[Federal Register Volume 64, Number 153 (Tuesday, August 10, 1999)]
[Proposed Rules]
[Pages 43318-43321]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20504]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-323-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 727 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of 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 AD also provides for an
optional terminating modification for the repetitive inspections. This
action would require a new terminating modification for the repetitive
inspections. For certain airplanes, this action would require new
repetitive inspections to detect discrepancies of the front spar web.
This proposal is prompted by a report indicating that the optional
terminating modification in the existing AD does not address the
identified unsafe condition. The actions specified by the proposed 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: Comments must be received by September 24, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 97-NM-323-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
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:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 97-NM-323-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 97-NM-323-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On December 21, 1989, the FAA issued AD 90-02-16, amendment 39-6452
(55 FR 602, January 8, 1980), applicable to certain Boeing Model 727
series airplanes, to require inspection of the front spar web of the
center section of the wings, and repair, if necessary. That action was
prompted by reports of cracks in the front spar web. The requirements
of that AD are intended to detect and correct such cracking, which
could lead to fuel leakage and/or depressurization of the cabin.
Actions Since Issuance of Previous Rule
Since issuance of AD 90-02-16, the FAA has received a report
indicating that modification procedures specified in Boeing Service
Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated
November 21, 1991; and Revision 2, dated September 16, 1993; do not
adequately address airplanes equipped with internal fuel tanks in the
center section of the wings. Specifically, the service bulletin does
not include procedures for application of the secondary fuel seal on
the forward side of the front spar and on the fillet seals on the aft
side of the front spar. The service bulletin also describes procedures
for the application of sealant Boeing material specification (BMS) 5-95
inside the fuel tank instead of the fuel-proof sealant BMS 5-26, and
the installation of non-fluid tight fasteners instead of fluid tight
fasteners.
Boeing Service Bulletin 727-57-0177, dated December 22, 1988, was
referenced in AD 90-02-16 as the appropriate source of service
information for accomplishment of the required modification and close
visual and high frequency eddy current (HFEC) inspections. Revisions 1
and 2 of that service bulletin were approved by the FAA as alternative
methods of compliance for accomplishment of those actions.
[[Page 43319]]
In light of this information, the FAA has determined that the
optional modification specified in AD 90-02-16 does not adequately
preclude fuel leakage into the air-conditioning distribution bay, which
could result in fuel fumes in the cabin of the airplane.
In addition, the FAA finds that the subject service bulletin does
not contain procedures for accomplishing an HFEC inspection as an
option to the close visual inspection, as required by paragraph A. of
AD 90-02-16. The actual procedures used to accomplish that HFEC
inspection and the effectiveness of those procedures are unknown to the
FAA. The FAA has determined that performing an HFEC inspection in
accordance with an unknown procedure does not ensure that cracks will
be detected in a timely manner. Therefore, the FAA has determined that
all affected airplanes must accomplish repetitive detailed visual
inspections to ensure that cracks are detected in a timely manner.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 727-57-
0177, Revision 3, dated February 15, 1996, which describes procedures
for repetitive detailed visual inspections to detect cracks of the
front spar web between the upper and lower seals of the center section
of the wings, and repair, if necessary. The service bulletin also
describes procedures for modification of the front spar web between the
upper and lower seals of the center section of the wings, which would
eliminate the need for the repetitive inspections. For certain
airplanes, the service bulletin describes procedures for repetitive
visual inspections 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. Accomplishment of the
actions specified in the service bulletin are intended to adequately
address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would supersede AD 90-02-16, amendment 39-6452 (55 FR 602,
January 8, 1980), to continue to require repetitive detailed visual
inspections of the front spar web between the upper and lower seals of
the center section of the wings, and repair, if necessary. The proposed
AD also would require modification of the subject front spar web, which
would constitute terminating action for the repetitive inspections. For
certain airplanes, the proposed AD would require repetitive visual
inspections 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. The actions would be
required to be accomplished in accordance with the service bulletin
described previously; except as discussed below.
The FAA has determined that, for airplanes equipped with integral
fuel tanks in the center section of the wings, the repairs and
modifications specified in Figure 2 and Figure 3 of Boeing Service
Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated
November 21, 1991; and Revision 2, dated September 16, 1993; do not
describe procedures for installation of a fuel proof sealant in these
tanks, which could lead to identified unsafe condition of this AD. The
procedures specified in the original version, Revision 1, and Revision
2 of the service bulletin are acceptable for airplanes without integral
fuel tanks in the center section of the wings. However, the FAA finds
that Revision 3 of the subject service bulletin does provide procedures
for installation of a fuel proof sealant for integral fuel tanks.
Other Relevant Rulemaking
The FAA has previously issued AD 94-05-04, amendment 39-8842 (59 FR
13442, March 22, 1994), which requires incorporation of certain
structural modification on certain Boeing Model 747 series airplanes.
Accomplishment of certain actions required by this proposed AD would
constitute terminating action for the requirements specified in
paragraph (a) of AD 94-05-04 with respect to the modification specified
in Boeing Service Bulletin 727-57-0177, dated December 22, 1998. 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.
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 would be affected by this proposed AD.
The detailed visual inspection that is currently required by AD 90-
02-16, and retained in this AD, takes 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 the currently required
detailed visual inspection on U.S. operators is estimated to be
$197,640, or $180 per airplane, per inspection cycle.
The modification that is proposed in this new AD action would take
approximately 360 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Required parts would cost
approximately $1,430 per airplane. Based on these figures, the cost
impact of the proposed modification required by this AD on U.S.
operators is estimated to be $25,286,940, or $23,030 per airplane.
For certain airplanes, the visual inspection that is proposed in
this new AD action would 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 the proposed modification required by
this AD 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 current or proposed
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 proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
[[Page 43320]]
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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), to read as follows:
Boeing: 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 Detailed Visual 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 with 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 with the last 700 flight cycles, 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; or Revision 3, dated February
15, 1996. 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 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: 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.
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 action 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.
(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; or Revision 3, dated February 15, 1996.
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.
(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; or Revision 3, dated February 15, 1996.
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. 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.
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.
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
[[Page 43321]]
dated 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 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.
(g)(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 tank in the center
section of the wings: Alternative methods of compliance, approved
previously in accordance with AD 90-02-15, are NOT approved as
alternative methods of compliance with this AD.
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.
Issued in Renton, Washington, on August 4, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-20504 Filed 8-9-99; 8:45 am]
BILLING CODE 4910-13-P