[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