[Federal Register Volume 65, Number 23 (Thursday, February 3, 2000)]
[Rules and Regulations]
[Pages 5235-5237]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-2086]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-323-AD; Amendment 39-11537; AD 2000-02-19]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY:  Federal Aviation Administration, DOT.

ACTION:  Final rule.

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SUMMARY:  This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 727 series airplanes, that 
currently requires repetitive inspections of the front spar web between 
the upper and lower seals of the center section of the wings, and 
repair, if necessary. That amendment also provides for an optional 
terminating modification for the repetitive inspections. This amendment 
requires a new terminating modification for the repetitive inspections. 
For certain airplanes, this amendment also requires new repetitive 
inspections to detect discrepancies of the front spar web. This 
amendment is prompted by a report indicating that the optional 
terminating modification in the existing AD does not adequately address 
the identified unsafe condition. The actions specified by this AD are 
intended to prevent fatigue cracks in the front spar web, which could 
lead to fuel leakage into the air-conditioning distribution bay and/or 
depressurization of the cabin, and to prevent fuel fumes in the cabin 
of the airplane.

DATES:  Effective March 9, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 9, 2000.

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:  Walter Sippel, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:  A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 90-02-16, 
amendment 39-6452 (55 FR 602, January 8, 1990), which is applicable to 
certain Boeing Model 727 series airplanes, was published in the Federal 
Register on August 10, 1999 (64 FR 43318). The action proposed to 
continue to require repetitive inspections of the front spar web 
between the upper and lower seals of the center section of the wings, 
and repair, if necessary. That action also proposed to require a new 
terminating modification for the repetitive inspections, and, for 
certain airplanes, new repetitive inspections to detect discrepancies 
of the front spar web.

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 Allow Alternative Inspection Method

    One commenter, the manufacturer, requests that the proposed rule be 
revised to allow accomplishment of repetitive high frequency eddy 
current (HFEC) inspections to detect cracks in the front spar web, in 
lieu of the repetitive detailed visual inspections specified in 
paragraph (a) of the proposed rule. (In the proposed rule, the FAA 
stated that this AD would not provide for an HFEC inspection in lieu of 
the detailed visual inspection because Boeing Service Bulletin 727-57-
0177, dated December 22, 1988, does not contain procedures for such an 
HFEC inspection, and, without such procedures, the FAA could not be 
sure that an HFEC inspection would detect cracks in a timely manner.) 
The commenter states that the option of an HFEC inspection would give 
operators more flexibility and reduce requests to the FAA for an 
alternative method of compliance. The commenter provides a reference 
for procedures for performing an HFEC inspection, and suggests a 
repetitive interval of 4,500 flight cycles. The commenter also states 
that it is revising Boeing Service Bulletin 727-57-0177 to incorporate 
procedures for an HFEC inspection and requests that the FAA delay 
issuance of the final rule until the release of Revision 4 of the 
service bulletin.
    The FAA concurs with the commenter's requests. Since the issuance 
of the notice of proposed rulemaking (NPRM), the FAA has reviewed and 
approved Boeing Service Bulletin 727-57-0177, Revision 4, dated October 
28, 1999. Revision 4 of the service bulletin is essentially similar to 
Revision 3 of the service bulletin, dated February 15, 1996. (Revision 
3 of the service bulletin was cited in the NPRM as an appropriate 
source of service information for accomplishment of the proposed 
actions.) However, Revision 4 of the service bulletin also incorporates 
procedures for accomplishment of an HFEC inspection as an alternative 
to the close visual inspection. The FAA finds that the HFEC inspection 
described in the service bulletin would ensure that any cracks are 
detected in a timely manner. Therefore, paragraph (a) of this final 
rule has been revised to provide for accomplishment of repetitive HFEC 
inspections in lieu of the repetitive detailed visual inspection 
proposed in the NPRM. For clarity, paragraphs (a)(1) and (a)(2) have 
been added to specify appropriate sources of service information and 
repetitive inspection intervals for the two types of inspection. Also, 
the cost impact section of the final rule has been revised to provide 
an estimate of the cost for the HFEC inspection. In addition, 
paragraphs (b), (c), (d), and (e) of this final rule have been revised 
to allow accomplishment of the actions specified in those paragraphs in 
accordance with Revision 4 of the service bulletin.

Request to Correct Typographical Errors

    One commenter requests that a reference to AD 90-02-15 in the 
``Alternative Method of Compliance'' section of the NPRM be revised to 
refer to AD 90-02-16. The FAA concurs with the commenter's request and 
acknowledges that the correct reference should have been to AD 90-02-
16. Paragraph (g)(2) of this AD has been revised accordingly.
    The same commenter requests that a reference to Boeing Model 747 
series airplanes in the ``Other Relevant Rulemaking'' section in the 
preamble of the NPRM be revised to refer instead to Boeing Model 727 
series airplanes. The

[[Page 5236]]

FAA acknowledges that the correct reference should have been to Boeing 
Model 727 series airplanes; however, that section is not restated in 
the final rule and, therefore, 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 described 
previously. 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 1,524 Model 727 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 1,098 
airplanes of U.S. registry will be affected by this AD.
    The detailed visual inspection that is currently required by AD 90-
02-16, and retained in this AD as one option for compliance, and the 
HFEC inspection that may be accomplished in lieu of the detailed visual 
inspection, take approximately 3 work hours per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of either the currently required detailed visual or the 
HFEC inspection on U.S. operators is estimated to be $197,640, or $180 
per airplane, per inspection cycle.
    The modification that is required by this new AD will take 
approximately 360 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will cost approximately 
$1,430 per airplane. Based on these figures, the cost impact of the new 
requirements of this AD on U.S. operators is estimated to be 
$25,286,940, or $23,030 per airplane.
    The visual inspection that is required for certain airplanes in 
this new AD action will take approximately 1 work hour per airplane to 
accomplish, 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 $60 per airplane, per inspection 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.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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 39-6452 (55 FR 
602, January 8, 1990), and by adding a new airworthiness directive 
(AD), amendment 39-11537, to read as follows:

2000-02-19   Boeing: Amendment 39-11537. Docket 97-NM-323-AD. 
Supersedes AD 90-02-16, Amendment 39-6452.

    Applicability: Model 727 series airplanes, as listed in Boeing 
Service Bulletin 727-57-0177, dated December 22, 1988; 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)(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 prevent fatigue cracks of the front spar web of the center 
section of the wings, which could lead to fuel leakage and/or 
depressurization of the cabin, or to prevent fuel fumes in the cabin 
of the airplane, accomplish the following:

Repetitive Inspections

    (a) For areas on which the front spar web between the upper and 
lower seals of the center section of the wings has not been repaired 
or modified in accordance with Figure 2 or 3 of Boeing Service 
Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated 
November 21, 1991; or Revision 2, dated September 16, 1993: Prior to 
the accumulation of 40,000 total flight cycles, or within the next 
2,300 flight cycles after February 12, 1990 (effective date of AD 
90-02-16, amendment 39-6452), whichever occurs later, unless 
accomplished within the last 700 flight cycles, accomplish the 
requirements of either paragraph (a)(1) or (a)(2) of this AD.
    (1) Perform a detailed visual inspection to detect cracks in the 
front spar web, in accordance with Figure 1 of Boeing Service 
Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated 
November 21, 1991; Revision 2, dated September 16, 1993; Revision 3, 
dated February 15, 1996; or Revision 4, dated October 28, 1999. 
Repeat the detailed visual inspection thereafter at intervals not to 
exceed 3,000 flight cycles, until accomplishment of the requirements 
specified in either paragraph (b) or (c) of this AD.

    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.''


    (2) Perform a high frequency eddy current (HFEC) inspection to 
detect cracks in the front spar web, in accordance with Boeing 
Service Bulletin 727-57-0177, Revision 4, dated October 28, 1999. 
Repeat the HFEC inspection thereafter at intervals not to exceed 
4,500 flight cycles, until accomplishment of the requirements 
specified in either paragraph (b) or (c) of this AD.

    Note 3:  Accomplishment of the high frequency eddy current 
(HFEC) inspection required by AD 90-02-16, is considered acceptable 
for compliance with the initial detailed visual inspection required 
by paragraph (a) of this AD.


[[Page 5237]]



Repair of Cracks

    (b) If any crack is detected during any inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish the 
actions specified in either paragraph (b)(1) or (b)(2) of this AD, 
as applicable. Accomplishment of the repair constitutes terminating 
action for the repetitive inspection requirements of paragraph (a) 
of this AD for that repaired area.
    (1) For airplanes equipped with integral fuel tanks in the 
center section of the wings: Repair in accordance with Figure 2 of 
Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 
1996; or Revision 4, dated October 28, 1999.
    (2) For airplanes not equipped with integral fuel tanks in the 
center section of the wings: Repair in accordance with Figure 2 of 
Boeing Service Bulletin 727-57-0177, dated December 22, 1988, 
Revision 1, dated November 21, 1991; Revision 2, dated September 16, 
1993; Revision 3, dated February 15, 1996; or Revision 4, dated 
October 28, 1999.

    Note 4:  Where there are differences between the referenced 
service bulletins and this AD, the AD prevails.

Modification

    (c) Except as provided by paragraph (d) of this AD, prior to the 
accumulation of 60,000 total flight cycles, or within 48 months 
after the effective date of this AD, whichever occurs later, 
accomplish the actions specified in either paragraph (c)(1) or 
(c)(2) of this AD, as applicable. Accomplishment of this action 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a) of this AD.
    (1) For airplanes equipped with integral fuel tanks in the 
center section of the wings: Modify the front spar web, between the 
upper and lower seals, of the center section of the wings, in 
accordance with Part I of the Accomplishment Instructions of Boeing 
Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; 
or Revision 4, dated October 28, 1999.
    (2) For airplanes not equipped with integral fuel tanks in the 
center section of the wings: Modify the front spar web, between the 
upper and lower seals, of the center section of the wings, in 
accordance with Boeing Service Bulletin 727-57-0177, dated December 
22, 1988, Revision 1, dated November 21, 1991; Revision 2, dated 
September 16, 1993; Revision 3, dated February 15, 1996; or Revision 
4, dated October 28, 1999.

Repetitive Visual Inspections and Repair/Modification of the Front Spar 
Web

    (d) For areas on which the front spar web between the upper and 
lower seals of the center section of the wings has been repaired or 
modified in accordance with Figure 2 or 3 of Boeing Service Bulletin 
727-57-0177, dated December 22, 1988; Revision 1, dated November 21, 
1991; or Revision 2, dated September 16, 1993: Accomplish the 
actions required by either paragraph (d)(1) or (d)(2) of this AD, as 
applicable.
    (1) For airplanes not equipped with integral fuel tanks in the 
center section of the wings: No further action is required by this 
AD for those areas repaired or modified.
    (2) For airplanes equipped with integral fuel tanks in the 
center section of the wings: Accomplish the actions required by both 
paragraphs (d)(2)(i) and (d)(2)(ii) of this AD.
    (i) Within 500 flight cycles after the effective date of this 
AD, perform a detailed visual inspection of the front spar web to 
detect fuel leakage and penetrations in the secondary fuel barrier, 
and to verify the installation of the secondary fuel barrier; in 
accordance with Boeing Service Bulletin 727-57-0177, Revision 3, 
dated February 15, 1996; or Revision 4, dated October 28, 1999. 
Repeat the visual inspection thereafter at intervals not to exceed 
1,500 flight cycles, until accomplishment of the actions required by 
paragraph (d)(2)(ii) of this AD.
    (ii) Prior to the accumulation of 14,000 flight cycles, or 
within 96 months after the effective date of this AD, whichever 
occurs later, repair/modify the front spar web in accordance with 
Part II of the Accomplishment Instructions of Boeing Service 
Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or 
Revision 4, dated October 28, 1999. Accomplishment of this action 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (d)(2)(i) of this AD for that repaired/
modified area.

Follow-On Corrective Action

    (e) During any inspection required by paragraph (d)(2)(i) of 
this AD, if any fuel leakage or penetration in the secondary fuel 
barrier is detected, or if any secondary fuel barrier is verified as 
not being installed, prior to further flight, repair in accordance 
with Part II of the Accomplishment Instructions of Boeing Service 
Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or 
Revision 4, dated October 28, 1999. Accomplishment of this action 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (d)(2)(i) of this AD for that repaired 
area.

Terminating Action for AD 94-05-04

    (f) Accomplishment of the actions required by paragraph (b), 
(c), (d)(2)(ii), or (e) of this AD constitutes terminating action 
for the requirements specified in paragraph (a) of AD 94-05-04, 
amendment 39-8842 (59 FR 13442, March 22, 1994), with respect to the 
modification specified in Boeing Service Bulletin 727-57-0177, dated 
December 22, 1988. This service bulletin is one of many service 
bulletins referenced in Boeing Document D6-54860, Revision G, 
Appendix A.3, dated March 5, 1993. All other service bulletins 
referenced in that document still apply.

Alternative Method of Compliance

    (g)(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, Transport Airplane Directorate. 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.


    (2) For airplanes not equipped with integral fuel tanks in the 
center section of the wings: Alternative methods of compliance, 
approved previously in accordance with AD 90-02-16, amendment 39-
6452, are approved as alternative methods of compliance with this 
AD. For airplanes equipped with integral fuel tanks in the center 
section of the wings: Alternative methods of compliance, approved 
previously in accordance with AD 90-02-16, are NOT approved as 
alternative methods of compliance with this AD.

Special Flight Permits

    (h) Special flight permits may be issued in accordance with 
Secs. 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) The actions shall be done in accordance with Boeing Service 
Bulletin 727-57-0177, dated December 22, 1988; Boeing Service 
Bulletin 727-57-0177, Revision 1, dated November 21, 1991; Boeing 
Service Bulletin 727-57-0177, Revision 2, dated September 16, 1993; 
Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 
1996; or Boeing Service Bulletin 727-57-0177, Revision 4, dated 
October 28, 1999; 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.
    (j) This amendment becomes effective on March 9, 2000.

    Issued in Renton, Washington, on January 24, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-2086 Filed 2-2-00; 8:45 am]
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