[Federal Register: November 4, 2003 (Volume 68, Number 213)]
[Proposed Rules]
[Page 62409-62415]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04no03-8]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NM-219-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
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SUMMARY: This document revises an earlier proposed airworthiness
directive (AD), applicable to all Boeing Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes, that would have superseded an
existing AD that currently requires repetitive inspections to find
cracks, fractures, or corrosion of each carriage spindle of the left
and
[[Page 62410]]
right outboard mid-flaps; and corrective action, if necessary. The
proposed AD would also have mandated the previously optional overhaul
or replacement of the carriage spindles, which would have ended the
repetitive inspections required by the existing AD. This new action
revises the proposed rule by adding a new requirement to the nickel
plating procedures and extending the compliance time for the overhaul
or replacement. The actions specified by this new proposed AD are
intended to prevent severe flap asymmetry due to fractures of the
carriage spindles on an outboard mid-flap, which could result in
reduced control or loss of controllability of the airplane. This action
is intended to address the identified unsafe condition.
DATES: Comments must be received by December 1, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2002-NM-219-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain ``Docket No. 2002-NM-219-AD'' in the subject line and need not
be submitted in triplicate. Comments sent via the Internet as attached
electronic files must be formatted in Microsoft Word 97 or 2000 or
ASCII text.
The service information referenced in the proposed rule may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Robert Hardwick, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6457; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this action may be changed in
light of the comments received.
Submit comments using the following format:
[sbull] Organize comments issue-by-issue. For example, discuss a
request to change the compliance time and a request to change the
service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed
AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each
request.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2002-NM-219-AD.'' The postcard will be date stamped
and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 2002-NM-219-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to all
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes, was published as a notice of proposed rulemaking (NPRM) in
the Federal Register on March 4, 2003 (68 FR 10188). That NPRM (the
``original NPRM'') proposed to supersede AD 2002-22-05, amendment 39-
12929 (67 FR 66316, October 31, 2002), which is applicable to all
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. That proposal would have continued to require repetitive
inspections to find cracks, fractures, or corrosion of each carriage
spindle of the left and right outboard mid-flaps; and corrective
action, if necessary. That NPRM also proposed to mandate the previously
optional overhaul or replacement of the carriage spindles, which would
end the repetitive inspections required by the existing AD. Fractures
of the carriage spindles on an outboard mid-flap could result in severe
flap asymmetry and consequent reduced control or loss of
controllability of the airplane.
Actions Since Issuance of Previous Proposal
Due consideration has been given to the comments received in
response to the original NPRM. Some of the comments have resulted in
changes to the original NPRM.
Request To Change Maximum Thickness of Nickel Plating
One commenter, the manufacturer, asks that the maximum thickness of
the nickel plating, as specified in paragraph (d)(2) of the original
NPRM, be changed. The commenter provides substantiating data which show
that, since the rate of plating is directly related to the rate of
hydrogen generation in the plating process, limiting the deposition
rate more efficiently minimizes hydrogen generation during plating and
reduces the potential for hydrogen embrittlement of the part. The
commenter asks that paragraph (d)(2) be changed to read, ``After
initial application of the plating current and during the plating
process, the rate of plating deposit must be maintained between .001-
inch-per-hour and a maximum of .002-inch-per-hour.''
The FAA partially agrees with the commenter. The material and
configuration of the outboard flap carriage are such that there is
increased concern for hydrogen embrittlement in the large diameter of
the spindle region. After reviewing the service experience and finding
no other existing related requirements, the FAA finds it necessary to
include the plating requirements in this AD. Controlling the deposition
rate is a direct method of controlling the quality of the plate and
generation of hydrogen during the plating process. The absorption and
diffusion of hydrogen into the metal during the plating process leads
to a condition known as ``hydrogen embrittlement.'' Metals affected by
hydrogen embrittlement have reduced ductility and may prematurely fail
during normal usage due to this condition. The original requirement of
0.020-inch-per-plating/baking cycle did not control the deposition
rate, and
[[Page 62411]]
there were wide variations. High deposition rates produce high rates of
hydrogen and poor-quality grain structure. The key parameter of 0.002-
inch-per-hour maximum deposition rate (which is a more stringent
requirement) provides a safeguard against high deposition rates. There
is no significant detrimental effect from low deposition rates, so the
minimum requirement requested will not be included. Therefore, we have
changed paragraph (d)(2) of this supplemental NPRM to read, ``The
maximum thickness of the nickel plating that is deposited in any one
plating/baking cycle must not exceed 0.002-inch-per-hour.''
Request To Remove Nickel Plating Requirement
One commenter asks that the nickel plating requirement specified in
paragraph (d)(2) of the original NPRM be removed. The commenter states
that if it performs the nickel plating per the new requirement, it must
perform a minimum of three plating/baking cycles, which would extend
the time necessary for overhaul of the carriage spindle by 15 days. The
commenter suggests two alternative methods to use in place of the
current proposed requirement, and provides documentation showing those
methods.
We do not concur that the nickel plating requirement should be
removed. However, as explained under ``Request to Change Maximum
Thickness of Nickel Plating,'' we have changed paragraph (d)(2) of this
supplemental NPRM to read, ``The maximum deposition rate of the nickel
plating that is deposited in any one plating/baking cycle must not
exceed 0.002-inch-per-hour.'' No other change to the supplemental NPRM
is necessary in this regard.
Requests To Extend Compliance Time
Several commenters request that the compliance time for the
overhaul or replacement specified in paragraphs (c), (c)(1), and (c)(2)
of the original NPRM be extended as follows:
[sbull] One commenter states that the proposed compliance time of 1
year after the effective date of the AD to replace the carriage
spindles on Model 737-200C series airplanes is restrictive. The
commenter asks that it be changed, due to inspection results, from ``1
year after the effective date of this AD'' to 24 to 36 months after the
effective date, to allow time for procurement/overhaul of the spindles
and to schedule the airplane during a heavy maintenance check. The
commenter also states that the proposed compliance time of 2 years
after the effective date of the AD to replace the spindles on Model
737-400 series airplanes is also restrictive. The commenter asks that
the compliance time be changed, due to inspection results, to 36 to 48
months after the effective date, to allow time for procurement/overhaul
of spindles and to schedule the airplane during a heavy maintenance
check.
[sbull] One commenter asks that carriage spindles that were
overhauled per Boeing 737 Component Maintenance Manual 57-53-36 before
the effective date of AD 2002-22-05, and have not had all finishes and
plating removed, be allowed to remain in service on the airplane for 8
years or 12,000 flight cycles, whichever comes later. The commenter
adds that it has found no fractured carriage spindles to date. The
commenter also asks that we allow 30 months instead of 24 months to
overhaul or replace with new, any in-service carriage spindles that
have not been overhauled per the referenced service bulletin. The
commenter states that this would allow scheduling of the replacement of
the carriage spindle during the current maintenance program without
undue burden to its in-service operations.
[sbull] One commenter states that it currently has 52 Model 737-200
and 26 Model 737-300 series airplanes that would be affected by the
original NPRM and has insufficient data for identifying the date each
carriage spindle was overhauled or replaced during heavy maintenance
visits. The commenter adds that, due to this fact, it would be forced
to overhaul/replace the carriage spindles at the earliest time allowed,
which is within 1 year for Model 737-200 series airplanes and 2 years
for Model 737-300 series airplanes. The commenter notes that the
manufacturer is unable to supply new carriage spindles to operators at
a rate that would allow the replacement to be done within the time
allotted. For Model 737-300 series airplanes, the manufacturer is
producing about two carriage spindles per month, and overhaul of the
part using an outside vendor takes approximately 3-4 weeks per
airplane. With this turnaround time, the commenter would be unable to
overhaul the parts in the timeframe required by the original NPRM. The
commenter makes no specific request. We infer that the commenter is
requesting that the compliance time be extended.
[sbull] One commenter asks that the compliance time for the initial
overhaul specified in paragraph (c) of the original NPRM be extended to
2.5 years. The commenter states that, in order to install overhauled
carriages on an aircraft, the flaps must be removed and reinstalled.
The commenter adds that it performs a one-quarter D-check every 2.5
years, and this structural visit is the opportune time to perform such
extensive maintenance.
[sbull] One commenter asks that the initial compliance times for
the overhaul on Model 737-100/200 series airplanes and 737-300/400/500
series airplanes be extended to at least 3 years and 4 years,
respectively, for the following reasons:
First, the compliance time for the initial inspection does not
appear to account for the nondestructive test (NDT) inspection
referenced in both the service bulletin and the existing AD. The
commenter adds that the inspection in the referenced service bulletin
is effective as an interim action in maintaining airplane safety, which
indicates there are no urgent reasons to adhere to the short compliance
time specified in the service bulletin for the spindle overhaul/
replacement.
Second, the carriage spindle overhaul requirement means, in the
commenter's case, that the spindle will have to be shipped off-site,
which would require additional spares support. The short initial
compliance timeframe creates a surge in demand for spares during the
first 1 to 2 years. After that time, all additional spares acquired by
the operators would sit on the shelf because that demand would go away
for the remainder of the 8-year period until the next overhaul.
Third, due to the short initial compliance time, operators will
have to remove the flaps outside the regularly scheduled maintenance
visits to gain access. According to the procedures in the Boeing 737-
300/-400/-500 Maintenance Planning Document D6-38278, the commenter
estimates that the initial compliance time should be between 6 and 8
years for Model 737-300, -400, and -500 series airplanes, and between 6
and 10 years for Model 737-100 and -200 series airplanes.
In conclusion, the commenter states that, with immediate safety
concerns already addressed in paragraph (a) of the original NPRM,
increasing the compliance time specified in paragraph (c) of the
original NPRM would allow accomplishment of the actions at regular
maintenance intervals and would avoid a sudden demand for spares.
[sbull] One commenter asks that the compliance time specified in
paragraph (c)(2)(ii) of the original NPRM (for the spindle overhaul/
replacement) be changed to read, ``Not later than the next major
maintenance (D-check), and, until that time, repeat the NDT inspection
of the spindles per the existing AD.'' The commenter states that
[[Page 62412]]
airplanes that have accumulated more than 12,000 total flight cycles,
and exceeded the 8-year limitation, will be subject to the proposed 2-
year compliance time. The commenter adds that, since no seed units have
been provided by Boeing, procurement of the spindle is expensive, and
the turnaround time is expected to be 20 days, there is no reason to
ground the airplane and send the spindle for overhaul without having
any spares.
[sbull] One commenter states that it will take about a year to
obtain parts after ordering them, and the overhaul cannot be completed
until the parts are received. The commenter states that it will be
impossible to overhaul/replace the flap carriage within the proposed 2-
year compliance time.
[sbull] One commenter asks for a change in the compliance time
specified in paragraph (c) of the original NPRM from 12,000 flight
cycles or 8 years, whichever occurs first, to 20,000 flight cycles or 8
years in-service, whichever occurs first. The commenter states that the
additional flight-cycle allowance would allow the work to be done at
every other D-check where time and resources to overhaul/replace the
spindles are available. The commenter requests that this change apply
to both the original inspection and the overhaul/replacement
requirements.
[sbull] One commenter asks that we evaluate the requirement to
overhaul or replace the spindles every 12,000 flight cycles or 8 years,
based on inspection results and parts replacement costs. The commenter
adds that the repetitive inspection intervals required by paragraph (a)
of the proposed AD should be extended from 180 days to 18 months, so
the airplane can be scheduled for inspection during heavy maintenance
check intervals.
[sbull] One commenter states that mandating the overhaul of the
carriage spindles every 8 years or 12,000 flight cycles, whichever is
sooner, will have a significant cost impact on its fleet. The commenter
adds that, under the current maintenance program, the carriage spindles
are overhauled every 8 years, which, at current flying rates, equates
to about 18,000 flight cycles. Therefore, a 12,000-flight-cycle
compliance time would require overhaul at every heavy maintenance
check, thereby doubling the overhaul cost. The commenter proposes that
the carriage spindles remain in service until the 8-year limit is
reached, provided the 180-day repetitive inspections are reinstated
once the airplane reaches 12,000 flight cycles. The commenter states
that this would provide an equivalent level of safety and give
operators a significant cost benefit.
We agree to extend the initial compliance time somewhat. In
revising this compliance time, we considered the safety implications,
parts availability, and typical maintenance schedules of affected
operators. In addition, the repetitive NDT inspections required by the
existing AD, and restated in paragraph (a) of this supplemental NPRM,
will allow operators more time to schedule maintenance and ensure
safety in the interim until accomplishment of the overhaul or
replacement. We have extended the compliance time specified in
paragraphs (c)(1)(i) and (c)(1)(ii) of this supplemental NPRM to the
later of the following: ``Before the accumulation of 20,000 total
flight cycles on the carriage spindle, or within 8 years since overhaul
of the spindle or installation of a new spindle, whichever is first,''
or ``Within 2 years after the effective date of this AD.'' We have
extended the compliance time specified in paragraphs (c)(2)(i) and
(c)(2)(ii) of this supplemental NPRM to the later of the following:
``Before the accumulation of 20,000 total flight cycles on the carriage
spindle, or within 8 years since overhaul of the spindle or
installation of a new spindle, whichever is first,'' or ``Within 4
years after the effective date of this AD.'' We have also extended the
compliance time in paragraph (c) of this supplemental NPRM for the
repetitive overhaul or replacement to every 20,000 flight cycles or 8
years, whichever is first. Extending the compliance time will not
adversely affect safety but will accommodate the time necessary for the
operators to obtain replacement parts and schedule the work.
We do not agree to extend the repetitive inspection intervals
required by paragraph (a) of the supplemental NPRM; those inspections
end when the overhaul or replacement specified in paragraph (c) of this
supplemental NPRM is done. In developing an appropriate compliance time
for the repetitive inspections, we 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,
and the practical aspect of accomplishing the repetitive inspections
within an interval of time that parallels normal scheduled maintenance
for the majority of affected operators. No change to the supplemental
NPRM is necessary in this regard.
Request To Change Compliance Time to Calendar Time
One commenter contends that corrosion associated with the
identified unsafe condition is a function of time rather than flight
cycles. We infer that the commenter requests that the original NPRM be
revised to reflect a compliance time for the spindle overhaul/
replacement in terms of calendar time rather than flight cycles. We do
not agree to use a calendar date in the AD because the compliance time
in this case is a function of fleet utilization, which is unrelated to
calendar dates. No change to the supplemental NPRM is necessary in this
regard.
Request for Credit for Previously Overhauled Carriage Spindles
One commenter asks that the carriage spindles overhauled before
issuance of AD 2002-22-05 (no finish/plating required) remain in
service for 8 years or 12,000 flight cycles, whichever comes first. The
commenter has been proactive on this issue, and started carriage
spindle overhauls prior to the effective date of the original NPRM. The
commenter adds that no fractured carriage spindles have been found to
date.
We do not agree with the commenter. Although we acknowledge the
fact that the commenter has not had any carriage spindle failures and
maintains a good track record for diligent completion of AD
requirements, many operators have been working to overhaul their fleets
before the release of the AD in order to minimize the impact on the
fleet. In light of the fact that the finish/plating removal was not
required before issuance of AD 2002-22-05, carriage spindles that were
overhauled before issuance of that AD may not have had the finishes/
platings removed, and would not be compliant with that AD. Therefore,
no change to the supplemental NPRM is necessary in this regard.
Request To Accept Alternative Methods of Compliance (AMOCs) Approved
for AD 2002-22-05
Two commenters ask that the original NPRM be revised to accept
certain AMOCs previously approved for AD 2002-22-05. One commenter
states that the original NPRM does not have a provision for such AMOCs,
and asks that a paragraph be added for previously approved AMOCs for
paragraphs (a) and (b) of the original NPRM. The commenter recognizes
that it would not be able to use previously approved AMOCs after
paragraph (c) of the supplemental NPRM is accomplished.
[[Page 62413]]
Another commenter asks that we allow for optional tracking of the
carriage part and serial number instead of the aircraft serial number
to demonstrate compliance. The commenter states that it currently has
an AMOC approved for AD 2002-22-05 that addresses this situation.
We agree with the commenters' requests to accept certain AMOCs
approved previously for AD 2002-22-05. We have added a new paragraph
(f)(2) to this supplemental NPRM to include AMOCs previously approved
for AD 2002-22-05. Regarding optional tracking of the carriage part and
serial number instead of the airplane serial number, the commenter may
submit substantiating data that support a request for an AMOC for this
proposed AD per paragraph (f)(1) of this proposed AD.
Request To Require Additional AD for Carriage Spindle Only
One commenter states that paragraph (d) of the original NPRM
describes two constraints on the overhaul process. The commenter notes
that paragraph (d)(1) of the original NPRM specifies the maximum time
allowed before carrying out the hydrogen embrittlement procedure, and
paragraph (d)(2) of the original NPRM defines the maximum thickness of
nickel plating that can be done at any one plating/baking cycle. The
commenter adds that the Boeing Standard Operating Procedures Manual for
nickel plating includes the requirements specified in paragraph (d)(1),
but the maximum plating requirements specified in paragraph (d)(2) are
not included in the Boeing Component Maintenance Manual (CMM) 57-53-56,
so compliance cannot be assumed by following the procedures in the CMM.
The commenter is concerned that if these elements are required in an
AD, there is a possibility that a flap carriage may be overhauled
without reference to the AD, and subsequently, since there is no
mechanism to prevent it, passed back to the operator without evidence
of compliance with requirements. The commenter suggests that, if the
relevant amendments are not placed in the CMM (against which the
overhaul is to be performed before the effective date of the AD), a
component AD against the flap carriage assemblies should be issued to
ensure that the overhaul requirements are both complied with and
certified as such before the assemblies are passed on to an operator.
The commenter adds that the magnetic particle inspection addresses only
the carriage, not the carriage spindle.
We do not agree with the commenter. Overhaul manuals are not FAA-
approved documents. Updating these manuals is done by the original
equipment manufacturer for the benefit of the operators. When an unsafe
condition exists, we issue an AD to correct that condition, and, if
additional safeguards are required as part of the mandated action,
those safeguards are included in the text of the AD, unless mandated in
other rulemaking actions. Ultimately, it is the responsibility of the
operator to ensure compliance with any ADs that affect the operator's
fleet. No change to the supplemental NPRM is necessary in this regard.
Request To Remove or Change Paragraph (a)
One commenter asks that the current inspections that would be
required by paragraph (a) of the original NPRM be removed or changed as
they are ineffective for finding cracks. The commenter states that it
performed the inspections and, approximately 10 days later, a carriage
spindle severed during flight. The commenter does not see any benefit
in performing the current inspections.
We do not agree with the commenter. The inspections mandated by AD
2002-22-05 are designed to find a fully failed spindle before the
second spindle fails due to load redistribution from the failed
spindle. AD 2002-22-05 is required to safeguard against a dual-spindle
failure. Further, the carriage spindle is manufactured from high
strength steel, which is a material not generally conducive to damage
tolerance methods. No change to the supplemental NPRM is necessary in
this regard.
Request To Add the Repetitive Overhaul in Paragraph (c) to the
Operator's Time Limit Index
One commenter asks that paragraph (c) of the original NPRM, which
requires repetitive overhaul of the carriage spindles every 12,000
flight cycles or 8 years, whichever is first, be incorporated into an
Operator's Time Limit Index (Hard Time Component Program). The
commenter states that this can be done by adding the following
statement to paragraph (c): ``Operators may incorporate the overhaul
requirement into the FAA-approved maintenance program if the Principal
Maintenance Inspector (PMI) approves that action.'' The commenter adds
that this would allow the PMI to approve the action, when appropriate,
without a concern that it violates the Code of Federal Regulations.
We do not agree with the commenter. To include the overhaul of this
part in a particular overhaul program would be an operations-dependent
procedure and cannot be done as a general option. The commenter
provides no data to substantiate that its request would provide an
acceptable level of safety. However, an affected operator may request
approval of an AMOC, as provided by paragraph (f)(1) of this AD, if
data are submitted to support that an alternative method would provide
an acceptable level of safety. No change to the supplemental NPRM is
necessary in this regard.
Request To Change Cost Impact Section
Two commenters ask the Cost Impact section of the original NPRM be
changed, as follows:
[sbull] One commenter states that the estimated cost of the
replacement of the carriage spindle ($45,000 per spindle, and $10,000
per spindle for the overhaul) does not include the out-of-service time
and work hours necessary.
[sbull] One commenter states that the ``short'' initial compliance
time would require operators to remove flaps outside their routine
maintenance program, which would take an additional 192 work hours per
airplane. The commenter estimates the additional labor cost at over
$500,000. The commenter adds that the overhaul of the carriage spindle
will require additional spare carriage spindles over the short initial
compliance timeframe. Based on an overhaul turnaround time of 30 days,
the commenter estimates it would need up to six shipments of spare
carriage spindles at a cost of approximately $1.2 million. All these
spares would then not be used for the remainder of the 8-year period
until the next overhaul. In addition, the commenter notes that the cost
for overhauling the carriage spindle is almost $100,000, based on the
cost estimate per airplane provided in the original NPRM.
We do not agree with the commenters. The cost impact information
describes only the costs of the specific actions required by this AD.
The number of work hours necessary to accomplish the overhaul or
replacement, as specified in the cost impact information, is consistent
with the service bulletin. This number represents the time necessary to
perform only the actions actually required by this AD. We recognize
that, in accomplishing the requirements of any AD, operators may incur
additional costs due to special circumstances when scheduling
maintenance visits. However, because maintenance schedules vary
significantly from operator to operator,
[[Page 62414]]
the hours necessary for access and close-up time, including out-of-
service time, are almost impossible to calculate. No change to the
supplemental NPRM is necessary in this regard.
Conclusion
Since certain changes described previously expand the scope of the
original NPRM, the FAA has determined that it is necessary to reopen
the comment period to provide additional opportunity for public
comment.
Changes to 14 CFR Part 39/Effect on the Proposed AD
On July 10, 2002, the FAA issued a new version of 14 CFR part 39
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness
directives system. This regulation now includes material that relates
to altered products, special flight permits, and alternative methods of
compliance (AMOCs). Because we have now included this material in part
39, only the office authorized to approve AMOCs is identified in each
individual AD.
Change in Labor Rate
We have reviewed the figures we have used over the past several
years to calculate AD costs to operators. To account for various
inflationary costs in the airline industry, we find it necessary to
increase the labor rate used in these calculations from $60 per work
hour to $65 per work hour. The cost impact information, below, reflects
this increase in the specified hourly labor rate.
Cost Impact
There are approximately 3,132 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 1,384 airplanes of U.S.
registry would be affected by this proposed AD.
The inspections that are currently required by AD 2002-22-05 take
approximately 10 work hours per airplane to accomplish, at an average
labor rate of $65 per work hour. Based on these figures, the cost
impact of the currently required inspections on U.S. operators is
estimated to be $899,600, or $650 per airplane.
It would take approximately 2 work hours per airplane to accomplish
the new detailed inspection, at an average labor rate of $65 per work
hour. Based on these figures, the cost impact of the inspection
proposed by this AD on U.S. operators is estimated to be $179,920, or
$130 per airplane, per inspection cycle.
Should an operator be required to accomplish the overhaul, it would
take approximately 32 work hours per airplane to accomplish, at an
average labor rate of $65 per work hour. Based on these figures, the
cost impact of the overhaul proposed by this AD is estimated to be
$2,080 per airplane.
Should an operator be required to accomplish the replacement, it
would take approximately 32 work hours per airplane to accomplish, at
an average labor rate of $65 per work hour. Required parts would cost
approximately $45,000 per carriage spindle. Based on these figures, the
cost impact of the replacement proposed by this AD is estimated to be
$47,080 per spindle, per airplane.
The cost impact figures discussed above are 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. 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.
Regulatory Impact
The regulations proposed herein would not have a substantial direct
effect on the States, on the relationship between the national
Government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, it
is determined that this proposal would not have federalism implications
under Executive Order 13132.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-12929 (67 FR
66316, October 31, 2002), and by adding a new airworthiness directive
(AD), to read as follows:
Boeing: Docket 2002-NM-219-AD. Supersedes AD 2002-22-05, Amendment
39-12929.
Applicability: All Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent severe flap asymmetry due to fractures of the
carriage spindles on an outboard mid-flap, which could result in
reduced control or loss of controllability of the airplane,
accomplish the following:
Restatement of Requirements of AD 2002-22-05
Repetitive Inspections
(a) Do general visual and nondestructive test (NDT) inspections
of each carriage spindle (two on each flap) of the left and right
outboard mid-flaps to find cracks, fractures, or corrosion at the
later of the times specified in paragraphs (a)(1) and (a)(2) of this
AD, as applicable, per the Work Instructions of Boeing Alert Service
Bulletin 737-57A1277, dated July 25, 2002. Thereafter, repeat the
inspections at intervals not to exceed 180 days until paragraph (b)
or (c) of this AD is done, as applicable.
(1) Before the accumulation of 12,000 total flight cycles or 8-
years-in-service on new or overhauled carriage spindles, whichever
is first.
(2) Within 90 days after November 15, 2002 (the effective date
of AD 2002-22-05, amendment 39-12929).
Note 1: 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.''
Corrective Action
(b) If any crack, fracture, or corrosion is found during any
inspection required by
[[Page 62415]]
paragraph (a) of this AD: Before further flight, do the applicable
actions for that spindle, as specified in paragraph (b)(1) or (b)(2)
of this AD, per the Work Instructions of Boeing Alert Service
Bulletin 737-57A1277, dated July 25, 2002. Thereafter, repeat the
inspections required by paragraph (a) of this AD at intervals not to
exceed 12,000 flight cycles or 8 years, whichever is first, on the
overhauled or replaced spindle only.
(1) If any corrosion is found in the carriage spindle, overhaul
the spindle.
(2) If any crack or fracture is found in the carriage spindle,
replace with a new or overhauled carriage spindle.
Note 2: Although Boeing Alert Service Bulletin 737-57A1277,
dated July 25, 2002, recommends that operators report inspection
findings of any crack or fracture in the carriage spindle to the
manufacturer, this AD does not contain such a reporting requirement.
New Requirements of This AD
Overhaul or Replacement
(c) Overhaul or replace, as applicable, all four carriage
spindles (two on each flap) of the left and right outboard mid-flaps
at the applicable time specified in paragraph (c)(1) or (c)(2) of
this AD, per the Work Instructions of Boeing Alert Service Bulletin
737-57A1218, Revision 3, dated July 25, 2002. Thereafter, repeat the
applicable overhaul or replacement at intervals not to exceed 20,000
flight cycles or 8 years, whichever is first. Accomplishment of this
paragraph ends the repetitive inspections required by paragraphs (a)
and (b) of this AD.
(1) For Model 737-100, -200, and -200C series airplanes,
overhaul or replace at the later of the times specified in
paragraphs (c)(1)(i) and (c)(1)(ii) of this AD.
(i) Before the accumulation of 20,000 total flight cycles on the
carriage spindle, or within 8 years since overhaul of the spindle or
installation of a new spindle, whichever is first.
(ii) Within 2 years after the effective date of this AD.
(2) For Model 737-300, -400, and -500 series airplanes, overhaul
or replace at the later of the times specified in paragraphs
(c)(2)(i) and (c)(2)(ii) of this AD.
(i) Before the accumulation of 20,000 total flight cycles on the
carriage spindle, or within 8 years since overhaul of the spindle or
installation of a new spindle, whichever is first.
(ii) Within 4 years after the effective date of this AD.
(d) During accomplishment of any overhaul required by paragraph
(c) of this AD, use the procedures specified in paragraphs (d)(1)
and (d)(2) of this AD during application of the nickel plating of
the carriage spindle in addition to those specified in Boeing 737
Standard Overhaul Practices Manual, Chapter 20-42-09.
(1) Begin the hydrogen embrittlement relief bake within 10 hours
after application of the plating, or less than 24 hours after the
current was first applied to the part, whichever is first.
(2) The maximum deposition rate of the nickel plating that is
deposited in any one plating/baking cycle must not exceed 0.002-
inch-per-hour.
(e) Overhauling or replacing the carriage spindles before the
effective date of this AD, in accordance with Boeing Alert Service
Bulletin 737-57A1277, dated July 25, 2002, is considered acceptable
for compliance with the overhaul or replacement specified in
paragraph (c) of this AD.
Alternative Methods of Compliance
(f)(1) In accordance with 14 CFR 39.19, the Manager, Seattle
Aircraft Certification Office, FAA, is authorized to approve
alternative methods of compliance for this AD.
(2) Alternative methods of compliance, approved previously per
AD 2002-22-05, amendment 39-12929, are approved as alternative
methods of compliance with paragraphs (a) and (b) of this AD.
Issued in Renton, Washington, on October 29, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-27672 Filed 11-3-03; 8:45 am]
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