[Federal Register Volume 69, Number 212 (Wednesday, November 3, 2004)]
[Proposed Rules]
[Pages 63965-63968]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-24544]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19495; Directorate Identifier 2003-NM-180-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, -100B, -100B SUD, 
-200B, and -300 Series Airplanes; and Model 747SR and 747SP Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for certain Boeing Model 747-100, -100B, -100B SUD, -
200B, and -300 series airplanes; and Model 747SR and 747SP series 
airplanes. That AD currently requires repetitive inspections to detect 
fatigue cracking in the upper deck floor beams located at certain body 
stations, and repair, if necessary. This proposed AD would lower the 
threshold for the existing inspections and would require new repetitive 
inspections of previously repaired areas, and repair if necessary. This 
proposed AD is prompted by the results of an additional detailed 
analysis that indicate fatigue cracks can initiate sooner than has 
previously been observed. We are proposing this AD to prevent failure 
of the upper deck floor beams at certain body stations due to fatigue 
cracking, which could result in rapid decompression and reduced 
controllability of the airplane.

DATES: We must receive comments on this proposed AD by December 20, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:
    Technical information: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6437; fax (425) 917-6590.
    Plain language information: Marcia Walters, [email protected].

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-19495; 
Directorate Identifier 2003-NM-180-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of our 
docket Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    On February 22, 2000, we issued AD 2000-04-17, amendment 39-11600 
(65 FR 10695, February 29, 2000), for certain Boeing Model 747-100, -
200, and -300 series airplanes. That AD requires repetitive inspections 
to detect fatigue cracking in the upper deck floor beams located at 
certain body stations, and repair, if necessary. That AD was prompted 
by a report from the manufacturer that, during a fatigue test at 
approximately 34,000 total flight cycles, the upper chord and web of 
the upper deck floor beams located at body

[[Page 63966]]

stations (BS) 340 and 360 were found severed. Another report by an 
operator indicated that, at approximately 33,000 total flight cycles, a 
severed upper chord and web were found in the upper deck floor beam at 
BS 380. In addition, cracking was found at multiple fastener hole 
locations. We issued that AD to prevent failure of the upper deck floor 
beams at certain body stations due to fatigue cracking, which could 
result in rapid decompression and reduced controllability of the 
airplane.

Actions Since Existing AD Was Issued

    Since we issued AD 2000-04-17, the results of an additional 
detailed analysis indicate that fatigue cracks can initiate sooner than 
has previously been observed. Subsequent to this analysis, the 
manufacturer issued, and we reviewed Revision 2 of Boeing Alert Service 
Bulletin 747-53A2431, dated June 13, 2002. (The original issue of the 
service bulletin was referred to in AD 2000-04-17 as the appropriate 
source of service information for the required actions). Revision 2 of 
the service bulletin changes the initial inspection threshold from 
28,000 total flight cycles to 22,000 total flight cycles. It also adds 
new repetitive inspections of areas repaired per earlier issues of the 
service bulletin, and repair of any crack. Depending on the location of 
the repair, the inspections include:
     Open-hole HFEC inspections to detect cracks at the 
fastener holes of the floor panel attachment and the inboard and 
outboard end fastener locations common to the repair strap; and
     Surface HFEC inspections to detect cracks of the upper 
chord along the edge of the trimmed surface.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. Therefore, we are proposing this AD, which 
would supersede AD 2000-04-17. This proposed AD would continue to 
require repetitive inspections to detect fatigue cracking in the upper 
deck floor beams located at certain body stations, and repair, if 
necessary. The proposed AD also would require the existing repetitive 
inspections at a lower threshold. In addition, the proposed AD would 
require new repetitive inspections of previously repaired areas, and 
repair of any crack. This proposed AD would require you to use the 
service information described previously to perform these actions, 
except as discussed under ``Differences Between the Proposed AD and 
Service Bulletin.''

Differences Between the Proposed AD and Service Bulletin

    Although the service bulletin recommends accomplishing the initial 
inspection before the accumulation of 22,000 total flight cycles, we 
have determined that the inspection threshold would not address the 
identified unsafe condition soon enough to ensure an adequate level of 
safety for the affected fleet. As described in AD 2004-03-11, amendment 
39-13455 (69 FR 5920, February 8, 2004), we have received a report 
indicating that cracks were found in the upper deck floor at BS 420 on 
a Boeing Model 747-200F series airplane with 19,598 total flight 
cycles. The upper chord and web of the floor beam were completely 
severed. AD 2004-03-11, applicable to certain Boeing Model 747-200C and 
-200F series airplanes, requires repetitive inspections to find fatigue 
cracking in the upper chord of the upper deck floor beams, and repair 
if necessary. For certain airplanes, that AD also provides an optional 
repair/modification, which extends certain repetitive inspection 
intervals. That AD is intended to find and fix cracking in certain 
upper deck floor beams, which extend and sever floor beams at a floor 
panel attachment hole location and could result in rapid decompression 
and consequent loss of controllability of the airplane.
    Since the issuance of AD 2004-03-11, we have received two reports 
of multiple-floor beam cracking on two Model 747-200F series airplanes 
with 19,687 and 23,561 total flight cycles. Numerous cracks up to 0.75 
inches long were found at the floor beams. Some of the cracks exceeded 
the repairable limits specified in Boeing Alert Service Bulletin 747-
53A2439, dated July 5, 2001 (cited in AD 2004-03-11 as the appropriate 
source of service information for the required actions). We are 
considering further rulemaking action to address these new findings.
    The upper deck floor beams at BS 340, 360, and 380 on Model 747-
100, -100B, -100B SUD, -200B, and -300 series airplanes, and Model 
747SR and 747SP series airplanes are a similar type design to those on 
Model 747-200C and -200F series airplanes. Therefore, we find that a 
18,000 flight-cycle compliance time represents an appropriate interval 
of time for affected airplanes to continue to operate without 
compromising safety.
    For locations that have been repaired by oversizing the fastener 
holes only (i.e., repair strap and/or clip not installed) as specified 
in Table 1 of Part 3 of the Accomplishment Instructions of the service 
bulletin, Part 4 of the Accomplishment Instructions of the service 
bulletin does not specify an inspection method or compliance time for 
that type of repaired location. Therefore, this proposed AD would 
require an open-hole HFEC inspection to detect cracks of the upper 
floor beams in accordance with Part 1 of the Accomplishment 
Instructions of the service bulletin. The compliance time for that 
inspection is before the accumulation of the applicable threshold 
specified in the ``New Inspection Threshold'' column in Table 1 of Part 
3 of the Accomplishment Instructions of the service bulletin, or within 
1,000 flight cycles after the effective date of this AD, whichever 
occurs later.
    The service bulletin specifies not to count flight cycles with a 
cabin pressure differential of 2.0 pounds per square inch (psi) or 
less, and that any flight cycles with momentary spikes in cabin 
pressure differential above 2.0 psi must be included as a full-pressure 
flight cycle. We find that insufficient data exist to support this 
adjustment to flight cycles. In fact, data are available which indicate 
that the use of a 2.0 adjustment factor provides inaccurate data and 
unjustified relief for inspection intervals. Consequently, this AD does 
not allow for this adjustment factor.
    The service bulletin specifies that you may contact the 
manufacturer for instructions on how to repair certain conditions, but 
this proposed AD would require you to repair those conditions in one of 
the following ways:
     Using a method that we approve; or
     Using data that meet the type certification basis of the 
airplane, and that have been approved by a Boeing Company Designated 
Engineering Representative who has been authorized by the FAA to make 
those findings.
    Although the service bulletin does not list a grace period in the 
compliance time for the post-repair inspection, this proposed AD adds a 
grace period to the compliance times. We find that a grace period will 
keep airplanes from being grounded unnecessarily.
    In addition, the effectivity of service bulletin incorrectly 
specifies ``747-300B'' as an affected airplane model. The correct model 
designation is 747-300, as specified in type certificate data sheet, 
A20WE, May 10, 2004. As explained further below, this AD specifies 
model designations in the applicability of this proposed AD as

[[Page 63967]]

published in the most recent type certificate data sheet.

Certain Changes to Existing AD

    We find that certain affected Model 747-100, -100B, -100B SUD, -
200B, and -300 series airplanes, and Model 747SR and 747SP series 
airplanes were not specifically identified by model name in the 
applicability of AD 2000-04-17. However, all of those airplanes were 
identified by manufacturer's fuselage numbers in the effectivity 
listing of Boeing Alert Service Bulletin 747-53A2431, dated February 
10, 2000, which was referenced in that AD as the appropriate source of 
service information for the required actions. Therefore, we have 
specified model designations in the applicability of this proposed AD 
as published in the most recent type certificate data sheet and 
Revision 2 of the referenced service bulletin for the affected models.
    This proposed AD would retain all requirements of AD 2000-04-17. 
Since AD 2000-04-17 was issued, the AD format has been revised, and 
certain paragraphs have been rearranged. As a result, paragraph (a) of 
AD 2000-04-17 has been redesignated as paragraph (g) in this proposed 
AD.

Costs of Compliance

    There are about 539 Model 747-100, -100B, -100B SUD, -200B, and -
300 series airplanes; and Model 747SR and 747SP series airplanes 
worldwide of the affected design. This proposed AD would affect about 
168 airplanes of U.S. registry.
    The actions that are currently required by AD 2000-04-17 and 
retained in this proposed AD take about 15 work hours per airplane, at 
an average labor rate of $65 per work hour. Based on these figures, 
estimated cost of the currently required actions is $163,800, or $975 
per airplane.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by removing amendment 39-11600 (65 FR 
10695, February 29, 2000) and adding the following new airworthiness 
directive (AD):

Boeing: Docket No. FAA-2004-19495; Directorate Identifier 2003-NM-
180-AD.

Comments Due Date

    (a) The Federal Aviation Administration must receive comments on 
this airworthiness directive (AD) action by December 20, 2004.

Affected ADs

    (b) This AD supersedes AD 2000-04-17, amendment 39-11600 (65 FR 
10695, February 29, 2000).

Applicability

    (c) This AD applies to Boeing Model 747-100, -100B, -100B SUD, -
200B, and -300 series airplanes; and Model 747SR and 747SP series 
airplanes; certificated in any category; as listed in Boeing Alert 
Service Bulletin 747-53A2431, Revision 2, dated June 13, 2002.

Unsafe Condition

    (d) This AD was prompted by the results of an additional 
detailed analysis that indicate fatigue cracks can initiate sooner 
than has previously been observed. We are issuing this AD to prevent 
failure of the upper deck floor beams at certain body stations (BS) 
due to fatigue cracking, which could result in rapid decompression 
and reduced controllability of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

New Initial Compliance Time

    (f) At the earlier of the times specified in paragraphs (f)(1) 
and (f)(2) of this AD, do the actions specified in paragraph (h) of 
this AD.
    (1) Before the accumulation of 28,000 total flight cycles, or 
within 60 days after March 15, 2000 (the effective date of AD 2000-
04-17, amendment 39-11600), whichever occurs later.
    (2) Before the accumulation of 18,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later.

Determining Number of Flight Cycles for Compliance Time

    (g) For the purposes of calculating the compliance threshold for 
the actions required by paragraph (f) of this AD, all pressurized 
flight cycles, including the number of flight cycles in which cabin 
differential pressure is at 2.0 pounds per square inch (psi) or 
less, must be counted when determining the number of flight cycles 
that have occurred on the airplane. Where the service bulletin and 
this AD differ, the AD prevails.

Requirements of AD 2000-04-17 and New Repair Method

    (h) At the time specified in paragraph (f) of this AD, perform 
the actions required by either paragraph (h)(1) or (h)(2) of this 
AD.
    (1) Gain access to the upper deck floor beams from above the 
upper deck floor, and perform an open-hole high frequency eddy 
current (HFEC) inspection to detect cracking of the upper deck floor 
beams at BS 340 and 360, and on both the left and right sides of the 
floor beam at BS 380 between buttock lines (BL) 40 and 76; in 
accordance with Part 1 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2431, Revision 2, dated June 13, 2002.
    (i) If no cracking is found, perform the actions required by 
paragraph (h)(1)(i)(A), (h)(1)(i)(B), or (h)(1)(i)(C) of this AD, in 
accordance with the alert service bulletin.
    (A) Repeat the inspection required by paragraph (h)(1) of this 
AD thereafter at intervals not to exceed 3,000 flight cycles.
    (B) Modify (oversize) the floor panel attachment fastener holes 
as specified in Figure 5 of the alert service bulletin, and repeat 
the inspection required by paragraph (h)(1) of this AD within 10,000 
flight cycles. Thereafter, repeat the inspection at intervals not to 
exceed 3,000 flight cycles.
    (C) Do the applicable repair procedures shown in Part 3 of the 
Accomplishment Instructions of the alert service bulletin; except 
where the service bulletin specifies to contact Boeing for 
appropriate action, before further flight, repair in accordance with 
paragraph (h)(1)(ii)(A) of this AD.
    (ii) If any cracking is found, before further flight, do the 
action specified in either paragraph (h)(1)(ii)(A) or (h)(1)(ii)(B) 
of this AD.
    (A) Repair in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate; or in accordance with data meeting the type 
certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative (DER) who has been authorized 
by the FAA to make

[[Page 63968]]

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.
    (B) Repair in accordance with Part 3 of the Accomplishment 
Instructions of the alert service bulletin; except where the service 
bulletin specifies to contact Boeing for appropriate action, before 
further flight, repair in accordance with paragraph (h)(1)(ii)(A) of 
this AD.
    (2) Gain access to the upper deck floor beams from below the 
upper deck floor; and perform a surface HFEC inspection to detect 
cracking of the floor beams at BS 340 and 360, and on both the left 
and right sides of the floor beam at BS 380 between BL 40 and 76; in 
accordance with Part 2 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2431, Revision 2, dated June 13, 2002.
    (i) If no cracking is found, repeat the inspection required by 
paragraph (h)(2) of this AD thereafter at intervals not to exceed 
750 flight cycles.
    (ii) If any cracking is found, before further flight, do the 
action specified in paragraph (h)(1)(ii) of this AD.

New Post-Repair Inspection

    (i) For areas repaired in accordance with paragraph (h)(1)(i)(C) 
or (h)(1)(ii)(B) of this AD: Before the accumulation of the 
applicable threshold specified in the ``New Inspection Threshold'' 
column in Table 1 of Part 3 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-53A2431, Revision 2, dated June 
13, 2002, after accomplishing the repair; or within 1,000 flight 
cycles after the effective date of this AD; whichever occurs later: 
Do the actions specified in paragraphs (i)(1) through (i)(3) of this 
AD, as applicable.
    (1) For locations that have been repaired by oversizing the 
fastener holes only (i.e., repair strap and/or clip not installed) 
as shown in Part 3 of the Accomplishment Instructions of Revision 1 
or 2 of the alert service bulletin: Perform an open-hole HFEC 
inspection to detect cracking of the upper deck floor beams, in 
accordance with Part 1 of the Accomplishment Instructions of the 
alert service bulletin.
    (2) For locations previously repaired as shown in Figure 8 of 
Revision 1 or 2 of the alert service bulletin: Do an open-hole HFEC 
inspection to detect cracks at the fastener holes of the floor panel 
attachment and the inboard and outboard end fastener locations 
common to the repair strap, in accordance with Part 4 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2431, Revision 2, dated June 13, 2002.
    (3) For locations previously repaired as shown in Figure 9 or 
Figure 10 of Revision 1 or 2 of the alert service bulletin: Do a 
surface HFEC inspection to detect cracks at the upper chord along 
the edge of the trimmed surface; and perform an open-hole HFEC 
inspection to detect cracks at the fastener holes of the floor panel 
attachment and the inboard and outboard end fastener locations 
common to the repair strap, in accordance with Part 4 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2431, Revision 2, dated June 13, 2002.
    (j) If no crack is detected during any inspection required by 
paragraphs (i)(1) through (i)(3) of this AD, repeat the applicable 
inspection thereafter at intervals not to exceed 3,000 flight 
cycles.
    (k) If any crack is detected during any inspection required by 
paragraph (i)(1) through (i)(3) of this AD, before further flight, 
do the action specified in paragraph (h)(1)(ii)(A) of this AD.
    (l) For areas repaired in accordance with paragraph 
(h)(1)(ii)(A) of this AD that do not have a post-repair inspection 
program approved by the Manager, Seattle ACO or by a Boeing Company 
DER who has been authorized by the Manager, Seattle ACO, to make 
those findings: Do the actions specified in paragraph (h) of this AD 
at the time specified in that paragraph.

Credit for Previous Released Alert Service Bulletin

    (m) Actions accomplished before the effective date of this AD 
per Boeing Alert Service Bulletin 747-53A2431, dated February 10, 
2000; or Revision 1, dated March 8, 2001; are acceptable for 
compliance with the applicable requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (n)(1) The Manager, Seattle ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested in accordance with the 
procedures found in 14 CFR 39.19.
    (2) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Seattle ACO, to make those findings. For 
a repair method to be approved, the approval must specifically refer 
to this AD.
    (3) AMOCs, approved previously per AD 2000-14-17, amendment 39-
11600, are approved as AMOCs with paragraph (h)(1)(ii)(A) of this 
AD, provided that a post-repair inspection program has been approved 
by the Manager, Seattle ACO, or by a Boeing Company Designated 
Engineering Representative who has been authorized by the Manager, 
Seattle ACO, to make those findings.

    Issued in Renton, Washington, on October 21, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-24544 Filed 11-2-04; 8:45 am]
BILLING CODE 4910-13-P