the repetitive inspection interval 
specified in paragraph (a) be increased from 8,000 flight hours to 
8,500 flight hours to facilitate inspections at the C-check.
    The FAA does not concur because the specified repetitive interval 
is based on the recommendation of the manufacturer and on the C-check 
schedule of the majority of operators. However, the FAA notes that the 
commenter may apply for an alternative method of compliance, in 
accordance with paragraph (c)(1) of this AD.

II. Comments to 2001-NM-02-AD

Request To Continue Terminating Action as Optional

    One commenter objects to the proposal to mandate accomplishment of 
the previously optional terminating action. The commenter cites two

[[Page 58914]]

reasons for its objection: (1) It has found no instances of backed-off 
primary retention nuts for the midspar fuse pins on the inboard and the 
outboard strut, and (2) there are two fuse pin retention devices in 
place, which are designed to prevent midspar fuse pin migration.
    The FAA does not concur that the previously optional terminating 
action should remain optional. The unsafe condition has resulted in at 
least three incidents of the primary retention nut on the midspar 
fitting fuse pin backing off. In one of these incidents, the primary 
retention nut contacted the secondary retention washer. This action 
will require that the terminating action be performed within 6 years. 
If the repetitive inspections reveal a discrepancy, the terminating 
action must be performed sooner. Therefore, no change to the final rule 
has been made in response to this comment.

Request for Clarification of Applicability

    The manufacturer requests that the wording in paragraph (a)(1) of 
the proposed AD be changed from ``For airplanes modified per the 
production equivalent of one of the AD's listed in Table 1 of this 
AD:'' to ``For airplanes having the production equivalent of one of the 
AD's listed in Table I of this AD:'' and that AD 99-10-10 be removed 
from Table 1.
    The FAA agrees that these changes will provide clarification and 
has changed paragraph (a)(1) of this AD accordingly. In line with this 
change, the FAA has also revised the applicability of this AD to 
specify this clarification.

Request To Revise Cost Impact

    One commenter requests that the FAA revise the Cost Impact 
paragraph to reflect that at least 12 work-hours may be necessary to 
perform the required action rather than the 4 work-hours cited in the 
proposed rule.
    The FAA does not concur. The cost analysis of the AD is limited to 
the cost of actions actually required by the rule. It does not consider 
the costs of ``on condition'' actions, such as replacing a nut, if 
replacement is needed during a required inspection. Such ``on-
condition'' actions would be required to be accomplished, regardless of 
AD direction, 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 
addition, the FAA recognizes that, in accomplishing the requirements of 
any AD, operators may incur ``incidental'' costs in addition to the 
``direct'' costs that are reflected in the cost analysis presented in 
the AD preamble. However, the cost analysis in AD rulemaking actions 
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 requirements. No change to the cost impact is 
necessary in the final rule.

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 described 
above. 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 Boeing Model 747 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 256 
airplanes of U.S. registry will be affected by this AD.
    The inspections that are currently required by AD 2001-05-05 take 
approximately 4 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required inspections on U.S. operators is 
estimated to be $61,440, or $240 per airplane, per inspection cycle.
    The terminating modification that is required by this new AD will 
take approximately 4 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Required parts will cost 
approximately $1,000 per airplane. Based on these figures, the cost 
impact of the modification required by this AD on U.S. will be 
$317,440, or $1,240 per airplane.
    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 removing amendment 39-12141 (66 FR 
13424, March 6, 2001), and by adding a new airworthiness directive 
(AD), amendment 39-12514, to read as follows:

2001-23-15  Boeing: Docket 2001-NM-02-AD. Supersedes AD 2001-05-05, 
amendment 39-12141.

    Applicability: Model 747 series airplanes, line numbers 1 
through 1046 that have accomplished Airworthiness Directives 95-10-
16, 95-13-05, 95-13-06, or 95-13-07; and line numbers 1047 through 
1271 inclusive; 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

[[Page 58915]]

alternative method of compliance in accordance with paragraph (c)(1) 
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 find and fix discrepancies of the installation of the midspar 
fuse pins of the inboard and outboard strut, which could result in 
loss of the secondary retention capability of the fuse pins, 
migration of the fuse pins, and consequent loss of the strut and 
engine from the airplane; accomplish the following:

Restatement of the Requirements of AD 2001-05-05

Inspections/Follow-On Actions

    (a) At the time specified in paragraph (a)(1) or (a)(2) of this 
AD, as applicable: Do a detailed visual inspection to find 
discrepancies (e.g., incorrect thread protrusion, which is less than 
two threads protruding from the nut between the nut and the 
secondary retention washer; incorrect gap between the fuse pin 
primary nut and secondary retention washer; cracked or broken torque 
stripe) of the installation of the midspar fuse pins of the inboard 
and outboard struts, per Figure 2 of Boeing Service Bulletin 747-
54A2206, Revision 1, dated February 22, 2001, or Revision 2, dated 
May 17, 2001.
    (1) For airplanes having the production equivalent of one of the 
AD's listed in Table 1 of this AD: Do the inspection at the later of 
the times specified in paragraphs (a)(1)(i) and (a)(1)(ii) of this 
AD.
    (i) Before the accumulation of 8,000 total flight hours, or 
within 24 months since manufacture of the airplane, whichever occurs 
first.
    (ii) Within 90 days after March 21, 2001 (the effective date of 
AD 2001-05-05, amendment 39-12141).
    (2) For airplanes modified per one of the AD's listed in Table 1 
of this AD: Do the inspection at the later of the times specified in 
paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. Table 1 follows:

                                 Table 1
------------------------------------------------------------------------
                                                               Amendment
                            AD No.                                No.
------------------------------------------------------------------------
AD 95-10-16..................................................    39-9233
AD 95-13-05..................................................    39-9285
AD 95-13-06..................................................    39-9286
AD 95-13-07..................................................    39-9287
------------------------------------------------------------------------

    (i) Within 8,000 flight hours or 24 months after the 
modification, whichever occurs first.
    (ii) Within 90 days after March 21, 2001.

    Note 2: Where there are differences between the AD and the 
service bulletin, the AD prevails.


    Note 3: 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.''

    (A) If no discrepancy is found: Repeat the inspection at 
intervals not to exceed 8,000 flight hours or 24 months, whichever 
occurs first, until you do the terminating modification specified in 
paragraph (b) of this AD.
    (B) If any discrepancy is found, and the primary nut has backed 
off and contacts the secondary retention washer: Before further 
flight, do the terminating modification specified in paragraph (b) 
of this AD.
    (C) If any discrepancy is found, and the primary nut does not 
contact the secondary retention washer: Repeat the inspection at 
intervals not to exceed 90 days. Within 18 months after the initial 
finding, or before March 21, 2001, whichever occurs later, do the 
terminating modification specified in paragraph (b) of this AD.

    Note 4: Inspections done prior to the effective date of this AD 
per Boeing Alert Service Bulletin 747-54A2206, dated October 19, 
2000, are acceptable for compliance with the inspections required by 
paragraph (a) of this AD.

New Requirements of This AD

Terminating Action

    (b) Within 6 years after the effective date of this AD: Do the 
terminating modification (replacement of the primary nut of the 
midspar fuse pin, installation of torque strip, a detailed visual 
inspection of the fuse pin threads for damage, and replacement, if 
necessary) per Figure 3 of Boeing Service Bulletin 747-54A2206, 
Revision 1, dated February 22, 2001, or Figure 3 of Boeing Service 
Bulletin 747-54A2206, Revision 2, dated May 17, 2001. Doing this 
modification ends the repetitive inspections required by this AD.

    Note 5: Doing the terminating modification prior to the 
effective date of this AD per Boeing Alert Service Bulletin 747-
54A2206, dated October 19, 2000, is acceptable for compliance with 
the terminating action required by paragraph (b) of this AD.

Alternative Methods of Compliance

    (c)(1) 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 Aircraft Certification 
Office (ACO), FAA. 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.
    (2) Any alternative method of compliance which was approved 
previously in accordance with AD 2001-05-05 is approved for 
compliance with this AD.

    Note 6: 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

    (d) 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

    (e) The actions shall be done in accordance with Boeing Service 
Bulletin 747-54A2206, Revision 1, dated February 22, 2001; or Boeing 
Service Bulletin 747-54A2206, Revision 2, dated May 17, 2001.
    (1) The incorporation by reference of Boeing Service Bulletin 
747-54A2206, Revision 2, dated May 17, 2001, is approved by the 
Director of the Federal Register, in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Service Bulletin 
747-54A2206, Revision 1, dated February 22, 2001, was approved 
previously by the Director of the Federal Register as of March 21, 
2001 (66 FR 13424, March 6, 2001).
    (3) 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

    (f) This amendment becomes effective on December 31, 2001.

    Issued in Renton, Washington, on November 15, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-29187 Filed 11-23-01; 8:45 am]
BILLING CODE 4910-13-U

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