[Federal Register Volume 66, Number 61 (Thursday, March 29, 2001)]
[Proposed Rules]
[Pages 17091-17094]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-7707]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 66, No. 61 / Thursday, March 29, 2001 / 
Proposed Rules  

[[Page 17091]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-302-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Equipped With General Electric Model CF6-45 or -50 Series Engines; or 
Pratt & Whitney Model JT9D-3, -7, or -70 Series Engines; and 747-E4B 
(Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747 
series airplanes equipped with General Electric Model CF6-45 or -50 
series engines; or Pratt & Whitney Model JT9D-3, -7, or -70 series 
engines; and all 747-E4B (military) airplanes. That AD currently 
requires repetitive inspections to detect cracking or fracture of the 
steel attachment fittings of the diagonal brace to the nacelle struts; 
and replacement of the attachment fittings with new steel fittings, if 
necessary. This action would add new repetitive inspections of the 
fasteners of the steel attachment fittings of the diagonal brace to the 
inboard and outboard nacelle struts to find discrepancies; and mandate 
certain one-time inspections of the existing attachment fittings, 
installation of new fasteners, and replacement or rework of the 
fittings, which would terminate the repetitive inspections. This 
proposal is prompted by a report of fatigue cracking in a steel 
attachment fitting of a diagonal brace to the number 2 nacelle strut. 
The actions specified by the proposed AD are intended to prevent such 
cracking, which could result in failure of a nacelle strut diagonal 
brace load path and possible separation of the nacelle from the wing.

DATES: Comments must be received by May 14, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-302-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-302-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    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: Tamara L. Anderson, Aerospace 
Engineer, Airframe Branch, ANM-120S, Seattle Aircraft Certification 
Office, FAA, 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-302-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. 2000-NM-302-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On April 16, 1999, the FAA issued AD 99-09-11, amendment 39-11144 
(64 FR 19883, April 23, 1999), applicable to certain Boeing Model 747 
series airplanes and all 747-E4B (military) airplanes, to require 
repetitive inspections to detect cracking or fracture of the steel 
attachment fittings of the diagonal brace to the nacelle struts; and 
replacement of the attachment fittings with new steel fittings, if 
necessary. That action was prompted by a report indicating that a steel 
attachment fitting of a diagonal brace to the number 2 nacelle strut 
had fractured; such fracturing has been attributed to fatigue cracking. 
The requirements of that AD are intended to detect and correct such 
fatigue cracking, which could result in failure of a nacelle strut 
diagonal brace load path and possible separation of the nacelle from 
the wing.

[[Page 17092]]

Actions Since Issuance of AD 99-09-11

    In the preamble to AD 99-09-11, the FAA indicated that the actions 
required by that AD were considered ``interim action'' and that further 
rulemaking action was being considered. The FAA now has determined that 
further rulemaking action is necessary, and this proposed AD follows 
from that determination.

Explanation of Relevant Service Information

    Subsequent to the issuance of AD 99-09-11, the manufacturer has 
issued, and the FAA has reviewed and approved, Boeing Service Bulletin 
747-54A2196, Revision 1, dated August 17, 2000, which describes 
procedures for the accomplishment of the following actions:
     Repetitive detailed visual inspections of the inboard and 
outboard steel attachment fittings of the diagonal brace to the nacelle 
struts to detect damage (wear, fretting deposits, cracked or broken 
fittings, loose or broken fasteners). Such inspections would eliminate 
the need for the (less extensive) repetitive detailed visual 
inspections of the inboard and outboard steel attachment fittings of 
the diagonal brace to the nacelle struts specified in the existing AD;
     Replacement of damaged fasteners and inspection and rework 
of fastener holes;
     If cracking of the fitting is found, a high frequency eddy 
current inspection of the fastener holes or, for the inboard attachment 
fittings, an ultrasonic inspection of the area around the suspected 
crack locations, to verify the cracking;
     Repetitive torque checks of fasteners common to the 
horizontal and vertical flanges of the fittings;
     Replacement or rework of the existing steel fittings, and 
installation of new fasteners, which would eliminate the need for the 
repetitive detailed visual inspections. Accomplishment of the actions 
specified in the service bulletin is 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 99-09-11 to continue to require 
repetitive inspections to detect cracking or fracture of the steel 
attachment fittings of the diagonal brace to the nacelle struts; and 
replacement of the attachment fittings with new steel fittings, if 
necessary. This proposed AD also would add new repetitive inspections 
of the fasteners of the steel attachment fittings of the diagonal brace 
to the inboard and outboard nacelle struts to find discrepancies; and 
would mandate certain one-time inspections of the existing attachment 
fittings, the installation of new fasteners, and replacement or rework 
of the fittings, which would terminate the repetitive inspections. The 
actions would be required to be accomplished per the service bulletin 
described previously, except as discussed below.

Differences Between This Proposed AD and the Service Bulletin

    Although the service bulletin specifies that the manufacturer may 
be contacted for disposition of certain conditions, this proposed AD 
requires those conditions to be accomplished per a method approved by 
the FAA, or per data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the FAA to make such 
findings.

Other Relevant Rulemaking

    The FAA previously issued AD 95-10-16, amendment 39-9233 (60 FR 
27008, May 22, 1995), applicable to certain Boeing Model 747 series 
airplanes equipped with Pratt & Whitney Model JT9D series engines 
(excluding Model JT9D-70 engines); and AD 95-13-07, amendment 39-9287 
(60 FR 33336, June 28, 1995), applicable to certain Boeing Model 747 
series airplanes equipped with General Electric Model CF6-45 or -50 
series engines, or Pratt & Whitney Model JT9D-70 series engines. These 
AD's require modification of the nacelle strut and wing structure. 
Accomplishment of the modification required by the applicable AD, 
before the effective date of this proposed AD, extends the compliance 
time for certain requirements of this proposed AD.

Cost Impact

    There are approximately 745 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 173 airplanes of U.S. registry 
would be affected by this proposed AD.
    The inspections that are currently required by AD 99-09-11 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 actions on U.S. operators is estimated 
to be $41,520, or $240 per airplane, per inspection cycle.
    The new detailed visual inspections/torque checks that are proposed 
in this AD action would take approximately 12 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 proposed inspections/torque 
checks of this AD on U.S. operators is estimated to be $124,560, or 
$720 per airplane, per inspection cycle.
    The new terminating actions (for the inboard pylon includes 
inspection of the existing steel fittings for cracks or damage; 
replacement if cracked; rework or replacement if damaged; or 
installation of new fasteners if no cracks; for the outboard pylon, 
detailed visual inspection of the fitting for damage, high frequency 
eddy current inspection of fastener holes and installation of new 
fasteners), that are proposed in this AD action would take 
approximately 76 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost $13,776 (for 
airplanes equipped with Pratt & Whitney JT9D series engines) or $31,083 
(for airplanes equipped with GE CF6-45 or -50 series engines). Based on 
these figures, the cost impact of the proposed terminating actions of 
this AD is estimated to be $18,336 per airplane (for airplanes equipped 
with Pratt & Whitney JT9D series engines) or $35,643 per airplane (for 
airplanes equipped with General Electric CF6-45 or -50 series engines).
    The cost impact figures discussed above are 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. 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action''

[[Page 17093]]

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 removing amendment 39-11144 (64 FR 
19883, April 23, 1999), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing:  Docket 2000-NM-302-AD. Supersedes AD 99-09-11, amendment 
39-11144.

    Applicability: Model 747 series airplanes equipped with General 
Electric Model CF6-45 or -50 series engines or Pratt & Whitney Model 
JT9D-3, -7, or -70 series engines, and all 747-E4B (military) 
airplanes; 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 per paragraph (i)(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 cracking or fracture of the steel attachment 
fittings of the diagonal brace to the nacelle struts, which could 
result in failure of a nacelle strut diagonal brace load path and 
possible separation of the nacelle from the wing, accomplish the 
following:

Restatement of Requirements of AD99-09-11: Repetitive Inspections

    (a) Gain access to the attachment fittings of the diagonal brace 
to the inboard and outboard nacelle struts through the aft fairing 
doors, and do a detailed visual inspection to find cracking or 
fracture of the steel attachment fittings of the diagonal brace to 
the inboard and outboard nacelle struts, at the applicable time 
specified in paragraph (a)(1) or (a)(2) of this AD.
    (1) For airplanes on which the strut and wing modification 
required by AD 95-10-16, amendment 39-9233, or AD 95-13-07, 
amendment 39-9287, has not been accomplished: Within 10 days after 
May 10, 1999 (the effective date of AD 99-09-11, amendment 39-
11144), accomplish the detailed visual inspection.
    (i) For airplanes equipped with General Electric Model CF6-45 or 
-50 series engines and/or Pratt & Whitney JT9D-3 or -7 series 
engines, repeat the inspection thereafter at intervals not to exceed 
180 flight cycles.
    (ii) For airplanes equipped with Pratt & Whitney JT9D-70 series 
engines, repeat the inspection thereafter at intervals not to exceed 
250 flight cycles.
    (2) For airplanes on which the strut and wing modification 
required by AD 95-10-16, or AD 95-13-07, has been accomplished: 
Within 30 days after May 10, 1999, or within 150 flight cycles after 
accomplishment of the modification, whichever occurs later, 
accomplish the detailed visual inspection.
    (i) For airplanes equipped with General Electric Model CF6-45 or 
-50 series engines or Pratt & Whitney JT9D-70 series engines, repeat 
the inspection thereafter at intervals not to exceed 600 flight 
cycles.
    (ii) For airplanes equipped with Pratt & Whitney JT9D-3 or -7 
series engines, repeat the inspection thereafter at intervals not to 
exceed 350 flight cycles.

New Requirements of this AD: Initial/Repetitive Inspections/Checks

    (b) For all airplanes: Do a detailed visual inspection and a 
torque check of the fasteners of the steel attachment fittings of 
the diagonal brace to the inboard and outboard nacelle struts to 
find discrepancies (cracks, loose or broken fasteners, etc.), at the 
latest of the times specified in paragraphs (b)(1), (b)(2), and 
(b)(3) of this AD; per Part 2 of the Accomplishment Instructions of 
Boeing Service Bulletin 747-54A2196, Revision 1, dated August 17, 
2000. Repeat the inspections/checks thereafter as specified in 
paragraph (c) of this AD. Accomplishment of the inspections/checks 
specified in this paragraph terminates the inspections required by 
paragraph (a) of this AD.
    (1) Before the accumulation of 3,000 total flight cycles on any 
diagonal brace attachment fitting.
    (2) Within 30 days after the effective date of this AD.
    (3) Within 150 flight cycles after accomplishment of AD 95-10-16 
or AD 95-13-07.

    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.''


    Note 3: Detailed visual inspections and torque checks 
accomplished before the effective date of this AD per Boeing Alert 
Service Bulletin 747-54A2196, dated April 2, 1999, are considered 
acceptable for compliance with the inspections/checks specified in 
paragraph (b) of this AD.

    (c) Except as provided by paragraph (d) of this AD: Repeat the 
detailed visual inspection required by paragraph (b) of this AD, as 
specified in Table 1 of this AD. Repeat the torque check required by 
paragraph (b) of this AD at intervals not to exceed 18 months. 
Repeat the inspections/checks until accomplishment of paragraph (h) 
of this AD. Table 1 follows:

        Table 1--Repetitive Detailed Visual Inspection Intervals
------------------------------------------------------------------------
                                   For airplanes in   Then repeat at the
          For the. . .                Group. . .          earlier of
------------------------------------------------------------------------
(1) Inboard nacelle struts......  (i) 1 or 4........  Intervals not to
                                                       exceed 350 flight
                                                       cycles or 18
                                                       months.
                                  (ii) 2, 3, or 5...  Intervals not to
                                                       exceed 600 flight
                                                       cycles or 18
                                                       months.
(2) Outboard nacelle struts.....  (i) 1, 2, or 4....  Intervals not to
                                                       exceed 350 flight
                                                       cycles or 18
                                                       months.
                                  (ii) 3 or 5.......  Intervals not to
                                                       exceed 600 flight
                                                       cycles or 18
                                                       months.
------------------------------------------------------------------------

    (d) For the attachment fittings of the diagonal brace to the 
inboard nacelle struts only: Instead of doing the repetitive 
detailed visual inspections per paragraph (c) of this AD, before 
further flight following the inspections required by paragraph (b) 
of this AD, do an ultrasonic inspection of the fasteners of the 
steel attachment fittings to find discrepancies, per Part 4 of the 
Accomplishment Instructions of Boeing Service Bulletin 747-54A2196, 
Revision 1, dated August 17, 2000.
    (1) Repeat the ultrasonic inspection at intervals not to exceed 
1,200 flight cycles, until accomplishment of paragraph (h) of this 
AD.
    (2) Repeat the detailed visual inspection and torque check 
required by paragraph (b)

[[Page 17094]]

of this AD at intervals not to exceed 18 months, until 
accomplishment of paragraph (h) of this AD.

Corrective Actions

    (e) If any crack indication is found during any inspection/check 
required by this AD, before further flight, verify the indication 
per Part 3 or Part 4 of the Accomplishment Instructions of Boeing 
Service Bulletin 747-54A2196, Revision 1, dated August 17, 2000, as 
applicable. If any cracking is verified, before further flight, 
replace the fasteners with new fasteners, and rework or replace the 
fitting, as applicable, per Part 5 of the Accomplishment 
Instructions of Boeing Service Bulletin 747-54A2196, Revision 1, 
dated August 17, 2000; which terminates the repetitive inspections 
required by this AD. Where the service bulletin specifies that the 
manufacturer may be contacted for disposition of certain repair 
actions, this AD requires such repair to be done per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA; or per data meeting the type certification basis of the 
airplane approved by a Boeing Company designated engineering 
representative (DER) who has been authorized by the Manager, Seattle 
ACO, to make such findings. For a repair method to be approved by 
the Manager, Seattle ACO, as required by this paragraph, the 
Manager's approval letter must specifically reference this AD.
    (f) If any loose or broken fastener is found during any 
inspection/check required by this AD, before further flight, do a 
high frequency eddy current inspection of the fastener hole to find 
cracking or damage, per Figure 6 of the Accomplishment Instructions 
of Boeing Service Bulletin 747-54A2196, Revision 1, dated August 17, 
2000. If no cracking or damage is found, before further flight, 
oversize the fastener hole and install a new fastener per Part 5 of 
the Accomplishment Instructions of the service bulletin. If any 
cracking or damage is found, before further flight, repair per a 
method approved by the Manager, Seattle ACO, or per data meeting the 
type certification basis of the airplane approved by a Boeing 
Company DER who has been authorized by the Manager, Seattle ACO, to 
make such findings. For a repair method to be approved by the 
Manager, Seattle ACO, as required by this paragraph, the Manager's 
approval letter must specifically reference this AD.
    (g) If any discrepancy of any attachment fitting is detected 
during any inspection/check required by this AD, before further 
flight, replace the fitting with a new steel fitting per a method 
approved by the Manager, Seattle ACO, or per data meeting the type 
certification of the airplane approved by a Boeing Company DER who 
has been authorized by the Manager, Seattle ACO, to make such 
findings. For a repair method to be approved by the Manager, Seattle 
ACO, as required by this paragraph, the Manager's approval letter 
must specifically reference this AD.

Terminating Action

    (h) Do the terminating action (for the inboard nacelle struts, 
includes inspection of the existing steel fittings for cracks or 
damage and replacement if cracked, rework or replacement if damaged, 
or installation of new fasteners if no cracks; for the outboard 
nacelle struts, includes a detailed visual inspection of the fitting 
for damage, HFEC inspection of fastener holes, and installation of 
new fasteners), per Part 5 of the Accomplishment Instructions of 
Boeing Service Bulletin 747-54A2196, Revision 1, dated August 17, 
2000, at the times specified in paragraph (h)(1) or (h)(2) of this 
AD, as applicable. Accomplishment of the actions specified in this 
paragraph constitutes terminating action for the repetitive detailed 
visual inspections/torque checks specified in paragraph (c) of this 
AD.
    (1) For steel attachment fittings of the diagonal brace to the 
inboard nacelle struts: Within 36 months after the effective date of 
this AD.
    (2) For steel attachment fittings of the diagonal brace to the 
outboard nacelle struts: Within 48 months after the effective date 
of this AD.

Alternative Methods of Compliance

    (i)(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.
    (2) Alternative methods of compliance, approved previously per 
AD 99-09-11, amendment 39-11144, are approved as alternative methods 
of compliance with this AD.

    Note 4: 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

    (j) Special flight permits may be issued per 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.

    Issued in Renton, Washington, on March 22, 2001.
Vi L. Lipski,
Manager,, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-7707 Filed 3-28-01; 8:45 am]
BILLING CODE 4910-13-U