[Federal Register Volume 69, Number 25 (Friday, February 6, 2004)]
[Proposed Rules]
[Pages 5765-5767]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-2469]



[[Page 5765]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-107-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Model 747 series airplanes. 
This proposal would require a repetitive detailed inspection of the aft 
pressure bulkhead for indications of ``oil cans'' and previous ``oil 
can'' repairs, and corrective actions, if necessary. An ``oil can'' is 
an area on a pressure dome web that moves when pushed from the forward 
side. This action is necessary to detect and correct the propagation of 
fatigue cracks in the vicinity of ``oil cans'' on the web of the aft 
pressure bulkhead, which could result in rapid decompression and 
overpressurization of the tail section, and consequent loss of control 
of the airplane. This action is intended to address the identified 
unsafe condition.

DATES: Comments must be received by March 22, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-107-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
<a href="/cdn-cgi/l/email-protection#221b0f434c4f0f4c52504f414d4f4f474c56624443430c454d54"><span class="__cf_email__" data-cfemail="1c25317d727131726c6e717f7371717972685c7a7d7d327b736a">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2003-NM-107-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplanes, PO Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Nicholas 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.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
    <bullet<ls-thn-eq> Organize comments issue-by-issue. For example, 
discuss a request to change the compliance time and a request to change 
the service bulletin reference as two separate issues.
    <bullet<ls-thn-eq> For each issue, state what specific change to 
the proposed AD is being requested.
    <bullet<ls-thn-eq> Include justification (e.g., reasons or data) 
for each request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2003-NM-107-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2003-NM-107-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that a 2.1-inch long crack 
in the web of the aft pressure bulkhead at the perimeter of an ``oil 
can'' was found on a Model 747SR series airplane. An ``oil can'' is an 
area on a pressure dome web that moves when pushed from the forward 
side. The cause of the crack is fatigue. This condition, if not 
detected and corrected, could result in the propagation of fatigue 
cracks in the vicinity of ``oil cans'' on the web of the aft pressure 
bulkhead, which could result in rapid decompression and 
overpressurization of the tail section, and consequent loss of control 
of the airplane.
    The subject area on Model 747SR series airplanes is almost 
identical to that on Model 747-100, -200B, -200F, -200C, -100B, -300, -
100B-SUD, -400, -400D, and -400F series airplanes; and Model 747SP 
series airplanes. Therefore, those airplanes may be subject to the 
unsafe condition revealed on the Model 747SR series airplanes.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2482, dated October 3, 2002, which describes procedures for 
performing a repetitive detailed inspection of the aft pressure 
bulkhead for indications of ``oil cans'' and previous ``oil can'' 
repairs, and corrective actions, if necessary. The corrective actions 
include performing a repetitive eddy current inspection of the web 
around the periphery of the ``oil can'' for cracks, and repair if 
necessary; and performing a detailed inspection of the web around 
previous ``oil can'' repairs for cracks. Repair of all ``oil cans'' 
eliminates the need for the repetitive eddy current inspection of 
existing ``oil cans.'' Accomplishment of the actions specified in the 
service bulletin is intended to adequately address the identified 
unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that when a previous ``oil can'' repair is 
found, section 3.B.9.a. of the service bulletin states that if no 
cracking is found, no

[[Page 5766]]

action on the repaired area is required at this time, and that the 
repetitive inspections of the aft pressure bulkhead for ``oil cans'' at 
2,000 flight cycle intervals are to continue. The FAA has determined, 
however, that the actions specified in the service bulletin for ``oil 
cans'' found at previous ``oil can'' repairs are insufficient. It is 
possible that the ``oil can'' that was originally repaired within the 
allowable limits of the service bulletin has since grown to exceed the 
allowable limits. In accordance with Figure 4 or Figure 5 of the 
service bulletin, this proposed AD would require an eddy current 
inspection for cracks if ``oil cans'' are found at previous ``oil can'' 
repairs. In addition, if no cracking is found, this proposed AD would 
require verification that any ``oil cans'' at previous ``oil can'' 
repairs are within the allowable limits of the service bulletin. For 
any ``oil can'' that meets the allowable limits, this proposed AD would 
require repetitive eddy current inspections at intervals not to exceed 
1,000 flight cycles until a repair that terminates the ``oil can'' is 
completed. For any ``oil can'' that does not meet the allowable limits, 
this proposed AD would require repair of the ``oil can'' and, if any 
``oil can'' remains after the repair, this proposed AD would require 
repetitive eddy current inspections at intervals not to exceed 1,000 
flight cycles.
    Operators should also 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, 
or per data meeting the type certification basis of the airplane 
approved by a Boeing Company Designated Engineering Representative who 
has been authorized by the FAA to make such findings.

Cost Impact

    There are approximately 1,140 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 254 airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 6 work hours per airplane to accomplish the proposed 
inspections, and that the average labor rate is $65 per work hour. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $99,060, or $390 per airplane, per 
inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 2003-NM-107-AD.

    Applicability: All Model 747 series airplanes; certificated in 
any category.
    Compliance: Required as indicated, unless accomplished 
previously.

    Note 1: This AD refers to certain portions of a Boeing service 
bulletin for inspections and repair information. In addition, this 
AD specifies requirements beyond those included in the service 
bulletin. Where the AD and the service bulletin differ, the AD 
prevails.

    To detect and correct the propagation of fatigue cracks in the 
vicinity of ``oil cans'' on the web of the aft pressure bulkhead, 
which could result in rapid decompression and overpressurization of 
the tail section, and consequent loss of control of the airplane, 
accomplish the following:

Service Bulletin References

    (a) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2482, dated October 3, 2002.

Initial and Repetitive Inspections

    (b) Prior to the accumulation of 30,000 flight cycles, or within 
1,000 flight cycles after the effective date of this AD, whichever 
is later, perform a detailed inspection of the aft pressure bulkhead 
for indications of ``oil cans'' and previous ``oil can'' repairs, in 
accordance with the service bulletin.

    Note 2: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

    (c) If no indication of an ``oil can'' is found and no 
indication of a previous ``oil can'' repair is found, during the 
detailed inspection required by paragraph (b) of this AD, repeat the 
detailed inspection thereafter at intervals not to exceed 2,000 
flight cycles.

Indication of ``Oil Can''

    (d) If any indication of an ``oil can'' is found during the 
detailed inspection required by paragraph (b) or (c) of this AD, 
before further flight, perform an eddy current inspection of the web 
around the periphery of the ``oil can'' indication for cracks, as 
shown in Figure 3 of the service bulletin.
    (e) If no crack is found during the eddy current inspection 
required by paragraphs (d) and (f)(2) of this AD, do the actions 
specified in paragraph (e)(1) or (e)(2) of this AD, as applicable.
    (1) For the ``oil can'' that meets the allowable limits 
specified in the service bulletin: Repeat the eddy current 
inspection specified in paragraph (d) of this AD thereafter at 
intervals not to exceed 1,000 flight cycles. As an option, repair 
the ``oil can'' in accordance with paragraph (e)(2) of this AD.
    (2) For the ``oil can'' that does not meet the allowable limits 
specified in the service bulletin: Before further flight, repair the 
``oil can'' in accordance with the service bulletin. If the repair 
eliminates the ``oil can,'' accomplishment of this repair 
constitutes a terminating action for the repetitive eddy

[[Page 5767]]

current inspection requirements of paragraph (e)(1) of this AD for 
this location only. However, the repetitive detailed inspection 
required by paragraph (c) of this AD is still required. If any ``oil 
can'' remains after the repair, repeat the eddy current inspection 
thereafter at intervals not to exceed 1,000 flight cycles.

Indication of Previous ``Oil Can'' Repairs

    (f) If any previous ``oil can'' repair is found during the 
detailed inspection required by paragraph (b) or (c) of this AD, 
before further flight, do a detailed inspection of the web for 
cracks and ``oil cans,'' as shown in Figure 4 or Figure 5 of the 
service bulletin, as applicable.
    (1) If no crack and no ``oil can'' are found, repeat the 
detailed inspection in accordance with paragraph (c) of this AD.
    (2) If any ``oil can'' is found, before further flight, do the 
eddy current inspection for cracks as shown in Figure 3 of the 
service bulletin.
    (3) If no crack is found during the eddy current inspection 
required by paragraph (f)(2) of this AD, do the actions specified in 
paragraph (e)(1) or (e)(2) of this AD, as applicable.

Repair of Cracks

    (g) If any crack is found during any inspection required by this 
AD, before further flight, repair in accordance with the service 
bulletin. If cracks or damage exceeds limits specified in the 
service bulletin and the service bulletin specifies to contact 
Boeing for appropriate action: Before further flight, repair per a 
method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or per data meeting the type certification basis 
of the airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the Manager, Seattle ACO, 
to make such findings. For a repair method to be approved, the 
approval must specifically reference this AD.

Alternative Methods of Compliance

    (h) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, 
FAA, is authorized to approve alternative methods of compliance for 
this AD.

    Issued in Renton, Washington, on January 29, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-2469 Filed 2-5-04; 8:45 am]
BILLING CODE 4910-13-P


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