[Federal Register Volume 69, Number 214 (Friday, November 5, 2004)]
[Proposed Rules]
[Pages 64517-64520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-24726]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19538; Directorate Identifier 2003-NM-99-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 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 series airplanes. That AD 
currently requires inspections to detect cracks in the front spar 
pressure bulkhead chord, and repair, if necessary. This proposed AD 
would require repetitive high frequency eddy current (HFEC) inspections 
of the body station (BS) 1000 bulkhead chord for cracks, repetitive 
detailed inspections of the bathtub fittings, if installed, for cracks, 
and corrective action, if necessary. Accomplishment of new inspections 
would end the inspections of the existing AD. This proposed AD would 
also revise the applicability of the existing AD to include additional

[[Page 64518]]

airplanes. This proposed AD is prompted by reports of cracks in the BS 
1000 bulkhead chord. We are proposing this AD to detect and correct 
fatigue cracks in the BS 1000 bulkhead chord, which, if not repaired 
before they reach critical length, could result in the failure of the 
adjacent structure and skin and lead to in-flight depressurization 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: Nick Kusz, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6432; 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-2004-19538; 
Directorate Identifier 2003-NM-99-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 April 19, 1990, we issued AD 90-09-09, amendment 39-6586 (55 FR 
17928, April 30, 1990), for certain Boeing Model 747 series airplanes 
(a correction of that AD was published in the Federal Register on May 
21, 1990 (55 FR 20894)). That AD requires repetitive high frequency 
eddy current (HFEC) inspections to detect cracks in the front spar 
pressure bulkhead chord, and repair, if necessary. That AD was prompted 
by a determination that accomplishing a certain modification may result 
in fuel leakage from the wing center section fuel tank. We issued that 
AD to prevent a potential fire hazard in the forward cargo compartment.

Actions Since Existing AD was Issued

    Since we issued AD 90-09-09 (applicable to Boeing Model 747-100, -
100B, -100B SUD, -200B, -200C, and -200F series airplanes, line numbers 
1 through 201 inclusive), we have received reports of cracks in the 
body station (BS) 1000 bulkhead chord of Boeing Model 747 series 
airplanes after line number 201. We have also received reports of 
cracking in the chords of airplanes that received the chord replacement 
per Boeing Service Bulletin 747-53-2362, dated March 26, 1992 (for 
Model 747-100, -100B, -100B SUD, -200B, -200C, and -200F series 
airplanes, line numbers 1 through 201 inclusive). Boeing Service 
Bulletin 747-53-2362 was intended to address cracking in the chord. 
Fatigue cracking in the BS 1000 bulkhead chord, if not repaired before 
they reach critical length, could result in the failure of the adjacent 
structure and skin and lead to in-flight depressurization of the 
airplane.

Related ADs Due to Common Access

    On May 23, 2000, we issued AD 2000-11-07 (65 FR 34932, June 1, 
2000), applicable to certain Boeing Model 747-200, -300, and -400 
series airplanes, that requires repetitive HFEC inspections to detect 
cracking of the front spar web of the center section of the wing, and 
repair, if necessary.
    On October 19, 2001, we issued AD 2001-22-04 (66 FR 54422, October 
29, 2001), applicable to all Boeing Model 747 series airplanes, that 
requires repetitive inspections for cracking of the fuselage skin 
adjacent to the drag splice fitting, and follow-on actions, if 
necessary.
    The inspections in the above ADs may be accomplished concurrently 
with this proposed AD due to common access but they are not required by 
this AD.

[[Page 64519]]

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2471, dated 
March 27, 2003. The service bulletin describes procedures for 
performing repetitive HFEC inspections of the BS 1000 bulkhead chord 
for cracks; performing repetitive detailed inspections of the bathtub 
fittings, if installed, for cracks; and corrective action, if 
necessary. Accomplishing the inspections would end the inspections 
required by AD 90-09-09. The corrective action includes replacing the 
BS 1000 bulkhead chord with a new chord and replacing the bathtub 
fittings with new bathtub fittings.
    Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.
    The service bulletin also recommends concurrent accomplishment, due 
to common access, of the inspections specified in Boeing Service 
Bulletin 747-53A2444 (Boeing Service Bulletin 747-53A2444, Revision 1, 
dated June 15, 2000; and Boeing Alert Service Bulletin 74753A2444, 
Revision 2, dated May 24, 2001, are listed as relevant sources of 
service information for AD 2001-22-04); Boeing Service Bulletin 747-57-
2297; and Boeing Service Bulletin 747-57A2298 (Boeing Alert Service 
Bulletin 747-57A2298, Revision 1, dated September 12, 1996; Boeing 
Service Bulletin 747-57A2298, Revision 2, dated October 2, 1997; and 
Boeing Alert Service Bulletin 747-57A2298, Revision 3, dated January 7, 
1999; are listed as relevant sources of service information for AD 
2000-11-07). These service bulletins are not required by this AD.

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 90-09-09. This proposed AD would continue to require 
repetitive HFEC inspections to detect cracks in the front spar pressure 
bulkhead chord, and repair, if necessary. This proposed AD would also 
require repetitive HFEC inspections of BS 1000 bulkhead chord for 
cracks, repetitive detailed inspections of the bathtub fittings, if 
installed, for cracks, and corrective action, if necessary. 
Accomplishment of new inspections would end the inspections of the 
existing AD. The proposed AD would also revise the applicability of the 
existing AD to include additional airplanes. This proposed AD would 
require you to use the service information described previously to 
perform these actions except as discussed under ``Difference Between 
the Proposed AD and the Service Bulletin.''

Difference Between the Proposed AD and the Service Bulletin

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for disposition of certain 
repair conditions, this proposed AD would require the repair of those 
conditions to be accomplished per a method approved by the FAA.

Clarification of Inspection Type

    Where Boeing Alert Service Bulletin 747-53A2471, dated March 27, 
2003, specifies to do a ``detailed visual inspection,'' this proposed 
AD specifies to do a ``detailed inspection.'' We have also added a note 
to the proposed AD to clarify the definition of detailed inspection.

Changes to Existing AD

    This proposed AD would retain the requirements of AD 90-09-09. 
However, the AD format has been revised, and certain paragraphs have 
been rearranged. As a result, the corresponding paragraph identifiers 
have changed in this proposed AD, as listed in the following table:

                      Revised Paragraph Identifiers
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                                             Corresponding  requirement
        Requirement in AD 90-09-09              in this  proposed AD
------------------------------------------------------------------------
Paragraph A...............................  Paragraph (f).
Paragraph B...............................  Paragraph (g).
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Costs of Compliance

    There are about 1,350 Model 747 series airplanes worldwide of the 
affected design. This proposed AD would affect about 245 airplanes of 
U.S. registry.
    The actions that are required by AD 90-09-09 and retained in this 
proposed AD take about 84 work hours per airplane, at an average labor 
rate of $65 per work hour. We estimate 102 airplanes of U.S. registry 
are affected by AD 90-09-09. Based on these figures, the estimated cost 
of the currently required actions is $556,920, or $5,460 per airplane, 
per inspection cycle.
    The new proposed inspections would take about 14 work hours per 
airplane, at an average labor rate of $65 per work hour. Based on these 
figures, the estimated cost of the new actions specified in this 
proposed AD for U.S. operators is $222,950, or $910 per airplane, per 
inspection cycle.

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 39-6586 (55 FR 
20894, May 21, 1990), and adding the following new airworthiness 
directive (AD):

Boeing: Docket No. FAA-2004-19538; Directorate Identifier 2003-NM-
99-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 90-09-09, amendment 39-6586 (55 FR 
20894, May 21, 1990.

Applicability

    (c) This AD applies to Model 747 series airplanes, line numbers 
1 through 1307

[[Page 64520]]

inclusive, 1309 through 1312 inclusive, and 1314; certificated in 
any category.

Unsafe Condition

    (d) This AD was prompted by reports of cracks in the body 
station (BS) 1000 bulkhead chord. We are issuing this AD to detect 
and correct fatigue cracks in the BS 1000 bulkhead chord, which, if 
not repaired before they reach critical length, could result in the 
failure of the adjacent structure and skin and lead to in-flight 
depressurization 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.

Restatement of Requirements of AD 90-09-09

    (f) For airplanes listed in Boeing Service Bulletin 747-53-2064, 
Revision 4, dated September 23, 1983, that have not been modified in 
accordance with Boeing Service Bulletin 747-53-2064, dated July 25, 
1972: Within the next 1,000 landings after October 15, 1984 (the 
effective date of AD 84-18-06, amendment 39-4912), or prior to the 
accumulation of 10,000 landings, whichever occurs later, and 
thereafter at intervals not to exceed 7,000 landings, conduct a high 
frequency eddy current (HFEC) inspection of the chord to detect 
cracks between stringers S-37 and S-39 at the chord radius, heel, 
and flanges adjacent to the fastener holes identified for inspection 
in Boeing Service Bulletin 747-53-2064, Revision 4, dated September 
23, 1983. If cracks are found in the pressure bulkhead chord, 
accomplish the repair in accordance with the service bulletin before 
further flight. Repair of cracks along the chord radius under 5 
inches in length, or across a chord flange that have not severed the 
chord flange, may be deferred 1,000 landings by stop drilling and 
reinspecting for crack progression every 200 landings using HFEC. If 
crack progression is found, repair in accordance with the service 
bulletin prior to further flight. Inspections are to continue at 
intervals not to exceed 7,000 landings after repair.
    (g) For airplanes listed in Boeing Service Bulletin 747-53-2064, 
Revision 4, dated September 23, 1983, that have been modified in 
accordance with Boeing Service Bulletin 747-53-2064, dated July 25, 
1972: Within the next 1,000 landings after October 15, 1984, or 
prior to the accumulation of 10,000 landings after the modification, 
whichever is later, and thereafter at intervals not to exceed 10,000 
landings, conduct an HFEC inspection to detect cracks in the front 
spar pressure bulkhead lower chord heel from stringers S-37 to S-39, 
and conduct an ultrasonic inspection to detect cracks in the 
fuselage skin originating at the indicated fastener holes beneath 
the forward drag splice fitting flanges, in accordance with the 
service bulletin. If any cracks are found, repair in accordance with 
Boeing Service Bulletin 747-53-2064, Revision 4, dated September 23, 
1983, before further flight. Inspections are to continue at 
intervals not to exceed 10,000 landings after repair.

New Requirements of This AD

Initial Inspections

    (h) At the later of the times specified in paragraph (h)(1), 
(h)(2), or (h)(3) of this AD: Except as provided by paragraph (i) of 
this AD, perform an HFEC inspection of BS 1000 bulkhead chord for 
cracks, a detailed inspection of the bathtub fittings, if installed, 
for cracks, and corrective action, as applicable, by accomplishing 
all the actions specified in the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-53A2471, dated March 27, 2003. Any 
applicable corrective action must be done before further flight. 
Accomplishment of the HFEC and detailed inspections required by 
paragraph (h) of this AD ends the requirements of paragraphs (f) and 
(g) of this AD.

    Note 1: For the purposes of this AD, a detailed inspection is 
``an intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirrors, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

    (1) Prior to the accumulation of 10,000 total flight cycles.
    (2) Within 18 months after the effective date of this AD.
    (3) For airplanes on which the repair (i.e., chord replacement) 
has been accomplished in accordance with Boeing Service Bulletin 
747-53-2362, dated March 26, 1992, or in accordance with paragraph 
(f) or (g) of this AD (i.e., per Boeing Service Bulletin 747-53-
2064, Revision 4, dated September 23, 1983): Within 3,000 flight 
cycles after the replacement was accomplished.

    Note 2: Repairs (i.e., chord replacement) accomplished prior to 
the effective date of this AD in accordance with Boeing Service 
Bulletin 747-53-2064, Revision 1, dated May 18, 1973; Revision 2, 
dated February 22, 1974; Revision 3, dated September 13, 1974; 
Revision 5, dated July 23, 1987; or Revision 6, dated June 22, 1989; 
are considered to be applicable to the inspection threshold 
specified in paragraph (h)(3) of this AD.

    (i) If any crack is found during any inspection required by 
paragraph (h) of this AD, and Boeing Alert Service Bulletin 747-
53A2471, dated March 27, 2003, specifies contacting Boeing for 
additional information: Before further flight, repair per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA. For a repair method to be approved by the Manager, 
Seattle ACO, as required by this paragraph, the Manager's approval 
letter must specifically refer to this AD.

Repetitive Inspections

    (j) Except as provided by paragraph (k) of this AD, repeat the 
inspections required by paragraph (h) of this AD thereafter at 
intervals not to exceed 3,000 flight cycles.
    (k) For airplanes on which both the chord replacement and 
bathtub fitting replacement were done in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2471, dated March 27, 2003: Repeat the inspections required by 
paragraph (h) of this AD within 6,000 flight cycles after 
accomplishing both replacements. Thereafter repeat the inspections 
at intervals not to exceed 3,000 flight cycles.

Alternative Methods of Compliance (AMOC)

    (l)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
ACO, FAA, is authorized to AMOCs for this AD.
    (2) AMOCs, approved previously in accordance with AD 90-09-09, 
amendment 39-6586, are approved as AMOCs with paragraph (f) or (g) 
of this AD, as applicable.

    Issued in Renton, Washington, on October 26, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-24726 Filed 11-4-04; 8:45 am]
BILLING CODE 4910-13-P