[Federal Register Volume 72, Number 43 (Tuesday, March 6, 2007)]
[Proposed Rules]
[Pages 9877-9880]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-3842]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27359; Directorate Identifier 2006-NM-042-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-
200F, 747-300, 747SR, and 747SP series airplanes. This proposed AD 
would require repetitive high frequency eddy current inspections for 
cracks of the fuselage skin at stringer 5 left and right between 
stations 340 and 350, and corrective actions if necessary. This 
proposed AD results from reports of fatigue cracks in the fuselage skin 
near stringer 5 between stations 340 and 350. We are proposing this AD 
to detect and correct fatigue cracking of the fuselage skin near 
stringer 5. Cracks in this area could join together and result in in-
flight depressurization of the airplane.

DATES: We must receive comments on this proposed AD by April 20, 2007.

[[Page 9878]]


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.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437; 
fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
27359; Directorate Identifier 2006-NM-042-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 
that 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 may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may 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 Docket Management System 
receives them.

Discussion

    We have received a report indicating that, during inspections on 
certain Boeing Model 747 airplanes, four operators found fatigue cracks 
in the fuselage skin at stringer 5, between stations 340 and 350. The 
airplanes had flown 18,000 to 20,000 total flight cycles. The cracks 
that were found ranged in length from a single crack of 0.25 inch to 
multiple cracks that were equivalent to a 10-inch long crack. Skin 
cracks in this area could join together and result in in-flight 
depressurization of the airplane.

Other Relevant Rulemaking

    On January 16, 1990, we issued AD 90-06-06, amendment 39-6490 (55 
FR 8374, March 7, 1990), for certain Boeing Model 747 series airplanes. 
That AD requires the incorporation of certain structural modifications 
(reference Boeing Service Bulletin 747-53-2272, Revision 12, dated 
December 22, 1988, identified in Boeing Document No. D6-35999). We 
issued that AD to prevent structural failure of the affected airplanes. 
One of the required modifications of AD 90-06-06 ends the repetitive 
inspections of certain structures that would also be required by this 
proposed AD.
    On April 1, 2005, we issued AD 2005-08-01, amendment 39-14053 (70 
FR 18290, April 11, 2005), for certain Boeing Model 747 series 
airplanes. That AD requires repetitive inspections; repetitive external 
detailed inspections for cracks or loose or missing fasteners of 
certain body skin on the left and right sides of the airplane; an 
internal detailed inspection for cracking of certain left- and right-
side frames and adjacent skin; repetitive high-frequency eddy current 
(HFEC) inspections of certain body frames between certain body 
stations; and repairs if necessary. We issued that AD to detect and 
correct fatigue cracks in the body frames, skin, and other internal 
structures in fuselage section 41, which could lead to rapid 
decompression and loss of the structural integrity of the airplane. 
Paragraph (s) of AD 2005-08-01 refers to Boeing Service Bulletin 747-
53-2272, dated January 12, 1987, and any revision through Revision 18, 
dated May 16, 2002, as the appropriate source of service information 
for accomplishing the terminating action described in that AD. That 
terminating action ends the repetitive inspections of certain 
structures that would also be required by this proposed AD.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2542, dated 
February 16, 2006 (referred to hereafter as ``the alert service 
bulletin''). For airplanes that do not have external skin doublers 
installed around the left- and right-side Number 3 flight deck windows 
in accordance with Boeing Service Bulletin 747-53-2272, the alert 
service bulletin describes procedures for repetitive HFEC inspections 
for cracks of the external surface of the fuselage skin at stringer 5 
left and right, between stations 340 and 350. The alert service 
bulletin specifies that the HFEC inspections be done at the compliance 
times specified in the following table.

                                      Compliance Times for HFEC Inspections
----------------------------------------------------------------------------------------------------------------
                                                      Initial compliance time     Repetitive interval  (not to
       Airplane group          Airplane condition    (whichever occurs later)                exceed)
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Group 1....................  Fewer than 16,000      Before accumulating 16,000  4,000 flight cycles.
                              total flight cycles.   total flight cycles or
                                                     within 2,000 flight
                                                     cycles \1\.
                             16,000 or more total   Before accumulating 18,000  None.
                              flight cycles.         total flight cycles or
                                                     within 250 flight cycles
                                                     \1\.
Group 2....................  Fewer than 20,000      Before accumulating 20,000  4,000 flight cycles.
                              total flight cycle.    total flight cycles or
                                                     within 2,000 flight
                                                     cycles \1\.

[[Page 9879]]

 
                             20,000 or more total   Before accumulating 22,000  None.
                              flight cycles.         total flight cycles or
                                                     within 250 flight cycles
                                                     \1\.
----------------------------------------------------------------------------------------------------------------
\1\ After the date on the alert service bulletin.

    The alert service bulletin also describes corrective actions to be 
done if any crack is found. If the total length of all cracks found is 
less than 1.0 inch, corrective actions include stop drilling the crack 
or cracks; and, either installing external skin doublers around the 
Number 3 flight deck window, or installing a temporary external 
structural repair manual (SRM) skin repair. If the total length of all 
cracks found is 1.0 inch or longer, corrective actions include trimming 
the cracked area of skin and installing a filler; and, either 
installing external skin doublers around the Number 3 flight deck 
window and installing a tripler, or installing a temporary external SRM 
skin repair. The alert service bulletin specifies that the corrective 
actions should be done before further flight. The alert service 
bulletin refers to Boeing Service Bulletin 747-53-2272 (currently at 
Revision 18, dated May 16, 2002) as an additional source of service 
information for installing the external skin doublers around the left- 
and right-side Number 3 flight deck windows.
    For Group 2 airplanes only: The alert service bulletin describes 
installing external skin doublers around the left- and right-side 
Number 3 flight deck windows before accumulating 24,000 total flight 
cycles or within 250 flight cycles after the effective date of the 
alert service bulletin, whichever occurs later. This constitutes 
terminating action for the repetitive HFEC inspections specified in 
this NPRM.
    For Group 1 airplanes only: AD 90-06-06 requires installation of 
external skin doublers around the Number 3 flight deck windows in 
accordance with Boeing Service Bulletin 747-53-2272, Revision 12, dated 
December 22, 1988, at or before 20,000 total flight cycles. This 
constitutes terminating action for the repetitive HFEC inspections 
specified in this NPRM.
    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 airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Difference Between the Proposed AD and Alert Service Bulletin.''

Difference Between the Proposed AD and Alert Service Bulletin

    The alert service bulletin specifies to contact the manufacturer 
for instructions on how to repair certain conditions, but this proposed 
AD would require repairing those conditions in one of the following 
ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.

Clarification of Reporting

    Although the alert service bulletin discusses reporting inspection 
results, the Accomplishment Instructions of the alert service bulletin 
do not specify sending such a report to Boeing. This proposed AD would 
not require such reporting.

Costs of Compliance

    There are about 281 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 92 airplanes of 
U.S. registry. The proposed inspection would take about 4 work hours 
per airplane, at an average labor rate of $80 per work hour. Based on 
these figures, the estimated cost of the proposed inspection for U.S. 
operators is $29,440, or $320 per airplane, per inspection cycle.
    For Group 2 airplanes (about 4 of U.S. registry), the mandatory 
terminating action for the repetitive inspections would take about 
1,240 work hours, at an average labor rate of $80 per work hour. The 
manufacturer states that it will supply required parts to the operators 
at no cost. Based on these figures, the estimated cost of the 
terminating action for U.S. operators is $396,800, or $99,200 per 
airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

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 and placed it in the AD docket. 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.

[[Page 9880]]

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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-27359; Directorate Identifier 2006-NM-
042-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by April 20, 
2007.

Affected ADs

    (b) AD 90-06-06, amendment 39-6490, paragraph A., requires 
installation of external skin doublers in the area near the flight 
deck windows for Group 1 airplanes, which ends the repetitive high-
frequency eddy current (HFEC) inspections required by this AD only 
for those airplanes. Installing external skin doublers as required 
by paragraph (g) of this AD ends certain repetitive inspections of 
the fuselage skin required by paragraph (f) of AD 2005-08-01, 
amendment 39-14053, only for the area near the flight deck windows 
modified by the external skin doublers.

Applicability

    (c) This AD applies to Boeing Model 747-100, 747-100B, 747-200B, 
747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, 
certificated in any category; as identified in Boeing Alert Service 
Bulletin 747-53A2542, dated February 16, 2006.

Unsafe Condition

    (d) This AD results from reports of fatigue cracks in the 
fuselage skin near stringer 5 between body stations 340 and 350. We 
are issuing this AD to detect and correct fatigue cracking of the 
fuselage skin near stringer 5. Cracks in this area could join 
together and result in 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.

Inspections and Corrective Actions

    (f) For any airplane that has not had external skin doublers 
installed around the left- or right-side Number 3 flight deck window 
in accordance with Boeing Service Bulletin 747-53-2272, Revision 18, 
dated May 16, 2002, or an earlier revision: Do the applicable 
actions described in paragraphs (f)(1) and (f)(2) of this AD. Do all 
the actions in and in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2542, dated 
February 16, 2006. Do the actions at the compliance times specified 
in paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
747-53A2542, dated February 16, 2006, on the side(s) of the airplane 
on which the doubler installation has not been done; except where 
the service bulletin specifies compliance times after the date on 
the service bulletin, this AD requires compliance times after the 
effective date of this AD. Installing external skin doublers around 
the left- or right-side Number 3 flight deck windows in accordance 
with Boeing Service Bulletin 747-53-2272, Revision 18, or an earlier 
revision; ends the repetitive HFEC inspections required by this 
paragraph on the side of the airplane on which the doubler is 
installed. After the effective date of this AD, only Boeing Service 
Bulletin 747-53-2272, Revision 18, may be used to install the 
external skin doublers around the left- and right-side Number 3 
flight deck windows.
    (1) Do a HFEC inspection for cracks of the fuselage skin at 
stringer 5, between body stations 340 and 350; and do all applicable 
corrective actions before further flight.
    (2) Repeat the HFEC inspection thereafter at the applicable 
interval specified in paragraph 1.E. of Boeing Alert Service 
Bulletin 747-53A2542.

Terminating Action

    (g) For Group 2 airplanes only: Before accumulating 24,000 total 
flight cycles, or within 250 flight cycles after the effective date 
of the AD, whichever occurs later, install external skin doublers 
around the left- and right-side Number 3 flight deck windows; in 
accordance with Boeing Service Bulletin 747-53-2272, Revision 17, 
dated November 18, 1999; or Revision 18, dated May 16, 2002. After 
the effective date of this AD, only Boeing Service Bulletin 747-53-
2272, Revision 18, may be used to accomplish the doubler 
installation around the left- and right-side Number 3 flight deck 
windows. Accomplishing this action ends the repetitive inspections 
required by paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (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) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

    Issued in Renton, Washington, on February 23, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-3842 Filed 3-5-07; 8:45 am]
BILLING CODE 4910-13-P