[Federal Register Volume 60, Number 98 (Monday, May 22, 1995)]
[Rules and Regulations]
[Pages 27008-27016]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11968]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-187-AD; Amendment 39-9233; AD 95-10-16]
Airworthiness Directives; Boeing Model 747 Series Airplanes
Equipped with Pratt & Whitney Model JT9D Series Engines (Excluding
Model JT9D-70 Engines)
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747 series airplanes, that requires
modification of the nacelle strut and wing structure, inspections and
checks to detect discrepancies, and correction of discrepancies. This
amendment is prompted by the development of a modification of the strut
and wing structure that improves the damage tolerance capability and
durability of the strut-to-wing attachments, and reduces reliance on
inspections of those attachments. The actions specified by this AD are
intended to prevent failure of the strut and subsequent loss of the
engine.
DATES: Effective June 21, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 21, 1995.
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: Tim Backman, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2776; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Boeing Model 747 series
airplanes was published in the Federal Register on December 21, 1994
(59 FR 65733). That action proposed to require modification of the
nacelle strut and wing structure, inspections and checks to detect
discrepancies in the adjacent structure, and correction of
discrepancies.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Revision of Descriptive Language
One commenter notes that the description of the unsafe condition
that appeared in the Discussion section of the preamble to the notice
refers to ``the structural fail-safe capability of the strut-to-wing
attachment.'' The commenter states that this description is inaccurate,
since it implies that the strut-to-wing attachment is inadequate. The
commenter suggests that a more accurate description would be ``damage
tolerance capability of the strut-to-wing attachment.'' The FAA
acknowledges that the commenter's wording is more accurate. The
pertinent wording this preamble to the final rule has been revised to
reflect this change. Furthermore, the FAA considers the new structure
of the strut as meeting the damage tolerance requirements of amendment
45 of section 25.571, ``Damage--tolerance and fatigue evaluation of
structure'' of the Federal Aviation Regulations (14 CFR 25.571,
amendment 45), which provides an even higher level of safety than
simply fail-safe requirements.
One commenter provides further information to describe the purpose
of the proposed modification of the nacelle strut and wing structure.
This commenter suggests that the rule should specify that the
modification not only significantly improves the load-carrying and
durability of the strut-to-wing attachments, but ``reduces the reliance
on non-routine inspections,'' as well. The FAA concurs with this
suggestion and has revised the Summary section of the preamble to this
final rule to include wording relevant to this aspect. -
One commenter provides clarification of the description in the
Explanation of Service Information section of the preamble to the
proposal. That section of the preamble described the various
terminating actions specified in the service bulletins listed in
paragraph I.C., Table 2, Prior or Concurrent Service
[[Page 27009]] Bulletins,'' on page 13 of Boeing Alert Service Bulletin
747-54A2159, dated November 3, 1994 (which was referenced in the notice
as the appropriate source of service information). The commenter notes
that it is replacement of the ``diagonal brace strut lower spar
fitting'' which is specified as a terminating action in that listing.
The notice, however, incompletely described that particular terminating
action as the replacement of ``the diagonal brace strut and wing and
attachment fittings.'' The FAA acknowledges that the commenter provides
a more complete description of that terminating action. However, since
the Explanation of Service Information section is not restated in this
rule, no change to the final rule is necessary.
Clarification of Note 1 -
One commenter requests that Note 1 of the proposal be clarified
since it is too vague to determine exactly when FAA approval of
alternative methods of compliance (AMOC) is necessary. The FAA concurs.
Although every effort is made to keep the language simple and clear, it
is apparent that some additional explanation is necessary to clarify
the intent of Note 1. Performance of the requirements of this final
rule is ``affected'' if an operator is unable to perform those
requirements in the manner described in this AD. For example, if an AD
requires a visual inspection in accordance with a certain service
bulletin, and the operator cannot perform that inspection because of
the placement of a repair doubler over the structure to be inspected,
then ``performance of the AD is affected.'' -
In addition, performance of the requirements is ``affected'' if it
is physically possible to perform the requirements, but the results
achieved are different from those specified in the AD. For example, if
the AD requires a non-destructive test (NDT) inspection in accordance
with a certain service bulletin, and the operator is able to move the
NDT probe over the specified area in the specified manner, but the
results are either meaningless or inaccurate because of a repair
doubler placed over that area, then ``performance of the AD is
affected.'' -
While Note 1 itself is not capable of addressing every possible
situation, ``affected'' is normally an easy standard to apply: either
it is possible to perform the requirements as specified in the AD and
achieve the specified results, or it is not possible. Therefore, if the
requirements of this AD cannot be performed, then operators must submit
a request for an approval of an AMOC from the FAA, in accordance with
the provision of paragraph (d) of this final rule. -
Accomplishment of any modification requirement of an AD, such as
the modification of the nacelle strut and wing structure required by
this final rule, does not ``affect performance of the AD;'' it is
performance of the AD. Every AD includes a provision, with which
operators are familiar, that states, ``Compliance required as
indicated, unless accomplished previously .'' If an operator performs
such a requirement before the AD is issued, the FAA is confident that
the operator will recognize that it has already complied with the AD
and no further action (including obtaining approval of an AMOC) is
required. This is consistent with current law and practice, which Note
1 is not intended to change.
Compliance Time for Modification -
One commenter requests that the compliance times of proposed
paragraph (a), which requires modification of the nacelle strut and
wing structure, be extended by 4 months. The commenter notes that a 4-
month extension of the compliance times would coincide with the times
recommended in the referenced Boeing Alert Service Bulletin 747-54A2159
for that modification. Furthermore, the commenter states that the
referenced alert service bulletin contains numerous errors, and a 4-
month extension would allow the manufacturer sufficient time to publish
a revision to that alert service bulletin to correct those errors. -
The FAA does not concur with the commenter's request. In developing
an appropriate compliance time for this action, the FAA considered not
only the degree of urgency associated with addressing the subject
unsafe condition, but the manufacturer's recommendation as to an
appropriate compliance time, the availability of required parts, and
the practical aspect of installing the required modification within a
maximum interval of time allowable for all affected airplanes to
continue to operate without compromising safety. Further, the FAA took
into account the 3-year and 5-year compliance times recommended by the
manufacturer, as well as the number of days required for the rulemaking
process; in consideration of these factors, the FAA finds that 32
months and 56 months after the effective date of this final rule will
fall approximately at the same time for compliance as recommended by
the manufacturer. Furthermore, the FAA does not consider that delaying
this action until after the release of the manufacturer's planned
revision to the alert service bulletin is warranted, since the changes
in the revised alert service bulletin are mostly minor and clarifying
in nature and do not affect the procedures to accomplish the
modification of the nacelle strut and wing structure.
However, under the provisions of paragraph (d) of the final rule,
any operator may submit requests for adjustments to the compliance time
along with data demonstrating that such requests will not compromise
safety. In evaluating such requests for adjustments to the compliance
time, the FAA will closely examine the operator's explanation of why an
extension is needed. The FAA will also consider the operator's good
faith attempt at complying within the compliance times contained in
this final rule, which can be demonstrated by accomplishing the
modification on a significant percentage of the airplanes in the
operator's fleet prior to submitting a request for adjustments to the
compliance times. The FAA will take into consideration the number of
airplanes in the operator's fleet on which the modification has been
accomplished and the number of unmodified airplanes remaining in the
operator's fleet. Additionally, the operator may be asked to submit a
schedule for accomplishing the modification on the airplanes remaining
in its fleet.
Calculation of Age of Affected Airplanes -
Several commenters request that the age of the airplanes be
measured as of the date of issuance of Boeing Alert Service Bulletin
747-54A2159, rather than as of the effective date of the AD, as
proposed in paragraphs (a)(1) and (a)(2). Some of these commenters
state that this change would coincide with the thresholds recommended
in that alert service bulletin. One of these commenters notes that this
change would move three of the airplanes in its fleet from the
applicability provisions of paragraph (a)(2) (which would allow it 32
months) to paragraph (a)(1) (which would allow it the maximum amount of
time of 56 months) to accomplish the modification of the nacelle strut
and wing structure. -
The FAA concurs. As discussed above, the FAA's intent was to align
the compliance times as closely as possible with those recommended by
the manufacturer in the referenced alert service bulletin. Therefore,
paragraphs (a)(1) and (a)(2) of the final rule have been revised to
specify that the age of the airplane is to be measured as of November
3, 1994, which is the date of issuance of the alert service bulletin.
[[Page 27010]]
Service Bulletins Listed in Note 2 -
Several commenters request that Note 2, which follows proposed
paragraph (a)(2)(i), be revised either to exclude or to add service
bulletins to the list of bulletins that describe modifications that
must be accomplished in order to gain the maximum time allowable (56
months) in which to accomplish the modification of the nacelle strut
and wing structure. One of these commenters requests that the list be
revised to exclude all Boeing service bulletins, with the exception of
the following two: -
1. Boeing Alert Service Bulletin 747-54A2155, dated September 23,
1993, which specifies inspection of the midspar fittings; and -
2. Boeing Alert Service Bulletin 747-54A2152, Revision 2, dated
September 16, 1993, which specifies installation of (third generation
fuse pins) upper link diagonal brace and midspar fuse pins [required by
AD 93-17-07, amendment 39-8678 (58 FR 45827, August 31, 1993)]. -
This commenter states that, if the other service bulletins are
excluded from the list, safety would not be compromised since various
repetitive inspections already are required by numerous other AD's that
are intended to ensure the structural integrity of the strut-to-wing
attachments and the fail-safe capability of the strut structure. -
The FAA does not concur. As stated in the preamble to the proposal,
one of the purposes of this rulemaking action is to reduce reliance on
inspections of the strut-to-wing attachments. The FAA has determined
that long term continued operational safety will be better assured by
actual modification of the airframe to remove the source of the
problem, rather than by repetitive inspections. Long term inspections
may not be providing the degree of safety assurance necessary for the
transport airplane fleet. This, coupled with a better understanding of
the human factors associated with numerous repetitive inspections, has
led the FAA to consider placing less emphasis on special procedures and
more emphasis on design improvements. The modification requirement of
this final rule is in consonance with these considerations.
Modification of Engine Mounts -
Two commenters request that the list of service bulletins be
revised to exclude Boeing Alert Service Bulletin 747-71A2269, Revision
1, dated July 7, 1994, which describes procedures for modification of
the engine mounts. These commenters state that modification of the
engine mounts is an entirely separate subject that is not related to
the unsafe condition addressed by the proposed rule. One of these
commenters believes that modification of the engine mounts is addressed
more appropriately in AD 94-10-05. -
The FAA does not concur. The FAA finds that the unsafe conditions
addressed in both AD 94-10-05 [amendment 39-8912 (59 FR 25288, May 16,
1994)] and this AD are closely related. AD 94-10-05 requires
replacement of the existing nut with a new castellated nut, and
references Boeing Alert Service Bulletin 747-71A2269 as the appropriate
source of service information. That AD addresses migration of the bolts
out of the engine lug joint, which may lead to loss of the engine from
the strut. Therefore, the FAA has determined that accomplishing the
requirements of AD 94-10-05, prior to accomplishing the requirements of
this final rule, reduces reliance on repetitive inspections, and
decreases the likelihood of the engine separating from the airplane.
Replacement of Diagonal Braces -
Certain commenters request that the list of service bulletins be
revised to exclude Boeing Service Bulletin 747-54-2123, which describes
procedures for replacement of the diagonal braces. One of these
commenters notes that it has found no significant discrepancies on any
of the airplanes in its fleet while performing the inspections of this
area that are required by AD 90-20-20. Therefore, this commenter
contends that replacement of the diagonal braces prior to
accomplishment of the proposed modification of nacelle strut and wing
structure is unnecessary if the brace lugs have been modified in
accordance with Boeing Service Bulletin 747-54-2126 and the diagonal
braces have been inspected in accordance with Boeing Service Bulletin
747-54-2123. -
Further, these commenters contend that temporarily replacing the
diagonal braces is cost-prohibitive: one of these commenters estimates
the cost at $50,000 per airplane, while the other commenter estimates
the cost at $60,000 per airplane. These commenters also point out that
these costs are unreasonable, especially in light of the fact that the
diagonal braces must be replaced once more as part of the proposed
modification of the nacelle strut and wing structure. -
Additionally, one of these commenters suggests that there is
potential for a parts availability problem if all operators choose to
replace these diagonal braces. Consequently, these commenters request
the removal of Boeing Service Bulletin 747-54-2123 from the list of
service bulletins.
The FAA does not concur. In addressing these particular comments,
the FAA points out that there are three types of diagonal braces
currently available:
1. ``Type 1 Braces'' have been addressed previously by two AD's:
--AD 89-07-15, amendment 39-6167 (54 FR 11693, March 22, 1989),
references Boeing Service Bulletin 747-54-2126. That AD requires the
lugs of Type 1 Braces to ultrasonically inspected every 1,000 flight
cycles. That AD was prompted by reports of cracking in the lugs that
had initiated at corrosion pits in the lug bores and was propagated by
fatigue. Terminating action for those inspections consists of removing
bushings, oversizing of the hole to eliminate corrosion, and installing
high interference fit bushings. There have been reports of 11 cracked
braces found during the inspections required by this AD.
--AD 90-20-20, amendment 39-6725 (55 FR 37859, September 14, 1990),
references Boeing Service Bulletin 747-54-2123. That AD requires Type 1
Braces to be either visually inspected every 1,000 flight cycles, or
ultrasonically inspected every 3,000 flight cycles; any cracked brace
is required to be replaced with either a serviceable Type 1 Brace or a
``Type 2 Brace'' (see below). That AD was prompted by the finding of a
completely separated brace in service. Separation was attributed to
circumferential cracks initiating from a tool mark in the brace's inner
surface. (There also has been one additional report of a crack found,
but separation did not occur.) Terminating action for these inspections
consists of replacing Type 1 Braces with ``Type 2 Braces.''
2. ``Type 2 Braces'' are not susceptible to the cracking conditions
of the brace's inner surface (as was found on the Type 1 Braces)
because of their revised internal and external surface finish.
Additionally, during production, the lugs associated with these Type 2
Braces were modified in accordance with the terminating action
specified in AD 89-07-15; with this modification, the ultrasonic
inspections required by that AD are not necessary on this type of
brace.
3. ``Type 3 Braces'' are those that are required to be installed as
part of the full strut modification program on which this AD is based.
These braces are optimal because they have increased
[[Page 27011]] strength and are not susceptible to the type of cracking
found in Type 1 Braces.
The FAA points out that this final rule provides operators 32
months in which to accomplish the full strut modification if Type 1
Braces are currently installed. Likewise, this final rule provides
operators 56 months in which to accomplish the full strut modification
if Type 2 Braces are currently installed, or if Type 2 Braces are
installed within 32 months (and the additional modifications specified
in the service bulletins listed in Note 2 are accomplished, as well).
Optimally, the FAA would prefer that all affected airplanes be
modified within 32 months. However, when developing the compliance time
for this AD, the FAA recognized the high costs (down time) that would
be imposed on operators when accomplishing the full strut modification
program. In so doing, the FAA looked for ways to lessen that economic
burden, while still ensuring that a higher level of safety would exist
than that currently provided. Based on analyses following relevant
accidents involving failure of the strut-to-wing attachment and
subsequent separation of the engine from the airplane during flight,
the FAA determined that the Type 1 Brace, with its extensive history of
service difficulties, is not adequate for long term assurance of
safety. Even with repetitive inspections, these Type 1 Braces have
inadequate damage tolerance. In light of this and the catastrophic
consequences of fatigue cracking and/or corrosion in the strut-to-wing
attachments, the FAA has determined that Type 1 Braces must be removed
from the fleet sooner than the other braces that have a better service
record.
As for the costs of replacement of the braces, the FAA finds that
the figures quoted by the commenters need clarification. The
manufacturer has provided the following figures relative to costs:
--Installation of Type 2 Braces requires from 88 to 116 work hours per
airplane, at an average labor rate of $60 per work hour. The cost of
each brace is, at most, $13,282 (in 1990 dollars) per brace; there are
4 braces on each airplane. Using these figures, the cost to install
four Type 2 Braces on an airplane would be, at most, $53,128 in parts
and $6,960 in labor charges.
--Parts and labor costs for the installation of Type 3 Braces, as part
of the full strut modification kit, will be absorbed by the
manufacturer.
Regardless of these costs, the FAA has determined that the safety
benefit justifiably outweighs the economic cost of replacing diagonal
braces. Further, the replacement of the Type 1 Brace with a Type 2
Brace is required only if the operator wants the longer compliance time
of 56 months for accomplishing the full strut modification. This
extended compliance time lessens the economic impact on operators in
terms of the costs of special scheduling and down time. The FAA notes
that certain operators have already accomplished the full strut
modification; these operators have found it to be more cost effective
to do so, since they incur no charges for parts. A full discussion of
the cost impact of this rule on U.S. operators is discussed later in
this preamble.
As for the availability of parts, the manufacturer has advised that
there would be a problem with parts availability only if many of the
affected operators elected to install the Type 2 Braces as an interim
measure. However, as a matter of fact, both the manufacturer and the
FAA expect that many operators will not elect to do this, but will opt
to install the full strut modification, which includes the Type 3
Brace. The manufacturer has indicated that there are ample numbers of
the full strut modification kits available.
Rework of Midspar Fitting Lugs
One commenter requests that the list of service bulletins be
revised to add Boeing Service Bulletin 747-54-2100 as an alternative to
Boeing Alert Service Bulletin 747-54A2152 (original or Revision 1). The
commenter believes that procedures for rework of the midspar fitting
lugs, which is described Service Bulletin 747-54-2100, is equivalent to
that specified in Service Bulletin 747-54A2152.
The FAA does not concur, since it does not find that the two
procedures described in the referenced service bulletins are
equivalent. For example, the rework procedure described in Boeing
Service Bulletin 747-54-2100 does not include an ``insurance'' cut that
is included in the rework procedure described in Boeing Alert Service
Bulletin 747-54A2152 (original issue and Revision 1). Further, Revision
2 of Boeing Alert Service Bulletin 747-54A2152 has refined the
procedure even further: this revision [which is referenced in
paragraphs (a)(2)(iii) and (a)(2)(iv) of the final rule] describes a
magnetic particle inspection to detect cracking of the midspar fitting
lugs. Consequently, the FAA finds the procedures described in Revision
2 of Boeing Alert Service Bulletin 747-54A2152 to be significantly
better in detecting and removing undetected cracks than those described
in the earlier versions of that alert service bulletin or in Boeing
Service Bulletin 747-54-2100.
Clarification of Requirements for Modified Airplanes
One commenter requests that the requirements of proposed paragraph
(a)(2)(i) be clarified. The commenter notes that Boeing Service
Bulletin 747-54-2062, Revision 5, which is referenced in the list of
modifications under Note 2 of the proposal, must be accomplished to
obtain the maximum amount of time allowable (56 months) in which to
accomplish the proposed modification of the nacelle strut and wing
structure. (These modifications are described in the service bulletins
listed in paragraph I.D., ``Compliance,'' on page 17 of Boeing Alert
Service Bulletin 747-54A2159, dated November 3, 1994.) However, the
commenter notes that Revision 7 of that service bulletin, which is
referenced in the list of terminating actions for the proposed rule,
must be accomplished prior to or concurrently with the proposed
modification of the nacelle strut and wing structure. (These
terminating actions are described in the service bulletins listed in
paragraph I.C., Table 2, ``Prior or Concurrent Service Bulletins,'' on
page 13 of Boeing Alert Service Bulletin 747-54A2159, dated November 3,
1994.)
The FAA concurs that clarification is warranted. Although Note 2
following paragraph (a)(2)(i) clearly states that subsequent revisions
of the service bulletins ``are acceptable and preferred for
accomplishment of the modifications,'' a footnote has been added to the
final rule following that list to point out specifically that
additional actions described in a subsequent revision of that service
bulletin are required to be accomplished prior to or concurrently with
the modification of the nacelle strut and wing structure, required by
paragraph (a) of the final rule.
Shortening the Compliance Times of Other Related AD's
One commenter considers it inappropriate to use the proposed rule
to shorten the 4,000-landing compliance time of AD 87-04-13 R1,
amendment 39-5546 (52 FR 3421, February 4, 1987). That AD requires
repetitive ultrasonic inspections of the fastener holes of the midspar
fittings. The commenter states that, if the 1,000-landing compliance
time specified in proposed paragraphs (a)(2)(ii)(B) and (a)(2)(iv)(B)
is appropriate to accomplish the requirements of the proposal, then it
[[Page 27012]] should also be appropriate for accomplishing the
inspection requirements of AD 87-04-13 R1.
-Similarly, the commenter states that it is equally inappropriate
to use the proposal to shorten the 5,000-landing compliance time of AD
93-17-07. That AD requires repetitive ultrasonic inspections of the
inboard midspar fitting lugs and references Boeing Alert Service
Bulletin 747-54A2152 (original issue or Revision 1) as the appropriate
source of service information. The commenter states that if the 2,500-
landing compliance time specified in proposed paragraphs (a)(2)(iii)(B)
and (a)(2)(iv)(C) is appropriate to accomplish the requirements of the
proposal, then it should also be appropriate for accomplishing the
requirements of AD 93-17-07. The commenter believes that the
appropriate means to effect a change to the compliance times of AD 87-
04-13 R1 and AD 93-17-07 should be by revising those AD's.
-The FAA concurs with the commenter's observations.
-As for AD 87-04-13 R1, the FAA will consider re-examining its
compliance time to determine if a revision to it is appropriate.
However, any revision to that AD would be proposed as a separate
rulemaking action. Further, in re-examining the compliance times of
proposed paragraphs (a)(2)(ii)(B), (a)(2)(iii)(B), (a)(2)(iv)(B), and
(a)(2)(iv)(C), the FAA finds that operators may not be afforded the
opportunity to obtain the maximum amount of time allowable to
accomplish the modification of the nacelle strut and wing structure if
the ``shortened'' compliance times of AD 87-04-13 R1 (from 4,000
landings to 1,000 landings) and AD 93-17-07 (from 5,000 landings or 5
years to 2,500 landings or 3 years) have already been exceeded.
Therefore, the FAA has revised those paragraphs of the final rule to
include a ``grace period.''
-As for AD 93-17-07, Note 4 of this final rule explains that the
compliance time of 2,500 landings or 3 years since rework of the lugs,
whichever occurs earlier, coincides with the compliance time
recommended in Revision 2 of Boeing Alert Service Bulletin 747-54A2152,
dated September 15, 1993, which the FAA has approved as an alternative
method of compliance for accomplishment of the requirements of AD 93-
17-07. However, the FAA will consider re-examining the compliance time
of AD 93-17-07 to determine if further rulemaking is warranted. In the
interim, the compliance time of paragraphs (a)(2)(iii)(B) and
(a)(2)(iv)(C) of this final rule will remain unchanged. Any revision to
the compliance time of AD 93-17-07, if deemed necessary, must be
proposed in a separate rulemaking action.
Inspection Interval for the Inboard Midspar Fitting Lugs
One commenter requests that proposed paragraph (a)(2)(iii)(B) be
revised to require the reduced 2,500-cycle compliance time only for the
ultrasonic inspection of the inboard midspar fitting lugs. This change
would make this requirement consistent with that of AD 93-17-07,
amendment 39-8678 (58 FR 45827, August 31, 1993). This commenter also
notes that outboard struts do not have spring beams.
-The FAA concurs. Further, the FAA finds that this change is also
applicable to paragraph (a)(2)(iv)(C) of the final rule. Therefore,
paragraphs (a)(2)(iii)(B) and (a)(2)(iv)(C) of the final rule have been
revised accordingly.
Correction of Typographical Error in Note 6
Three commenters request that a typographical error that appeared
in Note 6 [which follows proposed paragraph (a)(2)(v)] be corrected.
The commenters note that the Table in Note 6 erroneously referred to
Boeing Alert Service Bulletin 747-54A2159. The correct reference should
have been Boeing Alert Service Bulletin 747-54A2152, as it correctly
appeared in paragraphs (a)(2)(iii) and (a)(2)(iv) of the proposal. The
FAA concurs and has made the correction accordingly. Additionally, the
FAA has reformatted the Table in Note 6 for purposes of clarification:
the column headed ``Revision Level'' has been removed, and the revision
level of the service bulletin has been inserted adjacent to the service
bulletin number itself.
Requirements Redundant to Part 121
-One commenter requests that proposed paragraph (b) be deleted
since the proposed inspection and repair of components (referenced in
Notes 8, 9, and 10 of the Accomplishment Instructions on page 150 of
Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994) are
redundant to the requirements of part 121 of the Federal Aviation
Regulations (14 CFR 121). Furthermore, the commenter believes that the
proposed torque check of the fasteners of the diagonal brace fittings
(referenced in Note 11 of the alert service bulletin) should be
incorporated as part of the Accomplishment Instructions of the Boeing
Alert Service Bulletin 747-54A2159, rather than as merely a Note in the
Accomplishment Instructions.
The FAA does not concur with the commenter that the requirements of
paragraph (b) should be deleted from the final rule. According to
section 39.1 of the Federal Aviation Regulations (14 CFR 39.1), the
issuance of an AD is based on the finding that an unsafe condition
exists or is likely to develop in aircraft of a particular type design.
Further, it is within the FAA's authority to issue an AD to require
actions to address unsafe conditions that are not otherwise being
addressed (or addressed adequately) by normal maintenance procedures.
The FAA points out that fatigue cracking and corrosion in the strut-to-
wing attachments have resulted in several incidents and catastrophic
accidents. Although 14 CFR 121 addresses damage found on components
during other maintenance activities, the FAA has determined that the
catastrophic consequences of the unsafe condition are such that
reiterating the necessity of performing inspections and repairs when
any damage or corrosion is found while performing the modification of
the nacelle strut and wing structure is warranted and necessary. The AD
is the appropriate vehicle for mandating such actions.
AD's Terminated by This Final Rule
One commenter notes that the AD's listed in proposed paragraph (c)
as those that are terminated once the actions of the proposal are
accomplished, differs from those listed in Table 1 of Boeing Alert
Service Bulletin 747-54A2159.
The FAA concurs that a difference does exist. However, several of
the AD's included in the listing contained in the Boeing alert service
bulletin have been superseded by new AD's. The FAA points out that,
when an AD is superseded, it is deleted from the system, and as such,
no longer exists, since it has been replaced with a ``new'' AD that has
a new (different) AD number and amendment number. The FAA considers
that referencing nonexistent AD's would serve no meaningful purpose,
and may result in some confusion for affected operators. Consequently,
no change to paragraph (c) of the final rule is necessary.
Clarification of Cost Estimate Information
Two commenters request that the cost estimate be revised to include
the cost of out-of-service time for each aircraft during the time that
the modification is accomplished, and the additional fuel costs that
would be incurred due to the additional weight added to each aircraft
by the modification hardware.
The FAA does not concur that a revision is necessary. The
appropriate [[Page 27013]] number of hours required to accomplish the
required actions, specified as between 7,700 and 8,892 work hours in
the economic impact information, below, was developed with data
provided by the manufacturer. This number represents the time required
to gain access, remove parts, inspect, modify, install, and close up.
The cost analysis in AD rulemaking actions typically does not include
out-of-service time for each aircraft or additional fuel costs, as was
suggested by the commenter. These costs would be impossible to
calculate accurately due the differences in out-of-service time for
each operator. Furthermore, the increase in fuel costs due to the
weight added by the modification, would vary greatly from operator to
operator, depending upon airplane utilization.
The Air Transport Association of America (ATA) requests that the
FAA include costs ``beyond just parts and labor costs'' when
calculating the estimated costs to accomplish the proposed actions. The
ATA points out that the FAA should consider such costs to avoid
requiring actions that the ATA considers inconsequential.
The FAA does not concur. Contrary to the ATA's assertion, in
establishing the requirements of all AD's, the FAA does consider cost
impact to operators beyond the estimates of parts and labor costs
contained in AD preambles. For example, where safety considerations
allow, the FAA attempts to impose compliance times that generally
coincide with operators' maintenance schedules. However, because
operators' schedules vary substantially, the FAA is unable to
accommodate every operator's optimal scheduling in each AD. Each AD
does allow individual operators to obtain approval for extensions of
compliance times, based on a showing that the extension will not affect
safety adversely. Therefore, the FAA does not consider it appropriate
to attribute to the AD, the costs associated with the type of special
scheduling that might otherwise be required.
Furthermore, because the FAA generally attempts to impose
compliance times that coincide with operators' scheduled maintenance,
the FAA considers it inappropriate to attribute the costs associated
with aircraft ``downtime'' to the cost of the AD, because, normally,
compliance with the AD will not necessitate any additional downtime
beyond that of a regularly scheduled maintenance hold. Even if, in some
cases, additional downtime is necessary for some airplanes, the FAA
does not possess sufficient information to evaluate the number of
airplanes that may be so affected or the amount of additional downtime
that may be required. Therefore, attempting to estimate such costs
would be futile.
The FAA points out that this AD is an excellent example of the fact
that costs to operators are fully considered beginning at the earliest
possible stages of AD development. In this case, the service bulletin
that is referenced in this final rule was developed by Boeing only
after extensive and detailed consultations with large numbers of
operators of Model 747's. The compliance times and various optional
means of compliance presented in this AD are based on those
consultations, and were developed in order to minimize the economic
impacts on operators to the extent possible consistent with the service
bulletin's and this AD's safety objectives. Therefore, the costs that
the ATA asserts were not considered by the FAA have, in fact, been a
major consideration throughout this AD process; the fact that the FAA
has not attempted to quantify speculative costs does not diminish the
extent of this consideration.
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 600 Model 747 series airplanes equipped
with Pratt & Whitney Model JT9D series engines (excluding Model JT9D-70
engines) of the affected design in the worldwide fleet. The FAA
estimates that 146 airplanes of U.S. registry will be affected by this
AD.
The full strut modification required by this AD may take as many as
7,700 to 8,892 work hours to accomplish, depending upon the
configuration of the airplane. The manufacturer will incur the cost of
labor, on a pro-rated basis, with 20 years being the expected life of
these airplanes. The total cost impact of this AD on U.S. operators is
based on the median age for the fleet of Model 747 series airplanes
equipped with Pratt & Whitney Model JT9D series engines, which is
estimated to be 15 years. The average labor rate is estimated to be $60
per work hour. Required parts will be supplied by the manufacturer at
no cost to the operator. Based on these figures, the cost impact of
this proposal on U.S. operators is estimated to be between $50,589,000
($346,500 per airplane) and $58,420,440 ($400,140 per airplane).
This cost impact figure does not reflect the cost of the
terminating actions described in the service bulletins listed in
paragraph I.C., Table 2, ``Prior or Concurrent Service Bulletins,'' on
page 13 of Boeing Alert Service Bulletin 747-54A2159, dated November 3,
1994, that are required to be accomplished prior to or concurrently
with the modification of the nacelle strut and wing structure. Since
some operators may have accomplished certain modifications on some or
all of the airplanes in its fleet, while other operators may not have
accomplished any of the modifications on any of the airplanes in its
fleet, the FAA is unable to provide a reasonable estimate of the cost
of accomplishing the terminating actions described in the service
bulletins listed in Table 2 of the Boeing alert service bulletin.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the proposed requirements of
this AD action, and that no operator would accomplish those actions in
the future if this AD were not adopted. However, the FAA is aware that
some operators have already installed the strut modification that is
required by this AD; therefore, the future economic cost impact of this
rule on U.S. operators is reduced by that amount.
The FAA recognizes that the obligation to maintain aircraft in an
airworthy condition is vital, but sometimes expensive. Because AD's
require specific actions to address specific unsafe conditions, they
appear to impose costs that would not otherwise be borne by operators.
However, because of the general obligation of operators to maintain
aircraft in an airworthy condition, this appearance is deceptive.
Attributing those costs solely to the issuance of this AD is
unrealistic because, in the interest of maintaining safe aircraft,
prudent operators would accomplish the required actions even if they
were not required to do so by the AD.
A full cost-benefit analysis has not been accomplished for this AD.
As a matter of law, in order to be airworthy, an aircraft must conform
to its type design and be in a condition for safe operation. The type
design is approved only after the FAA makes a determination that it
complies with all applicable airworthiness requirements. In adopting
and maintaining those requirements, the FAA has already made the
determination that they establish a level of safety that is cost-
[[Page 27014]] beneficial. When the FAA, as in this proposed AD, makes
a finding of an unsafe condition, this means that the original cost-
beneficial level of safety is no longer being achieved and that the
required actions are necessary to restore that level of safety. Because
this level of safety has already been determined to be cost-beneficial,
a full cost-benefit analysis for this AD would be redundant and
unnecessary.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
95-10-16 Boeing: Amendment 39-9233. Docket 94-NM-187-AD.
Applicability: Model 747 series airplanes having line positions
001 through 814 inclusive, equipped with Pratt & Whitney Model JT9D
series engines (excluding Model JT9D-70 engines), 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 use the authority
provided in paragraph (d) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the strut and subsequent loss of the
engine, accomplish the following:
(a) Accomplish the modification of the nacelle strut and wing
structure in accordance with Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, at the time specified in either
paragraph (a)(1) or (a)(2) of this AD, as applicable. All of the
terminating actions described in the service bulletins listed in
paragraph I.C., Table 2, ``Prior or Concurrent Service Bulletins,''
on page 13 of Boeing Alert Service Bulletin 747-54A2159, dated
November 3, 1994, must be accomplished in accordance with those
service bulletins prior to or concurrently with the accomplishment
of the modification of the nacelle strut and wing structure required
by this paragraph.
(1) For airplanes that are younger than 15 years as of November
3, 1994, within 56 months after the effective date of this AD,
accomplish the modification.
(2) For airplanes that are 15 years or older as of November 3,
1994, accomplish the modification, and other required actions, at
the time specified in paragraph (a)(2)(i), (a)(2)(ii), (a)(2)(iii),
(a)(2)(iv), or (a)(2)(v) of this AD, as applicable.
(i) For airplanes on which all of the modifications described in
the service bulletins referenced by paragraph I.D., ``Compliance,''
on page 17 of Boeing Alert Service Bulletin 747-54A2159, dated
November 3, 1994, have been accomplished: Within 56 months after the
effective date of this AD, accomplish the modification of the
nacelle strut and wing structure and perform the inspections of the
adjacent structure that has not been replaced by the modification.
Note 2: Paragraph I.D., ``Compliance,'' on page 17 of Boeing
Alert Service Bulletin 747-54A2159, dated November 3, 1994,
references the following Boeing service bulletins. Subsequent
revisions of the following service bulletins are acceptable and
preferred for accomplishment of the modifications described therein:
------------------------------------------------------------------------
Service bulletin Revision
No. level Date
------------------------------------------------------------------------
747-54-2027..... 1......... February 23, 1973.
747-54-2030..... Initial February 23, 1973.
release.
*747-54-2062.... 5......... June 1, 1984.
747-54A2069..... 6......... October 22, 1982.
747-54-2118..... Initial July 25, 1986.
release.
747-54-2123..... 1......... March 1, 1990.
747-54A2151..... Initial October 6, 1992.
release.
747-54A2152..... 2......... September 16, 1993.
747-54A2155..... Initial September 23, 1993.
release.
747-57A2235..... Initial June 27, 1986.
release.
747-71A2269..... 1......... July 7, 1994.
------------------------------------------------------------------------
*AD 79-17-07, amendment 39-3533, requires inspection of the strut-to-
diagonal brace fittings, which may be terminated by replacing the
aluminum fittings with steel fittings in accordance with Revision 1
(or subsequent revisions) of Boeing Service Bulletin 747-54-2062.
Revision 7 of this service bulletin (referenced in paragraph I.C.,
Table 2, ``Prior or Concurrent Service Bulletins,'' on page 13 of
Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994)
specifies the replacement of aluminum fittings with steel fittings and
sealing the gap between the steel fitting and the closure web.
(ii) For airplanes on which all of the modifications described
in the service bulletins referenced by paragraph I.D.,
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, have been accomplished, excluding
the modification described in Boeing Service Bulletin 747-54-2118,
dated July 25, 1986:
(A) Within 56 months after the effective date of this AD,
accomplish the modification of the nacelle strut and wing structure
and perform the inspections of the adjacent structure that has not
been replaced by the modification.
(B) Repeat the ultrasonic inspections to detect cracking of the
aft-most two fastener holes in both strut midspar fittings on the
inboard and outboard nacelle struts, as required by AD 87-04-13 R1,
amendment 39-5546, within 4,000 landings following the immediately
preceding inspection performed in accordance with AD 87-04-13 R1 or
within 1,000 landings after the effective date of this AD, whichever
occurs earlier, in accordance with Boeing Service Bulletin 747-54-
2118, dated July 25, 1986, until the modification of the nacelle
strut and wing structure is accomplished in accordance with Boeing
Alert Service Bulletin 747-54A2159, dated November 3, 1994. Repeat
this [[Page 27015]] inspection thereafter at intervals not to exceed
1,000 landings.
Note 3: These inspections of the fastener holes are required by
AD 87-04-13 R1, amendment 39-5546, at 4,000-landing intervals.
Accomplishment of the inspections of the fastener holes, as required
by this paragraph at 1,000-landing intervals, constitutes compliance
with paragraph A. of AD 87-04-13 R1.
(iii) For airplanes on which all of the modifications described
in the service bulletins referenced by paragraph I.D.,
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, have been accomplished; except that
rework of the midspar fitting lugs was accomplished in accordance
with Boeing Alert Service Bulletin 747-54A2152, dated December 23,
1992, or Revision 1, dated July 15, 1993, instead of Revision 2,
dated September 16, 1993:
(A) Within 56 months after the effective date of this AD,
accomplish the modification of the nacelle strut and wing structure
and perform the inspections of the adjacent structure that has not
been replaced by the modification.
(B) Prior to the accumulation of 3 years since rework of the
inboard lugs, or within 6 months after the effective date of this
AD, whichever occurs later, perform an ultrasonic inspection to
detect cracking of the midspar fitting lugs of the inboard struts,
in accordance with Boeing Alert Service Bulletin 747-54A2152,
Revision 2, dated September 16, 1993. Repeat this inspection
thereafter as required by AD 93-17-07.
Note 4: This ultrasonic inspection is required by AD 93-17-07,
amendment 39-8678, to be performed prior to the accumulation of
5,000 landings or 5 years since accomplishment of the rework of the
lugs, whichever occurs earlier, in accordance with Boeing Alert
Service Bulletin 747-54A2152, dated December 23, 1992, or Revision
1, dated July 15, 1993. Repetitive inspections are required by that
AD at intervals not to exceed 500 landings for inboard struts and
1,000 landings for outboard struts. Since the issuance of that AD,
the FAA has approved Revision 2 of Boeing Alert Service Bulletin
747-54A2152, dated September 16, 1993, as an alternative method of
compliance for accomplishment of these ultrasonic inspections and
rework of the lugs. Revision 2 of the alert service bulletin
recommends that inboard lugs that have been reworked in accordance
with the original issue or Revision 1 of the alert service bulletin
be inspected prior to the accumulation of 2,500 landings or 3 years
since accomplishment of the rework of the lugs, whichever occurs
earlier. Therefore, accomplishment of ultrasonic inspections prior
to the accumulation of 2,500 landings or 3 years since
accomplishment of rework of the lugs, whichever occurs earlier, and
thereafter as required by AD 93-17-07, constitutes compliance with
paragraph (e)(2)(i)(A) of AD 93-17-07 for the inboard lugs.
(iv) For airplanes on which all of the modifications described
in the service bulletins referenced by paragraph I.D.,
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2152, dated November 3, 1994, have been accomplished; except that
rework of the midspar fitting lugs was accomplished in accordance
with the Boeing Alert Service Bulletin 747-54A2152, dated December
23, 1992, or Revision 1, dated July 15, 1993, instead of Revision 2,
dated September 16, 1993; and excluding the modification described
in Boeing Service Bulletin 747-54-2118, dated July 25, 1986:
(A) Within 56 months after the effective date of this AD,
accomplish the modification of the nacelle strut and wing structure
and perform the inspections of the adjacent structure that has not
been replaced by the modification.
(B) Repeat the ultrasonic inspections to detect cracking of the
aft-most two fastener holes in both strut midspar fittings on the
inboard and outboard nacelle struts, as required by AD 87-04-13 R1,
within 4,000 landings following the immediately preceding inspection
performed in accordance with AD 87-04-13 R1, or within 1,000
landings after the effective date of this AD, whichever occurs
earlier, in accordance with Boeing Service Bulletin 747-54-2118,
dated July 25, 1986, until the modification of the nacelle strut and
wing structure is accomplished in accordance with Boeing Alert
Service Bulletin 747-54A2159, dated November 3, 1994. Repeat this
inspection thereafter at intervals not to exceed 1,000 landings.
(C) Prior to the accumulation of 3 years since rework of the
inboard lugs, or within 6 months after the effective date of this
AD, whichever occurs later, perform an ultrasonic inspection to
detect cracking of the midspar fitting lugs of the inboard struts,
and repeat the inspection thereafter as required by AD 93-17-07,
until the modification of the nacelle strut and wing structure is
accomplished in accordance with Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994.
Note 5: Notes 3 and 4 are also applicable to this paragraph.
(v) For all other airplanes not subject to the requirements of
paragraph (a)(2)(i), (a)(2)(ii), (a)(2)(iii), or (a)(2)(iv) of this
AD: Within 32 months after the effective date of this AD, accomplish
the modification of the nacelle strut and wing structure and perform
the inspections of the adjacent structure that has not been replaced
by the modification.
Note 6: The following table graphically illustrates the
applicability and compliance times for accomplishing the
modification of the nacelle strut and wing structure as required by
paragraph (a)(2) of this AD.
------------------------------------------------------------------------
Compliance
Paragraph Accomplishment of service time
bulletins (months)
------------------------------------------------------------------------
(i)-......................... All in paragraph I.D.-...... 56
(ii)......................... All except 747-54-2118...... 56
(iii)........................ All except 747-54A2152, 56
Revision 2-.
(iv)......................... All except 747-54-2118 and 56
747-54A2152, Revision 2.
(v)-......................... (*)......................... 32
------------------------------------------------------------------------
*Paragraph (a)(2)(v) of this AD is applicable to all airplanes, other
than those addressed in paragraphs (a)(2)(i), (a)(2)(ii), (a)(2)(iii),
and (a)(2)(iv) of this AD. As such, these airplanes may have
accomplished some or none of the service bulletins listed in paragraph
I.D. of Boeing Alert Service Bulletin 747-54A2159, dated November 3,
1994.
(b) Perform the inspections and checks specified in paragraph
III, NOTES 8, 9, 10, and 11 of the Accomplishment Instructions on
pages 149 and 150 of Boeing Alert Service Bulletin 747-54A2159,
dated November 3, 1994, concurrently with the modification of the
nacelle strut and wing structure required by paragraph (a) of this
AD. Prior to further flight, correct any discrepancies found, in
accordance with the alert service bulletin.
(c) Accomplishment of the modification of the nacelle strut and
wing structure in accordance with Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, constitutes terminating action for
the inspections required by the following AD's:
----------------------------------------------------------------------------------------------------------------
Federal Register
AD No. Amendment No. citation Date of publication
----------------------------------------------------------------------------------------------------------------
94-17-17...................................... 39-9012 59 FR 44903 August 31, 1994.
94-10-05...................................... 39-8912 59 FR 25288 May 16, 1994.
93-17-07...................................... 39-8678 58 FR 45827 August 31, 1993.
93-03-14...................................... 39-8518 58 FR 14513 March 18, 1993.
92-24-51...................................... 39-8439 57 FR 60118 December 18, 1992.
92-07-11...................................... 39-8207 57 FR 10415 March 26, 1992.
90-20-20...................................... 39-6725 55 FR 37859 September 14, 1990.
90-17-18...................................... 39-6702 55 FR 33279 August 15, 1990.
89-07-15...................................... 39-6167 54 FR 11693 March 22, 1989.
87-04-13 R1................................... 39-5546 54 FR 3421 February 4, 1987.
[[Page 27016]]
86-08-03...................................... 39-5289 51 FR 12836 April 16, 1986.
86-07-06...................................... 39-5270 51 FR 10821 March 31, 1986.
86-05-11...................................... 39-5255 51 FR 8479 March 12, 1986.
86-23-01...................................... 39-5450 51 FR 37712 October 24, 1986.
82-22-02...................................... 39-4476 47 FR 46842 October 21, 1982.
80-08-02...................................... 39-3738- 45 FR 24450 April 10, 1980.
79-17-07...................................... 39-3533- 44 FR 50033 August 27, 1979.
----------------------------------------------------------------------------------------------------------------
(d) 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, Transport Airplane Directorate. 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.
Note 7: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(e) 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.
(f) The modification, inspections, checks, and correction of
discrepancies shall be done in accordance with Boeing Alert Service
Bulletin 747-54A2159, dated November 3, 1994. This incorporation by
reference was approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 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.
(g) This amendment becomes effective on June 21, 1995.
Issued in Renton, Washington, on May 10, 1995.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-11968 Filed 5-19-95; 8:45 am]
BILLING CODE 4910-13-U
