[Federal Register: June 5, 2007 (Volume 72, Number 107)]
[Proposed Rules]
[Page 31001-31003]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05jn07-18]
[[Page 31001]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28352; Directorate Identifier 2007-NM-037-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-200B, 747-300, 747-
400, 747-400D, and 747-400F Series Airplanes Equipped With General
Electric CF6-80C2 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 747-200B, 747-300, 747-400, 747-400D, and 747-
400F series airplanes. This proposed AD would require repetitive
inspections of the left- and right-hand flipper door assemblies of the
engine core cowls for migrated pins and damaged flipper doors, and
corrective actions if necessary. Modification of the hinge assemblies
terminates the repetitive inspections. This proposed AD results from
two reports of missing flipper doors for the engine core cowls. We are
proposing this AD to detect and correct migrated hinge pins and damaged
flipper doors, which could allow the flipper door to fall off,
resulting in the potential for an engine fire to propagate into the
flammable leakage zone of the strut and for the amount of fire
extinguishing agent reaching the fire to be diluted, and subsequent
uncontained fire in the engine strut.
DATES: We must receive comments on this proposed AD by July 20, 2007.
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.
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.
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: Sulmo Mariano, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6501; 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-
28352; Directorate Identifier 2007-NM-037-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://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 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://dms.dot.gov.
Examining the Docket
You may 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 located 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 Docket Management System
receives them.
Discussion
We have received two reports of missing flipper doors for the
engine core cowls on Boeing Model 747 series airplanes equipped with
General Electric CF6-80C2 engines. Investigation into the cause of the
missing flipper doors revealed that hinge pins for the flipper doors
were not secured correctly, and the vibration from the engine core
cowls caused the hinge pins to migrate, allowing the flipper doors to
fall off.
When the engine core cowl is opened during normal operation, the
flipper door opens to provide clearance for the hinge fittings. When
the engine core cowl is closed, the flipper door is clamped underneath
the strut seal, forming a continuous strut firewall. If a flipper door
is missing, it creates a 1-inch by 5-inch hole in the strut firewall.
According to requirements of the master minimum equipment list, an
airplane cannot depart with a missing flipper door.
This condition, if not corrected, could result in the potential for
an engine fire to propagate into the flammable leakage zone of the
strut and for the amount of fire extinguishing agent reaching the fire
to be diluted, and subsequent uncontained fire in the engine strut.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 747-71-
2310, dated October 13, 2005. The service bulletin describes procedures
for repetitively inspecting the left- and right-hand flipper door
assemblies for migrated hinge pins and damaged flipper doors, and
corrective actions if necessary. The corrective actions include
replacing any damaged flipper door with a new or serviceable flipper
door, and modifying the hinge assemblies if necessary. The modification
includes shortening the hinge pin and peening (deforming) both ends of
the hinge assembly to capture the pin. Modifying the hinge assemblies
eliminates the need for the repetitive inspections. Accomplishing the
actions specified in the service information is intended to adequately
address the unsafe condition.
The Boeing service bulletin refers to Rohr Service Bulletin TBC/
80C2-NAC-71-035, dated October 10, 2005, as an additional source of
service information for inspecting hinge pins of the flipper doors,
inspecting and replacing damaged flipper doors, and modifying the hinge
assemblies of the flipper doors.
[[Page 31002]]
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.
Costs of Compliance
There are about 297 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs for
U.S. operators to comply with this proposed AD.
Estimated Costs
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Number of
Work Average Cost per U.S.-
Action hours labor rate Parts airplane registered Fleet cost
per hour airplanes
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Inspection of flipper door assemblies, per 1 $80 $0 $80, per 42 $3,360, per inspection cycle.
inspection cycle. inspection
cycle
Modification of hinge assemblies, if 1 $80 $0 $80 Up to 42 Up to $3,360.
accomplished.
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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-2007-28352; Directorate Identifier 2007-NM-
037-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by July 20,
2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747-200B, 747-300, 747-400,
747-400D, and 747-400F series airplanes, certificated in any
category, equipped with General Electric CF6-80C2 engines.
Unsafe Condition
(d) This AD results from two reports of missing flipper doors
for the engine core cowl. We are issuing this AD to detect and
correct migrated hinge pins and damaged flipper doors, which could
allow the flipper door to fall off, resulting in the potential for
an engine fire to propagate into the flammable leakage zone of the
strut and for the amount of fire extinguishing agent reaching the
fire to be diluted, and subsequent uncontained fire in the engine
strut.
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.
Inspection of the Flipper Door Assemblies
(f) Within 24 months after the effective date of this AD: Do a
general visual inspection for migrated hinge pins and damaged
flipper doors of the left- and right-hand flipper door assemblies of
the engine core cowls, and do all applicable corrective actions, by
accomplishing all the actions specified in the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 747-71-
2310, dated October 13, 2005. Do all applicable corrective actions
before further flight. Repeat the inspection thereafter at intervals
not to exceed 18 months for that flipper door assembly, until doing
the modification specified in paragraph (g) of this AD.
Note 1: Boeing Special Attention Service Bulletin 747-71-2310,
dated October 13, 2005, refers to Rohr Service Bulletin TBC/80C2-
NAC-71-035, dated October 10, 2005, as an additional source of
service information for accomplishing the actions specified in
paragraph (f) of this AD.
Terminating Action for Repetitive Inspections
(g) Modifying a hinge assembly of a flipper door assembly of the
engine core cowls in accordance with the Accomplishment Instructions
of Boeing Special Attention Service Bulletin 747-71-2310, dated
October 13, 2005, terminates the repetitive inspection requirements
of this AD for that hinge assembly.
Parts Installation
(h) As of the effective date of this AD, no person may install,
on any airplane, a hinge assembly, part number 224-2335-69, for the
flipper door of the engine core cowl unless
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it has been modified in accordance with the requirements of
paragraph (g) of this AD.
Alternative Methods of Compliance (AMOCs)
(i)(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.
Issued in Renton, Washington, on May 25, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-10757 Filed 6-4-07; 8:45 am]
BILLING CODE 4910-13-P