[Federal Register: June 18, 2007 (Volume 72, Number 116)]
[Proposed Rules]
[Page 33411-33415]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18jn07-15]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2006-24270; Directorate Identifier 2005-NM-200-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 777 Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of
comment period.
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SUMMARY: The FAA is revising an earlier proposed airworthiness
directive (AD) for all Boeing Model 777-200, -300, and -300ER series
airplanes. The original NPRM would have required, for the drive
mechanism of the horizontal stabilizer, repetitive detailed inspections
for discrepancies; repetitive lubrication of the ballnut and ballscrew;
repetitive measurements of the freeplay between the ballnut and the
ballscrew; and corrective action if necessary. The original NPRM
resulted from a report of extensive corrosion of a ballscrew in the
drive mechanism of the horizontal stabilizer on a Boeing Model 757
airplane, which is similar in design to the ballscrew on Model 777
airplanes. This action revises the original NPRM by adding airplanes to
the applicability. We are proposing this supplemental NPRM to prevent
an undetected failure of the primary load path for the ballscrew in the
horizontal stabilizer and subsequent wear and failure of the secondary
load path, which could lead to loss of control of the horizontal
stabilizer and consequent loss of control of the airplane.
DATES: We must receive comments on this supplemental NPRM by July 13,
2007.
ADDRESSES: Use one of the following addresses to submit comments on
this supplemental NPRM.
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: Kelly McGuckin, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6490; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any relevant written data, views, or
arguments regarding this supplemental NPRM. Send your comments to an
address listed in the ADDRESSES section. Include the docket number
``FAA-2006-24270; Directorate Identifier 2005-NM-200-AD'' at the
beginning of your comments. We specifically invite comments on the
overall regulatory, economic, environmental, and energy aspects of this
supplemental NPRM. We will consider all comments received by the
closing date and may amend this supplemental NPRM in light of those
comments.
We will post all comments submitted, 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 supplemental NPRM. 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 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 in the Nassif Building at the DOT
street address stated in ADDRESSES. Comments will be available in the
AD docket shortly after the Docket Management System receives them.
[[Page 33412]]
Discussion
We proposed to amend 14 CFR part 39 with a notice of proposed
rulemaking (NPRM) for an AD (the ``original NPRM'') for all 777-200, -
300, and -300ER series airplanes. The original NPRM was published in
the Federal Register on March 30, 2006 (71 FR 16061). The original NPRM
proposed to require, for the drive mechanism of the horizontal
stabilizer, repetitive detailed inspections for discrepancies;
repetitive lubrication of the ballnut and ballscrew; repetitive
measurements of the freeplay between the ballnut and the ballscrew; and
corrective action if necessary.
Actions Since Original NPRM Was Issued
Since we issued the original NPRM, we have determined that all
Model 777 airplanes may be subject to the unsafe condition specified in
the original NPRM. Therefore, we are issuing this supplemental NPRM to
revise the applicability of the original NPRM to identify all Model 777
airplanes.
Comments
We have considered the following comments on the original NPRM.
Request To Remove Unnecessary Instruction
Two commenters, Boeing and Air Transport Association (ATA) on
behalf of its member United Airlines (UAL), assert that the added
instruction in paragraph (h) of the original NPRM regarding changing
the position of the horizontal stabilizer to permit inspecting the
entire ballscrew is not necessary as the Boeing 777 Aircraft
Maintenance Manual and task cards already require such a change of
position as part of the ballscrew inspection. A third commenter,
British Airways (BA), also notes that the required instruction already
exists as described. Boeing requests that we revise the description of
the detailed inspection in the original NPRM as the specified
instruction is unnecessary. UAL states that the phrase ``or in the
referenced AMM sections'' is incorrect and requests that it be deleted
from the first paragraph under the heading ``Differences Between the
Proposed AD and Service Information'' in the original NPRM.
We agree. The instruction to move the horizontal stabilizer is
sufficiently addressed as part of the required inspection in the Boeing
777 Aircraft Maintenance Manual and task cards and need not be repeated
in the AD. Since the ``Differences Between the Proposed AD and Service
Information'' section of the original NPRM is not carried forward,
there is no need to change the paragraph specified by UAL. However, we
have removed the unnecessary instruction ``changing the position of the
horizontal stabilizer as needed to allow inspecting the entire
ballscrew'' from paragraph (h) of the supplemental NPRM.
Request To Revise Maintenance Records Check
Boeing requests that we change the maintenance records check.
Boeing states that, as written, the original NPRM would require
production airplanes delivered after the effective date of the AD to
have a maintenance records check within 6 months after the effective
date. Further, Boeing states, airplanes delivered 6 months after the
effective date would immediately be out of compliance. Boeing requests,
therefore, that paragraph (g) of the original NPRM be revised to
include the following statement: ``This paragraph applies only to those
airplanes delivered prior to the effective date of this AD.''
We agree. We have determined that the maintenance records check
should apply only to airplanes that received a standard airworthiness
certificate or original export certificate of airworthiness prior to
the effective date of the AD. We have revised paragraphs (g), (h), (i),
and (j) of the supplemental NPRM to reflect this. We have also revised
the Cost of Compliance of the supplemental NPRM to reflect the cost of
the maintenance records check.
Request To Revise Prior Replacement of Actuator
ATA, on behalf of UAL, requests certain relief from the repetitive
inspections of the horizontal stabilizer ballscrew. UAL states that
paragraph (l) of the original NPRM does not state requirements for
operators who have replaced actuators with new or overhauled actuators.
UAL states it has ``hard-timed'' its actuators at 9 years to be removed
and overhauled per original equipment manufacturer (OEM) component
maintenance manual (CMM) specifications. UAL requests that credit for
repetitive inspections be given to operators who have a stabilizer trim
actuator overhaul maintenance program in place.
We agree. Any hard-time program that involves removing,
overhauling, and re-installing the stabilizer trim actuator
accomplishes the intent of performing one freeplay inspection, one
detailed inspection, and one lubrication of the stabilizer ballscrew
assembly, provided that the stabilizer ballscrew sub-assembly is
removed from the trim actuator and overhauled. We find that removing,
disassembling, and overhauling the stabilizer ballscrew sub-assembly in
accordance with OEM CMM specifications provides a thorough detailed
inspection and measurement of the condition of the stabilizer actuator
and ballscrew. Therefore, we have revised paragraph (l) of the
supplemental NPRM to give credit for accomplishing the actions required
by paragraphs (h), (i), and (j) of this AD for actuators which have
been overhauled as part of a hard-time program in accordance with OEM
CMM specifications.
Request To Revise Description of Affected Airplanes
Boeing requests that certain language of the original NPRM be
revised to clarify the extent to which Model 777 airplanes are
affected. Boeing states that, at this time, Alert Service Bulletin 777-
27A0059 applies to all Model 777 airplanes, current and future. Boeing
requests that the original NPRM be changed as follows:
That the Costs of Compliance be changed from ``there are
about 582 airplanes'' to ``there are currently 582 airplanes'' and from
``would affect about'' to ``would currently affect about''; and
That paragraph (c) Applicability be changed from ``Boeing
Model 777-200, -300, and -300ER series airplanes'' to ``all Boeing
Model 777 series airplanes.''
We partially agree. The costs of compliance estimate is understood
to be based on the best information about affected airplanes currently
in operation. There is no need to add ``currently'' to the costs of
compliance. However, in reviewing this comment, we determined that
there are about 596 airplanes in the worldwide fleet rather than 582
such airplanes, and about 203 airplanes of U.S. registry rather than
130 such airplanes. Further, we have determined that, as Alert Service
Bulletin 777-27A0059 applies to future Model 777 airplanes, the
applicability of the AD should be changed. Therefore, in this
supplemental NPRM, we have revised the Costs of Compliance to reflect
the increased number of airplanes and revised paragraph (c) to read
``all Boeing Model 777 airplanes.''
Suggestion To Change Governance of Maintenance Program
ATA, on behalf of its member American Airlines (AAL), suggests a
change of governance for the maintenance program. AAL has no objections
to the maintenance actions described in the original NPRM, but believes
the maintenance program should be governed and dictated
[[Page 33413]]
through the maintenance review board report (MRBR) prepared by the FAA
airplane evaluation groups (AEG), with proper oversight by the FAA
Flight Standards Office, not via ADs. AAL asserts that implementation
and oversight of ADs is costly to airlines, especially ADs which have
no terminating action.
We do not agree. We have determined that the maintenance actions
and intervals described in the original NPRM for the horizontal
stabilizer ballscrew can directly affect the safety of the airplane and
should be mandated because of the identified unsafe condition. To
prevent escalation of the intervals of maintenance tasks that are
directly linked both to airplane safety and to an accident, we found it
necessary to mandate these actions by issuance of the proposed AD. We
have not changed the supplemental NPRM in this regard.
Request To Change Intervals of Repetitive Actions
Two commenters, BA and Air France, do not agree with the repeat
intervals specified in the original NPRM for the lubrication; and BA
also does not agree with the repeat intervals specified in the original
NPRM for the detailed inspection and freeplay measurement. BA states
that the 777 Industry Steering Committee/Maintenance Review Board (ISC/
MRB) meeting, held in February 2004, produced the ``Re-analysis of the
Horizontal Stabilizer Control System MSG-3.'' BA asserts that this re-
analysis took into account Boeing's safety analysis, and the suggested
alternative repeat intervals were agreed to by numerous attendees at
the meeting, including Boeing, Boeing's designated engineering
representative (DER), the FAA Seattle Aircraft Evaluation Group (AEG),
and Model 777 operators. In addition, BA asserts that the use of an
improved synthetic oil-based grease (conforming to Boeing material
specification BMS3-33) and 10 years of operating experience support the
alternative repeat intervals. BA further asserts that Boeing's safety
analysis of the Model 777 stabilizer drive mechanism revealed no
problems with the configuration of that mechanism. BA therefore
requests that the repeat intervals of the original NPRM be revised as
follows:
Detailed inspection--6,000 flight hours or 400 days,
whichever comes first;
Freeplay inspection--25,000 flight hours or five years,
whichever comes first;
Lubrication--2,000 flight hours or 400 days, whichever
comes first.
Air France explains that its request is based on information from
the MRB Report revision of March 3, 2006, and the maintenance planning
document (MPD) revision of May 5, 2006. In addition, Air France states
that a decision was made at the ISC meeting of January 2006 to revise
the lubrication interval from 2,000 flight hours/400 days to 3,000
flight hours/400 days, based on in-service experience. Air France
further states that it has never found any applicable corrosion or
damage during 8 years of 777 operating experience. Air France states,
therefore, that it does not agree with the lubrication interval
specified in the original NPRM and requests that the interval be
changed to 3,000 flight hours or 400 days, whichever comes first.
We do not agree with this request. Consistent with our response
shown above to the comment regarding a change of governance for the
maintenance program, we have identified an unsafe condition and are
proposing an AD to control the tasks and intervals needed to address
this condition. The commenters assert that alternative repeat intervals
were agreed to by numerous attendees at the February 2004 ISC/MRB
meeting, however, those intervals are inconsistent with the intervals
developed by Boeing's safety organization and transmitted via letter to
the Seattle Aircraft Certification Office (ACO) in support of
development of this AD. The intervals for lubrication, detailed
inspection, and freeplay inspection that appear in the FAA-approved
Boeing service bulletin were determined from the results of a safety
review by means of testing, failure mode analysis, and fault tree
analysis and are based upon using BMS 3-33 grease or acceptable
substitute. Boeing has not revised those intervals, and the intervals
suggested by BA and Air France do not meet the requirements identified
by the safety review. Further, Boeing has advised us that it intends to
pursue revising the MPD task to reflect the compliance times specified
in this AD at the next revision cycle of the document. Task intervals
specified in maintenance programs may be increased based on positive
results obtained from previous repetitions of the task. We are
concerned with the practice of escalating safety related maintenance
intervals until negative findings are discovered. We have not changed
the supplemental NPRM as requested by the commenters. However, to
obtain longer compliance times, anyone may request approval of an
alternative method of compliance (AMOC) as specified in paragraph (n)
of this supplemental NPRM, provided data are submitted to demonstrate
that an acceptable level of safety will be maintained.
FAA's Determination and Proposed Requirements of the Supplemental NPRM
Certain changes discussed above expand the scope of the original
NPRM; therefore, we have determined that it is necessary to reopen the
comment period to provide additional opportunity for public comment on
this supplemental NPRM.
Costs of Compliance
There are about 596 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 203 airplanes of
U.S. registry.
The proposed maintenance records check would take about 1 work hour
per airplane, at an average labor rate of $80 per work hour. Based on
these figures, the estimated cost of the proposed inspection for U.S.
operators is $16,240, or $80 per airplane, per inspection cycle.
The proposed detailed inspection would take about 1 work hour per
airplane, at an average labor rate of $80 per work hour. Based on these
figures, the estimated cost of the proposed inspection for U.S.
operators is $16,240, or $80 per airplane, per inspection cycle.
The proposed freeplay measurement would take about 5 work hours per
airplane, at an average labor rate of $80 per work hour. Based on these
figures, the estimated cost of the proposed freeplay measurement for
U.S. operators is $81,200, or $400 per airplane, per measurement cycle.
The proposed lubrication would take about 1 work hour per airplane,
at an average labor rate of $80 per work hour. Based on these figures,
the estimated cost of the proposed lubrication for U.S. operators is
$16,240, or $80 per airplane, per lubrication cycle.
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
[[Page 33414]]
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 supplemental NPRM 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-2006-24270; Directorate Identifier 2005-NM-
200-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by July 13,
2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to all Boeing Model 777 airplanes,
certificated in any category.
Unsafe Condition
(d) This AD results from a report of extensive corrosion of a
ballscrew in the drive mechanism of the horizontal stabilizer of a
Boeing Model 757 airplane, which is similar in design to the
ballscrew on Model 777 airplanes. We are issuing this AD to prevent
an undetected failure of the primary load path for the ballscrew in
the drive mechanism of the horizontal stabilizer and subsequent wear
and failure of the secondary load path, which could lead to loss of
control of the horizontal stabilizer 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.
Service Bulletin Reference
(f) The term ``service bulletin,'' as used in this AD, means
Boeing Alert Service Bulletin 777-27A0059, Revision 1, dated August
18, 2005.
Note 1: The service bulletin refers to the Boeing 777 Aircraft
Maintenance Manual (AMM), subjects 12-21-05, 27-41-13, and 29-11-00,
as additional sources of service information for accomplishing the
actions required by this AD.
Maintenance Records Check
(g) For airplanes that have received a certificate of
airworthiness prior to the effective date of this AD: Within 180
days or 3,500 flight hours after the effective date of this AD,
whichever occurs first, perform a maintenance records check or
inspect to determine whether any horizontal stabilizer trim actuator
has been replaced for any issue described in the service bulletin
with a serviceable actuator that was not new or overhauled, and has
not received a detailed inspection and freeplay measurement since
the replacement.
Detailed Inspection
(h) Within the compliance times specified in paragraph (h)(1) or
(h)(2) of this AD, as applicable: Perform a detailed inspection for
discrepancies of the horizontal stabilizer trim actuator ballnut and
ballscrew in accordance with Part 1 of the Accomplishment
Instructions of the service bulletin. Repeat the detailed inspection
thereafter at intervals not to exceed 3,500 flight hours or 12
months, whichever occurs first. If any discrepancy is found during
any inspection required by this AD, before further flight, replace
the actuator with a new or serviceable actuator in accordance with
the service bulletin.
(1) For airplanes identified in paragraph (g) of this AD on
which the actuator has not been replaced: Before the accumulation of
15,000 total flight hours, or within 18 months after the effective
date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on
which the actuator has been replaced, and for airplanes having
received a certificate of airworthiness after the effective date of
this AD: Before the accumulation of 3,500 flight hours or within 24
months after the effective date of this AD, whichever occurs later.
Freeplay Measurement (Inspection)
(i) Within the compliance times specified in paragraph (i)(1) or
(i)(2) of this AD, as applicable: Perform a freeplay measurement of
the ballnut and ballscrew in accordance with Part 2 of the
Accomplishment Instructions of the service bulletin. Repeat the
freeplay measurement thereafter at intervals not to exceed 18,000
flight hours or 60 months, whichever occurs first. If the freeplay
is found to exceed the limits specified in the service bulletin
during any measurement required by this AD, before further flight,
replace the actuator with a new or serviceable actuator in
accordance with the service bulletin.
(1) For airplanes identified in paragraph (g) of this AD on
which the actuator has not been replaced: Before the accumulation of
15,000 total flight hours, or within 18 months after the effective
date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on
which the actuator has been replaced, and for airplanes having
received a certificate of airworthiness after the effective date of
this AD: Before the accumulation of 3,500 flight hours or within 24
months after the effective date of this AD, whichever occurs later.
Lubrication
(j) Within the compliance times specified in paragraph (j)(1) or
(j)(2) of this AD, as applicable: Lubricate the ballnut and
ballscrew in accordance with Part 3 of the Accomplishment
Instructions of the service bulletin. Repeat the lubrication
thereafter at intervals not to exceed 2,000 flight hours or 12
months, whichever occurs first.
(1) For airplanes identified in paragraph (g) of this AD on
which the actuator has not been replaced: Before the accumulation of
15,000 total flight hours, or within 18 months after the effective
date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on
which the actuator has been replaced, and for airplanes having
received a certificate of airworthiness after the effective date of
this AD: Before the accumulation of 3,500 flight hours or within 24
months after the effective date of this AD, whichever occurs later.
Credit for Using Original Issue of Service Bulletin
(k) Actions performed prior to the effective date of this AD in
accordance with Boeing Alert Service Bulletin 777-27A0059, dated
September 18, 2003, are considered acceptable for compliance with
the corresponding actions of this AD.
Credit for Hard-time Replacement of Actuator
(l) Any actuator overhauled within the compliance times
specified for paragraphs (h), (i), and (j) of this AD or before the
effective date of this AD--as part of a ``hard-
[[Page 33415]]
time'' replacement program that includes removal of the stabilizer
actuator from the airplane and overhaul of the stabilizer ballscrew
in accordance with original equipment manufacturer (OEM) component
maintenance manual (CMM) instructions--meets the intent of one
detailed inspection, one freeplay inspection, and one lubrication of
the stabilizer ballscrew. Therefore, any such actuator is considered
acceptable for compliance with the initial accomplishment of
paragraphs (h), (i), and (j) of this AD, and repetitions of those
paragraphs may be determined from the performance date of that
overhaul.
Parts Installation
(m) As of the effective date of this AD, no person may install,
on any airplane, a horizontal stabilizer trim actuator that is not
new or overhauled, unless a detailed inspection, freeplay
measurement, and lubrication of that actuator have been performed in
accordance with paragraphs (h), (i), and (j) of this AD.
Alternative Methods of Compliance (AMOCs)
(n)(1) 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.
(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.
Issued in Renton, Washington, on June 8, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-11679 Filed 6-15-07; 8:45 am]
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