DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-1046; Product Identifier 2018-CE-049-AD]
RIN 2120-AA64

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.

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SUMMARY: The FAA is revising an earlier proposal for certain Piper
Aircraft, Inc. (Piper) Models PA-28-140, PA-28-150, PA-28-151, PA-28-
160, PA-28-161, PA-28-180, PA-28-181, PA-28-235, PA-28R-180, PA-28R-
200, PA-28R-201, PA-28R-201T, PA-28RT-201, PA-28RT-201T, PA-32-260, and
PA-32-300 airplanes. The notice of proposed rulemaking (NPRM) was
prompted by a report of a wing separation caused by fatigue cracking in
a visually inaccessible area of the lower main wing spar cap. This
action revises the NPRM by adding and removing certain models of
airplanes in the Applicability, proposing to require the use of service
information that was issued since the NPRM, and clarifying some of the
proposed actions. The FAA is proposing this airworthiness directive
(AD) to address the unsafe condition on these products. Since these
actions would impose an additional burden over those proposed in the
NPRM, the FAA is reopening the comment period to allow the public the
chance to comment on these changes.

DATES: The comment period for the NPRM published in the Federal
Register on December 21, 2018 (83 FR 65592), is reopened.

The FAA must receive comments on this SNPRM by July 20, 2020.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: 202-493-2251.

Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.

Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

For service information identified in this SNPRM, Piper Aircraft,
Inc., 2926 Piper Drive, Vero Beach, Florida 32960; telephone: (772)
567-4361; internet: www.piper.com. You may view this service
information at the FAA, Airworthiness Products Section, Operational
Safety Branch, 901 Locust, Kansas City, Missouri 64106. For information
on the availability of this material at the FAA, call (816) 329-4148.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2018-1046;
or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this SNPRM, the NPRM, the regulatory evaluation, any comments received,
and other information. The street address for Docket Operations is listed
above. Comments will be available in the AD docket shortly after
receipt.

FOR FURTHER INFORMATION CONTACT: Dan McCully, Aerospace Engineer,
Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park, Georgia
30337; phone: (404) 474-5548; fax: (404) 474-5605; email:
william.mccully@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2018-1046;
Product Identifier 2018-CE-049-AD" at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this SNPRM. The FAA will
consider all comments received by the closing date and may amend this
SNPRM because of those comments.

The FAA will post all comments received, without change, to https://www.
regulations.gov, including any personal information you provide.
The FAA will also post a report summarizing each substantive verbal
contact received about this SNPRM.

Discussion

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to certain Piper Aircraft, Inc. (Piper) Models PA-28-140,
PA-28-150, PA-28-151, PA-28-160, PA-28-161, PA-28-180, PA-28-181, PA-
28-235, PA-28R-180, PA-28R-200, PA-28R-201, PA-28R-201T, PA-28RT-201,
PA-28RT-201T, PA-32-260, and PA-32-300 airplanes. The NPRM published in
the Federal Register on December 21, 2018 (83 FR 65592).

The NPRM was prompted by a fatal accident involving wing separation
on a Piper Model PA-28R-201 airplane. An investigation revealed a
fatigue crack in a visually inaccessible area of the lower main wing
spar cap. The NPRM included other model airplanes with similar wing
spar structures as the Model PA-28R-201. Based on airplane usage
history, the FAA determined that only those airplanes with higher risk
for fatigue cracks (airplanes with a significant history of operation
in flight training or other high-load environments) should be subject
to the inspection requirements proposed in the NPRM.

Because airplanes used in training and other high-load environments
are typically operated for hire and have inspection programs that
require 100-hour inspections, the FAA determined the number of 100-hour
inspections an airplane has undergone would be the best indicator of
the airplane's usage history. Accordingly, the FAA developed a factored
service hours formula based on the number of 100-hour inspections
completed on the airplane.

The NPRM proposed to require a review of the airplane maintenance
records to determine the number of 100-hour inspections and the
application of the factored service hours formula to identify when an
airplane meets the criteria for the proposed eddy current inspection of
the lower main wing spar bolt holes. The NPRM also proposed to require
inspecting the lower main wing spar bolt holes for cracks once a main
wing spar exceeds the specified factored service hours and replacing
any main wing spar when a crack is indicated. The maintenance records
review to determine the factored service hours proposed by the NPRM
would only apply when an airplane has either accumulated 5,000 or more
hours time-in-service (TIS); has had either main wing spar replaced
with a serviceable main wing spar (more than zero hours TIS); or has
missing and/or incomplete maintenance records.

Actions Since the NPRM Was Issued

After a review of the comments received on the NPRM and further
analysis, the FAA determined that some additional airplane models are
likely to be affected by the unsafe condition and should be included in
the applicability, while other models are not affected and should be
removed from the applicability. Consequently, this SNPRM revises the
applicability and the estimated cost associated with the proposed AD
actions. This SNPRM also clarifies the applicability and some of the
proposed actions. In addition, this supplemental NPRM no longer allows
replacement of the wing spar with a used part. The FAA determined
replacement of the wing spar with a part of unknown operational history
would not ensure an acceptable level of safety.

Since the NPRM was issued, Piper issued a service bulletin that
contains procedures for the eddy current inspection. This SNPRM
proposes to require that service bulletin to do the eddy current
inspection instead of the inspection procedure in the appendix to the
NPRM.

Since these actions impose an additional burden over that in the
NPRM, the FAA is reopening the comment period to allow the public the
chance to comment on this change.

Comments

The FAA gave the public the opportunity to comment on the NPRM and
received approximately 168 comments. The majority of the commenters
were individual maintenance personnel and operators. The remaining
commenters included Piper, governmental agencies such as the European
Union Aviation Safety Agency (EASA) and the National Transportation
Safety Board (NTSB), and organizations such as the Aircraft Owners and
Pilots Association (AOPA), the Experimental Aircraft Association (EAA),
and the General Aviation Manufacturers Association (GAMA). The
following presents the relevant comments received on the NPRM and the
FAA's response to each comment.

A. Supportive Comments

Fifteen comments were received in support of the NPRM. Five of
these commenters specifically supported the proposed eddy current
inspection method. The NTSB specifically supported the proposed
requirement to report inspection results to the FAA.

B. Comments Regarding the FAA's Justification of the Unsafe Condition

Many commenters requested that the FAA provide more information
about the root cause and clarify the FAA's unsafe condition
determination.

Requests for Information About the Accident Airplane

Mitchell Ross requested information regarding the background of the
accident airplane that prompted the NPRM, including its manufacturing
and maintenance history. This commenter and Robert Cunningham also
questioned the operational history of the accident airplane. Nine other
commenters questioned the FAA's determination that an unsafe condition
exists based on only one failure in 30 years.

The FAA agrees. All publicly available information about the
accident airplane, including the information requested by the
commenters, is available in the NTSB docket for accident number
ERA18FA120. This information can be viewed at https://dms.ntsb.gov/pubdms
/search/hitlist.cfm?docketID=62694&CFID=95094&CFTOKEN=b616b3892cb482f1-
5B544A63-5056-942C-92C71C2E6BFF1D97.

Requests for Information About the Root Cause of the Unsafe Condition

David Hedley and Dana Pyle noted that Piper's steel supplier
changed in the 1980s. These commenters and Robert Cunningham questioned
whether inferior metal could be a factor. Tom McIntosh, Dana Pyle, and
Robert Cunningham questioned whether coastal environments contributed
to the corrosion and metal fatigue. Steven Rosenfield asked the FAA to
confirm whether the fatigue cracking is caused by a design defect or a
manufacturing error. Some commenters suggested that the problem is
caused by other issues such as inadequate inspection and maintenance
practices, and hard landings that go unreported.

The FAA agrees to provide additional information. The NTSB
Materials Laboratory conducted hardness testing and electrical
conductivity testing of the accident spar and sent spar samples to an
independent laboratory for tension testing and chemical analysis. Tests
results showed that the spar material conformed to type design (see
NTSB report No. 18-061, Materials Laboratory Factual Report). Corrosion
was not determined to be a contributing factor. Regarding the concern
about inadequate inspections and maintenance practices, the NTSB report
did not indicate there was any evidence of inadequate inspection and
maintenance practices.

Request To Reference the Piper Model PA-28R-201 Accident

AOPA noted the absence of any specific mention of the April 4,
2018, Piper PA-28R-201 accident (NTSB Accident Number ERA18FA120) in
the NPRM. The commenter stated its belief that the accident is a
driving force behind the NPRM.

The FAA agrees. The preamble of this SNPRM has been revised to add
information related to the accident.

Requests To Wait for NTSB Final Report Before Issuing AD Action

Joseph Oh, The University of North Dakota (UND Aerospace), AOPA,
Navid Rahimi, Benjamin Morgan, and eight other commenters requested the
FAA wait for the conclusion of the NTSB investigation before issuing an
AD. These commenters stated or suggested that the proposed AD is
premature and that the NTSB's determinations would affect the content
or necessity of the proposed AD. Piper stated that the proposed AD
would likely interfere with the NTSB's investigation. Some of these
commenters specifically referenced the NTSB's investigation of a Piper
Model PA-28R-201 Arrow III that experienced an in-flight wing
separation on April 4, 2018.

The FAA does not agree. In accordance with 14 CFR 39.5, the FAA
issues airworthiness directives when an unsafe condition exists in the
product, and the condition is likely to exist or develop in other
products of the same type design. While the NTSB contributes critical
information to accident prevention efforts, the FAA's determinations of
unsafe conditions are not dependent on the outcome of NTSB
investigations. The FAA, Piper, and the NTSB concurred that the subject
failure was the result of an undetected fatigue crack in the wing spar.
This was supported by the NTSB's release of Preliminary Report
ERA18FA120 and a later Investigative Update, which disclosed additional
fatigue cracks on another airplane. Although the NTSB's final report
(issued after the NPRM published) provides additional details regarding
the accident, it does not yield information previously unknown to the
FAA that would have altered the content of the NPRM, nor did the NTSB
request the FAA delay issuing the NPRM pending its final report. The
NTSB reports may be found at https://www.ntsb.gov/investigations/pages/
era18fa120.aspx. The FAA did not make changes to this SNPRM based on
these comments.

Request To Withdraw the NPRM

Dwight Schrute, Ross Carbiner, Thomas Feminella, AOPA, EAA, GAMA,
Piper, and 21 other commenters stated that because the AD was issued as
an interim action with a reporting requirement, the AD is inappropriate
and does not address a known unsafe condition. Nine of those commenters
stated that a special advisory information bulletin (SAIB), service
bulletin, or other voluntary action is a more appropriate method of
addressing the wing spar fatigue cracking. Four of those commenters
opposed the AD generally. Michael Powell did not request to withdraw
the NPRM, but suggested the FAA obtain information from DeHaviland
Support, because this company has experience with a relevant wing spar
fatigue monitoring scheme that has been implemented for the DeHaviland
Model Chipmunk airplanes. Three other commenters suggested the FAA
gather data from voluntary inspections and salvage parts before issuing
an AD.

The FAA does not agree to withdraw the NPRM. The FAA may issue an
AD as an interim action for several reasons, including to obtain
inspection results to determine the necessity of additional action or
final action, while simultaneously requiring inspections to mitigate
the unsafe condition. The primary considerations in reaching the
decision for an interim AD were: (1) The catastrophic failure mode
resulting from this condition, and (2) the inability to detect the
subject cracking during a routine inspection. The NTSB accident
database shows a relatively small number of Piper Model PA-28 airplane
wing failures related to fatigue cracks (three known). However, the
only reported cracks were discovered after wing separations, since the
cracks developed and grew in a normally concealed structural area. In
addition, it can be predicted based on engineering priniciples of crack
propagation that a fatigue crack in this location will grow with each
load cycle and eventually result in wing spar failure. Due to the
fatality rate associated with the known failures, the risk analysis
protocol used by the FAA justifies mandatory corrective action. Both
the NPRM and this SNPRM employ methodology to screen out the majority
of lower-risk airplanes based on usage history. The FAA did not make
changes to this SNPRM based on these comments.

C. Comments Regarding Applicability

Requests To Revise the Airplane Models Listed in the Applicability
Section

Piper, EAA, and GAMA stated that the applicability of the proposed
AD is too broad and includes models with different structural layouts
and loads, or other key aspects that affect spar fatigue. Piper
specifically advised the FAA to rely on Piper's analysis and limit the
proposed AD to Piper Models PA-28R-180, PA-28R-200, PA-28R-201, PA-28R-
201T, PA-28RT-201, PA-28RT-201T, and PA-28-235 airplanes (all serial
numbers), and certain serial-numbered Models PA-32-260 and PA-32-300
airplanes. Eight other commenters agreed with the comments submitted by
Piper. AOPA and two individual commenters expressed concern that the
FAA did not accept Piper's recommendation on the limited scope of
airplanes that may be subject to the unsafe condition. The NTSB
supported the inclusion of Models PA-28-235, all PA-28R-series, PA-32-
260, and PA-32-300 airplanes in the proposed AD, and requested that the
FAA reconsider whether the proposed AD should include all PA-28-series
models (other than Model PA-28-235).

Thomas Rae identified Piper model seaplanes and airplanes that,
given their similar structure, hours in service, and/or use in flight
training, should be added to the Applicability section of the proposed
AD. Twelve other commenters requested the FAA clarify the inclusion or
exclusion of various specific models. Charles Martinak stated wingspan,
maximum gross takeoff weight, and retractable gear architecture should
be the main similarity factors for inclusion in the applicability.

The FAA agrees that the models listed in the Applicability of the
proposed AD should be revised. The Applicability section was designed
to screen out lower-risk airplanes from the inspection requirement by
applying only to airplanes with 5,000 or more hours TIS, unless
maintenance records are missing and/or incomplete or a wing has been
replaced. The subsequent maintenance records review to calculate
factored service hours was intended to eliminate an additional large
number of remaining airplanes from the AD requirements. Only the
airplanes at the highest risk for fatigue cracks would be required to
conduct the eddy current inspection.

Piper Aircraft provided the FAA with extensive analyses of
similarly structured airplanes, including comparison of factors such as
structural geometry, certificated weights, design airspeeds, bending
moments, and wing loading parameters including gust loads, maneuvering
loads, and landing loads. Although the FAA accepted all of Piper's
initial recommended models for effectivity, Piper's recommended
effectivity did not include the group of airplanes addressed in Piper
Aircraft, Inc. Service Bulletin No. 886, dated June 8, 1988 (Piper SB
886) (Wing Spar Inspection). Piper SB 886 includes the Model PA-28-181
airplane, which was involved in two wing separation accidents in 1987
and 1993. Both accident airplanes had fatigue cracks in the wing spar
as mentioned in the NTSB Final Accident Report ERA18FA120.

Due to the inability to visually inspect the specific area of the
structure once the wing has been assembled, cracks may go undetected
and unreported for a significant period of time. Consequently, a
reported crack at this location is more likely to come from an
investigation of a wing spar failure than as the result of a routine
inspection or maintenance. The FAA initially expanded on Piper's
recommended effectivity to include all airplane models in the
Applicability section of Piper SB 886.

Since issuing the NPRM, and partially in response to public
comments, the FAA has adopted a more focused risk criteria using load
data provided by Piper. This risk approach and the resulting change in
applicability adds three airplane models (Models PA-32R-300, PA-32RT-
300, and PA-32RT-300T) and removes five airplane models (Models PA-28-
140, PA-28-150, PA-28-160, PA-28-161, and PA-28-180) from the
Applicability section of this SNPRM, for a net reduction of
approximately 8,800 lower-risk aircraft. The FAA developed a more
precise methodology for identifying risk. Flight loads of all similar
models were compared to those of the PA-28R-201 (accident aircraft) as
a baseline. Those aircraft models with calculated wing loads greater
than or equal to 95 percent of baseline are considered at-risk and are
included in the new effectivity. While the additional parameters
included in the new screening method allowed us to remove many lower
risk aircraft, it also identified three models that were not captured
by the previous, broader, approach. Because this methodology considers
only the potential damage to the aircraft and not the actual load
history of an individual aircraft, the additional maintenance record
reviews are used to determine when the AD becomes applicable to a
specific aircraft.

D. Comments Regarding the "Factored Service Hours" Formula

Requests To Clarify and Revise the "Factored Service Hours" Formula

Floris Oldenbroek, Richard Davis, and three other commenters
expressed confusion at the formula and requested clarification and
guidance; two of these commenters specifically asked about the divisor
"17." Many commenters noted various flaws in the proposed methodology
for counting 100-hour inspections. Tom Rafferty, Kenneth Minck, Brian
Christie, and approximately 19 other commenters stated maintainers
often document 100-hour inspections as "annual" inspections or as
"annual/100-hour" inspections. EASA, AOPA, and three individual
commenters stated that the formula would cause issues with
international operators because, unlike the FAA's regulations, foreign
civil aviation authorities do not distinguish between 100-hour and
annual inspections. Several other commenters noted that using 100-hour
inspections is not an accurate way of determining high stress flight
hours. GAMA and five individual commenters noted that the formula does
not address operators that are on a progressive inspection program
under 14 CFR 91.409(d). Outer Banks Airlines and three individual
commenters stated that not all commercial operations, which will be
captured by counting 100-hour inspections, are used for flight
instruction. These commenters explained that charter flights operated
under 14 CFR part 135 are not subject to the harsh training environment
of training operations and are instead flown by highly trained pilots
on longer flights with fewer landings.

Many of the commenters proposed different methodologies to use in
determining the factored service hours. Chris Sobers, Thomas Downey,
and three other commenters suggested using total time on the airframe
("TTAF") as a less complex method. Floris Oldenbroek asked whether
the total time of the aircraft could be used instead of the factored
service hours formula if an airplane has only been utilized as a
trainer. Martin Kennett and Lawrence Mangus suggested using the number
of landing cycles/severe landings as a better indication of fatigue
damage. Suggestions from other commenters included: Omitting 100-hour
inspections performed in conjunction with an annual inspection;
omitting 100-hour inspections performed voluntarily and not required by
Sec. 91.409(b); using a severity factor to indicate primary use in
flight training; only including airplanes used by flights schools/
excluding airplanes with no history of use in training; and adding a
penalty for hard landings and major wing damage.

The FAA agrees to explain the formula based on these comments. The
FAA developed the factored service hours formula to determine an
approximate factored service life for any airplane, including those
with mixed usage history. The formula attributes 100 factored service
hours for each 100-hour inspection recorded in the airplane maintenance
records. For an airplane that has been inspected under Sec. 91.409(b)
for its entire lifecycle, the owner/operator may use hours TIS for the
factored service hours. The divisor of 17 accounts for the difference
in structural life expectancy between "normal" use and "training"
use, based on industry studies of crack growth development. Piper
adopted a similar formula for use in Piper SB 886 and Piper Service
Bulletin SB 978A, dated August 6, 1999 (Piper SB 978A).

This SNPRM includes guidance for determining the quantity "N" in
the factored service hours formula based on the various maintenance
record entry notations that may be used to indicate compliance with the
100-hour inspection requirements. As proposed in this SNPRM, the
airplane maintenance records review must consider any inspection that
was done to comply with the 100-hour inspection requirement under Sec.
91.409(b), which pertains to carrying persons for hire and providing
flight instruction for hire.

Regardless of whether the inspection is logged as an "annual" or
"100-hour," if the purpose was to comply with the 100-hour
requirement of Sec. 91.409(b), then the inspection must be counted.
The purpose of an inspection may be determined by noting the interval
between inspections (i.e., less than 10 months and typically from 90 to
110 flight hours would indicate a Part 91.409(b) inspection). A "100-
hour" inspection done concurrently with an annual inspection, not
required by Sec. 91.409(b), does not have to be counted. For operators
utilizing a "progressive" inspection program, only inspections that
complete each 100-hour cycle must be counted as a 100-hour inspection.

The FAA has considered the impact of the proposed formula on
international operators and agrees with EASA that civil airworthiness
authorities (CAAs) would have to develop a different approach instead
of fully adopting the FAA's AD. The FAA encourages CAAs to use their
equivalent inspection requirements to account for differences in
terminology relative to annual versus 100-hour inspections and other
unique operational requirements. The FAA is available to support any
such efforts as requested by a CAA.

The FAA has also considered the alternative methods suggested by
the commenters and determined that the formula in this SNPRM is the
best method for allowing personal-use airplanes to defer the
inspection. Using TTAF or TIS alone would not account for different
types of usage history. Other commenters' proposals, while logical and
valid, are not based on regulatory recordkeeping requirements and
therefore would create other difficulties for owners and operators. For
example, while use and history specifically in flight training, landing
cycles, and hard landings are valid indicators, there is no regulatory
requirement for U.S. operators to maintain such records, particularly
for personal use airplane maintenance records. The FAA considered
adding a penalty for any history of major repairs to the wing, but
determined it would not be necessary. Any cracks, as well as other
damage, would be detected and corrected during the repair to the wing,
as the FAA's maintenance regulations require restoring the wing to its
original or properly altered condition before approving it for return
to service. In addition, any operator that believes their airplane does
not fit the applicability/risk focus of this SNPRM may provide
substantiating data and request approval of an alternative method of
compliance (AMOC) to the AD action using the instructions found in
paragraph (o) of this AD. The FAA will consider all AMOC requests on a
case-by-case basis.

Request for Clarification of When To Calculate Factored Service Hours

Mark Talaga requested clarification on the correct hours to require
the eddy current inspection, 5,000 hours TIS or 5,000 factored service
hours. Richard Davis asked the FAA to clarify why the records review
would be done when the airplane has 5,000 hours TIS and not 6,000 hours
TIS.

The FAA agrees to provide additional information on this proposed
requirement. The applicability paragraph of the NPRM referenced a table
listing the potentially affected models and serial-numbered airplanes.
It also provided three criteria to determine if the AD applied to the
models listed in the table: (1) The airplane has accumulated 5,000 or
more hours TIS; (2) the airplane has had either main wing spar replaced
with a serviceable main wing spar (more than zero hours TIS); or (3)
the airplane maintenance records are missing and/or incomplete.

The 5,000 hours TIS criteria in paragraph (c), Applicability, is
only used to determine if the AD applies to the airplane. If the
airplane does not meet any of the three criteria, then the AD does not
yet apply to that airplane. Only if and when one of those three
conditions exist would the proposed AD require an airplane maintenance
records review to determine the factored service hours. Then, only if
the resulting calculation determines that the airplane has reached
5,000 factored service hours must an eddy current inspection be
completed within 100 hours TIS.

The 5,000 factored service hours compliance time is determined by
taking the known factored hours at spar failure, and regressing to
predict the time of crack initiation. Starting the inspection at 5,000
factored service hours provides a reasonable opportunity to detect a
crack before it reaches a dangerous length. Because it is impossible
for an aircraft to accumulate 5,000 factored service hours without
having flown 5,000 hours TIS, there is no need to review an airplane's
inspection record before 5,000 hours TIS.

Request To Change Quantity of 100-Hour Inspections Used in the
Calculation

John Longley requested limiting the 100-hour inspection calculation
to the past 5, 7, or at most 10 years rather than since the airplane
was new.

The FAA disagrees. The effect of fatigue on a structure is
cumulative regardless of when it occurred. The factored service hours
formula takes into account airplanes with mixed usage history and
provides credit for hours TIS accrued while in "normal" usage. The
FAA did not make changes to this SNPRM based on this comment.

Request To Allow the Owner/Operator To Review the Airplane Maintenance
Records

Tom McIntosh, Dennis Mulloy, and four other commenters requested
that the owner/operator be allowed to review the airplane maintenance
records and calculate the factored service hours. These commenters
objected to the cost associated with requiring a mechanic to do the
airplane maintenance record review, when the owner/operator is capable.

The FAA agrees. The FAA does not consider an airplane maintenance
records review to be a maintenance action, and the SNPRM has been
clarified to state that the owner/operator (pilot) may conduct the
review and calculate the factored service hours to determine if the
eddy current inspection proposed by this SNPRM is necessary. The
airplane maintenance records review cost estimate has been retained in
this SNPRM, since owners may choose to have a mechanic perform the
initial review and factored service hours calculation.

E. Comments Regarding Missing Records

Requests for Clarification of Missing Aircraft Maintenance Records

Dennis Mulloy requested clarification of what would constitute
missing or incomplete maintenance records. James Layton asked for
guidance where logbook entries may be missing but the airplane has
verifiable hours through the original tachometer. Michael Beasley
requested clarification for missing logbooks that are reconstructed by
the maintenance facility that serviced the airplane.

The FAA agrees to provide clarification. The premise of calculating
factored service hours to determine the risk category of an airplane is
based on the accuracy and completeness of the airplane maintenance
records for the entire history of the airplane. An absence of airplane
maintenance records entries over an extended period (as in the case of
dormant airplanes) does not constitute missing or incomplete
maintenance records if tachometer/Hobbs time continuity shows the
airplane did not operate during that time. For purposes of this proposed
AD, reconstructed records should be considered the same as missing or
incomplete records. Physically missing airplane maintenance records or
logbook pages that include unaccounted-for operational hours or records
not retained after work is superseded in accordance with 14 CFR 91.417
(b)(1), would be considered missing or incomplete maintenance records.

Requests for an Alternative Method for Missing Aircraft Maintenance
Records

Michael Graziano, Duke Ball, Stephen Allen, and Olmond Hall
requested that for airplanes with missing or incomplete maintenance
records, operators be allowed to assume that 100-hour inspections were
completed for the purposes of calculating the factored service hours,
instead of being automatically required to complete the eddy current
inspection. Four other commenters proposed or requested similar methods
for attributing unknown hours TIS.

The FAA disagrees. While the FAA does not object in theory with an
alternate method of computing factored service hours in the case of
missing airplane maintenance records, there are other issues to
consider. Missing airplane maintenance records may mask the replacement
of a tachometer or Hobbs meter, thus invalidating the total hours TIS.
Missing records may hide information on the history of the wing/wing
spar on the airplane. Without airplane maintenance records for the
entire airplane's history, an operator cannot determine if the airplane
has the original wing(s) or a replacement wing(s). For this reason, the
FAA determined that, for purposes of this proposed AD, operators with
missing or incomplete records must assume that the wing history is
unknown. An owner who can provide other documentation supporting the
history of the airplane or wing spar and show an acceptable level of
safety may request approval of an AMOC to the AD action with
substantiating data using the instructions found in paragraph (o) of
this SNPRM. The FAA will review all AMOC requests and may approved the
requests on a case-by-case basis. The FAA did not make changes to this
SNPRM based on these comments.

F. Comments Regarding Compliance Times

Thurman Bodenheimer, Christian Quitntero, and three other
commenters requested that the compliance times and intervals in the
NPRM be changed to match the airplane usage groups and intervals
contained in Piper SB 886 and Piper SB 978A.

The FAA disagrees. Piper SB 886 and Piper SB 978A classify
airplanes used in flight training as "normal usage," which puts
compliance for the initial inspection far beyond the initial (critical)
inspection time specified in the NPRM. The FAA has found that this
compliance time is not sufficient to address the unsafe condition.
Additionally, the compliance time charts in Piper SB 886 and Piper SB
978A specify the airplane's usage class based on subjective criteria
such as "significant time" flown below 1,000 feet during any part of
the airplane's history. There is no regulatory requirement for
operators to record or maintain hours TIS by operation at certain
altitudes; thus, most operators would have no way of determining this
information.

Hillel Glazer proposed a specific tiered approach for compliance
with the initial airplane maintenance records review by prioritizing
airplanes based on usage history, with the lowest tier requiring the
airplane maintenance record review within 100 hours TIS. Michael
Graziano requested changing the compliance time from 30 days to 50
hours TIS or at the next annual inspection, similar the service
information provided by Piper. The FAA disagrees. The usage rate of
each airplane after the effective date of the AD will vary, and the use
of calendar time ensures all operators review their maintenance records
within a specified timeframe. Also, this SNPRM has been revised to
allow the owner/operator (pilot) to do the maintenance records review.
If the review of the maintenance records and the factored service hours
indicate the operator must have an eddy current inspection done on the
airplane, the compliance time is within 100 hours TIS after the
factored service hours determination.

The FAA did not make changes to this SNPRM based on these comments.

G. Comments Regarding the Proposed Inspection

Requests To Remove Eddy Current Inspection Because of Possible Damage

Daniel Stanley, Thomas Wiedenbeck, Mitchell Ross, Dana Pyle, Don
Morris, Piper, and 17 other commenters stated that removal of wing
attach bolts for the purpose of conducting the bolt hole inspection
would create the potential of maintenance-induced damage to the
airplanes that would outweigh any benefits realized from the
inspection. Piper advised of reports of damaged spar bolt holes caused
by removal of the bolts to perform a voluntary inspection of the
fastener holes.

The FAA disagrees. Compliance with AD 87-08-08, Amendment 39-5615
(52 FR 15302, April 28, 1987) ("AD 87-08-08") and AD 87-08-08R1,
Amendment 39-5669 (52 FR 29505, August 10, 1987), which was rescinded
on May 22, 1989, resulted in the dye penetrant inspection of
approximately 560 airplanes and required removing and reinstalling 18
bolts per wing, or over 20,000 wing attach bolts. No known accidents
have been attributed to bolt hole damage resulting from these
inspections. While the FAA acknowledges the possibility of damage
during any maintenance action, the relatively non-intrusive, wing-in-
place inspection method proposed in the NPRM and in this SNPRM would
have minimal impact to affected airplanes. The FAA did not make changes
to this SNPRM based on these comments.

Requests To Use a Different Inspection Method

Forrest Benson, Charles Donnelly, James Graham, and twelve other
commenters proposed using a different inspection method than an eddy
current inspection, such as ultrasound, x-ray, dye/liquid penetrant, or
borescope inspections. Some of these commenters proposed using a
borescope because it would preclude removal of the bolts. Many
commenters expressed concern about the availability of qualified
inspectors to do the eddy current inspection and the need to deliver
the airplane to a distant facility to have the eddy current inspection
done.

The FAA disagrees. Borescope and dye penetrant methods are not
generally capable of detecting cracks in the targeted range of .030 to
.050 inch. Once a fatigue crack reaches a visibly detectable size,
growth can accelerate at a dangerous rate. It is imperative that
operators identify any cracks while within the targeted range. Also,
because the lower spar cap sits on the spar carry through and its upper
flanges are covered by the web doublers, the spar cap is not visually
inspectable when installed. The insides of the bolt holes are not
visible with a borescope inside the wing carry-through assembly without
removing the bolts. While the FAA acknowledges the value of x-ray
technology and ultrasound inspections in material identification and
thickness determination, those methods are not considered capable of
reliably detecting very small fatigue cracks. Changes made to the
proposed AD in response to other comments will increase the
availability of inspectors qualified to do the eddy current
inspections. The FAA did not make additional changes to this SNPRM as a
result of these comments.

Requests To Use a Different Eddy Current Inspection Method and
Equipment

Tony Brand submitted an eddy current inspection procedure and
requested approval to use this method as an alternative method of
compliance. John Longley, Jr. requested that the eddy current
inspection not require specific proprietary equipment. The FAA agrees
that alternate eddy current methods may be acceptable. For any owner/
operator who wishes to use a different procedure, the FAA will consider
requests for approval of an AMOC if sufficient data is submitted to
substantiate that it would provide an acceptable level of safety, using
the instructions in paragraph (o) of this AD. The FAA will consider all
AMOC requests on a case-by-case basis.

Neither the NPRM, nor this SPNRM, propose to require the use of any
particular model equipment. The NPRM and Piper Service Bulletin No.
1345, dated March 3, 2020, which this SNPRM proposes to incorporate by
reference, contain optional examples of equipment that meet the
requirements for conducting the eddy current inspection.
Requests for Clarification of Bolt Hole Inspection

EASA requested clarification on the bolt holes to be inspected.
EASA stated that Piper's service bulletins specify inspecting a larger
area of the lower spar cap and asked whether inspecting only the two
outboard holes, as proposed in the NPRM, is adequate. Blue Skies Flying
Services requested clarification on the difference between the proposed
inspection procedure in appendix 1 of the NPRM, which refers to only
the two lower outboard bolt holes, and the proposed requirement to
perform an eddy current inspection in paragraph (h) of the NPRM, which
refers to each bolt hole on the lower main wing spar cap.

The FAA agrees to clarify and revise the proposed requirement. The
FAA has determined that the requirements in the NPRM to inspect only
the two lower outboard bolt holes are adequate. The FAA has not
observed a pattern of cracking at other spar hole locations and has not
determined the benefit of inspecting additional holes would outweigh
the potential of damage from bolt removal. The FAA has revised the
proposed inspection requirements in this SNPRM to specify the two lower
outboard bolt holes.

Requests To Expand the Eddy Current Inspection Qualifications

Samuel Tucker, Norman Jones, and Humphrey Penney requested the
proposed requirement for NAS 410 Level II or Level III qualifications
to perform the eddy current inspection be expanded to include
equivalent certifications.

The FAA agrees. The FAA has revised the proposed AD to allow Level
II or Level III qualification standards for inspection personnel using
any of the inspector criteria approved by the FAA to conduct the eddy
current inspection. This proposed change would increase the
availability of inspectors qualified to do the eddy current
inspections.

Requests To Clarify/Develop Additional Actions

Mark Morris, Tony Brand, Michael Graziano, and Michael Beasley
requested information about recurring inspection requirements
associated with the NPRM. Forrest Benson asked whether the FAA and
Piper could develop a doubler repair instead of requiring replacement
of the spar due to parts unavailability. William Johnson noted that the
only permanent solution would be to produce a spar strap or reinforcing
plate. The FAA agrees to provide additional information related to
follow-on actions that may be associated with this proposed AD. As a
proposed interim action, this SNPRM would require a one-time inspection
for cracks and a reporting requirement. The FAA will evaluate the
results of the reports to determine if mandating terminating or
repetitive action is warranted. The FAA and Piper have discussed
possible contingent repetitive and terminating actions and determined
that a doubler repair is not a practical repair solution at this time.

Requests To Add Aft Wing Attach Fitting Inspection

Steven Ells and Pascal Robitaille expressed concern over the
integrity of the aft spar attach point as a contributing factor to the
fatigue cracking. These commenters requested including an inspection of
the aft wing attach fitting for excessive play as a step in the NPRM
and, if movement is detected, then performing the proposed eddy current
inspection. John Henry described experiences with the aft spar attach
and suggested criteria for a mandatory inspection.

The FAA acknowledges that the integrity of the forward and aft wing
spar attach points are relevant to loads imparted into the wing spar,
but the FAA disagrees with adding an inspection of the wing spar attach
points to this SNPRM. There is insufficient evidence to conclude that
the forward or aft wing spar attach points have contributed to the
unsafe condition addressed in this SNPRM. The FAA did not change this
SNPRM as a result of these comments.

Requests Regarding the Installation of Access Panels

David Sampson and Gerald Brown expressed concern that the NPRM
fails to address that holes have to be cut in the wing skin and access
panels installed to access the inspection area.

The FAA disagrees. The eddy current inspection proposed by the NPRM
does not require installing holes or access panels. The FAA did not
make changes to this SNPRM as a result of this comment.

H. Comment Regarding the Reporting Requirement

GAMA requested that the FAA revise the proposed AD to require
reporting inspection results to both the FAA and to Piper, the type
certificate holder.

The FAA agrees and has revised this SNPRM accordingly.

I. Comments Regarding Credit for Previous Maintenance Actions

Bryan Russell, Mark Maxwell, Art Sebesta, and Charles Martinak
asked for credit for airplanes that have previously complied with AD
87-08-08, Piper SB 886, or Piper SB 978A, which specified removal of
both wings and dye penetrant inspection of all main spar attach bolts.

The FAA disagrees. Dye penetrant inspection methods are not
generally capable of detecting cracks in the targeted range of .030 to
.050 inch. Additionally, the FAA is aware of one wing spar failure on
an airplane after having undergone the dye penetrant inspection
required by AD 87-08-08.

Barry Roberts and Mark Womack requested credit for airplanes with a
wing that has been replaced with a serviceable wing (over zero hours
TIS) with a documented service history. Daniel Stanley stating that the
proposed AD should not be required on airplanes that had a wing
replaced 40 years ago with a low time wing. (The commenter did not
state whether the documented wing history was available.)

The FAA disagrees. Replacement wings (over zero hours TIS) that do
not have a complete documented history raise the same considerations as
missing airplane maintenance records. For a documented serviceable wing
with less than 5,000 factored service hours, an owner/operator who can
provide documentation supporting the history of the airplane or wing spar
and show an acceptable level of safety may provide substantiating data and
request approval of an AMOC using the instructions found in paragraph
(o) of this AD. The FAA will consider all AMOC requests on a case-by-
case basis. The FAA did not make changes to this SNPRM based on these
comments.

J. Comments Regarding Special Flight Permits

Thomas Feminella requested that the proposed AD allow a one-time
ferry flight, because eddy current inspection facilities are scarce,
many owners may fly their airplanes somewhere away from their base to
get the inspection done, and if the wings fail the inspection the
airplane may be trapped at a location where no major repairs are
available. Charles Martinak also expressed concern of being grounded
after flying to a distant facility for testing, which may or may not
have repair capability.

The FAA disagrees. Once a crack in the wing spar area reaches a
detectable size, growth becomes rapid. The FAA does not allow ferry
flights with known cracks in primary structures. However, the FAA has
changed the inspector requirements, which will increase the number of
available inspectors. The FAA did not make additional changes based on
these comments.

K. Comments Regarding the Costs of Compliance

AOPA and nine individual commenters stated generally that the
estimated costs of the proposed AD are incorrect or too low.

Requests To Update the Cost of the Eddy Current Inspection

Doug Morrow and two other commenters noted that the FAA's estimated
labor rate is too low. Thomas Downey, Mitchell Ross, and twenty other
commenters stated that the estimated cost of the proposed inspection,
particularly the labor rate for an inspector qualified for eddy
current, was underestimated. Piper submitted a list of estimated costs
to conduct the eddy current inspection and to do any rework; nine other
commenters agreed with Piper's costs. EAA, GAMA, Steven Ells, Doug
Morrow, Piper, and two other commenters requested the estimated number
of work-hours for the inspection be increased.

The FAA agrees to revise the estimated cost of conducting the eddy
current inspection. The labor rate of $85 per hour is provided by the
FAA Office of Aviation Policy and Plans for use when estimating the
labor costs for complying with AD requirements. However, the FAA
acknowledges the higher hourly rate associated with the specialized
skills that would be required by the proposed AD. The FAA has increased
the cost estimate for the eddy current inspection to $600 in this
SNPRM.

The FAA observed several airplane inspections by private entities
and the NTSB investigative team, which included representatives from
NTSB, FAA, Piper, and Embry-Riddle. It took from 2 to 4 work-hours,
inclusive of gaining access and restoring the airplane, to do the
proposed inspections. However, in the NPRM the FAA did not take into
account that a portion of the labor requires a second person (bolt
removal and reinstallation). The FAA has revised the number of work-
hours estimated to do the inspections from 3 to 5 hours.

Requests To Update the Replacement Cost

Thomas Rae, Doug Morrow, AOPA and six other commenters raised
concerns about the cost to replace a spar or requested the FAA
significantly increase the cost/number of hours to replace a wing spar.
Two commenters noted that replacing a spar is not possible because
there are no parts available, and three commenters questioned why a
replacement spar must be a new spar. Piper recommended the FAA's
estimated costs include the cost of replacing the entire wing.

The FAA agrees with the comments concerning the number of labor
hours and has increased the number of work-hours estimated for the
wing-spar replacement from 32 to 80 hours. The FAA disagrees with
adding the cost for wing replacement. The cost estimate in AD
rulemaking actions include only the costs associated with complying
with the AD. Although the FAA agrees that replacing the wing is an
acceptable method of complying with a required spar replacement, that
method is optional and not required by the AD. Although the FAA
acknowledges the difficulty for some operators due to an unavailability
of parts, this does not negate the need to correct the identified
unsafe condition. The wing spar is critical for safe flight.

Requests To Include Indirect Costs

Four individual commenters noted that the FAA's cost estimate does
not include labor hours sufficient for indirect costs, such as
painting, crating and transportation, and the diminished value of the
aircraft.

The FAA acknowledges the concerns raised by these commenters.
However, the cost analysis in AD rulemaking actions typically includes
only the costs of actions actually required by the rule. Cost estimates
for ADs do not include indirect costs such as hours necessary for
closing actions, costs for transportation to or from facilities for
maintenance, or other losses. The FAA did not make changes to this
SNPRM based on these comments.

Request To Revise the Cost for the Records Review

AOPA requested the FAA revise the number of hours estimated to
review the maintenance records and calculate the number of factored
service hours. In support of its request, AOPA noted that the age of
affected aircraft may be several decades old, necessitating more than
the estimated two hours.

The FAA agrees. Most general aviation airplane maintenance record
entries are comprised of periodic inspections, which often include
annual maintenance items, thus making such a review fairly
straightforward. Flight schools and fleet operators often maintain
electronic records, making data retrieval a simple matter. The FAA
acknowledges that variations in record keeping styles encountered in
older maintenance records may require additional time to review.
Additionally, since the initial airplane maintenance records review to
determine factored service hours effectivity is not considered a
maintenance item, it can be accomplished by the owner/operator
(certified pilot). The FAA has revised the number of hours to review
the records from two hours to three hours and added language to clarify
that an owner/operator may review the airplane maintenance records in
this SNPRM.

Request To Increase the Number of Affected Airplanes in the Cost of
Compliance Section

Piper requested that the estimated costs be revised to include all
affected airplanes worldwide instead of the 19,696 U.S.-registered
airplanes identified in the NPRM. Piper further objected to the lack of
an estimated fleet cost for the eddy current inspections, and stated
40,856 airplanes should be included in the cost estimate because all
airplanes over 10 years of age would be potentially subject to the
inspections.

The FAA disagrees. The cost analyses in AD rulemaking actions
estimate the cost impact on U.S. operators. The FAA bases its estimate
on the number of affected airplanes on the U.S. registry. Including all
airplanes worldwide, as the commenter requested, would not
result in an estimate relevant to the cost impact of the proposed AD on
U.S. operators.

The FAA also disagrees that all 19,696 airplanes would be required
to calculate the factored service hours. A small sampling of
approximately 200 affected airplanes, aged 15 years and older,
indicated that only 34 percent had reached the 5,000 hours TIS that
would put them into the applicability of paragraph (c)(1) of the NPRM
and require further calculation of the factored service hours.
Therefore, the FAA estimates that a large number of the affected
airplanes will not have reached 5,000 hours TIS, have missing logbooks,
or have undergone a wing replacement and will therefore be able to
defer further review of airplane maintenance records. The FAA did not
makes changes to this SNPRM based on this comment.

L. Comment Regarding Effect of the Proposed AD on Intrastate Aviation
in Alaska

Piper requested the FAA correct the statement in the NPRM that the
proposed AD would have no effect on intrastate commerce in Alaska.
Piper stated that the proposed AD would affect 189 U.S. registered PA-
32-260 and PA-32-300 aircraft, which are widely utilized by many part
135 operators who serve the Alaska communities that rely on aviation as
their only mode of transportation.

The FAA agrees and added clarifying language that the AD does
affect operators in Alaska; however, it does not have a significant
enough effect to make a regulatory distinction.

M. Comments Requesting an Extension of the Comment Period

AOPA, EAA, GAMA, Piper, and seven individual commenters requested
the FAA extend the comment period (from 45 days to 90 days) to allow
additional time to comment because the NPRM was released preceding a
holiday and subsequent government shutdown. Also, these commenters
stated that additional time is needed for industry groups and the type
certificate holder to evaluate the impact of the NPRM and to develop a
solution.

The FAA partially agrees. At the time the FAA issued the NPRM, an
extension of the comment period was not necessary. During the partial
government shutdown of December 22, 2018, through January 25, 2019, the
online AD Docket at www.regulations.gov remained open and accepted
public comments on the NPRM. In spite of the proximity to the holidays,
over 170 separate submittals to the docket were received. However,
since the FAA has revised the proposed AD actions and added airplanes
to the Applicability, this SNPRM is reopening the comment period to
provide the public an opportunity to comment on these proposed changes.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Piper Aircraft, Inc. Service Bulletin No. 1345,
dated March 27, 2020 (Piper SB No. 1345). This service bulletin
contains procedures for doing an eddy current inspection and
instructions to report the results of the inspection to Piper and to
replace the wing, wing spar, or spar section as necessary. This service
information is reasonably available because the interested parties have
access to it through their normal course of business or by the means
identified in the ADDRESSES section.

Other Related Service Information

The FAA reviewed Piper SB 886 and Piper SB 978A. These service
bulletins contain procedures for determining initial and repetitive
inspection times based on the aircraft's usage and visually inspecting
the wing lower spar caps and the upper wing skin adjacent to the
fuselage and forward of each main spar for cracks. The FAA also
reviewed Piper Aircraft, Inc. Service Letter No. 997, dated May 14,
1987, which contains procedures for replacing airplane wings.

FAA's Determination

The FAA is proposing this AD because it evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Certain changes described above expand the scope of the NPRM. As a
result, the FAA has determined that it is necessary to reopen the
comment period to provide additional opportunity for the public to
comment on this SNPRM.

Proposed Requirements of This SNPRM

This SNPRM would require reviewing the airplane maintenance records
to determine the number of 100-hour inspections completed on each
installed main wing spar and using the number of 100-hour inspections
to calculate the factored service hours for each main wing spar. This
SNPRM would also require inspecting the two lower outboard main wing
spar bolt holes on each wing for cracks once a main wing spar exceeds
the specified factored service hours and replacing any main wing spar
when a crack is indicated. This SNPRM would only apply when an airplane
has either accumulated 5,000 or more hours TIS; has had either main
wing spar replaced with a serviceable main wing spar (more than zero
hours TIS); or has missing and/or incomplete maintenance records.

This SNPRM specifies that the owner/operator (pilot) may do the
aircraft maintenance records review and the factored service hours
calculation. Reviewing maintenance records is not considered a
maintenance action and may be done by a pilot holding at least a
private pilot certificate. This action must be recorded in the aircraft
maintenance records to show compliance with that specific action
required by the AD.

Differences Between This SNPRM and the Service Information

Piper SB 1345 specifies doing the eddy current inspection upon
reaching 5,000 hours TIS; however, this SNPRM proposes using the
factored service hours to identify the airplanes at the highest risk of
developing fatigue cracks. Piper SB No. 1345 also specifies using its
feedback form to report the eddy current inspection results, but this
SNPRM proposes the use of a different form attached as appendix 1. In
addition, this SNPRM requires replacement of the wing spar with a new
(zero hours TIS) wing spar if cracks are found; however, Piper SB No.
1345 allows replacement with parts that have been previously installed
on an airplane.

Interim Action

The FAA considers this SNPRM interim action. The inspection reports
will provide the FAA additional data for determining the number of
cracks present in the fleet. After analyzing the data, the FAA may take
further rulemaking action.

Costs of Compliance

The FAA estimates that this SNPRM affects 5,440 airplanes on U.S.
registry. There are 10,881 airplanes of U.S. registry with a model and
serial number shown in table 1 to paragraph (c) of the proposed AD.
Based on a sample survey, the FAA estimates that 50 percent of those
U.S.-registered airplanes will have reached the qualifying 5,000 hour
TIS necessary to do the required logbook review.

The FAA estimates the following costs to comply with this SNPRM:

Estimated Costs

The FAA estimates the following costs to do the eddy current
inspection. Because some airplanes are only used non-commercially and
will not accumulate the specified factored service hours in the life of
the airplane, the FAA has no way of determining the number of airplanes
that might need this inspection:

On-Condition Costs

The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
proposed inspection. The FAA has no way of determining the number of
aircraft that might need this replacement:

On-Condition Replacement Costs

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to be
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, completing and reviewing the collection of
information. All responses to this collection of information are
mandatory. Send comments regarding this burden estimate or any other
aspect of this collection of information, including suggestions for
reducing this burden to: Information Collection Clearance Officer,
Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX
76177-1524.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs
describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.

Regulatory Findings

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed
regulation:

(1) Is not a "significant regulatory action" under Executive
Order 12866,

(2) Will not affect intrastate aviation in Alaska to the extent
that it justifies making a regulatory distinction, 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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):