[Federal Register Volume 68, Number 23 (Tuesday, February 4, 2003)]
[Proposed Rules]
[Pages 5610-5613]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-2495]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-178-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747SP, and 747SR 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-100, 
747SP, and 747SR series airplanes. This proposal would require 
repetitive inspections to find fatigue cracking between the seal ribs 
of the front spar web of the wing, and repair of cracked structure. 
This proposal also provides for an optional modification of a certain 
area. This action is necessary to find and fix such fatigue cracking, 
which could result in fuel leakage into the area of the inboard 
engines, and consequent increased risk of a fire. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by March 21, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-178-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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. 2001-NM-178-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, PO 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, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (425) 917-6421; fax (425) 
917-6590.

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:
    [sbull] 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.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] 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 2001-NM-178-AD.'' The postcard will be date stamped 
and returned to the commenter.

[[Page 5611]]

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. 2001-NM-178-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that an operator found a 
24-inch crack in the front spar web of the right wing between front 
spar station inboard (FSSI) 637 through 662 on a Boeing Model 747-100 
series airplane having accumulated 14,830 total flight cycles and 
85,116 total flight hours. Metallurgical analysis of the cracked 
section of the web revealed three cracks originating from a hole common 
to a rib post located on the front spar at FSSI 656 (wing station 642). 
The cracks were initiated by fatigue at the hole and were spread by 
fatigue for a short distance; then the cracks separated by a 
combination of fatigue and ductile separation. The cracks resulted in a 
fuel leak which was found after post-flight inspection revealed fire 
damage to the exhaust sleeve of the inboard engine turbine. Another 
operator reported finding a crack in the web at approximately FSSI 694, 
just outboard of a web section recently replaced per AD 99-10-09, 
amendment 39-11162 (64 FR 25194, June 15, 1999). Such fatigue cracking, 
if not found and fixed, could result in fuel leakage into the area of 
the inboard engines and consequent increased risk of a fire.

Related Rulemaking

    This AD is related to the following rulemaking actions, which 
require the actions in the related service bulletins specified in 
Boeing Special Attention Service Bulletin 747-57-2313, Revision 1, 
including Appendices A and B, dated February 21, 2002:
    [sbull] AD 95-10-16, amendment 39-9233 (60 FR 27008, June 21, 
1995). That AD references Boeing Alert Service Bulletin 747-54A2159, 
dated November 3, 1994, as the appropriate source of service 
information for accomplishment of the modification of the nacelle strut 
and wing structure. That AD is applicable to certain Boeing Model 747 
series airplanes equipped with Pratt & Whitney Model JT9D series 
engines (excluding Model JT9D-70 engines). The AD requires modification 
of the nacelle strut and wing structure, inspections and checks to 
detect discrepancies, and correction of discrepancies. The modification 
specified in the AD also constitutes terminating action for the 
repetitive inspections required by certain other ADs, including AD 98-
15-21, amendment 39-10672 (63 FR 39487, July 23, 1998), which 
references Boeing Service Bulletin 747-57A2266 as the appropriate 
source of service information for accomplishment of the specified 
actions; and AD 90-17-18, amendment 39-6702 (55 FR 33279, August 15, 
1990), which references Boeing Service Bulletin 747-57A2259 as the 
appropriate source of service information for accomplishment of the 
specified actions.
    [sbull] AD 99-10-09, amendment 39-11162. That AD references Boeing 
Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997, as 
the appropriate source of service information for accomplishment of the 
actions specified. That AD is applicable to certain Boeing Model 747-
100, -200, and 747-SP series airplanes and military type E-4B 
airplanes, and requires repetitive inspections to detect cracking of 
the wing front spar web, and repair of cracked structure. That AD also 
provides for optional terminating action for the repetitive 
inspections.

Explanation of Relevant Service Information

    We have reviewed and approved Boeing Special Attention Service 
Bulletin 747-57-2313, Revision 1, including Appendices A and B, dated 
February 21, 2002. The service bulletin describes procedures for 
repetitive inspections to find fatigue cracking of the front spar web 
of the wing, and repair of cracked structure, as follows:
    [sbull] For airplanes on which the optional modification specified 
in AD 99-10-09 has not been done, the affected area is divided into two 
zones (A and B). Zone A is the area previously modified per the 
requirements specified in AD 95-10-16 for the wing front spar; and Zone 
B is the remaining area between FSSI 628 and 711.
    [sbull] For airplanes on which the optional modification specified 
in AD 99-10-09 has been done, the affected area is divided into three 
zones (A, B, and C). Zone A is the area previously modified per the 
requirements specified in AD 95-10-16 for the wing front spar, and is 
not affected by the requirements specified in AD 99-10-09; Zone C is 
the area affected by AD 99-10-09; and Zone B is the remaining area 
between FSSI 628 and 711.
    [sbull] The inspection specified in Part 1 of the service bulletin 
is for Zone A, B, or C, as applicable. If no cracking is found, the 
inspections are repeated at the intervals specified in Figure 1 of the 
service bulletin. If cracking is found, the inspections are also 
repeated at the intervals specified in Figure 1 after the cracking is 
repaired.
    [sbull] The modification specified in Part 2 of the service 
bulletin is for Zone B only. The modification includes removing the 
existing fasteners of the web to chord, web to rib post, and web to 
stiffener; straightening the holes; and doing an open-hole rotating 
probe high frequency eddy current inspection for cracking in the web. 
If no cracking is found, the service bulletin directs oversizing the 
holes and installing tension type fasteners in the holes; if any 
cracking is found, the service bulletin specifies contacting the 
manufacturer for repair instructions.
    The service bulletin recommends prior or concurrent accomplishment 
of Boeing Service Bulletins 747-57A2259, 747-57A2266, and 747-54A2159. 
Those service bulletins are referenced in the related rulemaking 
described previously.

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 require accomplishment of the actions specified in 
the service bulletin described above, except as discussed below.

Difference Between Service Information and Proposed Rule

    Although the service bulletin specifies that the manufacturer may 
be contacted for disposition of certain repair conditions, this 
proposal would require the repair of those conditions to be done 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.

Cost Impact

    There are approximately 109 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 59 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
25 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 proposed AD on U.S. operators is 
estimated to be $88,500, or $1,500 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

[[Page 5612]]

action, and that no operator would accomplish those actions in the 
future if this proposed 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.
    Should an operator elect to do the optional modification of Zone B, 
it would take approximately 480 work hours to accomplish at an average 
labor rate of $60 per work hour. Parts cost would be approximately 
$16,652. Based on these figures, the cost impact of the proposed 
modification is estimated to be $45,452 per airplane.

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'' 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 2001-NM-178-AD.

    Applicability: Model 747-100, 747SP, and 747SR series airplanes, 
as listed in Boeing Special Attention Service Bulletin 747-57-2313, 
Revision 1, including Appendices A and B, dated February 21, 2002; 
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 (f) 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 find and fix fatigue cracking between the seal ribs of the 
front spar web of the wing, which could result in fuel leakage into 
the area of the inboard engines, and consequent increased risk of a 
fire; accomplish the following:

Compliance Times

    (a) Where the compliance times in the service bulletin specify a 
compliance time interval calculated ``after the release of this 
service bulletin,'' this AD requires compliance within the interval 
specified in the service bulletin ``after the effective date of this 
AD.'' In addition, where the compliance time for the initial 
inspection in Tables 1 through 3 of Figure 1 of the service bulletin 
specifies ``flight hours,'' this AD requires a compliance time of 
``total flight hours.''

 Initial and Repetitive Inspections

    (b) Do detailed, high frequency eddy current and ultrasonic 
inspections to find cracking of the front spar web of the wing as 
specified in paragraphs (b)(1) and (b)(2) of this AD, per the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 747-57-2313, Revision 1, including Appendices A and B, 
dated February 21, 2002.
    (1) Do the applicable initial or post-modification inspection at 
the times specified for the inspections in Tables 1 through 3 of 
Figure 1 of the Accomplishment Instructions or Appendix A of the 
service bulletin.
    (2) After doing the applicable initial or post-modification 
inspection specified in paragraph (b)(1) of this AD: Repeat that 
inspection within the applicable intervals specified in Tables 1 
through 3 of Figure 1 of the Accomplishment Instructions or Appendix 
A of the service bulletin.

Repair

    (c) If any cracking is found during any inspection required by 
this AD: Before further flight, repair 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 who has 
been authorized by the Manager, Seattle ACO, to make such findings. 
For a repair method to be approved, the approval must specifically 
reference this AD.

Optional Modification

    (d) Accomplishment of the modification of Zone B per Part 2 of 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 747-57-2313, Revision 1, including Appendices A and B, 
dated February 21, 2002, would extend the threshold recommended in 
Tables 1 through 3 of Figure 1 of the Accomplishment Instructions or 
Appendix A of the service bulletin for the repetitive inspections of 
Zone B, to the new threshold specified in Tables 1 through 3 of 
Figure 1 of the service bulletin.

Previously Accomplished Inspections and Modifications

    (e) Inspections and modifications done before the effective date 
of this AD per Boeing Special Attention Service Bulletin 747-57-
2313, including Appendices A and B, dated April 19, 2001, are 
considered acceptable for compliance with the applicable actions 
specified in this AD.

    Note 2: Boeing Special Attention Service Bulletin 747-57-2313, 
Revision 1, including Appendices A and B, dated February 21, 2002, 
recommends prior or concurrent accomplishment of Boeing Service 
Bulletins 747-57A2259; 747-57A2266; and 747-54A2159. The 
modifications in those service bulletins are required by AD 95-10-
16, amendment 39-9233.

Alternative Methods of Compliance

    (f) 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. 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.

Special Flight Permit

    (g) 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.


[[Page 5613]]


    Issued in Renton, Washington, on January 29, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-2495 Filed 2-3-03; 8:45 am]
BILLING CODE 4910-13-P