[Federal Register Volume 70, Number 179 (Friday, September 16, 2005)]
[Proposed Rules]
[Pages 54677-54680]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-18400]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22426; Directorate Identifier 2005-NM-105-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR 
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 all Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-
200C, 747-300, 747-400, 747-400D, and 747SR series airplanes. This 
proposed AD would require a one-time inspection to determine whether 
any steel doubler (small or large) is installed at the lower forward 
and upper aft corners of the fuselage cutout at main entry doors (MEDs) 
number 3. Depending on the results of this inspection, this proposed AD 
also would require repetitive inspections for cracks of the skin, 
bearstrap, and small steel doubler (if installed) at the applicable 
corner or corners of the fuselage cutouts, and related investigative/
corrective actions if necessary. This proposed AD also would provide 
the optional terminating action for the repetitive inspections of 
installing a large steel doubler at the affected corners. This proposed 
AD is prompted by reports of cracks in the skin and bearstrap at the 
upper aft corner and at the lower forward corner of the fuselage cutout 
at MEDs number 3. We are proposing this AD to detect and correct cracks 
in the skin, bearstrap, and small steel doubler (if installed), which 
could propagate and result in rapid decompression of the airplane.

DATES: We must receive comments on this proposed AD by October 31, 
2005.

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.
     By 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 in person 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. This docket 
number is FAA-2005-22426; the directorate identifier for this docket is 
2005-NM-105-AD.

FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; 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 under ADDRESSES. Include ``Docket No. FAA-2005-22426; 
Directorate Identifier 2005-NM-105-AD'' in the subject line 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 submitted 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 website, 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 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.

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 Docket Management System 
(DMS) receives them.

Discussion

    We have received a report indicating that seven operators of the 
affected airplanes have found cracks in the skin and bearstrap at the 
upper aft corner of the fuselage cutout at main entry doors (MEDs) 
number 3. These cracks, which were between 0.6 inch and 2.5 inches in 
length, were found on airplanes that had accumulated between 12,140 and 
23,927 flight cycles. We have received other reports indicating that 
some operators also found cracks in the skin and bearstrap at the lower 
forward corner of the fuselage cutout at MEDs number 3. These cracks 
were between 0.5 inch and 4.0 inches in length, and were found on 
airplanes that had accumulated between 11,986 and 23,083 flight cycles. 
Cracks in the skin, bearstrap, and small steel doubler, if not detected 
and corrected, could propagate and result in rapid decompression of the 
airplane.

Other Relevant Rulemaking

    On December 8, 1992, we issued AD 92-27-04, amendment 39-8437 (57 
FR 59801, December 16, 1992) for certain Boeing Model 747 series 
airplanes. [A correction of that AD was published in the Federal 
Register on February 17, 1993 (58 FR 8693)]. We issued that AD to 
prevent the structural degradation of

[[Page 54678]]

the airplane by requiring various repetitive inspections of the 
airplane structure for cracks, and repair if any crack is found. AD 92-
27-04 refers to Section 4 of Boeing Document No. D6-35999, Revision C, 
dated January 21, 1992, as the appropriate source of service 
information for doing the various inspections and repairs. Boeing 
Document No. D6-35999 in turn refers to Boeing Service Bulletin 747-53-
2218, Revision 4, dated November 9, 1989, as the appropriate source of 
service information for doing the specific inspections of the lower 
forward corner of the fuselage cutout at MEDs number 3, and doing any 
necessary repairs. Installing a small or large steel doubler at the 
lower forward corner of the cutout in accordance with Boeing Service 
Bulletin 747-53-2218 terminates the repetitive inspection requirements 
of AD 92-27-04 for that area.
    On April 22, 1993, we issued AD 93-08-12, amendment 39-8559, (58 FR 
27927, May 12, 1993), for certain Boeing Model 747 series airplanes. 
That AD requires repetitive detailed visual internal inspections to 
detect cracks in various areas of the fuselage internal structure, and 
repair if necessary. Among other areas of the fuselage, AD 93-08-12 
requires inspection of the upper aft and lower forward corners of the 
fuselage cutout at MEDs number 3, with and without steel doublers 
installed at those corners. Boeing Service Bulletin 747-53A2512, 
Revision 1, dated August 11, 2005, which is described below and cited 
as the appropriate source of service information for this new proposed 
AD, refers to AD 93-08-12. However, on May 14, 2002, we issued AD 2002-
10-10, amendment 39-12756, (67 FR 36081, May 23, 2002) to supersede AD 
93-08-12. AD 2002-10-10 retains the requirements of AD 93-08-12 for the 
area affected by this new proposed AD, but adds new repetitive 
inspections for cracking in certain areas of the upper chord of the 
upper deck floor beams, and repair if necessary. AD 93-08-12 and AD 
2002-10-10 refer to Boeing Service Bulletin 747-53-2349, dated June 27, 
1991, as the appropriate source of service information for doing the 
inspections and repair if necessary. In addition, on April 1, 2005, we 
issued a proposed AD that would supersede AD 2002-10-10. That proposed 
AD (Docket No. FAA-2005-20880, Directorate Identifier 2003-NM-229-AD, 
70 FR 18332, April 11, 2005) would retain certain requirements of AD 
2002-10-10 but add repetitive inspections for cracking of additional 
areas of the fuselage internal structure and related investigative/
corrective actions.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 747-53A2512, including 
747-53A2512, Revision 1, dated August 11, 2005. The service bulletin 
describes procedures for repetitive inspections to determine the size 
and presence of any steel doubler installed at the lower forward and/or 
upper aft corners of the fuselage cutout at MEDs number 3. If a large 
steel doubler was previously installed in accordance with Boeing 
Service Bulletin 747-53-2218 (described below), or the Boeing 747-100/
200/300 Structural Repair Manual (SRM), Service Bulletin 747-53A2512 
states that no further action is required for that corner. For lower 
forward corners that have no steel doubler installed, the service 
bulletin states that inspections and any applicable repairs are done in 
accordance with Boeing Service Bulletin 747-53-2218 (AD 92-27-04).
    For all other corners and doubler configurations, the service 
bulletin gives various intervals for initial and repetitive inspections 
for cracks of the skin, bearstrap, and small steel doubler (if 
installed) at the lower forward and upper aft corners of the fuselage 
cutout at MEDs number 3. There are two options given in Boeing Service 
Bulletin 747-53A2512 for doing the initial and repetitive inspections. 
The first option is to do a detailed inspection. The second option is 
to do a high-frequency eddy current (HFEC) inspection. The service 
bulletin specifies that operators should also do a general visual 
inspection to detect cracks in the small steel doubler (if installed) 
and any previous repair trimouts in the bearstrap and skin at the same 
time as the initial detailed or HFEC inspection. The inspection 
thresholds and repetitive intervals specified in the service bulletin 
are described in the table below.

             Inspection Thresholds and Repetitive Intervals
------------------------------------------------------------------------
                                                     Repeat the detailed
                                  Do the first       or HFEC inspection
  For airplanes that have--    inspection of that       thereafter at
                                    corner--          intervals not to
                                                          exceed--
------------------------------------------------------------------------
A small steel doubler         At the later of       3,000 flight cycles.
 installed at the upper aft    10,000 total flight
 corner in production or in    cycles or within
 accordance with Boeing        1,000 flight cycles
 service bulletin 747-53-      after the original
 2025 (described below).       issue date of
                               Boeing Service
                               Bulletin 747-
                               53A2512.
A small steel doubler         At the later of       6,000 flight cycles.
 installed at the lower        10,000 total flight
 forward corner in             cycles or within
 production or in accordance   1,000 flight cycles
 with Boeing service           after the original
 bulletin 747-53-2218          issue date of
 (described below).            Boeing Service
                               Bulletin 747-
                               53A2512.
No steel doubler (large or    At the later of       1,000 flight cycles.
 small) installed at the       10,000 total flight
 upper aft corner.             cycles or within
                               1,000 flight cycles
                               after the original
                               issue date of
                               Boeing Service
                               Bulletin 747-
                               53A2512.
------------------------------------------------------------------------

    If the general visual inspection shows evidence of previous repair 
trimouts in the skin and/or bearstrap, the service bulletin gives 
procedures for doing a related investigative action. This related 
investigative action is doing an X-ray or detailed inspection for 
cracks at the repair trimouts. If no crack is found during the X-ray or 
detailed inspection, the service bulletin states that operators should 
repeat the applicable detailed or HFEC inspection at the applicable 
interval in the table above.
    If any crack is found during any detailed, HFEC, or X-ray 
inspection, the service bulletin specifies that operators should do 
another related investigative action before further flight. This 
related investigative action is a dye penetrant or HFEC inspection to 
measure the crack length in order to determine the procedures for 
corrective action. After the crack length is determined, the service 
bulletin then specifies that operators should do the applicable 
corrective action before further flight. If all cracks are inside 
certain zones specified in the service bulletin, the corrective action 
is repairing the area by trimming out or stop-drilling the crack,

[[Page 54679]]

and installing a large steel doubler at the applicable cutout corner. 
Installing a large steel doubler terminates the repetitive inspections 
for that corner. If any crack is outside certain zones specified in the 
service bulletin, the corrective action is asking Boeing for repair 
data so that the repair can be accomplished before further flight. The 
service bulletin also states that crack findings should be reported to 
Boeing.
    Accomplishing the actions specified in the service information 
described above is intended to adequately address the unsafe condition.
    Boeing Alert Service Bulletin 747-53A2512 refers to Boeing Service 
Bulletin 747-53-2218, Revision 4, dated November 9, 1989, as an 
additional source of service information for inspecting airplanes that 
do not have a steel doubler (large or small) installed at the lower 
forward corner of the fuselage cutout at MEDs number 3. AD 92-27-04 
refers to Section 4 of Boeing Document No. D6-35999, Revision C, dated 
January 21, 1992 as the appropriate source of service information for 
doing the various inspections and repairs. Boeing Document No. D6-35999 
in turn refers to Boeing Service Bulletin 747-53-2218, Revision 4, 
dated November 9, 1989, as the appropriate source of service 
information for doing the specific inspections of the lower forward 
corner of the fuselage cutout at MEDs number 3, and doing any necessary 
repairs.
    Boeing has also issued Boeing Service Bulletin 53-2025, Revision 2, 
dated March 22, 1974. This service bulletin describes procedures for 
reinforcing the cutout at MEDs number 3.

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. Therefore, we are proposing this AD, which 
would require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Differences Between the Proposed AD and Boeing Service Bulletin 747-
53A2512.''
    Although installing a small steel doubler at the lower forward 
corner of the cutout at MED number 3 terminates the repetitive 
inspection requirements of AD 92-27-04 for that area, inspections of 
that area would again be required by this proposed AD. Installing a 
large steel doubler in that area in accordance with this proposed AD or 
in accordance with Boeing Service Bulletin 747-53-2218 would terminate 
the repetitive inspection requirements of both AD 92-27-04 and this 
proposed AD for that area. Although AD 92-27-04 allows installation of 
a small steel doubler, this proposed AD would not allow that action 
after the effective date of the proposed AD.

Differences Between the Proposed AD and Boeing Service Bulletin 747-
53A2512

    Boeing Service Bulletin 747-53A2512 specifies compliance times 
relative to the date of issuance of the service bulletin; however, this 
proposed AD would require compliance before the specified compliance 
time after the effective date of this AD.
    Boeing Service Bulletin 747-53A2512 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 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.
    Although the Accomplishment Instructions of Boeing Service Bulletin 
747-53A2512 describe procedures for reporting crack findings to Boeing, 
this proposed AD would not require those actions. We do not need this 
information from operators.
    These differences have been coordinated with Boeing.

Clarification of Inspection Language

    Boeing Service Bulletin 747-53A2512 refers to a ``visual check of 
the MED number 3 cutout to determine if a small, large, or no steel 
doubler is installed.'' We have determined that the procedures in the 
service bulletin should be described as a ``general visual 
inspection.'' The service bulletin includes a definition of this 
inspection.

Costs of Compliance

    There are about 710 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Number of U.S.-
                    Action                       Work    Average labor                Parts                  Cost per       registered      Fleet cost
                                                hours    rate per hour                                       airplane        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
One-time general visual inspection...........        1             $65  None............................             $65             170         $11,050
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

[[Page 54680]]

    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 adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2005-22426; Directorate Identifier 2005-NM-
105-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by October 31, 2005.

Affected ADs

    (b) Installing a large steel doubler at the lower forward corner 
of the fuselage cutout at main entry doors (MEDs) number 3 in 
accordance with AD 92-27-04, amendment 39-8437, terminates the 
inspection requirements of this AD for that area only.

Applicability

    (c) This AD applies to all Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR 
series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of cracks in the skin and 
bearstrap at the upper aft corner and at the lower forward corner of 
the fuselage cutout at MEDs number 3. We are issuing this AD to 
detect and correct cracks in the skin, bearstrap, and small steel 
doubler (if installed), which could propagate and result in rapid 
decompression 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.

Service Bulletin Reference

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2512, Revision 1, dated August 11, 2005.

Inspection for Steel Doublers

    (g) Prior to the accumulation of 10,000 total flight cycles or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later: Do a general visual inspection of the lower 
forward and upper aft corners of the fuselage cutout at MEDs number 
3 to determine whether a small, a large, or no steel doubler is 
installed, and do the applicable action in paragraphs (g)(1) or 
(g)(2) of this AD. Do all actions in accordance with the service 
bulletin.
    (1) If a large steel doubler is installed, or if no steel 
doubler is installed at the lower forward cutout, no further action 
is required by this AD for that cutout corner, except the 
requirements of paragraph (m) of this AD continue to apply.


    Note 1: Boeing Alert Service Bulletin 747-53A2512 refers to 
Boeing Service Bulletin 747-53-2218, Revision 4, dated November 9, 
1989, as an additional source of service information for inspecting 
airplanes that are determined by the inspection required by 
paragraph (g) of this AD to have no steel doubler (large or small) 
installed at the lower forward corner of the fuselage cutout at MEDs 
number 3.


    (2) For all doubler configurations except those specified in 
paragraph (g)(1) of this AD, do the actions in paragraph (h) of this 
AD at the applicable time in that paragraph.

Inspections for Cracks, and Related Investigative and Corrective 
Actions

    (h) For the doubler configurations specified in paragraph (g)(2) 
of this AD (except as required by paragraph (i) of this AD), at the 
times specified in paragraph 1.E. ``Compliance'' of the service 
bulletin: Do the applicable inspections for cracks in the skin and 
bearstrap at the upper aft corner and at the lower forward corner of 
the fuselage cutout at MEDs number 3, and do any related 
investigative actions and corrective actions before further flight 
by doing all the actions in accordance with the service bulletin. 
Repeat the inspections thereafter at the intervals specified in 
paragraph 1.E, ``Compliance'' of the service bulletin. Where the 
service bulletin specifies to contact the manufacturer for 
instructions on how to repair certain conditions, do the repair 
using a method approved in accordance with the procedures specified 
in paragraph (n) of this AD.
    (i) Where the service bulletin specifies compliance times 
relative to the date of issuance of the service bulletin, this AD 
requires compliance relative to the effective date of this AD.

Terminating Action

    (j) Installing a large steel doubler in accordance with the 
service bulletin terminates the repetitive inspection requirements 
of this AD for the corner of the fuselage cutout at MEDs number 3 at 
which the large steel doubler is installed.

No Reporting Required

    (k) Although the service bulletin referenced in this AD 
specifies to submit certain information to the manufacturer, this AD 
does not include that a requirement.

Actions Done in Accordance With Original Issue of Service Bulletin

    (l) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin 747-53A2512, dated May 5, 
2005, are acceptable for compliance with the requirements with the 
corresponding actions of this AD.

Parts Installation

    (m) After the effective date of this AD, no person may install 
on any airplane a small steel doubler at the lower forward corner of 
the fuselage cutout at MEDs number 3, as described in Appendix A of 
the service bulletin.


    Note 2: Although AD 92-27-04, amendment 39-8437, has a 
terminating action of installing a small steel doubler in accordance 
with Boeing Service Bulletin 747-53-2218, Revision 4, dated November 
9, 1989, that action is not allowed after the effective date 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 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 September 7, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-18400 Filed 9-15-05; 8:45 am]
BILLING CODE 4910-13-P