[Federal Register Volume 69, Number 63 (Thursday, April 1, 2004)]
[Proposed Rules]
[Pages 17073-17076]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-7289]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-126-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 and -400D Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-400 and -
400D series airplanes. This proposal would require an inspection to 
detect missing fasteners in the section 42 skin and internal doubler at 
the cutout for the ground exhaust valve of the electrical equipment; 
modification and rework of the doubler; repetitive inspections of the 
skin for cracks; and corrective actions if necessary; as applicable. 
This action is necessary to detect and correct fatigue cracks in the 
section 42 skin at the cutout for the ground exhaust valve of the 
electrical equipment, which could result in rapid decompression of the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by May 17, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-126-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2003-NM-126-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the

[[Page 17074]]

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, P.O. 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: Candice Gerretsen, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6428; 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:
     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.
     For each issue, state what specific change to 
the proposed AD is being requested.
     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-126-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-126-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report that, during full-scale fatigue 
testing on a Boeing Model 747-400 fatigue test article, skin cracks 
were found at a skin cutout for the ground exhaust valve of the 
electrical equipment. One of the cracks was 18 inches long and was 
found at 33,000 total pressurization cycles. The configuration of the 
internal doubler installed around the cutout creates stress 
concentrations in the skin, which causes fatigue cracking of the skin. 
Also, Boeing records show that some fasteners may not have been 
installed on the skin doubler on certain Boeing Model 747-400 and -400D 
series airplanes during production. Fatigue cracks in the section 42 
skin at the cutout for the ground exhaust valve of the electrical 
equipment, if not detected and corrected, could result in rapid 
decompression of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2340, Revision 2, dated April 24, 2003, which describes the 
following procedures:
     For Group 1 airplanes: A general visual 
inspection to detect missing fasteners in the section 42 skin and 
internal doubler at the cutout for the ground exhaust valve of the 
electrical equipment, and applicable corrective actions, which include 
performing an open hole high frequency eddy current (HFEC) inspection 
for cracks and any applicable repair, oversizing and drilling of holes, 
and installing fasteners.
     For Group 1 and Group 2 airplanes: Modification 
and rework of the internal doubler, which includes performing an open 
hole HFEC inspection for cracks and any applicable repair, oversizing 
and drilling of holes, and installing fasteners.
     For Group 1 through Group 4 airplanes: 
Repetitive external HFEC inspections of the skin for cracks, and repair 
if necessary.
    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

    Although the service bulletin specifies that operators may contact 
the manufacturer for disposition of certain repair conditions, this 
proposed AD would require operators to repair those conditions 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.
    Operators should note that, although the service bulletin does not 
list a grace period in certain compliance times, this proposal adds a 
grace period to the compliance times. The FAA finds that such a grace 
period will keep airplanes from being grounded unnecessarily.

Clarification of Procedures in Service Bulletin

    Part 3 of the Accomplishment Instructions of the service bulletins 
specifies to ``Do a HFEC inspection of the skin and doubler as shown in 
FIGURE 8 for Group 1, 2 and 3 Airplanes and as show[n] in FIGURE 9 for 
Group 4 Airplanes.'' The correct area to accomplish this HFEC 
inspection is on the skin around the edge of the doubler, as specified 
in Figures 8 and 9.

Cost Impact

    There are approximately 142 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 22 airplanes of U.S. registry 
would be affected by this proposed AD.
    For Group 1 airplanes listed in Boeing Alert Service Bulletin 747-
53A2340, it would take approximately 1 work hour per airplane to 
accomplish the proposed inspection (Part 1), at an average labor rate 
of $65 per work hour. Based on these figures, the cost impact of this 
inspection proposed by this AD on U.S. operators is estimated to be $65 
per airplane.
    For Groups 1 and 2 airplanes listed in Boeing Alert Service 
Bulletin 747-53A2340, it would take approximately 40 work hours per 
airplane to accomplish the proposed modification and rework (Part 2), 
at an average labor rate of $65 per work hour. Based on

[[Page 17075]]

these figures, the cost impact of this modification and rework proposed 
by this AD on U.S. operators is estimated to be $2,600 per airplane.
    For Groups 1 through 4 airplanes listed in Boeing Alert Service 
Bulletin 747-53A2340, it would take approximately 1 work hour per 
airplane to accomplish the proposed inspection (Part 3), at an average 
labor rate of $65 per work hour. Based on these figures, the cost 
impact of this inspection proposed by this AD on U.S. operators is 
estimated to be $65 per airplane, per inspection cycle.
    The cost impact figures discussed above are 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-126-AD.

    Applicability: Model 747-400 and -400D series airplanes, as 
listed in paragraph 1.A., ``Effectivity,'' of Boeing Alert Service 
Bulletin 747-53A2340, Revision 2, dated April 24, 2003; certificated 
in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct fatigue cracks in the section 42 skin at 
the cutout for the ground exhaust valve of the electrical equipment, 
which could result in rapid decompression of the airplane, 
accomplish the following:

Part 1--Fastener Inspection and Corrective Actions If Necessary

    (a) For Group 1 airplanes listed in Boeing Alert Service 
Bulletin 747-53A2340, Revision 2, dated April 24, 2003: Within 250 
flight cycles or 4 months after the effective date of this AD, 
whichever occurs later, do a general visual inspection to detect 
missing fasteners in the section 42 skin and internal doubler at the 
cutout for the ground exhaust valve of the electrical equipment, per 
Part 1 of the Accomplishment Instructions of the service bulletin.
    (1) If all fasteners are installed, do the actions specified in 
paragraph (b) of this AD at the indicated time.
    (2) If any fastener is missing, before further flight, 
accomplish all applicable corrective actions (i.e., performing an 
open hole high frequency (HFEC) inspection for cracks and any 
applicable repair, oversizing and drilling of holes, and 
installation of fasteners), in accordance with Part 1 of the 
Accomplishment Instructions of the service bulletin, except as 
required by paragraph (f) of this AD.

Part 2--Modification and Rework

    (b) For Group 1 and Group 2 airplanes listed in Boeing Alert 
Service Bulletin 747-53A2340, Revision 2, dated April 24, 2003: 
Before the accumulation of 6,000 total flight cycles, or within 
1,500 flight cycles or 24 months after the effective date of this 
AD, whichever occurs later: Modify and rework the internal doubler 
(i.e., performing an open hole HFEC inspection for cracks and any 
applicable repair, oversizing and drilling of holes, and 
installation of fasteners) by accomplishing all actions specified in 
Part 2 of the Accomplishment Instructions of the service bulletin. 
Do the actions per the service bulletin, except as required by 
paragraph (f) of this AD. Any applicable repair must be accomplished 
before further flight.

Part 3--Repetitive Inspections and Repair If Necessary

    (c) At the applicable time specified in paragraph (c)(1) or 
(c)(2) of this AD, do an external HFEC inspection of the skin for 
cracks per Part 3 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2340, Revision 2, dated April 24, 2003.
    (1) For Group 1 and Group 2 airplanes listed in the service 
bulletin: Within 10,000 flight cycles after accomplishing the 
actions required by paragraph (b) of this AD, or within 1,500 flight 
cycles or 24 months after the effective date of this AD, whichever 
occurs later.
    (2) For Group 3 and Group 4 airplanes listed in the service 
bulletin: Before the accumulation of 15,000 total flight cycles, or 
within 1,500 flight cycles or 24 months after the effective date of 
this AD, whichever occurs later.
    (d) If no crack is detected during the external HFEC inspection 
required by paragraph (c) of this AD, repeat the external HFEC 
inspection thereafter at intervals not to exceed 5,000 flight 
cycles.
    (e) If any crack is detected during the external HFEC inspection 
required by paragraph (c) of this AD, before further flight, repair 
per Part 3 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2340, Revision 2, dated April 24, 2003, 
except as required by paragraph (f) of this AD. Repeat the external 
HFEC inspection in the unrepaired areas thereafter at intervals not 
to exceed 5,000 flight cycles.

Exception to Service Bulletin Actions

    (f) If any discrepancy is found during any inspection required 
by this AD, and the bulletin specifies to contact Boeing for an 
alternate repair: 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.

Credit for Previous Revisions of Service Bulletins

    (g) Actions accomplished before the effective date of this AD 
per Boeing Alert Service Bulletin 747-53A2340, original issue, dated 
August 1, 1991; or Revision 1, dated October 31, 1991, is acceptable 
for compliance with the requirements of this AD.

Alternative Methods of Compliance

    (h)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
ACO, FAA, is authorized to approve alternative methods of compliance 
(AMOCs) for this AD.
    (2) An AMOC that provides an acceptable level of safety may be 
used for any inspection or 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

[[Page 17076]]

make such findings. For an inspection or repair method to be 
approved, the approval must specifically reference this AD.

    Issued in Renton, Washington, on March 26, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-7289 Filed 3-31-04; 8:45 am]
BILLING CODE 4910-13-U