
[Federal Register: November 19, 2007 (Volume 72, Number 222)]
[Proposed Rules]               
[Page 64961-64964]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19no07-17]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0204; Directorate Identifier 2007-NM-083-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-100, -100B, -100B SUD, 
-200B, -200C, -200F, -300, 747SP, and 747SR Series Airplanes Powered by 
General Electric (GE) CF6-45/50 and Pratt & Whitney (P&W) JT9D-70, 
JT9D-3 or JT9D-7 Series Engines

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, -100B, -100B SUD, -200B, -200C, -
200F, -300, 747SP, and 747SR series airplanes powered by General 
Electric (GE) CF6-45/50 and Pratt & Whitney (P&W) JT9D-70, JT9D-3 or 
JT9D-7 series engines. This proposed AD would require repetitive 
inspections to find cracks and broken fasteners of the rear engine 
mount bulkhead of the inboard and outboard nacelle struts, and repair 
if necessary. For certain airplanes, this proposed AD mandates a 
terminating modification for certain inspections of the inboard and 
outboard nacelle struts. This proposed AD results from reports of web 
and frame cracks and sheared attachment fasteners on the inboard and 
outboard nacelle struts. We are proposing this AD to detect and correct 
cracks and broken fasteners of the inboard and outboard nacelle struts, 
which could result in possible loss of the rear engine mount bulkhead 
load path and consequent separation of the engine from the airplane.

DATES: We must receive comments on this proposed AD by January 3, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, 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: Tamara Anderson, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6421; 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-
0204; Directorate Identifier 2007-NM-083-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://
www.regulations.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://www.regulations.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday,

[[Page 64962]]

except Federal holidays. The Docket Operations office (telephone (800) 
647-5527) is located on the ground floor of the West 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

    On January 2, 2002, the FAA issued a notice of proposed rulemaking 
(NPRM), Docket No. 2001-NM-40-AD, to address the identified unsafe 
condition; that action was published in the Federal Register on January 
9, 2002 (67 FR 1167). That NPRM proposed to require repetitive 
inspections to find cracks and broken fasteners of the inboard and 
outboard nacelle struts of the rear engine mount bulkhead, and repair 
if necessary. For certain airplanes, that NPRM provided for an optional 
terminating modification for the inspections of the outboard nacelle 
struts. That NPRM was prompted by reports indicating that fatigue 
cracking of the inboard and outboard nacelle struts of the rear engine 
mount bulkhead was found. The unsafe condition is cracks and broken 
fasteners of the inboard and outboard nacelle struts. Subsequently, we 
worked with the manufacturer to ensure that the unsafe condition is 
adequately addressed and appropriate service instructions are 
available. We have also received many new reports of additional web and 
frame cracks and sheared attachment fasteners, and reports of cracks on 
the outboard struts of airplanes not identified in the applicability of 
that NPRM. In addition, we have considered comments submitted in 
response to that NPRM.
    In light of all this information, we have determined that the 
corrective actions required by that NPRM are inadequate for addressing 
the identified unsafe condition; therefore, we have withdrawn that NPRM 
and are issuing this new proposed AD to address the unsafe condition.

Relevant Service Information

    In light of those new reports, Boeing has issued Alert Service 
Bulletin 747-54A2202, Revision 1, dated June 22, 2006. The original 
issue, dated December 21, 2000, was referred to in the NPRM, Docket No. 
2001-NM-40-AD, as the appropriate source of service information for 
accomplishing certain actions. Revision 1 includes the following 
changes to the original issue:
     Adds additional airplanes powered by General Electric (GE) 
CF6-45/50 series engines to the effectivity (identified as Group 6 
airplanes).
     Adds modifications, inspections, and post-modification 
inspections for airplanes in Groups 1 through 5 (those included in the 
effectivity of the original issue of the service bulletin).
     Adds outboard strut inspections for Groups 3, 4, and 5 
airplanes included in the effectivity of the original issue of the 
service bulletin.
    The compliance times listed in the Part A Inspections, as specified 
in the service bulletin, are as follows: The compliance time for 
airplanes on which the detailed visual and high frequency eddy current 
(HFEC) inspections of the inboard and outboard strut rear engine mount 
bulkheads in the original issue of the service bulletin have been done 
ranges from 180 days to 18 months from the release date of Revision 1 
of the service bulletin or 350 flight cycles to 1,200 flight cycles, 
whichever occurs earlier; the repetitive interval ranges from 350 
flight cycles to 1,200 flight cycles or 18 months, whichever occurs 
earlier.
    The compliance time for airplanes on which the inspections in the 
original issue of the service bulletin have not been done is within 90 
days from the release date of Revision 1 of the service bulletin to 
within 18 months or 1,200 flight cycles, whichever occurs earlier; the 
repetitive interval ranges from 350 flight cycles to 1,200 flight 
cycles or 18 months, whichever occurs earlier. The compliance times 
depend on airplane configuration and nacelle strut position.
    The compliance times listed in the Part B Inspections--Post 
Modification, as specified in the service bulletin, are as follows: The 
compliance time for airplanes on which the repairs have been done 
ranges from 600 flight cycles to 7,200 flight cycles or 18 months after 
repair; the repetitive interval ranges from 600 flight cycles to 1,200 
flight cycles or 18 months, whichever occurs earlier. At 7,200 flight 
cycles after repair the repetitive interval changes from doing a 
detailed visual inspection every 1,200 flight cycles or 18 months, to 
doing detailed visual and HFEC inspections every 1,200 flight cycles or 
18 months.
    Depending on the group, the service bulletin specifies doing the 
following repairs, related investigative actions, and corrective 
actions:
     For Groups 1, 2, and 5 airplanes (on inboard struts only 
for Group 5): If any crack is found, do Repair 1 of the service 
bulletin. Replace cracked frames with new frames, and install repair 
doublers, chords, and corrosion resistant steel (CRES) repair angles 
before further flight. Repair 1 includes the following related 
investigative and corrective actions: Detailed visual and HFEC 
inspections for cracks of the bulkhead frame, replacement of cracked 
frames, inspection of holes in frames for cracks, inspection of holes 
in chords for cracks, replacement of cracked chords, inspection of 
holes in frame and skin for cracks, contacting Boeing for repair for 
cracks in skin, inspection of holes on aft left-hand and right-hand 
sides of bulkhead in frame and skin for cracks, inspection of frame 
edge for cracks, and inspection of the holes on the forward side of 
bulkhead in frame and skin for cracks.
     For Groups 1 and 5 airplanes (on inboard struts only for 
Group 5): If more than two broken fasteners are found, do Repair 2 or 3 
of the service bulletin (depending on configuration). Install doublers, 
chords, and CRES repair angles before further flight.

    --Repair 2 includes the following related investigative and 
corrective actions: Detailed visual and HFEC inspections for cracks of 
the bulkhead frame, repair or replacement of cracked frames, inspection 
of holes in frames for cracks, inspection of holes in chords for 
cracks, replacement of cracked chords, inspection of holes on aft left-
hand and right-hand sides of bulkhead in frame and skin for cracks, 
inspection of frame edge for cracks, and inspection of the holes on the 
forward side of bulkhead in frame and skin for cracks.
    --Repair 3 includes the following related investigative and 
corrective actions: Inspection of holes in frames for cracks, 
replacement of cracked frames, inspection of frame edge for cracks, and 
replacement of cracked frames.

     For Group 1 airplanes: If any new crack, extension of 
stop-drilled crack, or more than two broken fasteners are found, do 
Repair 4 of the service bulletin. Install additional CRES repair angles 
before further flight. Repair 4 includes the following related 
investigative and corrective actions: HFEC inspections of the fastener 
holes and open holes of the bulkhead frame for cracks, stop drill or 
trim out cracks found in the frame only, contact Boeing for repair of 
cracks in the existing doubler or repair angle, and fabricate and 
install certain repair angles.
     For Groups 1, 2, and 5 airplanes: If only one or two 
broken fasteners are found, do Repair 5 of the service bulletin, 
replace the fasteners before further flight, and do Repair 2, 3, or 4, 
depending on configuration, within 18 or 36 months from the release 
date of the service bulletin, as applicable. Repair 5 includes the 
following related investigative and corrective actions:

[[Page 64963]]

HFEC inspections of the fastener holes for cracks, and repair of any 
cracks.
     For Groups 3, 4, and 6 airplanes: If any crack, or more 
than two broken fasteners are found, do the applicable repair before 
further flight (contact Boeing or repair per the structural repair 
manual, depending on configuration).
     For Groups 3, 4, and 6 airplanes: If only one or two 
broken fasteners are found, do Repair 5 of the service bulletin before 
further flight.
     For Group 5 airplanes (outboard strut only): If any crack 
or broken fastener is found, repair and contact Boeing before further 
flight.
     For airplanes that have done post-modification 
inspections: If any crack or broken fastener is found, repair and 
contact Boeing before further flight.
    The procedures in the service bulletin specify doing the following 
modifications for Groups 1, 2, and 5 airplanes, depending on airplane 
configuration:
     If no crack or broken fastener is found, do Repair 2 or 3 
within 18 to 36 months.
     If no new crack, extension of stop drill cracking, or 
broken fastener is found, do Repair 4 within 36 months.

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 below.

Differences Between the Alert Service Bulletin and This Proposed AD

    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 Inspection Terminology

    In this NPRM, the ``detailed visual inspection'' specified in 
Boeing Alert Service Bulletin 747-54A2202, Revision 1, is referred to 
as a ``detailed inspection.''

Costs of Compliance

    There are about 460 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 135 airplanes of 
U.S. registry.
    It would take about 4 work hours per airplane to accomplish the 
proposed detailed inspection, at an average labor rate of $80 per work 
hour. Based on these figures, the estimated cost of the proposed 
inspection is $43,200, or $320 per airplane, per inspection cycle.
    It would take about 32 work hours per airplane to accomplish the 
proposed high frequency eddy current inspection, at an average labor 
rate of $80 per work hour. Based on these figures, the estimated cost 
of the proposed high frequency eddy current inspection is $345,600, or 
$2,560 per airplane, per inspection cycle.
    For Groups 1, 2, and 5 airplanes, it would take between 
approximately 10 and 95 work hours per strut (four struts per airplane) 
to accomplish the proposed modification, depending on airplane 
configuration, at an average labor rate of $80 per work hour. Parts 
cost for the fasteners only would be between $269 and $897 per strut. 
Based on these figures, the cost impact of the proposed modification 
would be between $4,276 and $33,988 per airplane. We are unable to 
provide specific information as to the cost of the actual parts other 
than the fasteners that would be required to accomplish the proposed 
modification since the parts would be supplied from operator stock.

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.

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-2007-0204; Directorate Identifier 2007-NM-
083-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
3, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Model 747-100, -100B, -100B SUD, 200B, 
200C, -200F, -300, 747SP, and 747SR series airplanes; certificated 
in any category; powered by General Electric (GE) CF6-45/50 and 
Pratt & Whitney (P&W) JT9D-70, JT9D-3 or JT9D-7 series engines; as 
identified in Boeing Alert Service Bulletin 747-54A2202, Revision 1, 
dated June 22, 2006.

[[Page 64964]]

Unsafe Condition

    (d) This AD results from reports of web and frame cracks and 
sheared attachment fasteners on the inboard and outboard nacelle 
strut. We are issuing this AD to detect and correct cracks and 
broken fasteners of the inboard and outboard nacelle struts, which 
could result in possible loss of the rear engine mount bulkhead load 
path and consequent separation of the engine from 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.

Compliance Times

    (f) Do all applicable actions specified in paragraphs (g), (h), 
and (i) of this AD at the applicable times specified in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 747-54A2202, 
Revision 1, dated June 22, 2006, except that where paragraph 1.E. of 
the service bulletin specifies starting the compliance time from ``* 
* * the release date of Revision 1 of this service bulletin,'' this 
AD requires starting the compliance time from the effective date of 
this AD.

Initial and Repetitive Inspections/Corrective Actions

    (g) For all airplanes: Perform detailed and high frequency eddy 
current inspections for cracks and broken fasteners of the rear 
engine mount bulkhead of the inboard and outboard nacelle struts, 
and do all applicable related investigative and corrective actions, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-54A2202, Revision 1, dated June 22, 2006. 
Repeat the applicable inspection and actions thereafter at the 
applicable interval specified in paragraph 1.E., ``Compliance,'' of 
the service bulletin. Accomplishing the applicable repair (Repair 1, 
2, 3, or 4, or repair per the 747 structural repair manual, section 
54-11-03 or 54-12-03) terminates the requirements in this paragraph 
for that nacelle strut only.

Modification

    (h) For Groups 1, 2, and 5 airplanes: Do the applicable 
modification (Repair 2, 3, or 4) of the rear engine mount bulkhead 
of the inboard and outboard nacelle struts, and all the applicable 
related investigative and corrective actions, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
54A2202, Revision 1, dated June 22, 2006. Accomplishing this 
modification terminates the requirements in paragraph (g) of this AD 
for that nacelle strut only.

Post-Modification Inspection/Corrective Actions

    (i) For Groups 1, 2, and 5 airplanes on which the applicable 
corrective actions (Repair 1, 2, 3, or 4) required by paragraph (g) 
of this AD have been accomplished; or the applicable modification 
(Repair 2, 3, or 4) required by paragraph (h) of this AD has been 
accomplished: At the applicable time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 747-54A2202, 
Revision 1, dated June 22, 2006, or within 6 months after the 
effective date of this AD, whichever occurs later, perform detailed 
and high frequency eddy current inspections for cracks and broken 
fasteners of the rear engine mount bulkhead of the inboard and 
outboard nacelle struts, and do all applicable related investigative 
and corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-54A2202, Revision 
1, dated June 22, 2006. Repeat the applicable inspections and 
actions thereafter at the applicable interval specified in paragraph 
1.E., ``Compliance,'' of the service bulletin.

Exception to Service Bulletin

    (j) If any crack or any broken fastener is found during any 
inspection required by this AD, and Boeing Alert Service Bulletin 
747-54A2202, Revision 1, dated June 22, 2006, specifies to contact 
Boeing for appropriate action: Before further flight, repair the 
discrepancy using a method approved in accordance with the 
procedures specified in paragraph (k) of this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(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) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.
    (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 November 7, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-22542 Filed 11-16-07; 8:45 am]

BILLING CODE 4910-13-P
