[Federal Register Volume 63, Number 64 (Friday, April 3, 1998)]
[Proposed Rules]
[Pages 16449-16451]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8710]
[[Page 16449]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-308-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes to revise an existing airworthiness
directive (AD), applicable to certain Boeing Model 747 series
airplanes, that currently requires repetitive inspections to detect
cracks, corrosion, or damage of the lower spar fitting body and lug,
and corrective actions, if necessary. That AD also provides for
optional terminating action for the repetitive inspection requirements.
The existing AD was prompted by reports that fatigue cracking was found
in the lower spar fitting lug on the number 3 pylon and in the lower
spar fitting body. The actions specified by that AD are intended to
detect and correct such fatigue cracking, which could result in failure
of the strut and separation of the engine from the airplane. This new
action references additional service bulletins for accomplishment of
the optional replacement, and clarifies that accomplishment of certain
AD's terminates the repetitive inspections.
DATES: Comments must be received by May 18, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-308-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; or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Tamara L. Dow, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2771; 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-308-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-308-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On September 15, 1997, the FAA issued AD 97-20-01, amendment 39-
10139 (62 FR 49431, September 22, 1997), applicable to certain Boeing
Model 747 series airplanes. That AD requires repetitive detailed visual
and ultrasonic inspections to detect cracks, corrosion, or damage of
the lower spar fitting body and lug, as applicable, and replacement, if
necessary. That AD also provides for an optional replacement of the
lower spar fitting with a new steel lower spar fitting, which
constitutes terminating action for the repetitive inspection
requirements. In lieu of accomplishing this replacement or the
repetitive inspections, that AD also provides for an optional
terminating modification of the nacelle strut and wing structure. That
action was prompted by reports that fatigue cracking was found in the
lower spar fitting lug on the number 3 pylon and in the lower spar
fitting body. The requirements of that AD are intended to detect and
correct such fatigue cracking, which could result in failure of the
strut and separation of the engine from the airplane.
Actions Since Issuance of Previous Rule
Since issuance of AD 97-20-01, the FAA finds that it inadvertently
omitted from paragraph (b) of that AD, the following service bulletins:
Boeing Service Bulletin 747-54-2062, Revision 1, dated
November 13, 1980;
Boeing Service Bulletin 747-54-2062, Revision 2, dated
March 19, 1981;
Boeing Service Bulletin 747-54-2062, Revision 3, dated
August 28, 1981;
Boeing Service Bulletin 747-54-2062, Revision 4, dated
June 30, 1982;
Boeing Service Bulletin 747-54-2062, Revision 5, dated
June 1, 1984;
Boeing Service Bulletin 747-54-2062, Revision 6, dated
October 2, 1986; and
Boeing Service Bulletin 747-54-2062, Revision 7, dated
December 21, 1994.
The FAA has reviewed and approved these service bulletins as
additional sources of service information for accomplishment of the
optional replacement specified in paragraph (b) of AD 97-20-01. The
replacement procedures are similar to those specified in Boeing Service
Bulletin 747-54-2062, Revision 8, dated August 21, 1997, which was
referenced in AD 97-20-01 as the appropriate source of service
information for accomplishing the optional replacement. Therefore, the
FAA has included these new service bulletins in paragraph (b) of this
proposed AD.
The FAA also finds that referencing Boeing Alert Service Bulletins
747-54A2159, dated November 3, 1994, and 747-54A2158, dated November
30, 1994, for accomplishment of the modification of the nacelle strut
and wing structure, rather than referencing the AD's associated with
those service bulletins, could be misleading to operators. Therefore,
the applicability, paragraph (a)(2)(ii), and paragraph (b) of the
proposed AD specify that accomplishment of the subject modification
required by AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 1995),
or AD 95-13-07, amendment
[[Page 16450]]
39-9287 (60 FR 33336, June 28, 1995) constitutes terminating action for
the repetitive inspection requirements of this proposed AD.
Explanation of the Requirements of the 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 action would revise AD 97-20-01 to continue to require
repetitive detailed visual and ultrasonic inspections to detect cracks,
corrosion, or damage of the lower spar fitting body and lug, as
applicable; and replacement, if necessary. It also would continue to
provide for an optional replacement of the lower spar fitting with a
new steel lower spar fitting, which would constitute terminating action
for the repetitive inspection requirements. In lieu of accomplishing
the repetitive inspections or replacement of the lower spar fitting,
this proposed AD would also continue to provide for an optional
terminating modification of the nacelle strut and wing structure. In
addition, the proposed AD references additional service bulletins for
accomplishment of the optional replacement, and clarifies that
accomplishment of certain AD's terminates the repetitive inspections.
Cost Impact
There are approximately 367 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 152 airplanes of U.S. registry
would be affected by this proposed AD, that it would take approximately
19 work hours per airplane to accomplish the proposed inspections, and
that the average labor rate is $60 per work hour. Based on these
figures, the cost impact of the inspections proposed by this AD on U.S.
operators is estimated to be $173,280, or $1,140 per airplane, per
inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the 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.
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 adding the following new
airworthiness directive:
Boeing: Docket 97-NM-308-AD. Revises AD 97-20-01, amendment 39-
10139.
Applicability: Model 747 series airplanes, having line numbers 1
through 500 inclusive, equipped with Pratt & Whitney Model JT9D-3, -
7, or -7Q engines, or having line numbers 202, 204, 232, or 257,
equipped with General Electric Model CF6 series engines;
certificated in any category; and on which the strut/wing
modification has not been accomplished in accordance with either of
the following AD's:
AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22,
1995), or
AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28,
1995).
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 (c) 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 fatigue cracking in the lower spar fitting
lug or the lower spar fitting body, which could result in failure of
the strut and separation of the engine from the airplane, accomplish
the following:
(a) Within 90 days after October 7, 1997 (the effective date of
AD 97-20-01, amendment 39-10139), perform a detailed visual
inspection and an ultrasonic inspection to detect cracks, corrosion,
or damage of the lower spar fitting body and lug, as applicable, in
accordance with Figures 9 and 10 of Boeing Service Bulletin 747-54-
2062, Revision 8, dated August 21, 1997.
Note 2: This AD does not require an inspection of the inboard
strut-to-diagonal brace attach fitting as described in Figure 1 of
Boeing Service Bulletin 747-54-2062, Revision 8, dated August 21,
1997. However, this inspection is required to be accomplished as
part of AD 95-20-05, amendment 39-9383 (60 FR 51705, October 10,
1995).
(1) If no crack, corrosion, or damage is detected, repeat the
detailed visual and ultrasonic inspections thereafter at intervals
not to exceed 400 landings.
(2) If any crack, corrosion, or damage is detected, prior to
further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii)
of this AD.
(i) Replace the lower spar fitting with a new steel lower spar
fitting, in accordance with Part II of the Accomplishment
Instructions of the service bulletin. Or
(ii) Modify the nacelle strut and wing structure in accordance
with AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 1995), or
AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28, 1995).
(b) Replacement of the lower spar fitting with a new steel lower
spar fitting, in accordance with Part II of the Accomplishment
Instructions of any of the following service bulletins listed below,
or accomplishment of modification of the nacelle strut and wing
structure required by AD 95-10-16, amendment 39-9233 (60 FR 27008,
May 22, 1995), or AD 95-13-07, amendment 39-9287 (60 FR 33336, June
28, 1995); constitutes terminating action for the repetitive
inspection requirements of this AD.
Boeing Service Bulletin 747-54-2062, Revision 1, dated
November 13, 1980;
Boeing Service Bulletin 747-54-2062, Revision 2, dated
March 19, 1981;
Boeing Service Bulletin 747-54-2062, Revision 3, dated
August 28, 1981;
Boeing Service Bulletin 747-54-2062, Revision 4, dated
June 30, 1982;
Boeing Service Bulletin 747-54-2062, Revision 5, dated
June 1, 1984;
Boeing Service Bulletin 747-54-2062, Revision 6, dated
October 2, 1986;
Boeing Service Bulletin 747-54-2062, Revision 7, dated
December 21, 1994;
[[Page 16451]]
Boeing Service Bulletin 747-54-2062, Revision 8, dated
August 21, 1997;
(c) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(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.
Issued in Renton, Washington, on March 27, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-8710 Filed 4-2-98; 8:45 am]
BILLING CODE 4910-13-P
