[Federal Register: January 11, 2006 (Volume 71, Number 7)]
[Proposed Rules]
[Page 1718-1721]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11ja06-13]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-23441; Directorate Identifier 2005-NM-199-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP
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 supersede an existing airworthiness
directive (AD) that applies to certain Boeing Model 747-100, 747-100B,
747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP
series airplanes. The existing AD currently requires repetitive
detailed and ultrasonic inspections of the thrust links of the rear
engine mounts for any crack or fracture and corrective actions if
necessary. This proposed AD would require repetitive replacement of the
thrust links with new or overhauled thrust links, which ends the
repetitive detailed and ultrasonic inspections. This proposed AD
results from the finding of fractured and cracked forward lugs of the
rear engine mount thrust link on the number one strut on two airplanes.
We are proposing this AD to prevent cracked or fractured thrust links
that could lead to the loss of the load path for the rear engine mount
bulkhead and damage to other primary engine mount structure, which
could result in the in-flight separation of the engine from the
airplane and consequent loss of control of the airplane.
DATES: We must receive comments on this proposed AD by February 27,
2006.
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 service information identified in this
proposed AD.
FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437;
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 ``Docket No.
FAA-2005-23441; Directorate Identifier 2005-NM-199-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 the DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or can
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.
[[Page 1719]]
Discussion
On September 6, 2005, we issued AD 2005-19-06, amendment 39-14271
(70 FR 54474, September 15, 2005), for certain Boeing Model 747-100,
747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR,
and 747SP series airplanes. (A correction to AD 2005-19-06 was
published in the Federal Register on September 30, 2005 (70 FR 57124).)
That AD requires repetitive detailed and ultrasonic inspections of the
thrust links of the rear engine mounts for any crack or fracture and
corrective actions if necessary. That AD resulted from the finding of a
fractured forward lug of the rear engine mount thrust link on the
number one strut. We issued that AD to detect and correct cracked or
fractured thrust links that could lead to the loss of the load path for
the rear engine mount bulkhead and damage to other primary engine mount
structure, which could result in the in-flight separation of the engine
from the airplane and consequent loss of control of the airplane.
Actions Since Existing AD Was Issued
In the preamble to AD 2005-19-06, we indicated that the actions
required by that AD were considered ``interim action.'' We also
indicated that we were considering further rulemaking action to require
repetitive replacement of the thrust link with a new or overhauled
thrust link. (The repetitive replacements are included as an optional
terminating action in AD 2005-19-06.) However, the planned compliance
time for that action was sufficiently long so that it was practicable
to allow notice and opportunity for prior public comment. We have now
determined that further rulemaking making action is indeed necessary,
and this NPRM follows from that determination. We point out that this
NPRM would require the repetitive replacements within a certain
compliance time, regardless of any inspection results.
Comments
We have considered the following comments to AD 2005-19-06.
Request To Use an Alternative Method of Compliance (AMOC)
One commenter states that it can reduce the work required for
replacing a thrust link by omitting the step for removing the engine to
gain access to the thrust link. Part 2 of the accomplishment
instructions of Boeing Alert Service Bulletin 747-71A2309, dated August
18, 2005, specifies removal of the engine. The commenter states,
however, that there is no load on the thrust link at static condition,
so the engine does not need to be removed. Instead, only the engine
exhaust sleeve needs to be removed to replace the thrust link. The
commenter also states that, in Boeing message No. 1-385158991-9, dated
September 16, 2005, the manufacturer agreed that removing the sleeve
would be an appropriate alternative procedure for replacing the thrust
link. On October 26, 2005, the commenter submitted this request for
approval as an AMOC.
We agree, since we have found the commenter's request for an AMOC
to be acceptable. We have approved removing the side cowls, as an
alternative to opening the side cowls as required by paragraph (g) of
AD 2005-19-06. We have also approved removal of the turbine exhaust
sleeve, as an alternative to removing the engine as required by
paragraph (j) of AD 2005-19-06 (corresponding to paragraph (k) of this
NPRM) provided that the engine is supported. We have included a
provision in paragraph (l)(5) of this NPRM to account for the
commenter's AMOC. Under the provisions of paragraph (l) of this NPRM,
we may consider other requests for approval of an alternative method of
compliance if sufficient data are submitted to substantiate that such a
method would provide an acceptable level of safety.
Request To Clarify Inspection Requirements
One commenter requests that we clarify the required actions of AD
2005-19-06 for thrust links having part number (P/N) 65B90360-7. The
commenter states that Boeing Alert Service Bulletin 747-71A2309
requires repetitive replacement of those thrust links, but that the
repetitive replacement is identified as an optional action in AD 2005-
19-06. The commenter would like to know if this means that there is no
mandatory requirement for thrust links having P/N 65B90360-7.
As discussed previously, repetitive replacement of the thrust links
as required by AD 2005-19-06 is considered an optional action because
the planned compliance time for that action was sufficiently long
enough to allow the public time to comment. This NPRM, however, would
require the repetitive replacement of thrust links having P/N 65B90360-
7 in agreement with the service bulletin. Also, we point out that AD
2005-19-06 does require the repetitive replacement of P/N 65B90360-7.
Although that action is conditional in AD 2005-19-06, depending on
whether P/N 65B90360-7 was installed while accomplishing the corrective
action as applicable or the optional terminating action, as specified
in paragraphs (h)(1)(ii) and (j)(2) of AD 2005-19-06, respectively.
Clarification of AMOC Paragraph
We have revised this action to clarify the appropriate procedure
for notifying the principal inspector before using any approved AMOC on
any airplane to which the AMOC applies.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to develop on other airplanes of the
same type design. For this reason, we are proposing this AD, which
would supersede AD 2005-19-06. This proposed AD would continue to
require repetitive detailed and ultrasonic inspections of the thrust
links of the rear engine mounts for any crack or fracture and
corrective actions if necessary. This proposed AD would also require
repetitive replacement of the thrust links with new or overhauled
thrust links, which would end the repetitive inspections.
Costs of Compliance
There are about 274 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs, at
an average labor rate of $65 per hour, for U.S. operators to comply
with this proposed AD.
Estimated Costs
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Number of U.S.-
Action Work hours Parts Cost per registered Fleet cost
airplane airplanes
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Inspection (required by AD 8 (2 per engine) None......... $520, per 100 $52,000, per
2005-19-06). inspection inspection
cycle. cycle.
[[Page 1720]]
Replacement (new proposed 4 (1 per engine) $41,424...... $41,684, per 100 $4,168,400, per
action). replacement replacement
cycle. cycle.
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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
removing amendment 39-14271 (70 FR 54474, September 15, 2005),
corrected at 70 FR 57124, September 30, 2005, and by adding the
following new airworthiness directive (AD):
Boeing: Docket No. FAA-2005-23441; Directorate Identifier 2005-NM-
199-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by February 27,
2006.
Affected ADs
(b) This AD supersedes AD 2005-19-06.
Applicability
(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series
airplanes, certificated in any category; equipped with Pratt & Whitney
JT9D-3 and -7 series engines, except JT9D-70 engines; as identified in
Boeing Alert Service Bulletin 747-71A2309, dated August 18, 2005.
Unsafe Condition
(d) This AD results from the finding of fractured and cracked
forward lugs of the rear engine mount thrust link on the number one
strut on two airplanes. We are issuing this AD to prevent cracked or
fractured thrust links that could lead to the loss of the load path for
the rear engine mount bulkhead and damage to other primary engine mount
structure, which could result in the in-flight separation of the engine
from the airplane and consequent loss of control of 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.
Restatement of Requirements of AD 2005-19-06
Service Bulletin References
(f) The term ``service bulletin,'' as used in this AD, means the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
71A2309, dated August 18, 2005.
Repetitive Inspections of Thrust Links
(g) Within 90 days after September 30, 2005 (the effective date of
AD 2005-19-06), do a detailed inspection and ultrasonic inspection of
thrust link lugs having part number (P/N) 65B90360-1 or -4 of the rear
engine mount of struts 1, 2, 3, and 4 for any crack or fracture, in
accordance with part 1 of the service bulletin. If the thrust link is
not found cracked or fractured: Repeat the inspections thereafter at
intervals not to exceed 1,200 flight cycles or 18 months, whichever is
first, until the repetitive replacement or overhaul of the thrust link
required by paragraph (k) of this AD is accomplished. Accomplishing the
repetitive replacement or overhaul of a thrust link as specified in
paragraph (h) or (k) of this AD terminates the repetitive inspections
for that thrust link only.
Corrective Actions
(h) If a cracked thrust link is found during any inspection
required by paragraph (g) of this AD or during any replacement or
overhaul done in accordance with the service bulletin: Before further
flight, do the actions specified in paragraph (h)(1) of this AD. If a
fractured thrust link is found during any inspection required by
paragraph (g) of this AD or during any replacement or overhaul done in
accordance with the service bulletin: Before further flight, do the
actions specified in paragraphs (h)(1) and (h)(2) of this AD.
(1) Replace the thrust link with a new or overhauled thrust link in
accordance with part 2 of the service bulletin; except as provided by
paragraph (i) of this AD. Repeat the replacement at the
[[Page 1721]]
applicable compliance time specified in paragraph (h)(1)(i) or
(h)(1)(ii) of this AD.
(i) For replacement with a thrust link assembly having P/N
65B90360-1 or -4: Thereafter at intervals not to exceed 6,000 flight
cycles.
(ii) For replacement with a thrust link assembly having P/N
65B90360-7: Thereafter at intervals not to exceed 12,000 flight cycles.
(2) Do the corrective actions in accordance with Parts 3, 4, and 5
of the service bulletin; except as provided by paragraph (i) of this
AD.
Exception to Service Bulletin
(i) Where the service bulletin specifies to contact Boeing for
appropriate action, do the corrective action using a method approved in
accordance with paragraph (m) of this AD.
Credit for Certain Corrective Actions
(j) Reworking the lugs on the bulkhead fitting of the rear engine
mount as specified in paragraphs (b)(2), (e), and (f) of AD 2001-15-15,
amendment 39-12349, is acceptable for compliance with accomplishing the
corrective action specified in ``Part 3--Rear Engine Mount Bulkhead
Inspection and Lug Overhaul and Upper Fitting Overhaul and Bolt
Replacement'' of the service bulletin.
New Requirements of This AD
Terminating Action--Repetitive Replacement or Overhaul of All Thrust
Links
(k) At the applicable compliance times specified in Table 1 of this
AD: Repetitively replace the thrust link of the rear engine mount of
struts 1, 2, 3, and 4 with a new or overhauled thrust link, in
accordance with part 2 of the service bulletin; except as provided by
paragraph (i) of this AD. During any replacement required by this
paragraph, an existing thrust link may be replaced with a new or
overhauled thrust link having P/N 65B90360-1, -4 or -7, provided that
the applicable repetitive interval specified in Table 1 of this AD is
complied with. If a fractured thrust link is found during any
replacement or overhaul done in accordance with this paragraph: Before
further flight, do the corrective actions specified in paragraph (h)(2)
of this AD. Repetitive replacement of all thrust links having P/N
65B90360-1 or -4 terminates the repetitive inspections required by
paragraph (g) of this AD. Accomplishing the repetitive replacement or
overhaul of a thrust link required by paragraph (h) of this AD
constitutes compliance with the requirements of this paragraph for that
thrust link only.
Table 1.--Compliance Times
------------------------------------------------------------------------
Initial replacement-- Repetitive interval--
For thrust link P/N--
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65B90360-1 or -4............ Within 36 months Thereafter at
after the effective intervals not to
date of this AD. exceed 6,000 flight
cycles.
65B90360-7.................. Within 12,000 flight Thereafter at
cycles after the intervals not to
new thrust link has exceed 12,000
been installed. flight cycles.
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Alternative Methods of Compliance (AMOCs)
(l)(1) The Manager, Seattle Aircraft Certification Office (ACO),
Transport Airplane Directorate, FAA, has the authority to approve AMOCs
for this AD, if requested in accordance with the procedures found in 14
CFR 39.19.
(2) Before using any AMOC approved in accordance with Sec. 39.19
on any airplane to which the AMOC applies, notify the appropriate
principal inspector in the FAA Flight Standards Certificate Holding
District Office.
(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.
(4) The actions identified in paragraphs (g) and (k) of this AD are
approved as an AMOC to paragraphs (c) and (d) of AD 2004-07-22,
amendment 39-13566, for the inspections of structural significant item
S-2, for the thrust links only, of Boeing Supplemental Structural
Inspection Document D6-35022, Revision G, dated December 2000. All
provisions of AD 2004-07-22 that are not specifically referenced in
this paragraph, including the initial inspection threshold required by
paragraph (d) of AD 2004-07-22, remain fully applicable and must be
complied with.
(5) AMOCs approved previously in accordance with AD 2005-19-06,
amendment 39-14271, are approved as AMOCs for the corresponding
provisions of this AD.
Issued in Renton, Washington, on December 23, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-136 Filed 1-10-06; 8:45 am]
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