DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2018-1077; Project Identifier 2018-NE-40-AD; Amendment
39-21354; AD 2020-25-12]
Airworthiness Directives; Superior Air Parts, Inc. Engines and
Lycoming Engines Reciprocating Engines With a Certain SAP Crankshaft
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Superior Air Parts, Inc. (SAP) Model IO-360-series and O-360-series
reciprocating engines and certain Lycoming Engines (Lycoming) Model
AEIO-360-, IO-360-, and O-360-series reciprocating engines with a
certain SAP crankshaft assembly installed. This SAP crankshaft assembly
is installed as original equipment on the affected SAP engines and as
replacement part under parts manufacturer approval (PMA) on the
affected Lycoming engines. This AD was prompted by three crankshaft
assembly failures that resulted in the loss of engine power and
immediate or emergency landings. This AD requires the removal from
service of all affected crankshaft assemblies. The FAA is issuing this
AD to address the unsafe condition on these products.
DATES: This AD is effective January 15, 2021.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2018-1077; 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 final rule, any
comments received, and other information. The address for Docket
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue
SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Justin Carter, Aviation Safety
Engineer, Fort Worth ACO Branch, FAA, 10101 Hillwood Parkway, Fort
Worth, TX 76177; phone: (817) 222-5146; fax: (817) 222-5245; email:
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all SAP Model IO-360-
series and O-360-series reciprocating engines and certain Lycoming
Model AEIO-360-, IO-360-, and O-360-series reciprocating engines with
certain SAP crankshaft assembly installed. The NPRM published in the
Federal Register on January 29, 2020 (85 FR 5173). The NPRM was
prompted by three crankshaft assembly failures that resulted in the
loss of engine power and immediate or emergency landings. The FAA
determined that the crankshaft assembly failures resulted from the
manufacturing process at SAP's crankshaft vendor during 2012 and 2014
causing excessive residual white layer of iron nitride forming on the
assemblies. This white layer is brittle and can lead to spalling or
fatigue cracking of the crankshaft assembly as a result of the normal
mechanical loads during engine operation. The FAA's analysis concluded
that all three SAP crankshaft assembly failures were the result of this
fatigue cracking. In the NPRM, the FAA proposed to require the removal
from service of all affected crankshaft assemblies. The unsafe
condition, if not addressed, could result in failure of the engine, in-
flight shutdown, and loss of the airplane.
Discussion of Final Airworthiness Directive Comments
The FAA received comments from seven commenters. The commenters
were SAP, the Aircraft Owners and Pilots Association (AOPA), and five
individual commenters. Three commenters requested that the FAA extend
the comment period. One commenter requested the withdrawal of the AD.
Two commenters asked the FAA to release more information. One commenter
asked for the status of the AD and if the crankshaft assembly is safe
to fly. The following presents the comments received on the NPRM and
the FAA's response to each comment.
Request To Withdraw the NPRM: White Layer Does Not Contribute to
SAP stated that data from an independent laboratory test does not
support the statement in the NPRM that the crankshaft failures were a
result of residual white layer formation, also known as a compound
layer, on certain crankshaft assemblies as a result of improper
manufacturing by a third-party vendor. SAP stated that the fractured
crankshafts were all within specifications. SAP found both the material
and the heat treatment to be within all engineering requirements and
consistent with other crankshafts in general aviation piston aircraft
engines. SAP noted that these requirements were consistent with the
engineering testing conducted by SAP in pursuit of FAA PMA
certification. Additionally, SAP stated the fractures were not
consistent with fatigue fractures due to excessive white layer, and
that no manufacturing or material defect was found in independent
metallurgical laboratory analysis. The FAA infers from this comment
that SAP is requesting that the FAA withdraw the NPRM.
The FAA disagrees with SAP's analysis. BakerRisk Project No. 01-
05929-003-17, dated August 15, 2017, for SAP crankshaft assembly S/N
SP14-0202, which failed on March 6, 2017, found that there was a
continuous white layer at the surface of the radius, extending up to
the location of the fracture, and that the white layer may have
contributed to early crack initiation. \1\ The continuous white layer
at the origin was 0.0007 inch. BakerRisk Project No. 01-05929-006-17,
Rev. 1, dated May 8, 2018, for SAP crankshaft assembly S/N SP14-0194,
which failed on August 3, 2017, found that the continuous white layer
at the surface of the forward journal radius, extending up to the
location of the fracture, was 0.0006 inch. According to the report,
this indicates that the process being used to remove the white layer
was not removing the entire white layer. Because it found that the
presence of the white layer can lower fatigue resistance and result in
premature fatigue crack initiation, the report included recommendations
to review the material and the processes that define the crankshaft
journals, especially the nitride case hardening and white layer removal
\1\ See pp. 2-3 of BakerRisk Project No. 01-05929-003-17.
\2\ See pp. 4-5 of BakerRisk Project No. 01-05929-006-17, Rev.
SAP's comment cited Hurst Metallurgical Research Laboratory, Inc.,
(Hurst) Report No. 73900, dated February 22, 2019, for SAP crankshaft
assembly S/N SP13-0150, which failed on October 31, 2018. This Hurst
report found that the continuous white layer of iron nitride at the
surface of the forward journal radius was 0.0001 inch. The FAA,
however, disagrees with the reported thickness of the white layer. The
report includes two scaled photographs (photographs No. 11 and 12),
magnified 100 times and 500 times, respectively. Using the scaling bar
provided in the photographs, the FAA determined that the white layer is
0.0009 inch. Although SAP stated a white layer of up to 0.001 inch is
allowed, SAP based this figure on an SAE Aerospace Material
specification and not on the original equipment manufacturer's (OEM)
specifications. A white layer of 0.0009 inch exceeds the amount allowed
by the OEM.
As supported by the reports, the FAA finds that white layer
contributed to the early crack initiation and, on all failed crankshaft
assemblies, exceeded OEM specifications. Based on the foregoing, the
FAA finds no basis to withdraw the NPRM.
Request To Withdraw the NPRM: White Layer Does Not Increase Fatigue
SAP stated that the presence of a white layer does not reduce the
fatigue resistance of material at the surface, but rather increases the
fatigue resistance of that same material. SAP cited a study by Major,
Jakl, and Hubalovsky for the observation that the
application of plasma carburizing can lead to about a 25% increase in
fatigue resistance.\3\ SAP stated a study by Hiraoka and Ishida \4\
shows a marked increase in fatigue limit in a specimen with a 10 mm
thick white layer as opposed to a specimen without a white layer, with
a slight increase in the fatigue limit in a specimen with a 20 mm
thick white layer as compared to the specimen with a 10 mm thick
white layer. The FAA infers from this comment that SAP is requesting
that the FAA withdraw the NPRM.
\3\ Stepan Major, Vladimir Jakl, &
Stepan Hubalovsky, Effect of carburizing
on fatigue life of high-strength steel specimen under push-pull
loading, Advances in Engineering Mechanics and Materials, 143
\4\ Yaushi Hiraoka & Akihiro Ishida, Effect of Compound Layer
Thickness Composed of y'-Fe4N on Rotated-Bending Fatigue
Strength in Gas-Nitrided JIS-SCM435 Steel, 58 MATERIALS TRANSACTIONS
The FAA disagrees with the applicability of these studies to the
unsafe condition identified in this AD. Although the application of
plasma carburizing can lead to an increase in the fatigue resistance,
the affected crankshaft assemblies were not plasma carburized.
Therefore, the Major, Jakl, and Hubalovsky study is not
relevant here. Although the Hiraoka and Ishida study did reveal an
increase in fatigue limit of gas nitrided steel with a white layer over
one without a white layer, the study's test environment did not
replicate the conditions applicable to an engine crankshaft as
identified in Advisory Circular No. 33.19-1, ``Guidance Material for 14
CFR Sec. 33.19, Durability, for Reciprocating Engine Redesigned
Parts,'' dated September 27, 2004 (AC 33.19-1). A crankshaft is a part
primary fatigue mechanism is a forced vibratory response in combination
resonant vibratory response that occurs at any engine speed at which the
frequency of the part (or assembly that includes the part) coincides
with the frequency of a combustion or inertia harmonic. AC 33.19-1
recommends 300 hours of engine tests, including a vibration test at
peak torsional resonance conditions, to test the fatigue strength of
The white layer is well-established to be problematic in that it is
brittle. The OEM removes the white layer during the manufacturing
process. As a PMA holder, 14 CFR 21.303 requires that SAP produce a
part that is equivalent to the OEM part. Based on the foregoing, the
FAA finds no basis to withdraw the NPRM.
Request To Withdraw the NPRM: Operation Outside of Normal Conditions
SAP stated the fractures of the crankshaft assemblies cited in the
NPRM were due to misuse, abuse, or lack of lubrication. In support, SAP
cited Hurst Report No. 73614, Rev. 1, dated December 7, 2018, for SAP
crankshaft assembly S/N SP14-0202 and Hurst Report No. 73617, Rev. 1,
dated December 7, 2018, for SAP crankshaft assembly S/N SP14-0194,
which indicate that the fractures were likely initiated by abnormal
service conditions, such as a propeller strike and a start-up of the
engine in a low-temperature (below optimal performing temperature)
environment. SAP also cited Hurst Report No. 73900 for SAP crankshaft
assembly S/N SP13-0150, which indicates that likely contributors of the
failure include rod sliding bearing failure due to insufficient
lubrication, misalignment of the crankshaft, and improper engine
performance from inadequate operation procedure resulting in high
bending moment at the radius locations from excessive force from the
piston assembly. SAP stated that all three of these crankshafts were
operated in a flight school environment. The FAA infers from this
comment that SAP is requesting that the FAA withdraw the NPRM.
The FAA disagrees that the fracture was initiated by the operation
of the engines outside of ``normal'' conditions or parameters. With
respect to Hurst Report No. 73614 for SAP crankshaft assembly S/N SP14-
0202 and Hurst Report No. 73617 for SAP crankshaft assembly S/N SP14-
0194, none of the engines exhibited evidence of propeller strikes, and
none were started below optimal performance temperature. According to
Lycoming,\5\ cold weather requiring the use of pre-heat to avoid a cold
engine start-up is 10 degrees Fahrenheit or below. Two of the incidents
occurred in August (Canada) and October (Florida), making cold engine
start-up unlikely. The third incident occurred in March
(Massachusetts), which had a low of 16 degrees Fahrenheit at 6 a.m. and
proceeded to a high of 41 degrees Fahrenheit in the afternoon.
\5\ Lycoming Service Instruction No. 1505, dated July 1, 2002:
``The use of pre-heat will facilitate starting during cold weather,
and is required when the engine has been allowed to drop to
temperatures below +10 [deg]F/-12 [deg]C.''
With respect to Hurst Report No. 73900 for SAP crankshaft assembly
S/N SP13-0150, the pilot and mechanic separately reported the engine
had good oil pressure, indicating that the engine did not suffer from
lack of proper lubrication at the time of the crankshaft assembly
failure. The report identifies possible contributors of single origin
fatigue failure, including the misalignment of the crankshaft assembly
or improper engine performance from inadequate operation procedure
resulting in high bending moment at the radius locations from excessive
force from the piston assembly. However, the report does not provide
evidence to support these contributors. Based on the foregoing, the FAA
declines to withdraw the NPRM.
Request To Review National Transportation Safety Board (NTSB) Reports
An individual commenter requested to review the NTSB reports on the
accidents mentioned in the NPRM. The commenter was unable to locate
anything in the NTSB database concerning engine stoppage in aircraft
powered by Lycoming or SAP O-360 or IO-360 engines.
The NTSB did not generate reports for the three incidents that
resulted from the crankshaft failures discussed in the NPRM. Therefore,
the FAA did not rely on NTSB reports and is not in possession of any
report generated as a result of the three incidents.
Request To Add Metallurgical Analyses to the Docket
An individual commenter requested that the FAA add its
metallurgical analyses to the docket. The commenter stated that it was
his understanding from discussions with the FAA that the FAA has shared
its metallurgical analyses with SAP.
The FAA agrees and has uploaded the BakerRisk and Hurst
metallurgical reports provided by SAP to the AD docket, as SAP has
agreed to release these reports to the public. The FAA, however, did
not perform its own metallurgical testing. The FAA instead relied on
metallurgical testing performed by BakerRisk and Hurst for SAP.
Request To Release Pertinent Information
An individual commenter requested that the FAA release information
it has on this issue, including the circumstances of the crankshaft
assembly failures, the cost of crankshaft assembly replacement, and the
scope of the proposed action.
The FAA agrees to provide additional information about the
circumstances of the failures. In each incident, the crankshaft
assembly broke into two pieces. The March 6, 2017, incident resulted in
the crankshaft separating at journal #2 while the August 3, 2017, and
October 31, 2018, incidents both resulted in a separation of the
crankshaft at journal #4. All of the incidents involved flight-training
aircraft. Additionally, as discussed previously, the FAA has uploaded
the metallurgical reports to the AD docket.
Both the NPRM and this final rule adequately explain the scope of
the AD and contain a detailed estimate of the costs of compliance
within this AD, including the cost of the crankshaft assembly
replacement, labor cost, and total estimated cost to U.S. operators.
This final rule also discusses the net benefit of this AD.
Request To Consider Costs of Implementing This AD
An individual commenter requested that the FAA consider the
financial costs and unintended consequences of this AD, such as
decreased aircraft value. The commenter estimates that the value of his
aircraft has been reduced by at least $15,000 since the publication of
The FAA disagrees. The cost analysis in AD rulemaking actions
typically includes only the costs associated with complying with the AD
and does not include indirect costs such as loss of aircraft value. The
FAA acknowledges that the general obligation of the operator to
maintain its aircraft in an airworthy condition is sometimes expensive.
However, and as discussed in more detail in the Benefits section, the
FAA estimates that the benefits of this AD greatly exceed its cost.
Request To Clarify Applicability
An individual commenter asked if SAP crankshaft assemblies earlier
than 2012 are affected by this AD.
The first affected SAP crankshaft assembly was shipped on July 31,
2012. SAP crankshaft assemblies assembled before July 31, 2012, are not
affected by this AD.
Request To Extend Comment Period
SAP and AOPA requested that the FAA extend the comment period by 60
days to enable SAP to gather more information. SAP asked for more time
to research, gather, and respond appropriately to the NPRM. AOPA
similarly requested an extension to review the costs and overall scope,
and to gather information to respond to the NPRM. SAP, AOPA, and an
individual commenter requested the FAA extend the comment period
because of delays due to the COVID-19 pandemic, such as the closure of
laboratories for further testing and the reduction in aircraft
The FAA disagrees. At SAP's request, the FAA met with SAP and AOPA
in April 2020 to discuss the NPRM. During that meeting, the
participants discussed certain aspects of the NPRM, including the white
layer and metallurgical reports, the three failed crankshaft
assemblies, and SAP's request for a 60-day extension to the comment
period. A summary of the meeting is available in the AD docket. None of
the information provided by SAP or AOPA justifies an extension of the
comment period. If investigations by SAP or others reveal information
that changes the FAA's determination regarding the unsafe condition,
the FAA will consider future rulemaking.
Request for a Status Update
An individual commenter requested information regarding the FAA's
progress on issuing this AD. The commenter stated that based on
feedback from SAP, the crankshaft assembly is safe and that a
metallurgy company inspected one of the affected crankshaft assemblies
and did not find any issues.
The FAA disagrees with the assessment from SAP. The FAA reviewed
the metallurgical reports from the incidents of failed crankshaft
assemblies and determined that an unsafe condition exists in other
crankshaft assemblies of the same type design. In each incident, the
crankshaft assembly broke into two pieces, leading to loss of engine
power. The crankshaft assemblies involved in the three incidents were
found to have excessive white layer. As a result, this AD requires
removing all affected crankshaft assemblies from service within 25
engine operating hours after the effective date of this AD.
The FAA reviewed the relevant data, considered the comments
received, and determined that air safety requires adopting the AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (Pub. L. 96-354, codified as
amended at 5 U.S.C. 601-612) (RFA) establishes ``as a principle of
regulatory issuance that agencies shall endeavor, consistent with the
objectives of the rule and of applicable statutes, to fit regulatory
and informational requirements to the scale of the businesses,
organizations, and governmental jurisdictions subject to regulation. To
achieve this principle, agencies are required to solicit and consider
flexible regulatory proposals and to explain the rationale for their
actions to assure that such proposals are given serious
consideration.'' Public Law 96-354, 2(b), September 19, 1980. The RFA
covers a wide-range of small entities, including small businesses, not-
for-profit organizations, and small governmental jurisdictions.
Agencies must perform a review to determine whether a rule will have a
significant economic impact on a substantial number of small entities.
If the agency determines that it will, the agency must prepare a
regulatory flexibility analysis as described in the RFA.
The FAA published an Initial Regulatory Flexibility Analysis (IRFA)
in the proposed rule to aid the public in commenting on the potential
impacts to small entities. The FAA considered the public comments in
developing the final rule and this Final Regulatory Flexibility
The FAA found that SAP, the manufacturer of the crankshaft
assemblies, sold 192 SAP crankshaft assemblies to date: 115 of these
crankshaft assemblies are estimated to be installed on type
certificated airplanes and the remaining 77 crankshaft assemblies are
estimated to be installed on experimental aircraft. The FAA's risk
analysis indicates that 100 percent of crankshaft assembly failures
will destroy the engine. Using the historical incident data (2000-
2014), the FAA assumes that 24.4 percent of crankshaft assembly
failures will result in aircraft hull loss while 22 percent of
crankshaft assembly failures will result in fatalities. There would be
an average of 2.1 fatalities per each crankshaft assembly accident.
Applying these probabilities to the estimated 115 crankshaft assemblies
installed on type certificated airplanes, the FAA estimates that if
these crankshaft assemblies are not replaced and continue to be used in
these airplanes, this will result in 53 fatalities (2.1 fatalities per
crankshaft accident x 22 percent probability of a crankshaft assembly
failure resulting in fatalities x 115 crankshaft assemblies) and 28
aircraft losses (24.4 percent probability of a crankshaft assembly
failure destroying the airplane). This AD will prevent all 53
fatalities and 28 aircraft losses.
Using an average price of $50,000 for a small single engine
airplane, an average price of $30,000 for a 360-series engine and the
Department of Transportation's $9.6 million estimate for the Value of
Statistical Life (VSL) from the ``Revised Departmental Guidance on
Valuation of a Statistical Life in Economic Analysis,'' \6\ the FAA
estimated this AD final rule will result in monetized benefits of
$512.8 million. \7\
\7\ 53 preventable fatalities will amount to $508.8 million in
benefits of this rule. (53 x $9.6 million). The value of 28 airplane
losses is $1.4 million (28 x $50,000). The remaining 75.6 percent of
crankshaft failures (100 percent-24.4 percent crankshaft failure
destroying the airplane) will result in $2.6 million in engine
damages. (115 x 0.756 probability of crankshaft failure damaging an
airplane engine x $30,000 value of 360 engine). Therefore, the total
estimated benefits are $512.8 million ($508.8 million preventable
fatalities + $1.4 million avoidable airplane loss + $2.6 million
preventable engine damages).
Costs of Compliance
The costs of compliance with this AD consist of the cost to remove
and replace a crankshaft assembly. The FAA estimates that this AD will
affect 115 crankshaft assemblies installed on airplanes of U.S.
registry. This cost estimate does not include 77 SAP crankshaft
assemblies installed on experimental engines since this AD does not
apply to these engines. The estimated compliance cost per crankshaft
assembly is identified below.
Labor cost = 61 hours per crankshaft assembly replacement x $85
Hourly Wage = $5,185.
Equipment costs per crankshaft assembly replacement = $9,636
(Source: Average of the two vendors).
$5,185 labor per crankshaft assembly + $9,636 equipment costs per
crankshaft assembly replacement = $14,821 compliance cost per engine.
The total costs to U.S. operators is $1,704,415 ($14,821 x 115), or
$119,309 in annualized costs in perpetuity using a 7 percent discount
rate. There are no additional costs after removing and replacing the
Therefore, the FAA estimates that the net benefit of this final
rule will be $511.1 million ($512.8 million benefits -$1.7 million
costs), or $35.77 million in annualized net benefits using a 7 percent
discount rate in perpetuity.
Final Regulatory Flexibility Analysis
Under Sec. 604(a) of the RFA, the final analysis must contain the
(1) A statement of the need for, and objectives of, the rule;
(2) A statement of the significant issues raised by the public
comments in response to the IRFA, a statement of the assessment of the
agency of such issues, and a statement of any changes made in the
proposed rule as a result of such comments;
(3) The response of the agency to any comments filed by the Chief
Counsel for Advocacy of the Small Business Administration (SBA) in
response to the proposed rule, and a detailed statement of any change
made to the proposed rule in the final rule as a result of the
(4) A description of and an estimate of the number of small
entities to which the rule will apply or an explanation of why no such
estimate is available;
(5) A description of the projected reporting, record-keeping, and
other compliance requirements of the proposed rule, including an
estimate of the classes of small entities which will be subject to the
requirement and the type of professional skills necessary for the
preparation of the report or record;
(6) A description of the steps the agency has taken to minimize the
significant economic impact on small entities consistent with the
stated objectives of applicable statutes, including a statement of the
factual, policy, and legal reasons for selecting the alternative
adopted in the final rule and why each of the other significant
alternatives to the rule considered by the agency which affect the
impact on small entities was rejected.
1. Need for and Objectives of the Rule
This final rule AD was prompted by three crankshaft assembly
failures that resulted in the loss of engine power and immediate or
emergency landings. The FAA is issuing this AD to prevent failure of
the crankshaft assembly by requiring the removal of all affected
crankshaft assemblies from service. Failure of a crankshaft assembly,
if not addressed, could result in failure of the engine, in-flight
shutdown, and loss of the airplane.
2. Significant Issues Raised in Public Comments
An individual commenter noted that some owners of affected aircraft
may not be in a position to absorb the $15,000 cost of the crankshaft
assembly replacement. The commenter proposed that the financial costs
of this AD would exceed the FAA estimates in some cases and, therefore,
the unintended consequences of this AD would destroy value out of
proportion to the preservation of the safety of the national airspace
system and the general public.
The FAA estimates the cost of replacing a single crankshaft
assembly at $14,821. The risk of not replacing the crankshaft is not
insignificant, and the crankshaft failure could cause engine loss,
airplane loss, or fatality valued at $30,000, $50,000, and $9.6
million, respectively. When these potentially substantial losses and
risks of fatality to each airplane owner and operator are considered,
the $14,821 compliance cost per airplane is minimal. Further, the FAA
estimates the benefits of this AD to be $512.8 million, which greatly
exceeds its cost of $1.7 million, justifying this final rule.
Based on the risk and benefits analysis above, the FAA determined
that no changes are necessary to the final rule as a result of this
3. Response to SBA Comments
The Chief Counsel for Advocacy of the SBA did not file any comments
in response to the proposed rule.
4. Small Entities to Which the Rule Will Apply
This AD applies to all SAP Model IO-360-series and O-360-series
reciprocating engines and certain Lycoming Model AEIO-360-, IO-360-,
and O-360-series reciprocating engines with a certain SAP crankshaft
assembly installed. This SAP crankshaft assembly is installed as
original equipment on the affected SAP engines and as a replacement
part under PMA on the affected Lycoming engines. These engines are
installed on airplanes performing various activities including, but not
limited to, flight training, charter flights, and agriculture.
Under the RFA, the FAA must determine whether a final rule
significantly affects a substantial number of small entities. The FAA
uses the SBA criteria for determining whether an affected entity is
small. For aircraft and engine manufacturers, aviation operators, and
any business using an aircraft, the SBA criterion is 1,500 or fewer
employees. The FAA estimates that this AD affects 115 crankshaft
assemblies installed on airplanes of U.S. registry. The FAA does not
have any information or data on whether these entities are small
businesses according to the definition established by the SBA. Although
in the NPRM the FAA requested comments and data that would allow the
agency to more accurately assess the number of employees and sales
revenues of the affected entities, no such comments or data was
received. Accordingly, the FAA assumes for purposes of this final rule
that some of the affected entities are small businesses.\8\ The FAA
determines that the estimated $14,821 compliance cost per aircraft due
to this rule will have a significant impact on a substantial number of
\8\ The FAA recognizes that many of these affected airplanes are
recreational. The 2016 GAMA Databook shows that of 141,141 active
General Aviation piston aircraft, 104,669 are used for personal or
recreational purposes (74 percent), Using this distribution, only 30
of the 115 crankshaft assemblies would be installed in airplanes
operated for business use.
5. Projected Reporting, Record-Keeping, and Other Compliance
There are no record-keeping costs or other compliance costs
associated with this final rule.
6. Significant Alternatives Considered
As part of the FRFA, the FAA is required to consider regulatory
alternatives that may be less burdensome. The FAA considered the
Do nothing: This option is not acceptable because the risk of
additional failures of these crankshaft assemblies constitutes a known
unsafe condition. The FAA estimates that this AD will prevent 53
fatalities and 28 aircraft losses, and monetized benefits of $512.8
Periodic inspections: This option is not possible as the crankshaft
assembly cannot be inspected without destroying it.
There is no direct safety alternative to the replacement of the
crankshaft assembly. The replacement addresses a safety issue aimed at
preventing the failure of the crankshaft assembly.
Therefore, the FAA rejected these two regulatory alternatives and
determined that this rulemaking may have a significant economic impact
on a substantial number of small entities.
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.
This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect on the States,
on the relationship between the national government and the States, or
on the distribution of power and responsibilities among the various
levels of government.
For the reasons discussed above, I certify that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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