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


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 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.
 
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 

  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 http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     By fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, 
on the plaza level of the Nassif Building, Washington, DC. This docket 
number is FAA-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 http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that website, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is 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