[Federal Register Volume 67, Number 1 (Wednesday, January 2, 2002)]
[Proposed Rules]
[Pages 38-40]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-32196]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-34-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200F, 747-300, 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, 747-
100B, 747-100B SUD, 747-200B, 747-200F, 747-300, 747SP, and 747SR 
series airplanes. This proposal would require one-time inspections for 
cracking in certain upper deck floor beams and follow-on actions. This 
action is necessary to find and fix cracking in certain upper deck 
floor beams. Such cracking could extend and sever floor beams adjacent 
to the body frame and result in rapid depressurization of the airplane. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by February 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-34-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. 2001-NM-34-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: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1153; 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 2001-NM-34-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. 2001-NM-34-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of fatigue cracking on the left and 
right ends of the upper chord of the station (STA) 340 upper deck floor 
beam on several Boeing Model 747 series airplanes. Also, during fatigue 
tests on a Boeing 747SR test airplane, multiple cracks up to 0.3 inch 
long were found in both the left and right ends of the upper chord of 
the STA 340 floor beam. On certain Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200F, 747-300, 747SP, and 747SR series 
airplanes, the STA 340 upper deck floor beam, as well as the floor beam 
at STA 360, are made from 7075 aluminum. Other upper deck floor beams 
on these models are made from 2024 aluminum, which is known to be more 
durable than 7075 aluminum against fatigue. Cracking of the upper deck 
floor beam at STA 340 or STA 360, if not corrected, could extend and 
sever floor beams adjacent to the body frame and result in rapid 
depressurization of the airplane.

[[Page 39]]

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2459, dated January 11, 2001, which describes procedures for 
one-time detailed visual and open-hole high frequency eddy current 
(HFEC) inspections for cracking in the upper deck floor beams at STA 
340 and STA 360, and follow-on actions. The follow-on actions consist 
of repair of any cracking found during the inspections or, if no 
cracking is found, modification of the upper deck floor beams. These 
follow-on actions are described below:
     The repair described in the service bulletin is identified 
as a ``time-limited repair'' and includes removing certain fasteners 
and the existing strap, performing open-hole HFEC inspections of the 
chord and web, stop-drilling web cracks, replacing the outboard section 
of the web, if necessary, and installing new straps. The service 
bulletin specifies that the time-limited repair must be replaced with a 
permanent repair after a certain amount of time and that operators are 
to contact Boeing for instructions for such permanent repair.
     The modification described in the service bulletin 
involves removing the existing straps, and installing new straps. Also, 
the service bulletin notes that, if this modification is not 
accomplished immediately following the inspections described 
previously, the inspections must be repeated one time, immediately 
before the modification is accomplished.
    The service bulletin also specifies accomplishment of repetitive 
post-repair or post-modification open-hole HFEC inspections for 
cracking of fastener holes common to the upper chord, reinforcement 
straps, and the body frame; or, alternatively, surface HFEC inspections 
for cracking along the lower edge of the upper chord of the floor beam 
at the intersection with the body frame. However, the service bulletin 
does not provide detailed instructions for these inspections or for 
repairs of any cracking that is found.

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 previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for disposition of certain 
repair conditions, including instructions for a permanent repair, if 
necessary, this proposal would require such repairs to be accomplished 
according to a method approved by the FAA, or according to 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 Aircraft Certification Office, to 
make such findings.
    Also, while the service bulletin specifies that instructions for 
post-modification/repair inspections will be included in future 
revisions of the service bulletin, paragraph (d) of the proposed AD 
would require post-modification/repair inspections to be done according 
to a method approved by the FAA, or according to 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 Aircraft Certification Office, to make such 
findings.

Cost Impact

    There are approximately 539 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 168 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 8 work hours per airplane to accomplish 
the initial inspections, at the average labor rate of $60 per work 
hour. Based on these figures, the cost impact of these proposed 
inspections on U.S. operators is estimated to be $80,640, or $480 per 
airplane.
    It would take approximately 24 work hours per airplane to 
accomplish the modification or permanent repair, at the average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the proposed modification or repair on U.S. operators is estimated to 
be $241,920 or $1,440 per airplane.
    It would take approximately 8 work hours per airplane to accomplish 
the post-modification/repair inspections, at the average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
proposed post-modification/repair inspections on U.S. operators is 
estimated to be $80,640 or $480 per airplane, per inspection cycle.
    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 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.

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-34-AD.


[[Page 40]]


    Applicability: Model 747-100, 747-100B, 747-100B SUD, 747-200B, 
747-200F, 747-300, 747SP, and 747SR series airplanes; line numbers 1 
through 810 inclusive; certificated in any category; and NOT 
equipped with a nose cargo door.

    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 (e) 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 cracking in certain upper deck floor beams, 
which could extend and sever floor beams adjacent to the body frame 
and result in rapid depressurization of the airplane, accomplish the 
following:

Inspections

    (a) At the compliance time specified in paragraph (a)(1) or 
(a)(2) of this AD, as applicable, perform one-time detailed visual 
and open-hole high frequency eddy current (HFEC) inspections for 
cracking in the upper deck floor beams at station (STA) 340 and STA 
360, according to Boeing Alert Service Bulletin 747-53A2459, dated 
January 11, 2001.
    (1) For airplanes with 22,000 or fewer total flight cycles as of 
the effective date of this AD: Do the inspections prior to the 
accumulation of 16,000 total flight cycles, or within 1,500 flight 
cycles after the effective date of this AD, whichever is later.
    (2) For airplanes with more than 22,000 total flight cycles as 
of the effective date of this AD: Do the inspections within 500 
flight cycles after the effective date of this AD.

    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.''

Modification

    (b) If no crack is found during the inspections per paragraph 
(a) of this AD: Within 5,000 flight cycles after the initial 
inspections, modify the upper deck floor beams at STA 340 and STA 
360, according to Boeing Alert Service Bulletin 747-53A2459, dated 
January 11, 2001. If this modification is not accomplished before 
further flight after the inspections required by paragraph (a) of 
this AD, those inspections must be repeated one time, immediately 
before accomplishing the modification in this paragraph. If any 
crack is found during these repeat inspections, before further 
flight, accomplish paragraph (c)(2) of this AD.

Repair

    (c) If any crack is found during the inspections per paragraph 
(a) of this AD: Before further flight, repair according to either 
paragraph (c)(1) or (c)(2) of this AD.
    (1) Accomplish repairs according to paragraphs (c)(1)(i) and 
(c)(1)(ii) of this AD.
    (i) Accomplish a temporary repair (including removing certain 
fasteners and the existing strap, performing open-hole HFEC 
inspections of the chord and web, stop-drilling web cracks, 
replacing the outboard section of the web, if applicable, and 
installing new straps) according to Boeing Alert Service Bulletin 
747-53A2459, dated January 11, 2001; except where the service 
bulletin specifies to contact Boeing for appropriate action, repair 
according to a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or according to 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. AND,
    (ii) Within 18 months or 1,500 flight cycles after installation 
of the temporary repair according to paragraph (c)(1)(i) of this AD, 
whichever is first, do paragraph (c)(2) of this AD.
    (2) Accomplish a permanent repair according to a method approved 
by the Manager, Seattle ACO, or according to 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.

    Note 3: Boeing Alert Service Bulletin 747-53A2459, dated January 
11, 2001, does not contain instructions for permanent repairs.

Repetitive Inspections: Post-Modification/Repair

    (d) Within 15,000 flight cycles after modification of the upper 
deck floor beams per paragraph (b) of this AD, or repair of the 
upper deck floor beams per paragraph (c) of this AD, as applicable: 
Perform either open-hole HFEC inspections for cracking of fastener 
holes common to the upper chord, reinforcement straps, and the body 
frame; or surface HFEC inspections for cracking along the lower edge 
of the upper chord of the floor beam at the intersection with the 
body frame; and repeat these inspections at the interval specified 
in paragraph (d)(1) or (d)(2) of this AD, as applicable. Perform 
these inspections and repair any cracking found during these 
inspections according to a method approved by the Manager, Seattle 
ACO, or according to 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 
an inspection or 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.
    (1) If the most recent inspection used the surface HFEC method: 
Repeat the inspection within 1,000 flight cycles.
    (2) If the most recent inspection used the open-hole HFEC 
method: Repeat the inspection every 3,000 flight cycles.

    Note 4: There is no terminating action at this time for the 
repetitive post-modification/repair inspections according to 
paragraph (d) of this AD, and instructions for these inspections are 
not provided in Boeing Alert Service Bulletin 747-53A2459, dated 
January 11, 2001.

Alternative Methods of Compliance

    (e) 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.

Special Flight Permits

    (f) 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 December 26, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-32196 Filed 12-31-01; 8:45 am]
BILLING CODE 4910-13-U