[Federal Register: April 15, 2003 (Volume 68, Number 72)]
[Rules and Regulations]
[Page 18107-18112]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15ap03-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2001-NM-329-AD; Amendment 39-13109; AD 2003-07-13]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757-200, -200CB, and -
200PF Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 757 series airplanes, that
currently requires repetitive inspections for excessive wear of the
internal and external splines of the torque tube couplings of the
trailing edge flaps, and replacement of the couplings, if necessary.
That AD also provides an optional modification that, if installed,
constitutes terminating action for the inspection requirements. This
amendment expands the applicability of the existing AD and requires new
inspections of the torque tube assemblies and certain gearbox
assemblies and universal joints in the drive system for the inboard
trailing edge flaps, and follow-on actions if necessary. For certain
airplanes, this amendment also adds a new optional modification, which,
if installed, terminates certain inspections. The actions specified by
this AD are intended to prevent separations in the drive system for the
inboard trailing edge flaps, which could cause a flap skew condition
that could result in damage to the flaps or fuselage, and consequent
reduced controllability of the airplane.
DATES: Effective May 20, 2003.
The incorporation by reference of certain publications, as listed
in the regulations, is approved by the Director of the Federal Register
as of May 20, 2003.
The incorporation by reference of certain other publications, as
listed in the regulations, was approved previously by the Director of
the Federal Register as of December 23, 1992 (57 FR 54298, November 18,
1992).
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Douglas Tsuji, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6487; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 92-25-01,
amendment 39-8416 (57 FR 54298, November 18, 1992), which is applicable
to certain Boeing Model 757 series airplanes, was published in the
Federal Register on May 29, 2002 (67 FR 37357). The action proposed to
continue to require repetitive inspections for excessive wear of the
internal and external splines of the torque tube couplings of the
trailing edge flaps, and replacement of the couplings, if necessary.
The action proposed to expand the applicability of the existing AD and
require new inspections of the torque tube assemblies and certain
gearbox assemblies and universal joints (U-joints) in the drive system
for the inboard trailing edge flaps, and follow-on actions if
necessary. For certain airplanes, the action also proposed to require a
previously optional modification and/or a new modification, which would
terminate certain inspections.
Explanation of New Relevant Service Information
Since the issuance of the proposed AD, the FAA has reviewed and
approved Boeing Service Bulletin 757-27A0125, Revision 2, dated July
25, 2002. The proposed AD refers to Revision 1 of that service
bulletin, dated December 2, 1999, as the appropriate source of service
information for the proposed inspections and corrective actions. Boeing
issued Revision 2 of the service bulletin primarily to reduce the
effectivity due to the installation of a flap-skew detection system on
airplanes with line numbers 981 and subsequent. Boeing also made
certain editorial changes in Revision 2 of the service bulletin. Since
there are no changes in Revision 2 of the service bulletin that affect
the actions required by this AD, we have revised paragraphs (b), (c),
(d), and (e) of this AD to refer to Revision 2 of the service bulletin
instead of Revision 1. The new paragraph (h) of this AD gives credit
for inspections accomplished before the effective date of this AD per
Revision 1 of the service bulletin.
Explanation of Changes to Proposed AD
Because the language in Note 5 of the proposed AD is regulatory in
nature, the provisions of that note have been included in paragraph (h)
of this AD. Subsequent paragraphs and notes have been reidentified
accordingly.
Also, for clarification, we have revised service bulletin
references in the body of this AD to specify that the appropriate
source for instructions is the Accomplishment Instructions of the
service bulletin.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
[[Page 18108]]
Support for the Proposal
One commenter concurs with the proposed AD.
Request To Remove Terminating Action
Two commenters request that we remove paragraphs (f) and (g) of the
proposed AD. Those paragraphs would require replacing the numbers 3 and
6 and numbers 4 and 5 torque tube assemblies. Both commenters state
that these replacements would be costly and burdensome to operators of
the affected airplanes. One of the commenters, the airplane
manufacturer, presents data that show that there have been no reported
cases of trailing edge flap skew since the release of the original
issue of Boeing Alert Service Bulletin 757-27A0125 on July 17, 1997.
The commenter states that these data show that the proposed inspections
are adequate to ensure the safety of the airplane fleet.
We partially concur with the commenters' request. We agree that it
is not necessary to mandate replacement of the torque tube assemblies
at this time. We consider three criteria for those situations where
repetitive inspections may be permitted to continue indefinitely, even
though a positive fix to the problem exists: (1) The area is easily
accessible, (2) the damage is easily detectable, and (3) the
consequences of the damage are not likely to be catastrophic. In
consideration of the excessive wear that may occur on torque tube
assemblies numbers 3 and 6 and numbers 4 and 5, we have determined that
the circumstances meet these three criteria warranting the ability of
owners and operators, at their option, to perform continual repetitive
inspections.
However, we find that some operators may wish to replace and
upgrade the affected torque tube assemblies in lieu of continuing to
inspect indefinitely. Thus, we have determined that it is appropriate
to leave the replacement of the torque tube assemblies as one option
for compliance with this AD. Therefore, we have retained paragraphs (f)
and (g) of the proposed AD in this final rule, but we have removed the
required compliance times from those paragraphs. In addition, we have
revised the Cost Impact section of the preamble of this AD to show the
terminating modifications as optional.
Request To Revise Compliance Times for Initial Inspections
Two commenters request that we extend the compliance time for
certain initial inspections that would be required by the proposed AD.
One commenter requests that we revise the initial compliance time for
paragraphs (c) and (e) of the proposed AD from the latest of 3,000
total flight cycles, 24 months after the airplane's date of
manufacture, and 18 months after the effective date of the AD, to the
later of 24 months and a certain flight-cycle limit (e.g., 3,000 flight
cycles) after the effective date of the AD. The second commenter
requests that we revise the initial compliance time to not less than 24
months after the effective date of the AD. (This commenter does not
specify to which paragraphs its request is intended to apply.) The
second commenter states that its data do not support the proposed
inspection timetable with respect to total flight cycles or calendar
time since date of manufacture. It contends that wear is a function of
cycles and should be free of calendar restriction. Both commenters are
seeking an extension of the compliance time so that it will coincide
with their approved ``C''-check interval.
We concur with the commenters' request. The original intent of the
18-month compliance option in paragraphs (b)(2), (c), and (e) of the
proposed AD was that it would coincide with ``C''-check intervals for
the majority of operators. This did not take into consideration that
certain freighter configurations of Model 757-200 series airplanes have
a ``C''-check interval of 24 months. Thus, we have revised paragraphs
(b)(2), (c), and (e) of this AD to require accomplishment of the
initial inspections associated with those paragraphs prior to the
accumulation of 3,000 total flight cycles, or within 24 months after
the effective date of this AD, whichever is later.
Request To Revise Repetitive Inspection Interval
One commenter requests that we revise the repetitive interval for
the inspections of the gearbox assemblies and U-joints specified in
paragraph (e) of the proposed AD. The proposed AD specifies that these
inspections must be performed every 3,000 flight cycles or 24 months,
whichever is first. The commenter requests that we revise the interval
to 3,000 flight cycles or 18 months, whichever comes first, to coincide
with its ``C''-check interval of the earliest of 6,000 flight hours,
3,000 flight cycles, and 18 months. The commenter presents data that
show that Model 757 series airplanes typically reach the 18-month limit
before they reach the 3,000-flight-cycle limit.
We partially concur with the commenter's request. We do not agree
that it is necessary to reduce the intervals to meet the commenter's
intent. Unless a ``minimum'' inspection interval is specified,
operators are always permitted to perform actions earlier than the
compliance time specified in an AD. In this case, it is at the
operator's discretion to inspect its affected airplanes at the earlier
of 18 months or 3,000 flight cycles, if that interval more closely fits
the operator's maintenance schedule.
However, for clarification, we find that a change in terminology
may be helpful. Therefore, we have revised paragraphs (b), (c), and (e)
of this AD to state that repetitive inspections must be accomplished
``at intervals not to exceed 3,000 flight cycles or 24 months,
whichever comes first.''
Request To Clarify Applicability of Inspection Requirement
One commenter points out that one airplane, line number (L/N) 412,
was omitted from paragraph (c) of the proposed AD. The commenter states
that paragraph (c) should be corrected to identify ``airplanes with L/
Ns 1 through 580 inclusive, which are identified as Groups 1 and 2
airplanes'' in the service bulletin.
We concur. While L/N 412 is included in Groups 1 and 2 in the
service bulletin, that L/N was inadvertently omitted from paragraph (c)
of the proposed AD. Our intention was for our AD to align with the
referenced service bulletin; no differences were noted in the preamble
of the proposed AD. Therefore, we have revised paragraph (c) of this AD
to include L/N 412. Because the airplane with L/N 412 is not a U.S.-
registered airplane, there is no economic impact on the U.S. fleet and,
thus, we find that making this change will not increase the scope of
the AD or the economic burden associated with the AD.
Request To Give Credit for Previously Accomplished Inspections
One commenter requests that credit be given for inspections
accomplished before the effective date of the AD per Revision 1 of the
service bulletin. The commenter states that the compliance time for the
first inspection should then be 3,000 flight cycles or 24 months from
the most recent inspection.
We concur but find that no change is necessary to meet the
commenter's intent. We give credit for actions accomplished before the
effective date of an AD by means of the phrase ``Compliance: Required
as indicated, unless accomplished previously,'' which appears in every
AD. As the commenter states, the next inspection must be done within
3,000 flight cycles or 24 months after the most recent
[[Page 18109]]
inspection, whichever is first. No change is necessary in this regard.
(Since we have revised this final rule to refer to Revision 2 of the
service bulletin, credit for inspections per Revision 1 of the service
bulletin is given in paragraph (h) of this AD.)
Request To Clarify Definition of Wear
One commenter requests that we more clearly define excessive wear
of the torque tube assemblies, as it pertains to the requirement for
measurements in paragraph (d) of the proposed AD. The commenter states
that normal, worn, and excessively worn areas are subject to
interpretation, and different individuals could interpret wear
differently.
We note that paragraph (d) of the proposed AD would require
measurements ``if any wear is found during any inspection required by
paragraph (b) or (c) of this AD. * * *.'' If wear is found during an
inspection per paragraph (b) or (c) of this AD, the follow-on
measurement required by paragraph (d) of this AD should provide
adequate guidance as to the necessary course of action. However, we
find that it may be helpful to provide examples of some types of wear
that may be found. Therefore, paragraphs (b), (c), and (d) of this AD
have been revised to include examples of wear that may be found.
Request To Revise Compliance Threshold for Paragraph (e) of Proposed AD
One commenter expresses concern over the inspections that would be
required by paragraph (e) of the proposed AD and the requirement to
replace the gearbox assembly and drive shaft assembly with new
components if certain measurements are outside the limits specified in
the service bulletin. The commenter is concerned about the potential
cost of replacement parts, which it states may be as high as $108,000.
A second commenter, the Air Transport Association of America, on behalf
of its members, requests that these costs be specified in the AD. The
first commenter is also concerned about the availability of necessary
parts within the compliance time specified in the proposed AD, and it
requests that we revise the initial compliance time to correspond with
spares availability. The commenter also requests that we allow
repetitive inspections of the gearbox assemblies and U-joints, as
allowed for the torque tubes elsewhere in the proposed AD, so that the
gearboxes or drive shaft assemblies do not have to be replaced before
further flight if the measurements are outside the specified limits.
We do not concur. The compliance times specified in this final rule
represent an acceptable interval of time wherein affected airplanes may
be allowed to operate without jeopardizing safety. Further, we find
that allowing repetitive inspections in lieu of requiring replacement
of discrepant parts with new parts would not ensure that the unsafe
condition is addressed in a timely manner. The measurement criteria
identified in paragraphs (e)(1) and (e)(2) of this AD represent the
maximum wear limits for the gearboxes and U-joints. To allow continued
use of these components, even with repetitive inspections, would
greatly increase the potential for a trailing edge flap skew. With
regard to the commenter's concern about parts availability, we have
reviewed available data and find that an adequate supply of parts
should be available. We have made no change to this final rule in this
regard.
We also do not concur with the other commenter's request that we
include the cost associated with replacing the gearboxes or U-joints in
the AD. The economic analysis included in AD actions is limited only to
the cost of actions actually required by the rule. It does not consider
the costs of ``on-condition'' actions, such as replacing a part if a
discrepancy is detected during a required inspection. Such ``on-
condition'' actions would be required to be accomplished--regardless of
AD direction--to correct an unsafe condition identified in an airplane
and to ensure operation of that airplane in an airworthy condition, as
required by the Federal Aviation Regulations.
Request To Revise Repetitive Interval for Paragraph (e) of Proposed AD
One commenter requests that we increase the repetitive interval for
the inspections of the gearbox assemblies and U-joints that would be
required by paragraph (e) of the proposed AD. The proposed AD states a
repetitive interval of 3,000 flight cycles or 24 months, whichever is
first; the commenter requests an interval of 4,500 flight cycles or 48
months, whichever is later. To justify its request, the commenter
presents data from three airplanes in its fleet. These data show that
no discrepancies were found on two of the airplanes, and only minor
wear of one torque tube was found on the third. The commenter also
contends that calendar time is not useful for gauging wear, as wear is
a function of flight cycles.
We do not concur. Three airplanes do not constitute an adequate
statistical sample size to determine that extension of the repetitive
interval would provide an acceptable level of safety. While in general
the number of flight cycles is a large contributor to wear on
components, the intent of this AD is to protect against all types of
wear. This includes wear accelerated by corrosion, which is a function
of calendar time. We have made no change to the final rule in this
regard.
Explanation of Additional Change to Proposed AD
We have added paragraph (i)(2) to this final rule to give credit
for accomplishment of certain alternative methods of compliance that
were approved previously in accordance with AD 92-25-01, amendment 39-
8416.
Also, throughout this final rule, we have changed the citation for
Boeing Service Bulletin 757-27-0107, dated June 16, 1994, to exclude
the Evaluation Form. The form is intended to be completed by operators
and submitted to the airplane manufacturer to provide input on the
quality of the service bulletin; however, this AD does not include such
a requirement.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Cost Impact
There are approximately 979 Model 757-200, -200CB, and -200PF
series airplanes of the affected design in the worldwide fleet.
In AD 92-25-01, we estimated that approximately 279 U.S.-registered
airplanes would be subject to the inspections in that AD. For these
airplanes, the currently required inspections take approximately 2 work
hours per airplane, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the currently required
actions on U.S. operators is estimated to be $33,480, or $120 per
airplane, per inspection cycle.
We estimate that approximately 283 U.S.-registered airplanes (Group
1 of Boeing Service Bulletin 757-27A0125, Revision 2) will be subject
to the required inspection of torque tube assemblies 3 and 6. This
inspection will take approximately 2 work hours per airplane, at an
average labor rate of $60 per work hour. Based on these figures, the
cost impact of this new inspection
[[Page 18110]]
required for U.S. operators of Group 1 airplanes is estimated to be
$33,960, or $120 per airplane, per inspection cycle.
We estimate that approximately 376 U.S.-registered airplanes
(Groups 1 and 2 of Boeing Service Bulletin 757-27A0125, Revision 2)
will be subject to the required inspection of torque tube assemblies 4
and 5. This inspection will take approximately 2 work hours per
airplane, at an average labor rate of $60 per work hour. Based on these
figures, the cost impact of these new inspections required for U.S.
operators of Groups 1 and 2 airplanes is estimated to be $45,120, or
$120 per airplane, per inspection cycle.
We estimate that 643 U.S.-registered airplanes (Groups 1, 2, and 3
of Boeing Service Bulletin 757-27A0125, Revision 2) will be subject to
the new required inspections of the gear box assemblies and U-joints of
the drive shaft assembly. These inspections will take approximately 4
work hours per airplane, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of these new inspections
required for U.S. operators is estimated to be $154,320, or $240 per
airplane, per inspection cycle.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the requirements of this
AD action, and that no operator would accomplish those actions in the
future if this AD were not adopted. The cost impact figures discussed
in AD rulemaking actions represent only the time necessary to perform
the specific actions actually required by the AD. These figures
typically do not include incidental costs, such as the time required to
gain access and close up, planning time, or time necessitated by other
administrative actions.
Should an operator elect to accomplish the modification that
involves replacement of torque tube assemblies 3 and 6, this
modification will take approximately 5 work hours per airplane, at an
average labor rate of $60 per work hour. Required parts will cost
approximately $4,550. Based on these figures, the cost impact of this
optional modification is estimated to be $4,850 per airplane.
Should an operator elect to accomplish the modification that
involves replacement of torque tube assemblies 4 and 5, this
modification will take approximately 5 work hours per airplane, at an
average labor rate of $60 per work hour. Required parts will cost
approximately $4,550. Based on these figures, the cost impact of this
optional modification is estimated to be $4,850 per airplane.
Regulatory Impact
The regulations adopted herein will 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. Therefore, it
is determined that this final rule does not have federalism
implications under Executive Order 13132.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. Section 39.13 is amended by removing amendment 39-8416 (57 FR 54298,
November 18, 1992), and by adding a new airworthiness directive (AD),
amendment 39-13109, to read as follows:
2003-07-13 Boeing: Amendment 39-13109. Docket 2001-NM-329-AD.
Supersedes AD 92-25-01, Amendment 39-8416.
Applicability: Model 757-200, -200CB, and -200PF series
airplanes; line numbers (L/Ns) 1 through 979 inclusive; certificated
in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (i)(1)
of this AD. The request should include an assessment of the effect
of the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent separations in the drive system for the inboard
trailing edge flaps, which could cause a flap skew condition that
could result in damage to the flaps or fuselage, and consequent
reduced controllability of the airplane, accomplish the following:
Restatement of Requirements of AD 92-25-01
Repetitive Visual Inspections and Corrective Actions
(a) For airplanes with L/Ns 1 through 411 inclusive and 413
through 432 inclusive: Prior to the accumulation of 2,000 total
flight cycles, or within the next 200 flight cycles after April 30,
1990 (the effective date of AD 90-08-16, amendment 39-6574),
whichever occurs later, and thereafter at intervals not to exceed
2,000 flight cycles, perform a general visual inspection of the
torque tube 3 and 6 coupling splines, in accordance with Boeing
Service Letter 757-SL-27-52-B, dated April 30, 1990.
Note 2: Operators who have conducted inspections of the torque
tube coupling splines prior to December 23, 1992 (the effective date
of AD 92-25-01, amendment 39-8416), in accordance with Boeing
Service Letter 757-SL-27-52, dated January 31, 1990, or Boeing
Service Letter 757-SL-27-52-A, dated March 21, 1990, are considered
to be in compliance with paragraph (a) of this AD.
(1) If the measurement over the pin, as detailed in the service
letter, is less than 1.8605 inches but equal to or greater than
1.8533 inches, repeat the inspection within 1,000 flight cycles,
until the requirements of paragraph (c) or (f) of this AD have been
accomplished.
(2) If the measurement over the pin, as detailed in the service
letter, is less than 1.8533 inches, replace the coupling before
further flight, in accordance with the service letter.
New Requirements of This AD
Note 3: For the purposes of this AD, a general visual inspection
is defined as: ``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 enhance visual access to all exposed 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.''
[[Page 18111]]
New Repetitive Inspections: Torque Tubes 3 and 6
Note 4: If the requirements of paragraph (f) of this AD have
been accomplished before the effective date of this AD, inspection
per paragraph (b) of this AD is not required.
(b) For airplanes with L/Ns 1 through 411 inclusive and 413
through 432 inclusive, which are identified as Group 1 airplanes in
Boeing Service Bulletin 757-27A0125, Revision 2, dated July 25,
2002: Do a general visual inspection for excessive wear of torque
tube assemblies 3 and 6, per the Accomplishment Instructions of the
service bulletin. Wear may include, but is not limited to, corrosion
or axial or radial freeplay relative to adjacent torque tubes or
gearbox. Do the initial inspection at the time specified in
paragraph (b)(1) or (b)(2) of this AD, as applicable. If no wear is
found, repeat the inspection at intervals not to exceed 3,000 flight
cycles or 24 months, whichever comes first, until paragraph (f) of
this AD has been accomplished. Doing paragraph (b) of this AD
terminates the requirements of paragraph (a) of this AD for torque
tube assemblies 3 and 6.
(1) For airplanes on which the inspection in paragraph (a) of
this AD has been done prior to the effective date of this AD:
Inspect within 3,000 flight cycles after the most recent inspection
done prior to the effective date of this AD per paragraph (a) of
this AD, or within 24 months after the effective date of this AD,
whichever is first.
(2) For airplanes on which the inspection in paragraph (a) of
this AD has not been done prior to the effective date of this AD:
Inspect prior to the accumulation of 3,000 total flight cycles, or
within 24 months after the effective date of this AD, whichever is
later.
New Repetitive Inspections: Torque Tubes 4 and 5
Note 5: If the requirements of paragraph (g) of this AD have
been accomplished before the effective date of this AD, inspection
per paragraph (c) of this AD is not required.
(c) For airplanes with L/Ns 1 through 580 inclusive, which are
identified as Groups 1 and 2 airplanes in Boeing Service Bulletin
757-27A0125, Revision 2, dated July 25, 2002: Prior to the
accumulation of 3,000 total flight cycles, or within 24 months after
the effective date of this AD, whichever is later, do a general
visual inspection for excessive wear of torque tube assemblies 4 and
5, per the Accomplishment Instructions of the service bulletin. Wear
may include, but is not limited to, corrosion or axial or radial
freeplay relative to adjacent torque tubes or gearbox. If no wear is
found, repeat the inspection at intervals not to exceed 3,000 flight
cycles or 24 months, whichever comes first, until paragraph (g) of
this AD has been accomplished.
Corrective Actions: Torque Tubes 3, 4, 5, and 6
(d) If any wear (including, but not limited to, corrosion or
axial or radial freeplay relative to adjacent torque tubes or
gearbox) is found during any inspection required by paragraph (b) or
(c) of this AD: Before further flight, measure the distance of the
measurement over pins, per the Accomplishment Instructions of Boeing
Service Bulletin 757-27A0125, Revision 2, dated July 25, 2002.
(1) If the distance is 1.8337 inches or more, repeat the general
visual inspection required by paragraph (b) or (c) of this AD at the
applicable interval specified in Table 1 of Figure 7 of the service
bulletin, until the actions in paragraphs (f) (for torque tube
assemblies 3 and 6) and (g) (for torque tube assembles 4 and 5) have
been done.
(2) If the distance is less than 1.8337 inches, do the actions
in paragraphs (d)(2)(i) and (d)(2)(ii) of this AD, per the
Accomplishment Instructions of the service bulletin.
(i) Before further flight, measure the distance of the outside
diameter, as shown in Table 1 of Figure 7 of the service bulletin.
(ii) Replace the affected torque tube assembly with a new torque
tube assembly at the applicable time specified in Table 1 of Figure
7 of the service bulletin.
New Repetitive Inspections: Gearbox Assemblies and Universal Joints
(e) For airplanes with L/Ns 1 through 979 inclusive: Prior to
the accumulation of 3,000 total flight cycles, or within 24 months
after the effective date of this AD, whichever is later, perform an
inspection to measure the axial movement of the angle and tee
gearbox assemblies and the distance between the upper and lower
yokes of the universal joints (U-joints) of the drive shaft
assemblies, per the Accomplishment Instructions of Boeing Service
Bulletin 757-27A0125, Revision 2, dated July 25, 2002. Repeat these
measurements at intervals not to exceed 3,000 flight cycles or 24
months, whichever comes first, and do paragraphs (e)(1) and (e)(2)
of this AD, as applicable.
(1) If any measurement of the axial movement of the gearbox
assembly is more than 0.015 inch, as specified in the service
bulletin: Before further flight, replace the gearbox assembly with a
new gearbox assembly, per the Accomplishment Instructions of the
service bulletin.
(2) If the distance between the upper and lower yokes of the U-
joints is more than 0.020 inch, as specified in Steps 3 and 6 of
Figure 6 of the service bulletin: Before further flight, replace the
drive shaft assembly with a new drive shaft assembly, per the
Accomplishment Instructions of the service bulletin.
Optional Terminating Action
(f) For airplanes with L/Ns 1 through 411 inclusive and 413
through 432 inclusive: Replacing torque tube assemblies number 3 and
6 with new, improved torque tube assemblies, and installing a
sealant plug in the shafts of four gearboxes, per the Accomplishment
Instructions of Boeing Service Bulletin 757-27-0099, dated March 12,
1992, terminates the inspections required by paragraphs (a) and (b)
of this AD.
(g) For airplanes with L/Ns 1 through 580 inclusive: Replacing
torque tube assemblies number 4 and 5 with new, improved torque tube
assemblies, and changing the related angle and tee gearbox
assemblies, per the Accomplishment Instructions of Boeing Service
Bulletin 757-27-0107, dated June 16, 1994, excluding Evaluation
Form, terminates the inspections required by paragraph (c) of this
AD. The changes for the related tee and angle gearbox assemblies are
shown in Figures 6 and 7, respectively, of the service bulletin.
Note 6: No terminating action has been identified for the
inspections specified in paragraph (e) of this AD.
Credit for Actions Accomplished Previously
(h) Inspections, measurements, and replacements done prior to
the effective date of this AD per Boeing Alert Service Bulletin 757-
27A0125, dated July 17, 1997; or Revision 1, dated December 2, 1999;
are considered acceptable for compliance with the corresponding
requirements of paragraphs (b), (c), (d), and (e) of this AD.
Alternative Methods of Compliance
(i)(1) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA. Operators shall submit their requests through an
appropriate FAA Principal Maintenance Inspector, who may add
comments and then send it to the Manager, Seattle ACO.
(2) Alternative methods of compliance, approved previously in
accordance with AD 92-25-01, amendment 39-8416, are approved as
alternative methods of compliance with paragraph (a) of this AD.
Note 7: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Special Flight Permits
(j) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Incorporation by Reference
(k) The inspections and corrective actions shall be done in
accordance with Boeing Service Letter 757-SL-27-52-B, dated April
30, 1990; and Boeing Service Bulletin 757-27A0125, Revision 2, dated
July 25, 2002; as applicable. The modifications, if accomplished,
shall be done in accordance with Boeing Service Bulletin 757-27-
0099, dated March 12, 1992; and Boeing Service Bulletin 757-27-0107,
dated June 16, 1994, excluding Evaluation Form; as applicable.
(1) The incorporation by reference of Boeing Service Bulletin
757-27A0125, Revision 2, dated July 25, 2002; and Boeing Service
Bulletin 757-27-0107, dated June 16, 1994, excluding Evaluation
Form; is approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
(2) The incorporation by reference of Boeing Service Letter 757-
SL-27-52-B, dated April 30, 1990; and Boeing Service Bulletin 757-
27-0099, dated March 12, 1992; was approved previously by the
Director of the Federal Register as of December 23, 1992 (57 FR
54298, November 18, 1992).
[[Page 18112]]
(3) Copies may be obtained from Boeing Commercial Airplane
Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be
inspected at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue, SW., Renton, Washington; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
Effective Date
(l) This amendment becomes effective on May 20, 2003.
Issued in Renton, Washington, on April 4, 2003.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-8742 Filed 4-14-03; 8:45 am]
BILLING CODE 4910-13-P