Airworthiness Directives; Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR Series Airplanes Equipped with General Electric (GE) CF6-45 or -50 Series Engines, 51-53 [04-28667]

Download as PDF 51 Proposed Rules Federal Register Vol. 70, No. 1 Monday, January 3, 2005 This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules. DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2004–19945; Directorate Identifier 2004–NM–22–AD] RIN 2120–AA64 Airworthiness Directives; Boeing Model 747–200B, 747–200C, 747–200F, 747–300, and 747SR Series Airplanes Equipped with General Electric (GE) CF6–45 or –50 Series Engines Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). AGENCY: SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747–200B, 747– 200C, 747–200F, 747–300, and 747SR series airplanes, equipped with GE CF6– 45 or –50 series engines. This proposed AD would require modifying the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings. This proposed AD is prompted by reports of a gap at the interface of the lower portion of the side cowl and the aft flange of the thrust reverser. We are proposing this AD to prevent an excessive quantity of air from entering the fire zone that surrounds the engine, which in the event of an engine fire, could result in an inability to control or extinguish the fire. DATES: We must receive comments on this proposed AD by February 17, 2005. ADDRESSES: Use one of the following addresses to submit comments on this proposed AD. • DOT Docket Web site: Go to https://dms.dot.gov and follow the instructions for sending your comments electronically. • Government-wide rulemaking Web site: Go to https://www.regulations.gov and follow the instructions for sending your comments electronically. VerDate jul<14>2003 14:41 Dec 30, 2004 Jkt 205001 • 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 https:// 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–2004– 19945; the directorate identifier for this docket is 2004–NM–22–AD. FOR FURTHER INFORMATION CONTACT: Dan Kinney, Aerospace Engineer, Propulsion Branch, ANM–140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055–4056; telephone (425) 917–6499; fax (425) 917–6590. SUPPLEMENTARY INFORMATION: Comments Invited We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include ‘‘Docket No. FAA– 2004–19945; Directorate Identifier 2004–NM–22–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 https:// 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, PO 00000 Frm 00001 Fmt 4702 Sfmt 4702 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 https:// dms.dot.gov. Examining the Docket You can examine the AD docket on the Internet at https://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 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 DMS receives them. Discussion We have received reports indicating that a gap may form at the interface of the lower portion of the side cowl and the aft flange of the thrust reverser on certain Boeing Model 747–200B, 747– 200C, 747–200F, 747–300, and 747SR series airplanes, equipped with General Electric CF6–45 or –50 series engines. The gap forms when high engine thrust is applied, but may not always close when thrust is reduced. The gap is attributed to axial deflection of the engine case combined with the difference in the rate of expansion due to heat between the aluminum frame of the thrust reverser and the titanium frame of the engine. The gap may allow an excessive quantity of air into the nacelle surrounding the engine, which is a fire zone that is equipped with fire detection, containment, and extinguishing provisions. However, excess air in the area could defeat some or all of the fire protection provisions. This condition, if not corrected, could result in an inability to control or extinguish an engine fire. Relevant Service Information We have reviewed Boeing Service Bulletin 747–71–2300, Revision 1, dated October 30, 2003. The service bulletin describes procedures for modifying the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings. The procedures for replacing the existing wear plates include performing open-hole high frequency eddy current (HFEC) E:\FR\FM\03JAP1.SGM 03JAP1 52 Federal Register / Vol. 70, No. 1 / Monday, January 3, 2005 / Proposed Rules inspections for cracking of existing fastener holes, and creating new fastener holes and plugging existing holes if necessary. The procedures for installing the new stop fittings involves installing brackets, channels, and wear pads; replacing existing fasteners with new fasteners if necessary; performing openhole HFEC inspections for cracking of fastener holes; and oversizing fastener holes and installing different-sized fasteners if necessary. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. Boeing Service Bulletin 747–71–2300, Revision 1, refers to Boeing Service Letter 747-SL–71–045-C, dated April 10, 2003, as the applicable source of service information for doing certain recommended actions. Among other actions, Boeing Service Letter 747-SL– 71–045-C describes procedures for improving the aerodynamic smoothness of the side cowl assemblies by removing bulb seals that may have been installed on the trailing edge of the fan thrust reverser in accordance with a previous issue of Boeing Service Letter 747-SL– 71–045. The procedures for removing the bulb seals include plugging open holes on the trailing edge of the fan thrust reverser, and adjusting the cowl latches if necessary. 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 modifying the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates, and installing new stop fittings. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed under ‘‘Differences Between the Proposed AD and Service Information.’’ Differences Between the Proposed AD and Service Information Section 1.B., ‘‘Concurrent Requirements,’’ of Boeing Service Bulletin 747–71–2300, Revision 1, states that the service bulletin ‘‘assumes that the cowls have had wear plates installed per Service Bulletin 747–54–2093.’’ We have determined that Boeing Service Bulletin 747–71–2300, Revision 1, refers to Boeing Service Bulletin 747–54–2093 only because Boeing Service Bulletin 747–71–2300, Revision 1, removes certain parts that may have been installed according to Boeing Service Bulletin 747–54–2093. We have discussed this matter with Boeing and have determined that the Accomplishment Instructions in Boeing Service Bulletin 747–71–2300, Revision 1, are effective regardless of whether Boeing Service Bulletin 747–54–2093 has been done. In light of this information, this proposed AD would not require the actions in Boeing Service Bulletin 747–54–2093. Boeing Service Bulletin 747–71–2300, Revision 1, also ‘‘assumes’’ that one certain airplane has been modified to have a narrower trailing edge strip. We have determined that the subject airplane has been modified; thus, this proposed AD would not require this modification. As described previously, Boeing Service Bulletin 747–71–2300, Revision 1, recommends that bulb seals installed previously in accordance with a previous issue of Boeing Service Letter 747–SL–71–045 be removed in accordance with Boeing Service Letter 747–SL–71–045–C, dated April 10, 2003. If the bulb seals were previously installed, paragraph (g) of this proposed AD would require you to remove them concurrent with or before further flight after accomplishing the actions in Boeing Service Bulletin 747–71–2300, Revision 1. Costs of Compliance This proposed AD would affect about 38 airplanes of U.S. registry and 140 airplanes worldwide. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. ESTIMATED COSTS Action Work hours Modification per Boeing Service Bulletin 747–71–2300, Revision 1 ....... Authority for This Rulemaking The FAA’s authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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. This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, ‘‘General requirements.’’ Under that section, the FAA is charged 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 VerDate jul<14>2003 14:41 Dec 30, 2004 Jkt 205001 Average labor rate per hour 72 because it addresses an unsafe condition that is likely to exist or develop on products identified in this proposed AD. 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; PO 00000 Frm 00002 Fmt 4702 Sfmt 4702 $65 Parts $25,736 Cost per airplane $30,416 Fleet cost $1,155,808 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. 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, E:\FR\FM\03JAP1.SGM 03JAP1 Federal Register / Vol. 70, No. 1 / Monday, January 3, 2005 / Proposed Rules 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. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD): Alternative Methods of Compliance (AMOCs) (h) 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. Issued in Renton, Washington, on December 20, 2004. Kevin M. Mullin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 04–28667 Filed 12–30–04; 8:45 am] BILLING CODE 4910–13–P Boeing: Docket No. FAA–2004–19945; Directorate Identifier 2004–NM–22–AD. Comments Due Date. (a) The Federal Aviation Administration (FAA) must receive comments on this AD action by February 17, 2005. ENVIRONMENTAL PROTECTION AGENCY Affected ADs [R06–OAR–2004–TX–0003; FRL–7856–6] (b) None. Applicability (c) This AD applies to Boeing Model 747– 200B, 747–200C, 747–200F, 747–300, and 747SR series airplanes; certificated in any category; equipped with General Electric CF6–45 or –50 series engines. Unsafe Condition (d) This AD was prompted by reports of a gap at the interface of the lower portion of the side cowl and the aft flange of the thrust reverser. We are issuing this AD to prevent an excessive quantity of air from entering the fire zone that surrounds the engine, which, in the event of an engine fire, could result in an inability to control or extinguish the fire. 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. Modification (f) Within 24 months after the effective date of this AD: Modify the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings, by doing all actions according to the Accomplishment Instructions of Boeing Service Bulletin 747–71–2300, Revision 1, dated October 30, 2003. Any applicable corrective actions must be done before further flight. On Condition: Removal of Bulb Seals and Other Specified Actions (g) If bulb seals were installed on the trailing edge of the fan thrust reverser in accordance with Boeing Service Letter 747– SL–71–045: Concurrent with or before further flight after accomplishing paragraph (f) of this AD, remove the bulb seals, plug the open holes in the trailing edge of the fan thrust reverser, and adjust the cowl latches as applicable, in accordance with Boeing Service Letter 747–SL–71–045–C, dated April 10, 2003. VerDate jul<14>2003 15:23 Dec 30, 2004 Jkt 205001 40 CFR Part 52 Approval and Promulgation of Implementation Plans; Texas; Victoria County Maintenance Plan Update Environmental Protection Agency (EPA). ACTION: Proposed rule. AGENCY: SUMMARY: EPA is proposing to approve a State Implementation Plan (SIP) revision submitted by the Texas Commission on Environmental Quality (TCEQ) on February 18, 2003, concerning the Victoria County 1-hour ozone maintenance area. This SIP revision satisfies the Clean Air Act requirement as amended in 1990 for the second 10-year update to the Victoria County 1-hour ozone maintenance area. DATES: Written comments should be received on or before February 2, 2005. ADDRESSES: Comments may be mailed to Mr. Thomas Diggs, Chief, Air Planning Section (6PD–L), Environmental Protection Agency, 1445 Ross Avenue, Suite 1200, Dallas, Texas, 75202–2733. Comments may also be submitted electronically or through hand delivery/ courier by following the detailed instructions in the ADDRESSES section of the direct final rule located in the rules section of this Federal Register. FOR FURTHER INFORMATION CONTACT: Peggy Wade, Air Planning Section (6PD–L), Environmental Protection Agency, Region 6, 1445 Ross Avenue, Suite 700, Dallas, Texas 75202–2733, telephone (214) 665–7247; fax number 214–665–7263; e-mail address wade.peggy@epa.gov. SUPPLEMENTARY INFORMATION: In the final rules section of this Federal Register, EPA is approving the State’s SIP submittal as a direct final rule without prior proposal because the Agency views this as a noncontroversial PO 00000 Frm 00003 Fmt 4702 Sfmt 4702 53 submittal and anticipates no adverse comments. A detailed rationale for the approval is set forth in the direct final rule. If no adverse comments are received in response to this action rule, no further activity is contemplated. If EPA receives adverse comments, the direct final rule will be withdrawn and all public comments received will be addressed in a subsequent final rule based on this proposed rule. EPA will not institute a second comment period. Any parties interested in commenting on this action should do so at this time. Please note that if EPA receives adverse comment on an amendment, paragraph, or section of this rule and if that provision may be severed from the remainder of the rule, EPA may adopt as final those provisions of the rule that are not the subject of an adverse comment. For additional information, see the direct final rule which is located in the rules section of this Federal Register. Dated: December 17, 2004. Richard E. Greene, Regional Administrator, Region 6. [FR Doc. 04–28701 Filed 12–30–04; 8:45 am] BILLING CODE 6560–50–P ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [R04–OAR–2004–KY–0002–200424; FRL– 7856–8] Approval and Promulgation of Implementation Plans for Kentucky: Inspection and Maintenance Program Removal for Jefferson County, KY; Source-Specific Nitrogen Oxides Emission Rate for Kosmos Cement Kiln Environmental Protection Agency (EPA). ACTION: Proposed rule. AGENCY: SUMMARY: EPA is proposing to approve a revision to the Jefferson County, Kentucky portion of the Kentucky State Implementation Plan (SIP) which requests removal of three regulations from the active portion of the Kentucky SIP related to the Jefferson County inspection and maintenance (I/M) program. Kentucky requested in a September 22, 2003, SIP revision that these I/M regulations be moved to the contingency measures section of the Kentucky portion of the Louisville 1Hour Ozone Maintenance Plan. EPA is also proposing to approve a sourcespecific SIP revision amending the nitrogen oxides (NOX) emission rate for Kosmos Cement Company’s cement kiln E:\FR\FM\03JAP1.SGM 03JAP1

Agencies

[Federal Register Volume 70, Number 1 (Monday, January 3, 2005)]
[Proposed Rules]
[Pages 51-53]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 04-28667]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 70, No. 1 / Monday, January 3, 2005 / 
Proposed Rules

[[Page 51]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19945; Directorate Identifier 2004-NM-22-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200B, 747-200C, 747-
200F, 747-300, and 747SR Series Airplanes Equipped with General 
Electric (GE) CF6-45 or -50 Series Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 
747SR series airplanes, equipped with GE CF6-45 or -50 series engines. 
This proposed AD would require modifying the side cowl assemblies on 
the engines by replacing existing wear plates with new extended wear 
plates and installing new stop fittings. This proposed AD is prompted 
by reports of a gap at the interface of the lower portion of the side 
cowl and the aft flange of the thrust reverser. We are proposing this 
AD to prevent an excessive quantity of air from entering the fire zone 
that surrounds the engine, which in the event of an engine fire, could 
result in an inability to control or extinguish the fire.

DATES: We must receive comments on this proposed AD by February 17, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to https://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to https://
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 
https://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-2004-19945; the directorate identifier for this docket is 
2004-NM-22-AD.

FOR FURTHER INFORMATION CONTACT: Dan Kinney, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6499; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-19945; 
Directorate Identifier 2004-NM-22-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 https://
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 https://dms.dot.gov.

Examining the Docket

    You can examine the AD docket on the Internet at https://
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 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 DMS receives them.

Discussion

    We have received reports indicating that a gap may form at the 
interface of the lower portion of the side cowl and the aft flange of 
the thrust reverser on certain Boeing Model 747-200B, 747-200C, 747-
200F, 747-300, and 747SR series airplanes, equipped with General 
Electric CF6-45 or -50 series engines. The gap forms when high engine 
thrust is applied, but may not always close when thrust is reduced. The 
gap is attributed to axial deflection of the engine case combined with 
the difference in the rate of expansion due to heat between the 
aluminum frame of the thrust reverser and the titanium frame of the 
engine. The gap may allow an excessive quantity of air into the nacelle 
surrounding the engine, which is a fire zone that is equipped with fire 
detection, containment, and extinguishing provisions. However, excess 
air in the area could defeat some or all of the fire protection 
provisions. This condition, if not corrected, could result in an 
inability to control or extinguish an engine fire.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 747-71-2300, Revision 1, 
dated October 30, 2003. The service bulletin describes procedures for 
modifying the side cowl assemblies on the engines by replacing existing 
wear plates with new extended wear plates and installing new stop 
fittings. The procedures for replacing the existing wear plates include 
performing open-hole high frequency eddy current (HFEC)

[[Page 52]]

inspections for cracking of existing fastener holes, and creating new 
fastener holes and plugging existing holes if necessary. The procedures 
for installing the new stop fittings involves installing brackets, 
channels, and wear pads; replacing existing fasteners with new 
fasteners if necessary; performing open-hole HFEC inspections for 
cracking of fastener holes; and oversizing fastener holes and 
installing different-sized fasteners if necessary. Accomplishing the 
actions specified in the service information is intended to adequately 
address the unsafe condition.
    Boeing Service Bulletin 747-71-2300, Revision 1, refers to Boeing 
Service Letter 747-SL-71-045-C, dated April 10, 2003, as the applicable 
source of service information for doing certain recommended actions. 
Among other actions, Boeing Service Letter 747-SL-71-045-C describes 
procedures for improving the aerodynamic smoothness of the side cowl 
assemblies by removing bulb seals that may have been installed on the 
trailing edge of the fan thrust reverser in accordance with a previous 
issue of Boeing Service Letter 747-SL-71-045. The procedures for 
removing the bulb seals include plugging open holes on the trailing 
edge of the fan thrust reverser, and adjusting the cowl latches if 
necessary.

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 modifying the side cowl assemblies on the engines by 
replacing existing wear plates with new extended wear plates, and 
installing new stop fittings. The proposed AD would require you to use 
the service information described previously to perform these actions, 
except as discussed under ``Differences Between the Proposed AD and 
Service Information.''

Differences Between the Proposed AD and Service Information

    Section 1.B., ``Concurrent Requirements,'' of Boeing Service 
Bulletin 747-71-2300, Revision 1, states that the service bulletin 
``assumes that the cowls have had wear plates installed per Service 
Bulletin 747-54-2093.'' We have determined that Boeing Service Bulletin 
747-71-2300, Revision 1, refers to Boeing Service Bulletin 747-54-2093 
only because Boeing Service Bulletin 747-71-2300, Revision 1, removes 
certain parts that may have been installed according to Boeing Service 
Bulletin 747-54-2093. We have discussed this matter with Boeing and 
have determined that the Accomplishment Instructions in Boeing Service 
Bulletin 747-71-2300, Revision 1, are effective regardless of whether 
Boeing Service Bulletin 747-54-2093 has been done. In light of this 
information, this proposed AD would not require the actions in Boeing 
Service Bulletin 747-54-2093.
    Boeing Service Bulletin 747-71-2300, Revision 1, also ``assumes'' 
that one certain airplane has been modified to have a narrower trailing 
edge strip. We have determined that the subject airplane has been 
modified; thus, this proposed AD would not require this modification.
    As described previously, Boeing Service Bulletin 747-71-2300, 
Revision 1, recommends that bulb seals installed previously in 
accordance with a previous issue of Boeing Service Letter 747-SL-71-045 
be removed in accordance with Boeing Service Letter 747-SL-71-045-C, 
dated April 10, 2003. If the bulb seals were previously installed, 
paragraph (g) of this proposed AD would require you to remove them 
concurrent with or before further flight after accomplishing the 
actions in Boeing Service Bulletin 747-71-2300, Revision 1.

Costs of Compliance

    This proposed AD would affect about 38 airplanes of U.S. registry 
and 140 airplanes worldwide. The following table provides the estimated 
costs for U.S. operators to comply with this proposed AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                            hours
                                                        Average                                             labor
                 Action                   Work hours   labor rate     Parts       Cost per    Fleet cost    rate
                                                        per hour                  airplane                airplane
                                                                                                          per hour
-------------------------------------------------------------------------------------------------------- ----------
Modification per Boeing Service                   72          $65      $25,736      $30,416   $1,155,808
 Bulletin 747-71-2300, Revision 1......
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. 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.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, the FAA is charged 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 
proposed AD.

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. 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,

[[Page 53]]

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-2004-19945; Directorate Identifier 2004-NM-
22-AD. Comments Due Date.

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by February 17, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-200B, 747-200C, 747-
200F, 747-300, and 747SR series airplanes; certificated in any 
category; equipped with General Electric CF6-45 or -50 series 
engines.

Unsafe Condition

    (d) This AD was prompted by reports of a gap at the interface of 
the lower portion of the side cowl and the aft flange of the thrust 
reverser. We are issuing this AD to prevent an excessive quantity of 
air from entering the fire zone that surrounds the engine, which, in 
the event of an engine fire, could result in an inability to control 
or extinguish the fire.

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.

Modification

    (f) Within 24 months after the effective date of this AD: Modify 
the side cowl assemblies on the engines by replacing existing wear 
plates with new extended wear plates and installing new stop 
fittings, by doing all actions according to the Accomplishment 
Instructions of Boeing Service Bulletin 747-71-2300, Revision 1, 
dated October 30, 2003. Any applicable corrective actions must be 
done before further flight.

On Condition: Removal of Bulb Seals and Other Specified Actions

    (g) If bulb seals were installed on the trailing edge of the fan 
thrust reverser in accordance with Boeing Service Letter 747-SL-71-
045: Concurrent with or before further flight after accomplishing 
paragraph (f) of this AD, remove the bulb seals, plug the open holes 
in the trailing edge of the fan thrust reverser, and adjust the cowl 
latches as applicable, in accordance with Boeing Service Letter 747-
SL-71-045-C, dated April 10, 2003.

Alternative Methods of Compliance (AMOCs)

    (h) 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.

    Issued in Renton, Washington, on December 20, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-28667 Filed 12-30-04; 8:45 am]
BILLING CODE 4910-13-P
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