[Federal Register: January 24, 2005 (Volume 70, Number 14)]
[Proposed Rules]
[Page 3320-3322]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24ja05-12]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-20110; Directorate Identifier 2004-NM-114-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes
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 737-600, -700, -700C, -800, and -900 series
airplanes. This proposed AD would require repetitive general visual
inspections for dirt, debris, and drain blockage and cleaning of the
aft fairing cavities of the engine struts; and modification of the aft
fairings, which would terminate the repetitive general visual
inspections. This proposed AD is prompted by a report indicating that
water had accumulated in the cavities of the engine strut aft fairings.
We are proposing this AD to prevent drain blockage by debris that, when
combined with leaking, flammable fluid lines passing through the engine
strut aft fairing, could allow flammable fluids to build up in the
cavity of the aft fairing, and consequently could be ignited by the
engine exhaust nozzle located below the engine strut, resulting in an
explosion or uncontrolled fire.
DATES: We must receive comments on this proposed AD by March 10, 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 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-2005-20110; the directorate identifier for this docket is
2004-NM-114-AD.
FOR FURTHER INFORMATION CONTACT: Doug Pegors, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone
(425) 917-6504; 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 under ADDRESSES. Include ``Docket No. FAA-2005-20110;
Directorate Identifier 2004-NM-114-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 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 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 located on the plaza level of the Nassif Building at the DOT
street address stated in the ADDRESSES
[[Page 3321]]
section. Comments will be available in the AD docket shortly after the
DMS receives them.
Discussion
We have received a report indicating that water had accumulated in
the cavities of the engine strut aft fairings on several Boeing Model
737-700 series airplanes. Build up of debris in the sump area of the
cavity of the aft fairing had blocked the drain, which caused
approximately 12 inches of water to accumulate. Debris and water had
entered through gaps between the engine strut fairing and the thrust
reverser skirt fairing at the wing interface blade seal. A drain
blocked by debris in combination with flammable fluid lines, which pass
through the engine strut aft fairing and occasionally leak, could cause
a hazardous amount of flammable fluid to build up in the cavity of the
aft fairing. This condition, if not corrected, could result in the
ignition of the flammable fluid by the exhaust nozzle located below the
engine strut and consequent explosion or uncontrolled fire.
The aft fairing of the engine strut on certain Boeing Model 737-
600, -700C, -800, and -900 series airplanes are identical to those on
the affected Model 737-700 series airplanes. Therefore, all of these
models may be subject to the same unsafe condition.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 737-54-
1041, dated January 22, 2004. The service bulletin describes procedures
for repetitive general visual inspections for dirt, debris, and drain
blockage and cleaning of the aft fairing cavities of the left and right
engine struts; and modification of the aft fairings of the left and
right engine struts, which eliminates the need for repetitive general
visual inspections. Modification involves installing new, improved
seals on the inboard and outboard sides of the aft fairings of the left
and right engine struts. Accomplishing the actions specified in the
service information is intended to adequately address the unsafe
condition.
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 repetitive general visual inspections for dirt, debris,
and drain blockage and cleaning of the aft fairing cavities of the left
and right engine struts; and modification of the aft fairings of the
left and right engine struts, which would terminate the repetitive
general visual inspections. Modification involves installing new,
improved seals on the inboard and outboard sides of the aft fairings of
the left and right engine struts. 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 Bulletin.''
Differences Between Proposed AD and Service Bulletin
Boeing Special Attention Service Bulletin 737-54-1041, dated
January 22, 2004, specifies that operators may accomplish the general
visual inspection and cleaning of the aft fairing cavities in
accordance with either the Boeing 737-600/700/800/900 Airplane
Maintenance Manual (AMM) or an ``approved equivalent procedure.''
However, this proposed AD would require operators to accomplish the
actions in accordance with the procedures specified in Chapter 54-55-02
of the Boeing 737-600/700/800/900 AMM. An ``approved equivalent
procedure'' may be used only if approved as an alternative method of
compliance in accordance with paragraph (j) of this AD.
The proposed AD would require inspecting and cleaning the drain
system of an aft fairing after the modifications required by paragraph
(i) of this AD. We have determined that modification alone would not
eliminate the build up of debris and flammable fluids in the cavity of
the aft fairing since the most previous inspection. Therefore,
operators must inspect and clean the aft fairings when the modification
is done.
Costs of Compliance
This proposed AD would affect about 1,406 airplanes worldwide. The
following table provides the estimated costs for U.S. operators to
comply with this proposed AD.
Estimated Costs
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Average Number of
Work labor Cost per U.S.-
Action hours rate per Parts airplane registered Fleet cost
hour airplanes
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Inspection, per inspection 2 $65 None........... $130, per 549 $71,370, per
cycle. inspection inspection
cycle. cycle.
Modification................ 5 65 $294........... 619............ 549 339,831.
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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, 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 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,
[[Page 3322]]
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, 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-2005-20110; Directorate Identifier 2004-NM-
114-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by March 10, 2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-600, -700, -700C, -800,
and -900 series airplanes, certificated in any category; as listed
in Boeing Special Attention Service Bulletin 737-54-1041, dated
January 22, 2004.
Unsafe Condition
(d) This AD was prompted by a report indicating that water had
accumulated in the cavities of the engine strut aft fairings. We are
issuing this AD to prevent drain blockage by debris that, when
combined with leaking, flammable fluid lines passing through the
engine strut aft fairing, could allow flammable fluids to build up
in the cavity of the aft fairing, and consequently could be ignited
by the engine exhaust nozzle located below the engine strut,
resulting in an explosion or uncontrolled 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.
Service Bulletin Reference
(f) The term ``service bulletin,'' as used in this AD, means the
Accomplishment Instructions of Boeing Special Attention Service
Bulletin 737-54-1041, dated January 22, 2004.
Repetitive Inspections of the Engine Strut Aft Fairings
(g) Within 4,000 flight cycles or within 30 months after the
effective date of this AD, whichever occurs first: Do the actions
specified in paragraphs (g)(1) and (g)(2) of this AD.
(1) Do a general visual inspection for dirt, debris, and drain
blockage and clean the aft fairing cavity of the left engine strut,
in accordance with Part I of the service bulletin, except as
provided by paragraph (h) of this AD. Thereafter at intervals not to
exceed 4,000 flight cycles or 30 months, whichever occurs first:
Repeat the inspection until the aft fairing of the left engine strut
has been modified in accordance with paragraph (i)(1) of this AD.
(2) Do a general visual inspection for dirt, debris, and drain
blockage and clean the aft fairing cavity of the right engine strut,
in accordance with Part II of the service bulletin, except as
provided by paragraph (h) of this AD. Thereafter at intervals not to
exceed 4,000 flight cycles or 30 months, whichever occurs first:
Repeat the inspection until the aft fairing of the right engine
strut has been modified in accordance with paragraph (i)(2) of this
AD.
Note 1: For the purposes of this AD, a general visual inspection
is: ``A visual examination of an interior or exterior area,
installation, or assembly to detect obvious damage, failure, or
irregularity. This level of inspection is made from within touching
distance unless otherwise specified. A mirror may be necessary to
ensure visual access to all surfaces in the inspection area. This
level of inspection is made under normally available lighting
conditions such as daylight, hangar lighting, flashlight, or
droplight and may require removal or opening of access panels or
doors. Stands, ladders, or platforms may be required to gain
proximity to the area being checked.''
Approved Equivalent Procedure
(h) If the service bulletin specifies that the general visual
inspection and cleaning of the aft fairing cavity of the left or
right engine strut may be accomplished per an ``approved equivalent
procedure'': The general visual inspection or cleaning must be
accomplished in accordance with the chapter of the Boeing 737-600/
700/800/900 Airplane Maintenance Manual specified in the service
bulletin.
Modification of the Engine Strut Aft Fairings
(i) Within 9,000 flight cycles after the effective date of this
AD, do the actions specified in paragraphs (i)(1) and (i)(2) of this
AD.
(1) Modify the aft fairing of the left engine strut, in
accordance with Part III of the service bulletin; and after
accomplishing the modification but before further flight, inspect
and clean the drain system of the aft fairing in accordance with
Part I of the service bulletin. This modification terminates the
repetitive inspections required by paragraph (g)(1) of this AD.
(2) Modify the aft fairing of the right engine strut, in
accordance with Part IV of the service bulletin; and after
accomplishing the modification but before further flight, inspect
and clean the drain system of the aft fairing in accordance with
Part II of the service bulletin. This modification terminates the
repetitive inspections required by paragraph (g)(2) of this AD.
Alternative Methods of Compliance (AMOCs)
(j) The Manager, Seattle Aircraft Certification Office, 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 January 12, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-1220 Filed 1-21-05; 8:45 am]
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