AD 2020-25-12

[Federal Register Volume 85, Number 239 (Friday, December 11, 2020)]
[Rules and Regulations]
[Pages 79828-79833]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2020-27149]


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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]
RIN 2120-AA64


Airworthiness Directives; Superior Air Parts, Inc. Engines and 
Lycoming Engines Reciprocating Engines With a Certain SAP Crankshaft 
Assembly

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
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 a 
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 <a href="https://www.regulations.gov">https://www.regulations.gov</a> 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: 
<a href="/cdn-cgi/l/email-protection#95ffe0e6e1fcfbbbf6f4e7e1f0e7d5f3f4f4bbf2fae3"><span class="__cf_email__" data-cfemail="7f150a0c0b1611511c1e0d0b1a0d3f191e1e51181009">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

[[Page 79829]]

Background

    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 a 
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 
Fracture

    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 
process. \2\
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    \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. 
1.
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    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 
Resistance

    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 Hub[aacute]lovsk[yacute] 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 [mu]m 
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 [mu]m 
thick white layer as compared to the specimen with a 10 [mu]m thick 
white layer. The FAA infers from this comment that SAP is requesting 
that the FAA withdraw the NPRM.
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    \3\ [Scaron]tep[aacute]n Major, Vladimir Jakl, & 
[Scaron]tep[aacute]n Hub[aacute]lovsk[yacute], Effect of carburizing 
on fatigue life of high-strength steel specimen under push-pull 
loading, Advances in Engineering Mechanics and Materials, 143 
(2014).
    \4\ Yaushi Hiraoka & Akihiro Ishida, Effect of Compound Layer 
Thickness Composed of [gamma]'-Fe4N on Rotated-Bending Fatigue 
Strength in Gas-Nitrided JIS-SCM435 Steel, 58 MATERIALS TRANSACTIONS 
993 (2017).
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    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 Hub[aacute]lovsk[yacute] 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,

[[Page 79830]]

2004 (AC 33.19-1). A crankshaft is a part whose primary fatigue 
mechanism is a forced vibratory response in combination with a resonant 
vibratory response that occurs at any engine speed at which the natural 
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 crankshaft.
    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.
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    \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.''
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    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 a 
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 NPRM.
    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.

[[Page 79831]]

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 
operations.
    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.

Conclusion

    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 
Analysis (FRFA).

Benefits

    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\
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    \6\ <a href="https://www.transportation.gov/office-policy/transportation-policy/revised-departmental-guidance-on-valuation-of-a-statistical-life-in-economic-analysis">https://www.transportation.gov/office-policy/transportation-policy/revised-departmental-guidance-on-valuation-of-a-statistical-life-in-economic-analysis</a>.
    \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).
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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

[[Page 79832]]

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 
crankshaft assembly.
    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 
following:
    (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 
comments;
    (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 
individual comment.

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 
small entities.
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    \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.
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5. Projected Reporting, Record-Keeping, and Other Compliance 
Requirements

    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 
following alternatives:
    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 
million.
    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.

[[Page 79833]]

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

    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 
reference, Safety.

The Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2020-25-12 Superior Air Parts, Inc.: Amendment 39-21354; Docket No. 
FAA-2018-1077; Project Identifier 2018-NE-40-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective January 15, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the reciprocating engine models identified in 
paragraphs (c)(1) and (2) of this AD with a Superior Air Parts, Inc. 
(SAP) crankshaft assembly, part number (P/N) SL36500-A20 or P/N 
SL36500-A31, with serial numbers 82976-01; 82976-02; SP12-0003 
through SP12-0089, inclusive; SP13-0034 through SP13-0150, 
inclusive; or SP14-0151 through SP14-0202, inclusive; installed.
    (1) With SAP crankshaft assembly, P/N SL36500-A20, installed:
    (i) SAP Model IO-360-series and O-360-series reciprocating 
engines.
    (ii) Lycoming Engines (Lycoming) Model IO-360-B2F, IO-360-L2A, 
O-360, O-360-A2A, O-360-A2D, O-360-A2E, O-360-A2F, O-360-A2G, O-360-
B2A, O-360-C2A, O-360-C2C, O-360-C2D, O-360-C2E, O-360-D2A, and O-
360-D2B reciprocating engines.
    (2) With SAP crankshaft assembly, P/N SL36500-A31, installed:
    (i) SAP Model IO-360-series and O-360-series reciprocating 
engines.
    (ii) Lycoming Model AEIO-360-H1A, IO-360-B1A, IO-360-B1B, IO-
360-B1D, IO-360-B1E, IO-360-B1F, IO-360-M1A, O-360, O-360-A1A, O-
360-A1C, O-360-A1D, O-360-A2A, O-360-C1A, O-360-C1G, O-360-C1C, O-
360-C1E, and O-360-C1F reciprocating engines.
    Note 1 to paragraph (c): This SAP crankshaft assembly may be 
installed as a replacement part under parts manufacturer approval on 
the affected Lycoming engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 8520, Reciprocating 
Engine Power Section.

(e) Unsafe Condition

    This 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. The unsafe condition, if not addressed, could 
result in failure of the engine, in-flight shutdown, and loss of the 
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Action

    Within 25 engine operating hours after the effective date of 
this AD, remove the crankshaft assembly from service.

(h) Special Flight Permit

    A one-time special flight permit may be issued to fly the 
aircraft to a maintenance facility to perform the actions of this AD 
with the following limitations: No passengers, visual flight rules 
(VFR) day conditions only, and avoid areas of known turbulence.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Fort Worth ACO Branch, FAA, has the authority 
to approve AMOCs for this AD, if requested using the procedures 
found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your 
request to your principal inspector or local Flight Standards 
District Office, as appropriate. If sending information directly to 
the manager of the certification office, send it to the attention of 
the person identified in Related Information.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    For more information about this AD, 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: <a href="/cdn-cgi/l/email-protection#96fce3e5e2fff8b8f5f7e4e2f3e4d6f0f7f7b8f1f9e0"><span class="__cf_email__" data-cfemail="acc6d9dfd8c5c282cfcdded8c9deeccacdcd82cbc3da">[email&#160;protected]</span></a>.

(k) Material Incorporated by Reference

    None.

    Issued on December 3, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-27149 Filed 12-10-20; 8:45 am]
BILLING CODE 4910-13-P