Document ID: FAA-2012-0002-0660
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Continental Motors, Inc. Reciprocating Engines
Posted Date: 2016-08-11T04:00Z

[Federal Register Volume 81, Number 155 (Thursday, August 11, 2016)]
[Rules and Regulations]
[Pages 52975-52991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-18708]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0002; Directorate Identifier 2011-NE-42-AD; 
Amendment 39-18610; AD 2016-16-12]
RIN 2120-AA64

Airworthiness Directives; Continental Motors, Inc. Reciprocating 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Continental Motors, Inc., (CMI) San Antonio (formerly known as 
Airmotive Engineering Corp. (AEC)), replacement parts manufacturer 
approval (PMA) cylinder assemblies marketed by Engine Components 
International Division (ECi). On July 17, 2015, AEC was purchased by 
CMI and is now operating as ``Continental Motors--San Antonio.'' These 
cylinder assemblies are used on all CMI model -520 and -550 
reciprocating engines, and on all other CMI engine models approved for 
the use of model -520 and -550 cylinder assemblies, such as the CMI 
model -470 when modified by supplemental type certificate (STC). This 
AD was prompted by reports of multiple cylinder head-to-barrel 
separations and cracked and leaking aluminum cylinder heads. This AD 
requires removal of the affected cylinder assemblies, including 
overhauled cylinder assemblies, according to a phased removal schedule. 
We are issuing this AD to prevent failure of the cylinder assemblies, 
which could lead to failure of the engine, in-flight shutdown, and loss 
of control of the airplane.

DATES: This AD is effective September 15, 2016.

ADDRESSES: For service information identified in this AD, contact 
Continental Motors, Inc., San Antonio, 9503 Middlex Drive, San Antonio, 
TX 78217; phone: 210-820-8100; Internet: http://www.continentalsanantonio.com. You may view this service information

[[Page 52976]]

at the FAA, Engine & Propeller Directorate, 1200 District Avenue, 
Burlington, MA. For information on the availability of this material at 
the FAA, call 781-238-7125. It is also available on the Internet at 
http://www.regulations.gov by searching for and locating Docket No. 
FAA-2012-0002.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2012-
0002; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this AD, the regulatory evaluation, any comments received, and 
other information. The address for the Docket Office (phone: 800-647-
5527) is Document Management Facility, 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: Jurgen E. Priester, Aerospace 
Engineer, Delegation Systems Certification Office, FAA, Rotorcraft 
Directorate, 10101 Hillwood Parkway, Fort Worth, TX 76177; phone: 817-
222-5190; fax: 817-222-5785; email: jurgen.e.priester@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

August 12, 2013--NPRM

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain CMI San Antonio 
replacement PMA cylinder assemblies marketed by ECi. These assemblies 
are used on CMI model -520 and -550 reciprocating engines, and all 
other CMI engine models approved for the use of models -520 and -550 
cylinder assemblies such as the CMI model -470 when modified by STC. 
The NPRM published in the Federal Register on August 12, 2013 (78 FR 
48828) (referred to herein after as the ``August 12, 2013, NPRM''). The 
August 12, 2013, NPRM proposed to require initial and repetitive 
inspections, immediate replacement of cracked cylinder assemblies, and 
replacement of cylinder assemblies at reduced times-in-service (TIS) 
since new. The August 12, 2013, NPRM also proposed to prohibit the 
installation of affected cylinder assemblies into any engine.

September 26, 2013-March 12, 2014--Posting Technical Documents/
Extension of Comment Period/Initial Regulatory Flexibility Analysis 
(IRFA)

    We received several hundred comments to our August 12, 2013, NPRM. 
In response to this high-level of public interest, we undertook several 
actions to help the public understand and provide further comment on 
our proposed rule. These actions included:
     Extending the comment period to the August 12, 2013, NPRM;
     publishing an IRFA; and
     adding several technical documents that were posted to 
Docket No. FAA-2012-0002 (see Addresses section of this final rule for 
information on locating the docket) on September 20, 2013.
    Documents added to the docket include:
    (1) FAA Safety Recommendations 08.365, 08.366, and 11.216, which 
were written against the subject ECi cylinder assemblies;
    (2) NTSB Safety Recommendation A-12-7, also written against the 
subject ECi cylinder assemblies;
    (3) The original ECi AD worksheet for 2011-NE-42-AD, which 
documents the reasons for the proposed rule;
    (4) A list of separations of ECi cylinder assemblies;
    (5) A white paper \1\ on failures of ECi cylinders by the FAA Chief 
Scientific and Technical Adviser (CSTA) for Engine Dynamics;
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    \1\ An authoritative report that informs readers about a complex 
issue.
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    (6) Figures showing ECi Dome Separation Failures;
    (7) A briefing on ``ECi Cylinder Head Failures on Continental IO 
520 & 550 Engines''; and
    (8) FAA Policy Memorandum on ``Risk Assessment for Reciprocating 
Engine Airworthiness Directives,'' dated May 24, 1999.
    We notified the public of these actions on September 26, 2013, via 
the Federal Register (78 FR 59293). In that notification, we extended 
the comment period for the August 12, 2013, NPRM to December 11, 2013. 
This extension allowed the public additional time to comment on our 
August 12, 2013, NPRM and the additional information we had added to 
the docket.
    We also determined that we needed to add to the docket a detailed 
regulatory flexibility analysis to estimate the effects of the proposed 
rule on small business entities. We published an Initial Regulatory 
Flexibility Analysis in Docket FAA-2012-0002 on March 12, 2014 (79 FR 
13924).

September 3-4, 2014--Challenge Team's Review of August 12, 2013, NPRM

    Because the response to our August 12, 2013, NPRM was so negative--
we received over 500 comments, most disagreeing with the NPRM--we 
established a Challenge Team to review our proposed AD. The Challenge 
Team was an independent, multi-disciplinary team, consisting of three 
FAA CSTAs, FAA Aircraft Certification Service (AIR) managers, and other 
FAA technical experts from all four Directorates.
    The Challenge Team reviewed the technical information that formed 
the basis for our proposed AD and the public comments we had received 
concerning our proposal. The CSTA for Aircraft Safety Analysis also 
independently computed a new risk assessment using the earlier failure 
reports, and the additional failure reports that we received from the 
public as comments to our August 12, 2013, NPRM.
    Based on their review of this data and the new risk assessment of 
failures of affected cylinder assemblies, the Challenge Team determined 
that an AD was still required. But, they suggested changes to make 
compliance less aggressive and substantially reduce cost. Their 
recommended changes included revising the compliance schedule in favor 
of a phased removal schedule, clarifying that overhauled cylinder 
assemblies are included in the proposed phased removal schedule, 
eliminating the reporting requirement for removed cylinder assemblies, 
and removing the requirement for initial and repetitive inspection.

January 8, 2015--First Supplemental Notice of Proposed Rulemaking 
(SNPRM)

    We adopted the Challenge Team's recommendations, and we then 
published them as an SNPRM in the Federal Register on January 8, 2015 
(80 FR 1008) (referred to herein after as the ``January 8, 2015, 
SNPRM''). The January 8, 2015, SNPRM proposed to modify the schedule 
for removal of the affected cylinder assemblies, added that overhauled 
affected cylinder assemblies be removed within 80 hours, eliminated a 
reporting requirement, and removed a requirement for initial and 
repetitive inspections.
    We also responded in our January 8, 2015, SNPRM, to the several 
hundred comments that we received to the August 12, 2013, NPRM. Many of 
these comments were repetitious, so we grouped the comments and 
provided our responses to the different groups,

[[Page 52977]]

depending on the nature of the comment. For example, some comments 
claimed that airplanes can operate safely with a separated cylinder 
head; others suggested that pilot error was causing cylinder head 
separations; and others recommended adopting less stringent compliance 
requirements. Each of these groups received our response to the group's 
comment.

June 9, 2015--Meeting With National Transportation Safety Board (NTSB)

    The NTSB, in its comments to our August 12, 2013, NPRM; January 8, 
2015, SNPRM; and in its Safety Recommendation A-12-07, did not fully 
support our approach to resolving the unsafe condition that is the 
subject of this final rule. Therefore, we met with the NTSB on June 9, 
2015 to understand the technical basis for their recommendation and 
their technical objections to our proposed AD. At this meeting, we 
presented the NTSB the technical information upon which we based our AD 
as amended. Information that was reviewed included failure reports, the 
risk assessment by the FAA's CSTA for Aircraft Safety Analysis, FAA 
safety recommendations, and the data supporting our conclusion that 
field inspections had an insufficient probability of cylinder failure 
detection.
    The NTSB noted in this meeting that Safety Recommendation A-12-7, 
and the NTSB's comments to the August 12, 2013, NPRM and the January 8, 
2015, SNPRM, were based on the information available to them at that 
time. The NTSB also indicated it would reassess its recommendation and 
comments to our proposed rule based on the presentations and the 
supporting data that we had presented.

June 23, 2015--Additional Technical Documents Posted

    We received additional comments to our August 12, 2013, NPRM and 
our January 8, 2015, SNPRM, requesting that we provide additional 
information that supports this AD. Commenters also requested that we 
identify the data that we relied on in drafting this AD and to explain 
why that data supported our conclusion that an unsafe condition exists. 
Based on these comments, we concluded that further additional public 
participation in our proposed AD was appropriate. Specifically, we 
concluded that we would post to the docket the additional technical 
information responsive to the comments. So, on June 23, 2015, we posted 
the additional technical information to Docket No. FAA-2012-0002 (see 
ADDRESSES section of this final rule for information on locating the 
docket). These documents provide further technical rationale for this 
AD. This additional technical information included:
    (1) The risk analysis process conducted by the FAA's CSTA for 
Aircraft Safety Analysis--referenced in Docket No. FAA-2012-0002 as the 
``Proposed Airworthiness Directive for ECi Cylinders Risk Analysis 
Process,'' referred to herein as the ``risk analysis'';
    (2) A risk analysis using the Small Airplane Risk Analysis (SARA) 
methods used by the FAA's Small Airplane Directorate (SAD)--referenced 
in Docket No. FAA-2012-0002 as ``SARA Worksheet Systems/Propulsion'';
    (3) A June 2011, presentation by AEC to the FAA concerning its ECi 
cylinder assemblies;
    (4) A list of ECi cylinder assembly failure reports consisting of 
only those reports where both cylinder serial number and time in 
service are included in the reports;
    (5) A list of additional failures of ECi cylinder assemblies 
reported by a maintenance organization; and
    (6) AEC Technical Report 1102-13, dated April 30, 2011.

August 28, 2015--2nd SNPRM

    We published a second SNPRM in the Federal Register on August 28, 
2015 (80 FR 52212, referred to herein after as the ``August 28, 2015, 
SNPRM''). The August 28, 2015, SNPRM retained the compliance 
requirements proposed by the January 8, 2015, SNPRM. We published the 
August 28, 2015, SNPRM to provide the public a final opportunity to 
comment on the proposed AD and the additional technical documentation 
we had added to the docket on June 23, 2015.
    Also, since many commenters had cited NTSB support for their 
positions, we wanted to clarify our rationale for disagreeing with the 
compliance actions proposed by the NTSB in its Safety Recommendation A-
12-7, and the NTSB's comments to the August 12, 2013, NPRM and the 
January 8, 2015, SNPRM.
    The NTSB did submit a final comment to our August 28, 2015, SNPRM, 
that was posted to the docket on November 23, 2015. In the NTSB's final 
comment, the NTSB indicated that it now considers that our proposed 
compliance actions satisfy the intent of Safety Recommendation A-12-7. 
The information we covered with the NTSB, including copies of FAA 
presentations to the NTSB, were subsequently posted to Docket No. FAA-
2012-0002 (see ADDRESSES section of this final rule for information on 
locating the docket) on April 6, 2016.

Comments

Introduction

    We have, through the August 12, 2013, NPRM; the September 26, 2013, 
posting of additional information; our extension of the August 12, 
2013, NPRM comment period; the January 8, 2015, SNPRM; and August 28, 
2015, SNPRM, given the public the opportunity to participate in 
developing this AD. The public, as noted already, has participated 
deeply in this rule making; providing hundreds of comments.
    This final rule includes our responses to any previously 
unaddressed comments to the August 12, 2013, NPRM and to the January 8, 
2015, SNPRM, that we may have left without response, and to the August 
28, 2015, SNPRM.
    To organize comments and facilitate their review, we again grouped 
like comments and responses. These groupings in this final rule's 
comments section are:
    (1) Comments to withdraw or revise the SNPRMs for technical 
reasons--these comments, and the resulting groupings, were similar to 
those we used in responding to the August 12, 2013, NPRM. They include, 
for example, requests to withdraw the SNPRM because the commenters 
claim that ECi cylinder assemblies are not unsafe; airplanes can 
operate safely with a separated cylinder head; or the root cause of 
cylinder failure is unknown.
    (2) Comments to the FAA's risk assessment processes and policies--
these comments generally asserted that the SNPRMs should be withdrawn 
because the FAA had not appropriately followed its risk assessment 
processes and policies in determining that the failure of ECi cylinder 
assemblies represents an unsafe condition.
    (3) Comments to the FAA's rulemaking processes--these comments 
generally requested that the SNPRMs be withdrawn, alleging that the FAA 
had failed to follow its rulemaking processes and was adopting a rule 
that is ``arbitrary and capricious.''
    (4) Comments to the cost of compliance--these comments indicated 
that the cost of compliance to this AD was higher than the FAA has 
estimated and will have a substantial effect on small entities.
    (5) Administrative comments--these were generally comments that did 
not pertain to the substance of this AD, such as requests for names and 
phone numbers of FAA personnel involved in this rulemaking.
    (6) Support for the SNPRMs--these were comments in support of 
issuing the SNPRMs.

[[Page 52978]]

A. Comments To Withdraw or Revise the SNPRMs for Technical Reasons

Request To Withdraw the SNPRMs Because ECi Cylinder Assemblies Are Not 
Unsafe
    Comment. Several organizations and individuals, commenting to the 
August 12, 2013, NPRM, commented also to the January 8, 2015, and 
August 28, 2015, SNPRMs, that the affected ECi cylinder assemblies have 
an equivalent, or lower, failure rate than that of cylinder assemblies 
manufactured by the original equipment manufacturer (OEM). The 
commenters also indicated that there have been no failures of ECi 
cylinder assemblies in the last 3 years. These commenters request the 
FAA withdraw this AD because they believe that the ECi cylinder 
assemblies are not unsafe.
    Response. We disagree. The rate of separation for the affected ECi 
cylinder assemblies is at least 32 times greater than that of OEM 
cylinder assemblies over the same period. Although there are 
approximately four times as many OEM cylinder assemblies in service 
than ECi cylinder assemblies, the ECi cylinder assemblies suffered more 
cylinder head separations than OEM cylinder assemblies since 2004. This 
data is available for review in Docket No. FAA-2012-0002 (see ADDRESSES 
section of this final rule for information on locating the docket). In 
addition, we have continued to receive field reports of failures of the 
affected cylinders in the past three years. We did not withdraw the 
August 28, 2015, SNPRM.
    Comment. Commenters also questioned the validity of the data that 
the FAA used to justify the proposed AD.
    Response. We interpret the comment as suggesting that the data used 
to justify the rule is not valid. We disagree. We used warranty reports 
from ECi and RAM Aircraft, which is a major overhauler of CMI engines, 
STC holder for an increased horsepower version of the affected model 
engine, and the largest user of the affected ECi cylinders. We also 
used service difficulty reports (SDRs), and other field service reports 
regarding ECI cylinder separations. We did not withdraw the August 28, 
2015, SNPRM.
    Comment. The IPL Group LLC (IPL Group) commented that the FAA has 
mischaracterized ``quality enhancements'' in production as ``design 
changes.'' IPL Group noted that ECi had applied experience gained 
during manufacturing, as well as through service feedback, to make 
quality improvements in production and the changes made to the design 
data were not due to design deficiencies.
    Response. We disagree. We correctly stated that ECi has made 
increases in the dome transition radius through cylinder serial number 
33697, and has made incremental increases in the head-to-barrel 
interference fit at least through cylinder serial number 61177 (see 
Airmotive Engineering Technical Report 1102-13) to address the two 
identified inherent design deficiencies associated with the effected 
cylinder assemblies. These changes are design changes. We did not 
withdraw the August 28, 2015, SNPRM.
    Comment. RAM Aircraft commented that when it submitted its December 
9, 2013, comment, it calculated the likelihood of a cylinder 
separation. RAM Aircraft indicated it provided a significant amount of 
data that proves that the likelihood of a cylinder separation is 
``extremely remote.'' RAM commented that at that time their data showed 
one cylinder separation for every: 21,808 multi-engine aircraft flight 
hours, or 172 average years of active service; and 42,057 single engine 
aircraft flight hours, or 455 average years of active service. Further, 
that the fleet of aircraft using the cylinders subject to the January 
8, 2015, SNPRM have continued to fly for an additional 14 months since 
December 9, 2013. RAM Aircraft indicated that there is no doubt that 
both the 21,808 multi-engine aircraft flight hour number, and the 
42,057 single engine aircraft flight hour number, would both be now 
much larger, thereby, further reducing the likelihood of a cylinder 
separation.
    Response. We disagree. RAM Aircraft's data does not substantiate 
its claimed failure rate. Without knowing the total number of hours 
flown on all affected cylinders, it is not possible to accurately 
calculate an hours-based failure rate. This data is not available for 
general aviation aircraft. We, therefore, find RAM Aircraft's estimate 
to be unreliable. We did not withdraw the August 28, 2015, SNPRM.
    Comment. RAM Aircraft also indicated that a statement by the FAA in 
the January 8, 2015, SNPRM regarding numbers of failures of affected 
cylinder assemblies was grossly misleading. RAM Aircraft assumes that 
the FAA is referring to reports entered via the SDR system. RAM 
Aircraft indicated that it has provided evidence in an earlier comment 
that not every piece of information in the SDR system can be taken at 
face value. With respect to this SNPRM, RAM suggested that it is very 
important to distinguish between the ``SNPRM failure modes'' 
(quotations not in original comment) and other types of ``nuisance'' 
cracks that are common occurrences in all manufacturer's air-cooled 
aircraft cylinders. The SNPRM failure modes do not include cracks 
between spark plug holes, valve seats, injector ports, etc. There is no 
doubt that the ``hundreds of failures'' referenced by the FAA were 
never researched to determine which were of the SNPRM failure mode and 
which were of the ``nuisance'' variety.
    Response. We disagree. Our response in the January 8, 2015, SNRPM 
is not misleading. On the contrary, under-reporting of cylinder 
assembly cracks in the SDR system further reinforces the need for this 
AD. Further, the FAA did not include the SDR failure reports referred 
to by the commenter as of the ``nuisance'' variety in the list of 
separations that were used to substantiate the need for this AD. We did 
not base this AD on nuisance cracks in the affected cylinder 
assemblies. We did not withdraw the August 28, 2015, SNPRM.
    Comment. One commenter stated that the separated cylinders that 
were determined to be the precipitating root cause events for the two 
fatal accidents cited by the FAA in the January 8, 2015, SNPRM were 
overhauled cylinders, so they therefore should not be considered in the 
determination as to whether or not the proposed corrective action 
should be implemented.
    Response. We disagree. The ECi cylinder heads, P/N AEC 65385, of 
the separated cylinder assemblies that precipitated the two referenced 
fatal accidents were of the same type design and within the same 
affected cylinder assembly serial number range as are used in new ECi 
cylinder assemblies. The cast and then machined aluminum cylinder head 
shrink band region has the predominant features that define the final 
interference fit of the overall cylinder assembly, not the steel 
barrel. This is further supported by the fact that the design changes 
that ECi made to the interference fit were accomplished by modification 
of the cylinder head. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Holdings commented that the FAA should withdraw 
the August 28, 2015 SNPRM because the FAA failed to establish that the 
affected product, i.e., the ECi cylinder assemblies, do not meet the 
established minimum safety standards established by 14 CFR part 33.
    Response. We disagree. The operational history of the affected ECi 
cylinder assemblies established that the affected ECi cylinder 
assemblies present an unacceptable compromise to safety, an unsafe 
condition, when installed in operating aircraft engines. We did not 
withdraw the August 28, 2015, SNPRM.

[[Page 52979]]

    Comment. Danbury Holdings also stated that the ``same unsafe 
condition'' that is addressed by this AD is present in the cylinders of 
all manufacturers and that the FAA failed to consider similar failures 
of the OEM cylinders.
    Response. We disagree. The affected ECi PMA cylinders have 
separated at a significantly higher rate than the OEM cylinders over 
the same service period since the ECi PMA cylinders entered service. 
ECi itself identified two root causes for the separations. See AEC 
Technical Report 1102-13 in Docket No. FAA-2012-0002 (see ADDRESSES 
section of this final rule for information on locating the docket) 
which recommends withdrawal from service of the affected ECi cylinders. 
We compared the number of separations of these affected ECi PMA 
cylinders to the number of OEM separations over the same service 
period, since the ECi PMA cylinders entered service in meaningful 
numbers. Over the same period of time the affected ECi PMA cylinders 
and OEM cylinders were in service, the ECi cylinders experienced eight 
times the number of OEM separations, even though only one-quarter as 
many ECI cylinders were in service as the OEM's. Further, the SDR 
database does not reveal similar separation rates or similar failure 
modes for OEM cylinders. Therefore, we have no reason to regard the OEM 
cylinder assemblies as subject to the same or similar unsafe condition. 
We did not withdraw the August 28, 2015, SNPRM.
Request To Withdraw the SNPRMs Because Airplanes Can Operate Safely 
With a Separated Cylinder Head
    Comment. Several commenters indicated that we should not issue this 
AD because airplanes can continue to operate safely even after a 
cylinder head separation.
    Response. We disagree. An in-flight cylinder head separation is an 
unsafe condition that presents multiple secondary effects. For example, 
in-flight fire and loss of aircraft control. Accident data confirms 
that separated cylinders have also been a precipitating event in fatal 
accidents. Therefore, the safety consequences represented by a cylinder 
head separation in flight are significant, and represent an unsafe 
condition appropriate for an AD. We did not withdraw the August 28, 
2015, SNPRM.
    Comment. Several commenters added that airplane engines are 
designed and certified to safely operate with one failed cylinder.
    Response. We disagree. Applicants are not required to show that 
their engines are designed to operate with one cylinder failed or with 
a separated cylinder, nor that doing so constitutes safe operation of 
an engine. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Aerospace commented that the docket contains 
evidence from RAM Aircraft that valid and verifiable testing 
establishes that a head-to-barrel separation results in less than 20 
percent power loss to the engine.
    Response. We disagree. The RAM Aircraft testing that is included in 
Docket FAA-2012-0002 only quantified the horsepower output per 
cylinder. The RAM Aircraft testing was of an uninstalled engine in a 
test cell and RAM Aircraft did not attempt to assess the impact of 
reduced engine horsepower output on airplane level performance. We 
estimate that a 20% reduction in engine horsepower on a single-engine 
airplane results in a nearly 40% reduction in aircraft rate of climb, 
which is a hazardous condition. It is also a potentially hazardous 
condition for twin-engine airplanes due to the resultant asymmetric 
thrust condition. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Aerospace indicated that FAA guidance material 
does not define this condition as ``hazardous'' in the certification 
process.
    Response. We interpret the comment to be that the FAA has no 
definition of hazardous event that includes loss of one cylinder in a 
six-cylinder engine, within the engine certification regulations (14 
CFR part 33). We agree. The certification process does not define 
``hazardous events.'' The FAA establishes through the engine 
certification process the minimum standards that an engine needs to 
meet to be considered airworthy. For example, Sec.  33.19 establishes 
durability standards that are designed to minimize the development of 
an unsafe condition between overhaul periods. These minimum safety 
standards must also be met by PMA parts, either through establishing 
identicality or through test and computation. FAA Policy PS-ANE100-
1997-00001, provides guidance for the certification of PMA applications 
for reciprocating engine critical, highly stressed or complex parts, 
including, but not limited to crankshafts and cylinder heads. We did 
not withdraw the August 28, 2015, SNPRM.
    Comment. RAM Aircraft commented that it has run tests that 
substantiate and document the power loss as a ``minor power loss'' in 
the event of a cylinder separation.
    Response. We interpret the comment to be that any power loss from 
cylinder head separation is only minor. We disagree. The loss of one 
cylinder's power would equate to approximately a 17 to 20% reduction in 
engine horsepower output. Further, loss of a cylinder at critical 
phases of flight, for example, during climb-out where like here, the 
failure is at increased probability of occurring, produces a power loss 
sufficient to result in a 40% reduction in airplane rate of climb. This 
would constitute a hazardous condition during a critical phase of 
flight like departure/climb. We did not withdraw the August 28, 2015, 
SNPRM.
    Comment. RAM Aircraft suggested that this minor power loss would be 
classified as a ``minor hazard,'' based on guidance from the FAA's 
``Policy Statement on Risk Assessment for Reciprocating Engine 
Airworthiness Directives'' (PS-ANE100-1999-00006). According to the FAA 
policy statement, minor hazards are candidates for AD action only when 
the probability of the event is very high.
    Response. We disagree. FAA policy classifies service problems that 
do not result in a significant power loss, such as a partial power 
loss, rough running, pre-ignition, backfire, single magneto failures, 
as ``minor.'' We found that cylinder separations results in a 17 to 20% 
reduction in engine horsepower output results in an approximately 40% 
reduction in airplane excess power, which translates into a 40% 
reduction in airplane rate of climb. This constitutes a hazardous 
condition that is not a ``minor hazard.'' We did not change this AD 
based on this comment.
    Comment. RAM Aircraft commented that Appendix VI of the SAD 
Airworthiness Directives Manual Supplement includes examples of 
conditions that potentially have a ``minor'' affect. The loss of one 
engine (multi-engine aircraft) is listed as a condition with a 
``minor'' effect. Given the ``minor'' effect of the loss of one engine 
and the likelihood of the cylinder separation being extremely remote, 
then this AD should not be issued against multi-engine aircraft.
    Response. We disagree. By comparing the risk analysis computed by 
the CSTA for Aircraft Safety Analysis with either the Small Airplane 
Risk Analysis guidelines used by the SAD or the Engine and Propeller 
Directorate (E&PD) Continued Airworthiness Assessment Process (CAAP) 
Handbook guidelines, demonstrates that an AD is needed for both single 
and twin-engine aircraft. We did not withdraw the August 28, 2015, 
SNPRM.
    Comment. RAM Aircraft commented that they are not aware of any 
substantiated fact of a ``fire,'' or any other significant consequence 
of a

[[Page 52980]]

cylinder head separation. Further, RAM Aircraft noted that in its May 
12, 2014, comment, it had documented the research it had done to refute 
the ``rumor'' of a fire resulting from a cylinder head separation of an 
ECi cylinder.
    Response. We disagree. RAM Aircraft itself submitted data to the 
FAA indicating that a fire could occur from cylinder head separation. 
FAA requested to see that information. FAA's subsequent visit to RAM 
Aircraft confirmed that a failed cylinder caused an in-flight fire on a 
Cessna 414 airplane. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Aerospace cited FAA documents that indicate that 
the design of an aircraft engine, for reciprocating engines, should 
incorporate mitigating features. For example, Danbury quoted SAD 
Standards Staff (ACE-110) Memorandum, dated May 6, 1986, and an E&PD 
Standards Staff (ANE-110) memorandum, dated May 24, 1997.
    Response. We agree. However, the regulatory requirement for a 
designer to mitigate a possible reciprocating engine failure prior to 
certification is different than correcting an unsafe condition found to 
exist after certification. This AD addresses an unsafe condition--
cylinder head separation, found after certification. A regulatory 
requirement to mitigate in the aircraft design an engine failure is not 
the subject of this AD. We did not withdraw the August 28, 2015, SNPRM.
    Comment. IPL Group commented that we were misusing the term 
``catastrophic'' when describing the effects of potential cylinder 
failures.
    Response. We disagree. As to the use of ``catastrophic,'' we did 
not use the term in the August 12, 2013, NPRM, the two SNPRMs, or in 
this final rule AD. We did not change the August 28, 2015, SNPRM based 
on this comment.
    Comment. IPL Group argued that a cylinder head separation does not 
cause an unsafe event and that there is ``zero evidence'' in Docket No. 
FAA-2012-0002 to support the showing that a failed cylinder causes an 
unsafe condition.
    Response. We disagree. Cylinder separations can cause partial or 
complete engine failure which can cause a subsequent loss of power and 
control of the airplane. Loss of control of the airplane may result in 
the loss of the airplane and injuries or death. Additionally, we note 
the NTSB has stated that cylinder head separations could result in a 
loss of control of the airplane (see NTSB's comment to ``Docket No FAA-
2008-0052; Directorate Identifier 2008-NE-01-AD, dated September 25, 
2009''). We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Holdings commented that the FAA had not provided 
any information to substantiate the FAA's position that cylinder 
separations have a ``significant'' effect on airplane safety or that 
cylinder separations would result in a fire.
    Response. We disagree. The impact of a cylinder separation in-
flight is an unacceptable compromise to safety. To clarify this point, 
we changed the AD to use ``unacceptable.'' We disagree that cylinder 
head separations might not result in fire. Cylinder separations can 
result in engine failure and/or fire. As an example, on November 29, 
1987, a Piper PA-46 airplane experienced a cylinder head separation 
followed by an in-flight fire. We did not withdraw the August 28, 2015, 
SNPRM.
    Comment. Danbury Holdings also stated that the FAA did not issue a 
similar AD against the OEM cylinder assemblies because the OEM 
manufactured more such cylinder assemblies.
    Response. We disagree. The FAA did not mandate actions similar to 
those specified in this AD against the OEM cylinders because the OEM 
cylinders do not have the inherent design deficiencies that the ECi PMA 
cylinders have. Also, the service history of the OEM cylinders 
indicates that the OEM separation rate is approximately 32 times lower 
than the ECi cylinders. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Holdings further commented that ADs are never 
justified for any cylinder manufacturer.
    Response. We interpret the comment as suggesting that we should not 
issue an AD when engine design deficiencies related to cylinders are 
found. We disagree. Cylinders are engine parts whose structural failure 
can result in a degradation to or total loss of, engine power output, 
and loss of control of an airplane. Cylinder separations aloft can also 
cause an in-flight fire. We will exercise our regulatory arm to issue 
ADs when we determine doing so is necessary to resolve an unsafe 
condition in a product. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Aerospace commented that 14 CFR part 33.43 
requires assessment of crankshaft vibration for one cylinder not firing 
because the condition is not an engine failure event condition.
    Response. We disagree. As we noted in our January 8, 2015, SNPRM, 
14 CFR part 33 does not require continued safe operation following a 
cylinder separation or following any other engine structural failure. 
Section 33.43(d), addressing the engine vibration survey of Sec.  
33.43(a), requires assessment of crankshaft vibration for an engine 
that has one cylinder that ``is not firing.'' We require vibration 
testing with a critical cylinder inoperative because it is a failure 
condition where stresses may exceed the endurance limit of the 
crankshaft material. We need to know the speed ranges where the 
excessive stresses occur so operational information may be provided to 
flight crews so they can avoid these speed ranges when a cylinder is 
inoperative. We did not withdraw the August 28, 2015, SNPRM.
Request To Withdraw the SNPRMs Because Root Cause of Cylinder Failure 
Is Unknown
    Comment. Several commenters indicated that the FAA has failed to 
identify the root cause(s) of cylinder head separations.
    Response. We disagree. We have identified the root cause of 
cylinder failure as design deficiencies inherent in the affected ECi 
cylinder assemblies. These ECi cylinder assemblies have two inherent 
design deficiencies: Insufficient dome radius and insufficient head-to-
barrel interference fit. These design deficiencies are identified in 
AEC Technical Report 1102-13, dated April 30, 2011, that we posted to 
Docket No. FAA-2012-0002 (see ADDRESSES section of this final rule for 
information on locating the docket). We did not withdraw the SNPRMs.
    Comment. Danbury Aerospace commented that root cause analysis is 
absolutely essential to determining compliance with regulations and if 
an unsafe condition has been created. Therefore the agency has not 
properly identified the unsafe condition.
    Response. We disagree. We identified the unsafe condition in the 
engine: Cylinder head separation. The purpose of this AD is to correct 
that unsafe condition. We also identified that cylinder head 
separations are due to at least two inherent design deficiencies. All 
cylinders prior to S/N 33697 have insufficient dome transition radius, 
and all cylinders prior to S/N 61177 insufficient head-to-barrel 
interference fit. ECi characterized both of these as ``inherent design 
deficiencies'' in its AEC Technical Report 1102-13. We did not withdraw 
the August 28, 2015, SNPRM.

[[Page 52981]]

Request To Withdraw the SNPRMs Because Pilot Error Is Causing Cylinder 
Head Separations
    Comment. Danbury Aerospace and Danbury Holdings commented that 
cylinder head separations involving the ECi cylinder assemblies 
affected by this AD were caused by excessive CHTs, presumably caused 
pilot error, rather than by design deficiencies of the cylinder 
assemblies.
    One operator observed that operators who use the ECi cylinder 
assemblies and operate them within limits and with good instrumentation 
are not having issues. This operator noted that everyone, with the 
exception of the FAA, believes that overheating beyond CHT limits by 
operators has a direct effect on cylinder head separation.
    Response. We disagree. Although pilot error may cause excessive 
CHT, we have no data to suggest it is the cause of the unsafe condition 
that is the subject of this AD. If pilot error results in excessive 
CHT, which leads to cylinder head separation, then we would expect to 
see similar damage in engines with other than ECi cylinder assemblies 
installed where the pilots exceeded the same limitation(s). However, we 
do not have any such data. Also, we have no evidence that either 
intentional or inadvertent exceedance of CHT limits has caused cylinder 
separation. Further ECi identified several design deficiencies in AEC 
Technical Report 1102-13, dated April 30, 2011.We did not withdraw the 
SNPRMs.
Request To Withdraw the SNPRMs Because of the Risk of Maintenance 
Errors
    Comment. Several commenters commented that the FAA should withdraw 
the SNPRMs because the removal and replacement of affected cylinder 
assemblies before time between overhaul (TBO) would result in 
maintenance errors that would adversely affect safety. For example, IPL 
Group indicated that replacement of the cylinder assemblies would 
likely result in events of main bearings losing clamp-up and turning, 
resulting in cylinder through-bolt and flange stud failures, which 
would likely result in total engine failure.
    Response. We disagree. Our regulatory framework presumes that 
maintenance will be performed correctly by experienced personnel 
authorized by the FAA to return aircraft to service in an airworthy 
condition. Further, we have not observed any negative effects on safety 
due to removal of these cylinder assemblies during maintenance. Also, 
cylinder removal and replacement is a maintenance action addressed in 
engine maintenance manuals. We did not withdraw the SNPRMs.
Request To Justify 80-Hour Removal Requirement for Overhauled Cylinder 
Assemblies
    Comment. Danbury Aerospace and Danbury Holdings requested that the 
FAA provide evidence (including engineering analysis) supporting its 
conclusion that overhauled cylinder assemblies should be removed within 
80 hours after the effective date.
    Response. We interpret the comment to be that the commenters 
disagree that the phased removal plan required by this AD is 
appropriate. We disagree. This AD mandates a phased removal of affected 
cylinders with the intent to retire all affected cylinders by initial 
TBO. The FAA recognizes that some cylinders in service may already have 
exceeded their initial TBO. Metal fatigue damage is cumulative, and the 
longer a cylinder head remains in service, the more likely it will fail 
due to one of the inherent design deficiencies. Overhauled cylinders 
have likely experienced more load and temperature cycles than lower 
time cylinders and the total time in service since new of overhauled 
cylinders often cannot be determined. Our determination of 80 hours is 
supported by our Challenge Team's findings and our risk analysis that 
we uploaded to FAA Docket No. FAA-2012-0002 (see Addresses section of 
this final rule for information on locating the docket). We did not 
change this AD based on this comment.
    Comment. Danbury Aerospace and Danbury Holdings also stated that 
the FAA had not substantiated that the overhaul of a cylinder does not 
reduce the existing fatigue damage that a cylinder may have incurred 
while in service.
    Response. We disagree. Fatigue strength of metal alloys operated at 
high temperatures continuously decreases with cycles until failure. 
This is particularly true for aluminum alloys, including the aluminum 
alloy used to cast cylinder heads. Metallic structural elements that 
are operated at high temperatures are more susceptible to time 
dependent fatigue. The overhaul of a cylinder assembly does not reverse 
the fatigue damage that had been previously accumulated in the aluminum 
cylinder head casting. We did not change the AD based on this comment.
Request To Revise Applicability
    Comment. Danbury Holdings commented that the FAA has no evidence 
that all cylinders through S/N 61176 are at risk for separation in the 
first thread due to insufficient head-to-barrel interference fit.
    Response. We disagree. The SDR database and other field reports 
document instances of first-thread failures of cylinders manufactured 
to design data applicable to all cylinders prior to S/N 61177. For this 
reason, all cylinders through S/N 61176 are subject to the corrective 
actions of this AD. We did not change this AD based on this comment.
    Comment. One commenter stated that he has an O-470 engine converted 
by P. Ponk Aviation to the equivalent of an O-520 engine. He indicated 
that those engines should not be affected by this AD.
    Response. We disagree. The affected S/N cylinders are installed on 
-470 engines, as well as the -520 and -550 engine models. Any engine 
that uses one of these affected cylinders is at risk. We have received 
at least one report of a separation of these affected S/N cylinders on 
-470 engines. Although the unmodified -470 engines have lower engine 
horsepower output, their brake mean effective pressure (BMEP) is 
actually higher than that of the -520 and -550 engines. BMEP is 
proportional to the ratio of horsepower per cubic inch of displacement. 
Therefore, the actual operating stresses in the same cylinder wall are 
even higher when these same cylinders are installed in an unmodified -
470 engines than it would be for either the -520 or the -550 engines. 
The P. Ponk Aviation STC increases the displacement of the unmodified -
470 engine to -520 cubic inches by installing the -520 cylinders on the 
-470 engine. Given that no valid sensitivity analysis exists showing 
the relationship of BMEP to fatigue life of these cylinders, and since 
the crack propagation rate is also unknown, we have included all the -
470 engines, including those modified by the P. Ponk Aviation STC, in 
the effectivity of this AD. We did not change this AD based on this 
comment.
Request To Adopt Less Stringent Compliance Requirements
    Comment. AOPA, RAM Aircraft, as well as operators and private 
citizens, requested that we adopt less stringent requirements than 
those in the proposed AD. The commenters indicated that the affected 
cylinder assemblies should be inspected at regular intervals, but 
removed at TBO. For example, one

[[Page 52982]]

commenter suggested recurring inspections every 60 hours. Several 
commenters cited the NTSB in support of its recommendation. RAM 
Aircraft commented that the FAA may be jumping to conclusions by 
eliminating these inspections. RAM Aircraft noted that the failure of a 
compression/soap test to detect a particular crack in a cylinder 
assembly on several occasions does not mean that the test will fail to 
detect cracked cylinders on most occasions. By their very nature and 
design compromises, i.e., steel barrels to contain the forces of 
combustion combined with lighter cylinder head alloys to reduce weight 
so that aircraft engines have commercial viability and value, and the 
harsh conditions, altitudes, and temperatures in which they operate, 
reciprocating aircraft engine cylinders will inevitably crack. RAM 
Aircraft indicated that there is no question but that some cylinders 
are going to crack, and that therefore, they must be properly operated, 
maintained, and inspected.
    Response. We disagree. Repetitive inspections until TBO, as 
suggested by the commenters, do not adequately address the unsafe 
condition in this particular case. Repetitive inspections would not 
detect cracks until they have already progressed completely across the 
cylinder head wall thickness.
    Several operators and mechanics have reported that they 
successfully passed the compression/soap test with a partially 
separated cylinder. Others have reported that they successfully passed 
the compression/soap test and then experienced an in-flight separation 
before the next scheduled 50-hour inspection.
    Therefore, we conclude that these tests are not sufficiently 
reliable. Also, engine overhaul is not a requirement for all operators. 
Therefore, tying the proposed recurrent inspection to engine overhaul 
would not resolve the unsafe condition. Based on its comment to the 
August 28, 2015, SNPRM, we know that the NTSB now considers this rule 
consistent with the rationale they have provided in the past in support 
of NTSB Safety Recommendation A-12-7 regarding these affected cylinder 
assemblies (Reference NTSB Comment FAA-2012-0002-0653, dated September 
24, 2015 in Docket FAA-2012-0002). We did not change this AD based on 
this comment.
    Comment. One commenter indicated it was incorrect to apply the same 
requirement to remove the cylinders at specified intervals to different 
CMI engine models. He noted, for example, that the TSIO-520-J engine 
that is allowed to produce 36 inches of manifold pressure and 310 
horsepower will produce less stress on a cylinder head than a TSIO-520-
NB engine that is allowed 41 inches of manifold pressure and 325 
horsepower, as installed on a Cessna 414 airplane.
    Response. We disagree. Service history indicates that the affected 
cylinder assemblies have cracked on -470, -520, and -550 engine models. 
The AD, therefore, applies to all affected CMI -470, -520 and -550 
engine models. We have no engineering analysis or test data to justify 
varying compliance times by engine model or applying the corrective 
actions of this AD to only the higher power engines. We did not change 
this AD based on this comment.
    Comment. Danbury Aerospace observed that the average number of 
cylinder assemblies, P/N AEC 631397, in the serial number range in the 
January 8, 2015, SNPRM that are still in operation have less than 500 
hours left to TBO. Danbury Aerospace indicated that the early removal 
of these cylinders is not justified by a statistical analysis developed 
in accordance with the E&PD CAAP Handbook.
    Response. We disagree. We do not know the exact number of total 
hours TIS for each affected cylinder assembly. We have no data to 
support the claim that the existing fleet of cylinder assemblies 
already has accumulated 1,200 or more hours TIS. Service history also 
shows that most of the separations occurred well before initial TBO. 
Therefore, removal of the affected cylinder assemblies before TBO is 
appropriate. We did not change this AD based on this comment.
    Comment. Danbury Holdings commented that the FAA had not provided 
evidence that there have been separations within the originally 
proposed 50-hour recurrent compression test/soap inspection interval.
    Response. We disagree. We received several field reports of 
cylinder separations occurring within 50 hours of passing either the 
originally proposed 50-hour recurrent compression test/soap inspection 
in the August 12, 2013, NPRM. SDR report No. SQP2011F00000 was 
submitted by a part 135 operator who operated a Cessna T210N with an 
affected ECi cylinder assembly installed. The operator reported that on 
September 9, 2011, that affected ECI cylinder head separated at the 5th 
cooling fin on-head. At the time of the failure, the engine and failed 
cylinder had 817.6 hours time since overhaul/time since new, and its 
last compression check inspection was at 19.2 hrs. prior. Other field 
reports also document separated cylinders (for example, see SDR Report 
2010FA0000179) that recently passed the compression test/soap 
inspections. We did not change this AD based on this comment.
    Comment. One commenter commented that, based on his experience, ECi 
has an aluminum head cracking issue and that these cylinders seem to 
crack more than CMI cylinders. The commenter further indicated that he 
believed the number of cylinder failures is underreported in the SDR 
database. The commenter further noted that in his 30 plus years of 
aircraft maintenance experience, he has never seen a cylinder failure 
rate this high. The commenter welcomed an AD that requires these 
cylinders to be inspected at around 100 hours and the reports of cracks 
sent to an FAA database.
    Response. We note the comment. We agree that the ECi failure rate 
is much higher than the OEM failure rate over the same field service 
period and that cylinder cracks are under-reported. For example, many 
of the RAM failures listed in the docket were not reported under the 
SDR system or as required by 14 CFR 21.3. We did not change this AD 
based on this comment.
    Comment. RAM Aircraft commented that, based on its previous 
comments, the FAA should withdraw the SNPRMs. RAM Aircraft recommended 
that the FAA consider education and requiring inspections of all 
reciprocating airplane engine cylinders on the terms and conditions the 
FAA determines to be appropriate.
    Response. We disagree. Our analysis indicates that an AD is 
required to resolve the unsafe condition presented by installed 
affected ECi cylinder assemblies. We did not withdraw the SNPRMs based 
on this comment.
    Comment. One commenter suggested that users of a JPI or other 
engine monitoring system should be subject to a different compliance 
interval.
    Response. We disagree. As noted previously, the root cause of these 
cylinder failures are design deficiencies. The affected cylinders may 
fail without overtemping. Therefore, use of an engine monitoring system 
like JPI would be insufficient to detect the unsafe condition. We did 
not change this AD based on this comment.
Request To Use Mandatory Service Bulletin Instead of This AD
    Comment. One commenter requested that the FAA use a mandatory 
service bulletin instead of this AD to implement corrective action.
    Response. We disagree. Requiring a manufacturer to issue a 
mandatory service bulletin is outside the scope of

[[Page 52983]]

the FAA's authority. We did not change this AD based on this comment.

B. Comments to the FAA's Risk Assessment Processes and Polices

Request That the FAA Follow Its Own Risk Assessment Policies and 
Guidance
    Comment. Multiple commenters, including Danbury Aerospace, Danbury 
Holdings, and the Aeronautical Repair Station Association (ARSA) 
commented that the FAA did not follow its own risk assessment policies 
and guidance, such as FAA Order 8110.107A, Monitor Safety/Analyze Data 
(MSAD), dated October 1, 2012, and FAA Order 8040.4A, Safety Risk 
Management Policy, dated April 30, 2012, and the E&PD CAAP Handbook, 
dated September 23, 2010.
    Response. We interpret this comment as a comment that we failed to 
follow FAA Order 8110.107A, FAA Order 8040.4A, and the CAAP Handbook. 
We disagree. We performed the process as required by FAA Order 
8110.107A, Monitor Safety/Analyze Data (MSAD), dated October 1, 2012, 
to analyze data and determine corrective action for continued 
operational safety issues. We acquired the failure event data from the 
MSAD, SDR, NTSB databases, ECi, and outside sources. We conducted a 
hazard criteria analysis where we filtered the data to identify 
relevant events. We performed a qualitative preliminary risk assessment 
and determined that this safety problem required corrective action. We 
performed risk analyses in conjunction with the E&PD risk assessment 
criteria. We identified that the ECi model separations have two 
inherent design deficiencies: Insufficient dome radius and insufficient 
head-to-barrel interference fit. Finally, we coordinated with our 
Corrective Action Review Board, which determined and agreed to the 
proposed corrective action in our August 12, 2013, NPRM.
    Later, as part of the Challenge Team's meeting in September, 2014, 
the CSTA for Aircraft Safety performed a risk analysis that confirmed 
the need for this AD and shaped its compliance plan. We compared the 
results of the CSTA's risk analysis to the guidelines used by the SAD 
in its SARA and to the guidelines in the E&PD's CAAP Handbook and 
determined that an AD is required.
    FAA Order 8040.4A requires a risk assessment methodology as 
outlined in the Order. FAA Order 8040.4A notes that the safety risk is 
a composite of two factors: The potential ``severity'' or worst 
possible consequence(s) or outcome of an adverse event that is assumed 
to occur, and also the expected frequency of occurrence or likelihood 
of occurrence (failure rate) for that specific adverse event. Each of 
these factors is assessed independent of the other and then entered as 
separate inputs into a risk matrix that yields an overall level of risk 
for the event.
    We performed the risk assessment required by FAA Order 8040.4A and 
concluded that this AD was necessary. Therefore, our August 12, 2013, 
NPRM, as revised by the January 8, 2015 SNPRM, and as republished on 
August 28, 2015, are consistent with FAA Order 8040.4A, FAA Order 
8110.107A, and the CAAP Handbook. We did not change this AD based on 
this comment.
    Comment. Commenters, including Danbury Holdings, commented that the 
FAA should not have included the failure rate of the affected ECi 
cylinders in the FAA risk assessments that were used to substantiate 
the need for the corrective actions in this AD. Danbury Holdings 
indicated that the failure rate is irrelevant to the unsafe condition.
    Response. We disagree. We did not use the failure rate in the risk 
analysis, however, we used the number of reported failures. A risk 
analysis involves using past data; both successful operation as well as 
failures (including cracks), to develop a relationship between part 
parameters, including age and usage, and risk of failure. Therefore, 
our use of failures was appropriate in this risk analysis. We did not 
change this AD based on this comment.
    Comment. Danbury Aerospace commented that the FAA ignored its own 
standards for what constitutes an unsafe condition and therefore has 
failed to identify one.
    Response. We disagree. The FAA followed its standard risk analysis 
processes in determining that the unsafe condition represented by the 
affected ECi cylinder assemblies exists. 14 CFR part 39 prescribes that 
we issue an AD when an unsafe condition exists in a product and that 
condition is likely to exist or develop in other products of the same 
type design. We did not change this AD based on this comment.
    Comment. Danbury Holdings commented that the basis for the FAA's 
risk analysis is seriously flawed because the unsafe condition must be 
the basis for the failure, not one unsubstantiated fatality.
    Response. We disagree. The unsafe condition in the engine presented 
by the presence of affected ECi cylinders is the basis of this AD. We 
did not change this AD based on this comment.
    Comment. Danbury Holdings further commented that the FAA had failed 
to establish a connection between the cylinder separation issue 
addressed by this AD and the official reports of the two fatal 
accidents that the FAA references.
    Response. We disagree. Reports by the Bahamas Department of Civil 
Aviation and the NTSB establish that these accidents in the Bahamas and 
in Swanzey, New Hampshire involved separated ECi cylinders (see Report 
AAIPU# A10-01312 and NTSB Accident Report No. NYC02FA178, 
respectively). We have determined that the separation of the affected 
ECi cylinder assemblies represents an unsafe condition. We are not 
required to establish any further connection with these accidents. We 
did not change this AD based on this comment.
    Comment. Danbury Holdings added that the FAA should not have 
included the fatal accident in the Bahamas in the FAA's risk 
assessments because the NTSB full narrative for that accident 
(ERA11WA008) made no mention of a cylinder separation.
    Response. We interpret the comment as the fatal accident in the 
Bahamas is not relevant to this AD. We disagree. As noted in the 
previous comment response, we have determined that the separation of 
the affected ECi cylinder assemblies, as occurred in the accident in 
the Bahamas, represents an unsafe condition. We did not change this AD.
    Comment. Danbury Holdings also stated that the root cause of the 
other fatal accident, the Swanzey, New Hampshire, accident (see NTSB 
Accident Report No. NYC02FA178) that the FAA included in its risk 
assessments was unsafe and improper operation of the airplane by the 
pilot not cylinder separation.
    Response. We disagree. As noted in the preceding comment 
discussion, we have determined that the separation of the affected ECi 
cylinder assemblies, as occurred in the accident in Swanzey, New 
Hampshire, represents an unsafe condition and is therefore relevant to 
this AD. We did not change this AD based on this comment.
    Comment. Danbury Aerospace added that the accident in the Bahamas 
should not be included in the FAA's risk analysis because: (1) It did 
not concern a U.S.-registered aircraft and therefore cannot be used in 
this rulemaking; (2) loss of control and uncontrolled flight was cited 
as the cause; and (3) even if the accident could be included, it does 
not meet hazard level thresholds required for rulemaking.
    Response. The commenter presents three comments, which have three 
parts. We disagree with all three parts. As to part one, the Bahamas 
accident involved a U.S.-type certificated product, an engine with 
affected ECi cylinders

[[Page 52984]]

installed. Therefore, the product is the proper subject of this AD. As 
to part two, the accident involved an engine with an ECI cylinder 
separation, a failure of a part of the engine, during flight. A 
cylinder separation during flight represents an unsafe condition in the 
engine. Therefore, our action in issuing this AD is appropriate. As to 
the part three, the cylinder failure presented a hazard to the engine 
and an unsafe condition, and therefore, meets the threshold for an AD. 
The need for this AD was confirmed by comparing the result of the risk 
analysis to the guidelines in the SAD's SARA and the E&PD's CAAP 
Handbook. We did not change this AD based on this comment.
Request That the FAA Define Guidelines Used To Define an Unsafe 
Condition
    Comment. Danbury Holdings commented that the FAA had not defined 
the guidelines that it used to establish the existence of an unsafe 
condition.
    Response. We interpret the comment to be a request to identify what 
guidance defines an unsafe condition. The comment therefore, is not to 
the technical merits of this AD, but a request for general guidance. As 
such, a response is unnecessary per the Administrative Procedures Act 
(APA), and we recommend that the commenter seek his answer through a 
direct request to the FAA Aircraft Certification Service or Flight 
Standards Division. We did not change this AD based on this comment.
Request To Withdraw the August 28, 2015, SNPRM Because Supporting 
Documents Do Not Support Issuing This AD
    Comment. Danbury Holdings commented that the documents provided by 
the FAA in Docket No. FAA-2012-0002 do not support issuance of this AD. 
The supporting documents referred to by Danbury Holdings are: (1) The 
risk analysis conducted by the FAA's CSTA for Aircraft Safety Analysis; 
(2) a risk analysis using the Small Airplane Risk Analysis (SARA) 
methods; (3) a June 2011, presentation by Airmotive Engineering to the 
FAA concerning its ECi cylinder assemblies; (4) a list of ECi cylinder 
assembly failure reports consisting of only those reports where both 
cylinder serial number and time in service are included in the reports; 
(5) a list of additional failures of ECi cylinder assemblies reported 
by a maintenance organization; and (6) Airmotive Engineering 
Corporation Technical Report 1102-13, dated April 30, 2011.
    Response. We disagree. The supporting documents that Danbury 
Holdings referred to, identified above, support that the FAA followed 
its process and were used to help determine that an unsafe condition 
exists. We have also uploaded additional documents to Docket No. FAA-
2012-0002 on June 23, 2015 (see ADDRESSES section of this final rule 
for information on locating the docket).
    The risk analysis performed by the FAA's CSTA for Aircraft Safety 
Analysis, recommends removal and replacement of the affected ECi 
cylinder assemblies as specified in this AD. The SARA applied to 
failures of ECi cylinder assemblies confirms that an AD is necessary. 
AEC Technical Report 1102-13 states that a root cause for the first 
thread separations was an inherent design deficiency in the form of 
insufficient head-to-barrel design interference fit. AEC Technical 
Report 1102-13 recommended withdrawing these cylinder assemblies from 
service. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Holdings commented that that the FAA's risk 
analyses and other technical information were ``flawed, improperly 
applied, and replete with unsubstantiated conclusions.''
    Response. The commenter failed to provide any examples of FAA 
technical information that was flawed, improperly applied, or replete 
with unsubstantiated conclusions. Without those details, we are unable 
to consider the comment as having technical merit. Accordingly, we 
interpret the comment as a general objection to the need for the AD. We 
disagree. Our Challenge Team applied the risk assessments by the FAA's 
CSTA for Aircraft Safety Analysis, against the SAD's SARA guidelines 
and the E&PD's CAAP guidelines and independently concluded that an AD 
is required to mitigate the unsafe condition presented by installed 
affected ECi cylinder assemblies. We presented both risk assessments in 
Docket No. FAA-2012-0002 (see ADDRESSES section of this final rule for 
information on locating the docket). We did not change this AD based on 
this comment.
    Comment. Danbury Holdings commented that it found no relationship 
between the risk analysis using SARA methods and any analysis or 
conclusion provided by the agency in this rulemaking. We interpret 
Danbury Holding's comment as suggesting that no relationship exists 
between the risk analysis using SARA methods and any analysis or 
conclusion provided by the agency in this rulemaking.
    Response. We disagree. In comments to the August 12, 2013, NPRM 
some commenters requested that we use the SARA to determine if an AD 
was warranted. We used the SARA, and it confirmed the need for an AD. 
We did not change this AD based on this comment.
    Comment. Danbury Holdings commented that RAM Aircraft had 
concluded, through its own risk analysis, that ``the probability of a 
cylinder separation is extremely remote'' and that ``historical data 
and information thus far evident leads to the conclusion that there has 
been no physical discomfort to pilots or passengers and no damage to 
any aircraft as a result of the subject cylinders.''
    Response. We interpret the comment as two parts; first, that our 
risk assessment reached a wrong conclusion, and second, that a cylinder 
head separation does not result in any discomfort to pilots or 
passengers, or damage to the aircraft. We disagree. FAA Order 8040.4A, 
``Safety Risk Management Policy'', dated April 30, 2012, FAA Order 
8110.107A, ``Monitor Safety/Analyze Data,'' and the guidance in Engine 
& Propeller Directorate memorandum ``Risk Assessment for Reciprocating 
Engine Airworthiness Directives,'' PS-ANE-100-1999-00006, dated May 24, 
1999, direct how we do a risk assessment.
    We analyze safety risk, per FAA Order 8040.4A, as a composite of 
two factors: The potential ``severity'' or worst possible 
consequence(s) or outcome of an adverse event that is assumed to occur, 
and also the ``expected frequency of occurrence'' for that specific 
adverse event. FAA Order 8040.4A directs us to assess both factors 
independently, then enter each as separate inputs into a risk matrix. 
The matrix yields an overall level of risk for the event. The overall 
risk is then categorized as either ``Unacceptable Risk,'' ``Acceptable 
Risk with Mitigation,'' or ``Acceptable Risk.'' The corrective 
action(s), if any, is driven by the assessed overall risk. Table C-1 of 
Appendix C of FAA Order 8040.4A defines five levels of severity and 
Table C-2 defines five levels of event frequency that are used in the 
determination of composite risk.
    The FAA classification for the ``severity'' of an engine cylinder 
head separation event, per FAA Order 8040.4A, is ``hazardous'' for both 
single-engine and light-twin airplanes for several reasons. Cylinder 
head separations can significantly reduce the power of the airplane 
such that under some conditions it may not be able to safely takeoff 
and climb out. It could

[[Page 52985]]

also create a dangerous asymmetric thrust condition for twin-engine 
airplanes. If the separation occurs in cruise flight, the airplane may 
have insufficient excess power to continue safe flight at any altitude. 
Cylinder head separations have also caused in-flight fires. These are 
all unsafe conditions that warrant a ``hazardous'' severity level for 
risk assessment purposes.
    Table C-2 in FAA Order 8040.4A defines ``extremely improbable'' as 
``So unlikely that it is not expected to occur, but it is not 
impossible.'' It defines ``extremely remote'' as ``Expected to occur 
rarely.'' It defines ``Remote'' as ``Expected to occur infrequently.'' 
It defines ``probable'' as ``Expected to occur often.'' Finally, it 
defines ``frequent'' as ``expected to occur routinely.''
    Service history failure reports indicate that in a population of 
43,000 cylinders, that 1 of every 1,000 cylinders could separate on 
average; either in the dome radius or the first thread. A single-engine 
airplane has six of these cylinders, so the actual risk of a separation 
of any one of those six cylinders for any given airplane is 6/1,000: 1 
of every 166 engines. Similarly, a twin-engine airplane will have 12 
cylinders, so the risk of experiencing a separation of one cylinder on 
a twin-engine aircraft is twice that of a single engine, 12/1,000, 1 of 
every 83 twin-engine airplanes that use these model cylinders.
    Separation event under-reporting occurs. This is evidenced by RAM 
Aircraft's submittal of 23 additional reported failures of the subject 
ECi cylinders after the August 12, 2013 NPRM was issued. Photos of 
these failures are available in Docket No. FAA-2012-0002 (see ADDRESSES 
section of this final rule for information on locating the docket). The 
calculated separation rate, therefore, is likely higher than what we 
used in our analysis. Also based on service experience, we expect more 
ECi cylinder head separations in the future. Therefore, we concluded 
that the most appropriate assessment for the frequency of occurrence 
for these cylinder separations is ``Remote C''; ``Expected to occur 
infrequently.''
    Figure C-1 of FAA Order 8040.4A is a risk matrix that yields an 
overall risk based on the severity classification and the assessed 
frequency of occurrence. Using the FAA severity classification of 
``hazardous'' and the FAA assessed frequency of occurrence ``Remote 
C'', yields an overall risk that is ``unacceptable.'' The corrective 
actions required by this final rule AD are based on and consistent with 
this overall risk assessment.
    We, therefore, disagree with claims by RAM Aircraft and other 
commenters that a cylinder head separation will have a negligible 
effect on airplane safety. Also, several documented in-flight fires 
were precipitated by a cylinder head separation. We did not change this 
AD based on this comment.
    Comment. Danbury Holdings also commented that AEC Technical Report 
1102-13 was ``disavowed'' by AEC [now CMI San Antonio] since it was 
obtained under questionable circumstances and has since been proven 
incorrect given its predictions did not come to fruition.
    Response. We disagree. AEC originally provided the analysis to the 
FAA when it was considering a service bulletin for the affected ECi 
cylinder assemblies. ECi requested the FAA return or destroy ECi 
Technical Report 1102-13 after they learned the FAA was considering an 
AD. We found the data in this report useful in our determination of an 
unsafe condition. We did not change this AD based on this comment.
    Comment. Danbury Holdings commented that the FAA has not 
substantiated that the affected ECi cylinder assemblies have separated 
at 32 times the rate of the OEM cylinders. Danbury Holdings stated that 
the FAA had not provided any supporting documentation to substantiate 
the FAA's estimate that the OEM has produced approximately 4 times as 
many cylinders as ECi did over the same period of time. Danbury 
Holdings further commented that that the FAA ignores separations of 
other cylinder manufacturers.
    Response. We disagree. We uploaded supporting information, 
including service history, to Docket No. FAA-2012-0002 (see ADDRESSES 
section of this final rule for information on locating the docket). We 
determined the comparative failure rate of affected ECi cylinders to 
OEM cylinders through comparing the service history of ECi cylinders to 
the OEM's since ECi received their PMA. That service history shows that 
the affected ECi cylinders have had approximately eight times as many 
separations over the same period of time as that of the OEM cylinders; 
since ECi received its PMA. We compared the affected ECi cylinder 
production rates from ECi, to that of the OEM since ECi received its 
PMA. From ECi's and the OEM's production information, we concluded that 
the OEM has produced approximately four times as many cylinders as ECi 
since ECi received its PMA. This yields a normalized failure rate that 
is approximately 8 (comparative cylinder failure rate) x 4 (comparative 
production rate), which showed an overall failure rate 32 times higher 
for ECi cylinders.
    Since we first published that rate information, we subsequently 
learned of more failures of affected ECi cylinders. Those additional 
failures would, if included, increase the ECi failure rate. We did not 
update the failure rate to higher than 32 times that of the OEM's 
because it did not affect our decision regarding this AD. We did not 
change this AD based on this comment.
    The FAA has also issued ADs against other cylinder manufacturers, 
including mandating early retirement of cylinders to preclude cracking 
and separation. For example, ADs 2014-05-29 and 2007-04-19R1 both apply 
to certain Superior Air Parts cylinder assemblies. We did not change 
this AD based on this comment.
    Comment. Danbury Holdings also commented that the FAA failed to 
place all information in its purview into the docket and that the 
agency had failed to link its analyses to verifiable data.
    Response. We disagree. As previously noted, we have uploaded the 
relevant documents used in the decision-making process of this AD in 
Docket No. FAA-2012-0002 (see ADDRESSES section of this final rule for 
information on locating the docket). Our analysis shows that the FAA's 
actions are based on the data that we included in the docket. Our 
analysis is therefore linked to ``verifiable data.'' We did not change 
this AD based on this comment.
    Comment. Danbury Holdings commented that the FAA had failed to 
provide any evidence that cylinder separations have resulted in engine 
failures, in-flight shutdowns, and/or loss of control of an airplane 
and that the agency had included accidents that were not the direct 
result of a cylinder separation.
    Response. We disagree. A cylinder separating from its engine is an 
engine failure. We did not change this AD based on this comment.
    Comment. RAM Aircraft commented that it assumes that the failures 
of ECi cylinder assemblies shown in the supporting document titled 
``ECi AD--Additional Failures Reported by RAM Aircraft'' are based on 
letters RAM Aircraft sent to the FAA in 2013. RAM Aircraft, therefore, 
commented that this is not new information since the issuance of the 
January 8, 2015, SNPRM. Also, of the 38 photographs of damaged cylinder 
assemblies, RAM Aircraft noted that only 23 failures actually represent 
ECi cylinder assemblies.
    Response. We partially agree. First, we agree that the failed 
cylinder

[[Page 52986]]

assemblies identified in the supporting document ``ECi AD--Additional 
Failures Reported by RAM Aircraft'' do not represent new information 
since the issuance of the January 8, 2015, SNPRM. These failures are 
not represented in the SDR database but are consistent with our view 
that failures of these cylinder assemblies are under-reported.
    Second, we agree that some of the cylinder photographs uploaded to 
the docket are not cylinder assemblies affected by this AD. The FAA 
sent a letter to RAM Aircraft specifically requesting any information 
that RAM Aircraft had relative to failures of ECi cylinder assemblies, 
P/N AEC 631397, after we learned of possible failures that had not been 
reported as required by 14 CFR 21.3. RAM Aircraft responded to this 
request with the photographs and data that we uploaded into Docket FAA-
2012-0002 (see ADDRESSES section of this final rule for information on 
locating the docket). These photographs did not have any effect on our 
decision to issue this AD. We did not change this AD based on this 
comment.
Request To Describe FAA's Validation Process
    Comment. Danbury Holdings requested that the FAA provide a 
description of the validation process that was used for each of the 
cylinder separations that the FAA used to substantiate the need for 
this AD.
    Response. We interpret this comment as a request for identification 
of how we found out about the failures of ECi cylinder assemblies. We 
found out about the ECi cylinder assembly failures from the FAA SDR 
database and warranty information at ECi and RAM Aircraft, and failure 
reports from operators. Many of the operator SDR reports contained 
detailed information describing the nature and specific location of the 
separation. The findings of ECi Technical Report 1102-13 agreed with 
the original failure reports. We did not change this AD based on this 
comment.

C. Comments to the FAA's Rulemaking Processes

Request To Follow the APA
    Comment. IPL Group, RAM Aircraft, and Danbury Holdings commented 
that the FAA had failed to follow the requirements of the APA when it 
dispositioned previous comments to the August 12, 2013, NPRM, and the 
January 8, 2015, SNPRM. IPL Group indicated that the FAA had, for 
example, summarily discounted previous comments, failed to conduct 
appropriate investigations of the failed cylinder assemblies, and 
mischaracterized hazard levels in the proposed ADs.
    RAM Aircraft also commented that its previous comments were 
dispositioned in general categories in the January 8, 2015, SNPRM. RAM 
Aircraft, however, does not believe that the specifics of its comments 
were adequately or properly responded to, as required by the APA.
    Response. We disagree. The commenters failed to provide any 
examples of where we failed to comply with the APA in our handling of 
comments to the August 12, 2013, NPRM, and by extension, the January 8, 
2015, and August 25, 2015, SNPRMs. We have in our responses to the NPRM 
and the SNPRMs, and herein in this final rule, fully responded to all 
comments, including those comments concerning our investigation of the 
unsafe condition, hazard levels, and conclusions.
    We carefully considered all comments we received. In our January 8, 
2015, SNPRM and August 28, 2015, SNPRM, we responded to several hundred 
comments that we had received. Many were substantively the same and, 
therefore, as previously discussed we grouped them into several 
categories and answered the comments by category. The commenters have 
not indicated what, if anything, is improper about doing so nor how 
doing as we did might have violated the requirements of the APA. In 
this final rule, we responded to all remaining comments. We again used 
categories to group and answer comments that were similar if not 
identical. As to improperly recognizing affected ECi cylinder 
assemblies, we based our applicability of this AD on the reports of 
failure provided by ECi, the manufacturer, the reports required by 14 
CFR that form the basis for the SDR, and the reports of the commenters 
themselves. We did not change this AD based on this comment.
Request To Withdraw the SNPRMs Because They Are Arbitrary and 
Capricious
    Comment. Danbury Holdings and ARSA referred to the proposed rule as 
``arbitrary and capricious'' because it does not apply equally to 
cylinder assemblies manufactured by the OEM. Danbury Holdings observed 
that the OEM's cylinders also separate and that the FAA has singled out 
ECi with this AD action.
    Response. We disagree. The FAA is not mandating similar corrective 
actions against the OEM's cylinders because OEM service history data is 
different. Our review of OEM service history indicates that OEM 
cylinder assembly failures, unlike ECi cylinder assembly failures, are 
not traceable to any specific design or manufacturing anomaly. In 
contrast, the ECi PMA cylinder separations are traceable to design 
deficiencies, which ECi itself identified in ECi Technical Report 1102-
13. We did not find the ECi cylinder assembly design deficiencies in 
cylinder assemblies produced by any other manufacturer. Further, ECi's 
failure rate is some 32 times greater than the OEM's. We did not change 
this AD based on this comment.
    Comment. ARSA also indicated the rule is arbitrary and capricious 
because the FAA has failed to ``examine the relevant data and 
articulate a satisfactory explanation for its action including a 
`rational connection between the facts found and the choice made.'' 
Further, ARSA cites the APA as requiring federal agencies to allow 
meaningful public participation in the rulemaking process and provide a 
``statement of basis and purpose'' justifying a rule's issuance.'' ARSA 
notes the obligation of the FAA to demonstrate a sound factual basis 
for the issuance of a rule by specifically disclosing to interested 
parties the material upon which a prospective rule would be fashioned.
    Response. We disagree. Beyond its generalized allegation, the 
commenter did not identify any examples of agency shortcoming. We 
examined the relevant data, including the failure rate of the ECi 
assemblies, the ECi cylinder assembly design deficiencies, and the 
consequences to the engine and airplane when an ECi cylinder assembly 
failed. We reviewed and applied the applicable FAA Orders and policies.
    The agency therefore, has articulated a satisfactory explanation 
for its action including a ``rational connection between the facts 
found and the choice made.''
    We provided the public several opportunities to participate in this 
rule making; through extending the comment period and the two 
supplemental notices with their comment periods. For example, we first 
published an NPRM on August 12, 2013 (78 FR 48828), then published an 
extension of the comment period on September 26, 2013 (78 FR 59293) to 
allow the public additional time to comment on the proposed rule. We 
then issued a notice of availability of an initial regulatory 
flexibility analysis on March 12, 2014 (79 FR 13924). We reviewed the 
over 500 comments to the proposed rule that we had received, determined 
that we needed to review how we proposed to address the unsafe 
condition, formed a team to review the technical basis of the

[[Page 52987]]

proposed rule, the numerous public comments, and the additional failure 
information provided by commenters to the NPRM. Through this team we 
confirmed that an AD is needed to correct the unsafe condition 
represented by the subject cylinder assemblies installed in aircraft 
engines, but that we could do so through a lengthier compliance 
interval. We published that revised compliance interval in our January 
8, 2015, SNPRM.
    After publication of the January 8, 2015, SNRPM, we issued the 
August 28, 2015, SNPRM to allow us to explain the rationale for this AD 
action. We also added several documents to Docket No. FAA-2012-0002 
(see ADDRESSES section of this final rule for information on locating 
the docket), including the risk analyses by our CSTA for Aircraft 
Safety Analysis, and one using SARA methods, and various technical 
documents that list failures of ECi cylinder assemblies. For each of 
the documents we published, we allowed the public an opportunity to 
provide comments. We did not change this AD based on this comment.
    Comment. ARSA also commented that presentation of relevant comments 
is further stymied by the agency's conclusory and unsupported responses 
to the NPRM submissions. ARSA commented that the agency stated that it 
was irrelevant that the root cause of the cylinder failures is unknown 
and that it ``disagreed'' that pilot error was a factor.
    Response. We disagree. The purpose of this AD is to remove an 
unsafe condition in aircraft engines, not to identify root cause of 
cylinder failure(s). This AD resolves the unsafe condition by removing 
the affected cylinder assemblies from service in the engine models 
listed in this AD. We did not change this AD based on this comment.
    Comment. Danbury Holdings also commented that the FAA had not 
provided substantiation for a change in the design requirement that 
ensures safe operation with one inoperative cylinder.
    Response. The comment is not germane to this AD. We direct the 
commenter to the regulations relevant to design requirements, as found 
in 14 CFR. We did not withdraw the August 28, 2015, SNPRM.
    Comment. Danbury Holdings commented that the FAA has admitted that 
the SDR database is problematic and that the FAA picked and chose data 
to fit a conclusion.
    Response. We disagree. The SDR database reflects input received 
from field reporting. The SDR database may not reflect all service 
difficulty problems with affected ECI cylinder assemblies, but what 
information it contains indicates the need for this AD. Moreover, the 
SDR database is only one tool in our decision-making process. We did 
not change this AD based on this comment.
    Comment. Several commenters commented that the FAA should withdraw 
the January 8, 2015, SNPRM because it unfairly targets ECi.
    Response. We disagree. This AD does not ``target'' ECi, the PMA 
manufacturer of the affected cylinder assemblies. The AD resolves an 
unsafe condition in a product. We did not change this AD based on this 
comment.
Request To Substantiate That This AD Does Not Affect Airplanes Operated 
by Federal or State Agencies
    Comment. Danbury Holdings commented that the FAA had not provided 
documentation to substantiate that no affected airplanes are operated 
by federal or state agencies.
    Response. The comment is not relevant to whether this AD is 
necessary to resolve the unsafe condition presented by the engine with 
the affected ECi cylinders installed. We did not change this AD based 
on this comment.
Request To Substantiate That Airplanes Operating in Alaska Are Not 
Affected
    Comment. Danbury Holdings stated that the FAA had not provided 
documentation that substantiates that remote locations of Alaska are 
not served by airplanes affected by this AD.
    Response. The comment is not relevant to the technical basis for 
this AD. Further we state that this AD will not affect intrastate 
aviation in Alaska to the extent that it justifies making a regulatory 
distinction. We did not change this AD based on this comment.
Request To Send Proposed Rule to Office of Information and Regulatory 
Affairs (OIRA) and Small Business Administration (SBA)
    Comment. Danbury Aerospace commented that per Executive Order 
(E.O.) No. 13272, the FAA should provide the draft rule to the OIRA in 
the Office of Management and Budget (OMB) under E.O. No. 12866 and to 
the SBA's Chief Counsel for Advocacy.
    Response. We partially agree. We do not agree that this rule meets 
the criteria of a significant regulatory action under E.O. 12866. 
Therefore, we did not provide the draft rule to the OMB. We agree that 
the rule has a significant effect on a substantial number of small 
entities. We, therefore, provided a copy of the rule to the SBA's Chief 
Counsel for Advocacy for comment. We received no comments from the SBA.

D. Comments to the Cost of This AD

Request To Revise and Provide Supporting Data for Number of Affected 
Cylinder Assemblies and Engines
    Comment. Danbury Aerospace and RAM Aircraft indicated that the FAA 
has under-estimated the numbers of airplanes and engines affected and 
up to 11,000 aircraft may be affected based on the aircraft registry, 
or otherwise hasn't provided the data it used to determine the affected 
population of engines and cylinders.
    Response. We disagree in part. We do not agree that 11,000 aircraft 
may be affected by this AD, or that we haven't provided the data used 
to determine the affected populations. Not all aircraft and engines on 
the aircraft registry use the affected ECi cylinder assemblies. 
Further, the commenter hasn't provided any factual basis for its 
assumption that all aircraft on the aircraft registry use ECi cylinder 
assemblies.
    We agree that we could better estimate the number of engines 
affected by this AD. We again reviewed our estimate. We now estimate 
that approximately 6,200 engines are affected by this AD. That number 
is based on our initial estimate of approximately 43,000 affected 
cylinder assemblies produced by ECi from 2002 to 2011. This number is 
supported by AEC Technical Report 1102-13, dated April 30, 2011. We 
then reduced 43,000 by our estimated number of cylinder assemblies that 
would have been removed from service.
    Our review indicates that approximately 6,000 of the 43,000 
cylinder assemblies would have been retired from service by the time of 
the publication of this AD. Therefore, we estimate 37,000 cylinder 
assemblies may be in service, as of June 1, 2016. We divided this 
number by 6 cylinders per engine to give us an estimated 6,167 engines 
in service. To increase the conservatism of our cost estimate, we 
rounded this figure to 6,200 engines. We revised our cost estimate to 
reflect these updated calculations.
Request To Revise the Number of Labor Hours to Perform This AD
    Comment. A few commenters, including IPL Group, indicated that the 
number of hours to replace 6 cylinders would be greater than the 18 
hours that we estimated in our costs of compliance.
    Response. We agree. In the August 12, 2013, NPRM, and the January 
8, 2015, and August 28, 2015, SNPRM, we

[[Page 52988]]

estimated 18 work hours. Although the commenters did not provide data 
to support increasing the number of work hours, we held discussions 
with manufacturers regarding the number of hours they would allow to 
perform this work. Based on these more recent discussions, we revised 
our estimate for the number of work hours to replace 6 cylinder 
assemblies to 32 hours.
Request To Revise Cost of Replacing a Cylinder Assembly in This AD
    Comment. Danbury Aerospace, Danbury Holdings, RAM Aircraft, and IPL 
Group commented that the cost of a cylinder assembly, as calculated by 
the FAA, does not accurately represent replacement costs. The 
commenters indicated that the FAA's use of ``pro-rated cost'' allows a 
vast underestimation of actual expenses that would be incurred by 
owners. The agency must at least provide sound reasoning and facts 
supporting the assertion that the pro-rated cost ``more accurately 
reflects'' replacement cost. IPL Group further commented that a ``pro-
rated value'' is inconsistent with FAA policy and the Regulatory 
Flexibility Act.
    Response. We disagree in part. Industry, including ECi, uses pro-
rated cost in its cost estimates. For example, ECi, in its MSB 05-8, 
Revision No. 1, dated December 29, 2005, used a similar time in service 
based pro-rated cost calculation to determine the discounted cost to 
operators for replacement cylinders, instead of providing the cylinders 
to the operators at no cost. Further, we typically use pro-rated cost 
for larger, turbofan engines when life-limited parts are involved. 
Operators of those engines are typically airlines and other large 
operators. Pro rata estimating therefore, is an acceptable method of 
estimating cost.
    We agree however, that engines with affected ECi cylinders 
installed may be installed on airplanes owned by individual operators 
in the general aviation community, who are less familiar with the 
concept of pro-rated costs to ADs. In consequence, we revised our 
estimate to use the full replacement cost of each cylinder assembly 
even though this will likely result in an over-estimate of the total 
cost of this AD. We, therefore, used the replacement cost of 6 cylinder 
assemblies in this final rule. This resulted in an increase from $4,202 
in the SNPRMs to $11,520 in this final rule.
Request To Include Additional Costs in the Overall Cost Estimate
    Comment. IPL Group and Danbury Aerospace requested that we add 
additional costs to our overall cost estimate. IPL Group indicated that 
the FAA should include costs for loss of use of the aircraft, test 
flight, and break-in expenses. Danbury Aerospace commented that we 
should account for loss of overhauled assemblies as replacement items 
and new costs associated strictly with their replacement.
    Response. We disagree. In constructing our cost estimate, we 
followed the guidance of the FAA's Airworthiness Directives Manual, 
FAA-IR-M-8040.1C, dated May 17, 2010, which states ``Do not state any 
costs beyond initial work-hours and parts costs. . . .'' The additional 
costs cited by the commenters are not appropriate to our cost 
estimates. We did not change this AD based on this comment.
Request To Withdraw the SNPRMs Because of Excessive Overall Cost
    Comment. Several commenters commented that the FAA should withdraw 
the January 8, 2015, SNPRM and the August 28, 2015, SNPRMs because the 
FAA has underestimated the cost of compliance of this AD. These 
commenters represented that the true cost is too high and that the FAA 
has ignored the broader impact of this AD on industry. Most commenters 
failed to provide any data to support these claims, however, IPL Group 
provided some calculations to show that the total cost of this AD 
should be somewhere between $168,666,625 and $320,360,156.
    Response. We disagree. We considered the impact that this AD would 
have on operators. As explained in response to the comments above, we 
increased our estimates of inspection costs, labor costs, and 
replacement costs of the cylinder assemblies. Although we increased our 
cost estimate, we still conclude that the unsafe condition represented 
by the affected cylinder assemblies requires an AD. We did not withdraw 
the SNPRMs based on this comment.
Request To Substantiate Record-Keeping and Time Estimates
    Comment. Danbury Holdings also stated that the FAA had not provided 
documentation to substantiate its estimated record keeping cost and 
time estimates.
    Response. We agree in part. We interpret this comment as a 
reference to both time spent on checking log books and reporting 
requirements. We withdrew our reporting requirement when we published 
the January 8, 2015, SNPRM, so we have no need to account for that 
cost. We added an inspection cost in this final rule for the time 
operators spend determining if they own an ECi cylinder assembly 
affected by this AD. The Costs of Compliance section now states ``We 
estimate 0.5 hours will be needed to check log books to determine if an 
engine is affected by this AD.''

E. Administrative Comments

Request To Clarify Address
    Comment. The Continental Motors Group commented that the business 
at the address and telephone number listed in the August 28, 2015, 
SNPRM (9503 Middlex Drive, San Antonio, Texas 78217, Phone 210-820-
8101) is now that of Continental Motors Inc., San Antonio. Continental 
Motors Group also indicated that the associated company Web site 
(http://www.eci.aero/pages/tech_svcpubs.aspx) listed in the August 28, 
2015, SNPRM is not functional at this time.
    Response. We agree. We updated the address and Web site information 
listed in the ADDRESSES and ``Related Information'' sections of this 
AD.
Request To Provide Names of Those Involved in the AD Process
    Comment. Danbury Aerospace and Danbury Holdings commented that the 
FAA should provide the names and technical positions of each of the 
members of the multi-disciplinary/multi-directorate team that were 
involved in the review of this service difficulty problem, along with 
the dates, locations, and minutes for any meetings that were held.
    Response. We disagree. The names and positions of personnel 
associated with reviewing this AD are not necessary to the public's 
participation in the development of this AD. We did not change this AD 
based on this comment.

F. Support for the SNPRM

    Comment. The NTSB commented that it believes that the August 28, 
2015, SNPRM will satisfy the intent of NTSB Safety Recommendation A-12-
7. An individual commenter indicated that he had reviewed the SDR 
database and determined that the separation rate of ECi cylinder 
assemblies is approximately 10 times the rate of OEM cylinder 
assemblies.
    Response. We note the comment.

[[Page 52989]]

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD as proposed.

Costs of Compliance

    We estimate that this AD affects about 6,200 CMI model IO-520, 
TSIO-520, IO-550, and IOF-550 reciprocating engines and all other CMI 
engine models approved for the use of CMI models -520 and -550 cylinder 
assemblies (such as the CMI model -470 when modified by STC), installed 
on airplanes of U.S. registry. The average labor rate is $85 per hour. 
We estimate 0.5 hours will be needed to check log books to determine if 
an engine is affected by this AD. We estimate that about 32 hours will 
be required to replace all six cylinder assemblies of an engine during 
overhaul. We estimate the cost of replacement of six cylinder 
assemblies to be, on average, about $11,520 per engine. Based on these 
figures, we estimate the total cost of this AD to U.S. operators to 
change all ECi cylinder assemblies to be $88,551,500.

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.
    We are 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 Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a 
principle of regulatory issuance that agencies shall endeavor, 
consistent with the objective of the rule and of applicable statutes, 
to fit regulatory and informational requirements to the scale of the 
business, organizations, and governmental jurisdictions subject to 
regulation.'' To achieve that principle, the RFA requires agencies to 
solicit and consider flexible regulatory proposals and to explain the 
rationale for their actions. 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 proposed or 
final 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 Act. The FAA determined that this rule will have a significant 
economic impact on a substantial number of small entities and, 
accordingly, as required by Section 603(a) of the RFA, the FAA prepared 
and published an initial regulatory flexibility analysis (IRFA) (79 FR 
13924, March 12, 2014) as part of the NPRM (79 FR 48828, August 12, 
2013) and initial SNPRM (80 FR 1008, January 8, 2015) for this rule. 
For the second SNPRM, the FAA inadvertently stated that there would be 
no significant impact on a substantial number of entities. We also 
omitted the IRFA from the second SNPRM because we thought republication 
unnecessary as costs had not changed and the IRFA had already been 
published in the first SNPRM. In addition to the IRFA, Section 604 of 
the RFA also requires an agency to publish a final regulatory 
flexibility analysis (FRFA) in the Federal Register when issuing a 
final rule.
    With this FRFA we correct our misstatement in the second SNPRM and 
restate our previous conclusions for the NPRM and in the first SNPRM 
that the rule will have a significant impact on a substantial number of 
small entities. Accordingly, in the following section we undertake the 
regulatory flexibility analysis.

Final Regulatory Flexibility Analysis

    Under Section 604(a) of the RFA, the Final analysis must address:
    (1) Statement of the need for, and objectives of, the rule.
    This final rule AD was prompted by failure reports of multiple 
cylinder head-to-barrel separations and cracked and leaking aluminum 
cylinder heads. This AD will apply to certain CMI San Antonio 
replacement PMA cylinder assemblies marketed by ECi, used on the CMI 
model -520 and -550 reciprocating engines, and all other engine models 
approved for the use of CMI model -520 and -550 cylinder assemblies 
such as the CMI model -470 when modified by STC.
    (2) Statement of the significant issues raised by the public 
comments in response to the initial regulatory flexibility analysis, 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.
    Danbury Holdings commented that the FAA had not provided the raw 
data that was used in the IRFA. We note that the provision of raw data 
is not required by the FAA's rulemaking procedures or orders.
    In response to comments about problems with the repetitive 
compression/soap test proposed by the NPRM, the FAA agrees that these 
tests do not always reliably detect a cracked cylinder of this failure 
mode and therefore the costs associated with such tests outweigh the 
safety benefits. In the January 8, 2015 SNPRM the FAA removed the 
requirement for repetitive compression/soap inspection tests.
    The FAA received comments questioning the reduction of the 
estimated number of smaller air service businesses (in addition to the 
estimated 609 small part 135 operators) that would be affected by the 
rule, from 5,000 in the IRFA to 2,000 in the January 8, 2015, SNPRM. We 
note that in both cases the FAA stated that a substantial number of 
small entities would be affected. Given the lack of available data, the 
FAA is unable to make an accurate estimate of the number of smaller air 
service businesses that will be affected by this rule, but acknowledges 
that this number is substantial. In addition to the 609 small part 135 
operators, we therefore estimate in this final rule that the number of 
smaller air service businesses affected is substantial.
    After publication of the NPRM and after publication of each of the 
two SNPRMs, we also received comments from small businesses concerning 
understated compliance costs. Some commenters stated that the labor 
rate and the hours required to replace an affected engine's cylinders 
are underestimated. We agree with this comment in part and have 
increased our estimate of the labor hours required to replace an 
affected engine's six cylinder assemblies from 18 to 32 hours, with a 
corresponding labor cost increase from $1,530 to $2,720.
    In response to comments we have also increased our cost of 
materials estimate from a loss-of-service estimate of $4,202 to the 
full cost to replace all six cylinders, which has increased to $11,520. 
Our estimate of the total cost to replace all six cylinders has 
therefore increased from $5,732 to $14,240.
    After publication of the August 28, 2015, SNPRM, we received 
negative comments concerning the inadvertent change from our original 
determination of a significant economic impact on a

[[Page 52990]]

substantial number of small entities in the IRFA (and the January 8, 
2015, SNPRM) to a determination of no significant impact on a 
substantial number of small entities. As noted in the introductory 
section, we are correcting this oversight in this FRFA.
    (3) The response of the agency to any comments filed by the Chief 
Counsel for Advocacy of the Small Business Administration 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.
    The SBA did not submit comments.
    (4) Description and an estimated number of small entities to which 
the final rule will apply.
    Of the 610 part 135 operators we found to be affected by this rule, 
we identified 609 that meet the Small Business Administration (SBA) 
definition of a small entity (entities with 1,500 or fewer employees) 
that will be affected by this final rule. On this basis alone, we 
conclude that the final rule will affect a substantial number of small 
entities. In addition, we estimate that a substantial, but undetermined 
number of smaller air services businesses will be affected by this 
final rule. The FAA is unaware of the assets or financial resources of 
these businesses. The affected part 135 and smaller air services fly 
fixed wing aircraft; employ less than 1,500 employees; and conduct a 
variety of air services such as fly passengers and cargo for hire.
    (5) Description of the record keeping and other compliance 
requirements of the final rule.
Record Keeping Requirement
    The FAA estimates 0.5 hours will be needed to check log books to 
determine if an engine is affected by this AD. At a wage rate of $85 
per hour, the estimated cost will be $42.50 per engine. As the affected 
small part 135 operators have between one and 88 affected airplanes, 
the costs of this requirement range from $42.50 to $3740 per part 135 
operator.
Compliance Requirement To Replace Cylinder Assemblies of Affected 
Engines
    This AD applies to certain CMI model IO-520, TSIO-520, IO-550, and 
IOF-550 reciprocating engines and all other engine models approved for 
the use of CMI models -520 and -550 cylinder assemblies (such as the 
CMI model -470 when modified by STC), installed on airplanes of U.S. 
registry. For the affected engines the AD requires replacement of the 
cylinder assemblies at reduced times-in-service.
    As noted above our estimate of the total cost to replace all six 
cylinders has increased from $5,732 to $14,240. As the number of 
airplanes held by affected small part 135 operators ranges from one to 
88, the costs of required cylinder assembly replacement per operator 
range from about $14.2 thousand to about $1.3 million.
    To determine whether compliance costs will have a significant 
economic impact, we measured the cost of replacing cylinder assemblies 
of affected engines relative to the value of the affected airplanes 
held by the small part 135 operators. The estimated asset value of the 
affected airplanes held by the small part 135 operators ranges from 
$22,000 to $19.6 million. We find that the cost of replacing cylinder 
assemblies relative to affected airplane asset value is greater than 5 
percent for 468 of the 609 affected small part 135 operators.\2\ We 
therefore conclude that the final rule will have a significant economic 
impact on a substantial number of small entities.
---------------------------------------------------------------------------

    \2\ This assessment does not take into account record keeping 
requirement costs. These costs, however, are minor and do not affect 
our assessment of the number of small part 121 operators 
significantly impacted by the final rule.
---------------------------------------------------------------------------

    (6) 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 one of the other significant alternatives to the rule 
considered by the agency which affect the impact on small entities was 
rejected.
    In response to comments about problems with repetitive compression/
soap test, the FAA agrees that these tests do not always reliably 
detect a cracked cylinder of this failure mode and the costs associated 
with such tests outweigh the safety benefit. The FAA removed that 
requirement for repetitive compression/soap inspection tests. We also 
considered these following alternatives:
    (a) Do nothing--This option is not acceptable due to the number of 
failures of ECi cylinder head assemblies and the consequences of the 
failures.
    (b) Periodic inspections only (no forced removals)--Though the NTSB 
recommended this option in its comments to the NPRM (August 12, 2013, 
78 FR 48828), the service history has shown that such inspections may 
not reliably detect existing cracks and the rate of crack growth to 
separation is unknown and variable. The NTSB also submitted a later 
comment, in response to the August 28, 2015, SNPRM, that the revised 
rule as adopted in this final rule, meets the intent of its Safety 
Recommendations A-12-7.
    (c) Forced removal with periodic inspections--Periodic inspections 
may not reliably detect cracks and even with removal the rate of crack 
growth to separation is unknown and variable. Forced removal is the 
only remaining option.

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,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, and
    (4) Will 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.

Adoption of 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 (AD):

2016-16-12 Continental Motors, Inc. (formerly Teledyne Continental 
Motors, Inc., formerly Continental): Amendment 39-18610; Docket No. 
FAA-2012-0002; Directorate Identifier 2011-NE-42-AD.

(a) Effective Date

    This AD is effective September 15, 2016.

(b) Affected ADs

    None.

[[Page 52991]]

(c) Applicability

    This AD applies to all Continental Motors, Inc. (CMI) model -520 
and -550 reciprocating engines, and to all other CMI engine models 
approved for the use of model -520 and -550 cylinder assemblies such 
as the CMI model -470 when modified by supplemental type certificate 
(STC), with Continental Motors Inc., San Antonio (formerly Airmotive 
Engineering Corp.), replacement parts manufacturer approval (PMA) 
cylinder assemblies, marketed by Engine Components International 
Division (hereinafter referred to as ECi), part number (P/N) AEC 
631397, with ECi Class 71 or Class 76, serial number (S/N) 1 through 
S/N 61176, installed.

(d) Unsafe Condition

    This AD was prompted by multiple failure reports of cylinder 
head-to-barrel separations and cracked and leaking aluminum cylinder 
heads. We are issuing this AD to prevent failure of the cylinder 
assemblies, which could lead to failure of the engine, in-flight 
shutdown, and loss of control of the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) Review the engine maintenance records to determine if any 
affected cylinder assemblies are installed.
    (2) If you cannot determine based on review of engine 
maintenance records if any affected cylinder assemblies are 
installed, comply with paragraph (e)(4) of this AD.
    (3) If you do not have any of the affected ECi cylinder 
assemblies installed on your engine, no further action is required.
    (4) Cylinder Identification and Serial Number Location
    (i) Check the cylinder assembly P/N and Class number. The ECi 
cylinder assembly, P/N AEC 631397, Class 71 or Class 76, is stamped 
on the bottom flange of the cylinder barrel. Guidance on the P/N and 
Class number description and location can be found in ECi Service 
Instruction No. 99-8-1, Revision 9, dated February 23, 2009.
    (ii) If you cannot see the cylinder assembly P/N when the 
cylinder assembly is installed on the engine, you may use the 
following alternative method of identification:
    (A) Remove the cylinder assembly rocker box cover.
    (B) Find the letters ECi, cast into the cylinder head between 
the valve stems.
    (C) Check the cylinder head casting P/N. Affected cylinder 
assemblies have the cylinder head casting, P/N AEC 65385, cast into 
the cylinder head between the valve stems.
    (D) Find the cylinder assembly S/N as specified in paragraphs 
(e)(4)(iii) or (e)(4)(iv) of this AD, as applicable.
    (iii) For ECi cylinder assemblies, P/N AEC 631397, manufactured 
through 2008, find the cylinder assembly S/N stamped on the intake 
port boss two inches down from the top edge of the head.
    (iv) For ECi cylinder assemblies, P/N AEC 631397, manufactured 
on or after January 1, 2009, find the cylinder assembly S/N stamped 
just below the top edge of the head on the exhaust port side.
    (5) Removal From Service
    (i) For any affected cylinder assembly with 680 or fewer 
operating hours time-in-service (TIS) since new on the effective 
date of this AD, remove the cylinder assembly from service before 
reaching 1,000 operating hours TIS since new.
    (ii) For any affected cylinder assembly with more than 680 
operating hours TIS since new and 1,000 or fewer operating hours TIS 
since new on the effective date of this AD, remove the cylinder 
assembly from service within the next 320 operating hours TIS or 
within 1,160 operating hours TIS since new, whichever occurs first.
    (iii) For any affected cylinder assembly with more than 1,000 
operating hours TIS since new on the effective date of this AD, 
remove the cylinder assembly from service within the next 160 
operating hours or at next engine overhaul, whichever occurs first.
    (iv) For any affected cylinder assembly that has been 
overhauled, remove the cylinder assembly from service within the 
next 80 operating hours TIS after the effective date of this AD.

(f) Installation Prohibitions

    After the effective date of this AD:
    (1) Do not repair, or reinstall onto any engine, any cylinder 
assembly removed per this AD.
    (2) Do not install any affected ECi cylinder assembly that has 
been overhauled, into any engine.
    (3) Do not install any engine that has one or more affected 
overhauled ECi cylinder assemblies, onto any aircraft.
    (4) Do not return to service any aircraft that has an engine 
installed with an ECi cylinder assembly subject to this AD, if the 
cylinder assembly has 1,000 or more operating hours TIS.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, Delegation Systems Certification Office or Fort 
Worth Aircraft Certification Office, may approve AMOCs for this AD. 
Use the procedures found in 14 CFR 39.19 to make your request.

(h) Related Information

    (1) For more information about this AD, contact Jurgen E. 
Priester, Aerospace Engineer, Delegation Systems Certification 
Office, FAA, Rotorcraft Directorate, 10101 Hillwood Parkway, Fort 
Worth, TX 76177; phone: 817-222-5190; fax: 817-222-5785; email: 
jurgen.e.priester@faa.gov.
    (2) For ECi Service Instruction No. 99-8-1, Revision 9, dated 
February 23, 2009, which is not incorporated by reference in this 
AD, contact Continental Motors--San Antonio, 9503 Middlex Drive, San 
Antonio, TX 78217; phone: 210-820-8101; Internet: http://www.continentalsanantonio.com.
    (3) You may view this service information at the FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 
781-238-7125.

(i) Material Incorporated by Reference

    None.

    Issued in Burlington Massachusetts, on July 19, 2016.
Colleen M. D'Alessandro,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-18708 Filed 8-10-16; 8:45 am]
 BILLING CODE 4910-13-P