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Safety Recommendation Details

Safety Recommendation A-12-007
Details
Synopsis: Since 2000, the National Transportation Safety Board (NTSB) has examined numerous Engine Components, Inc. (ECi) reciprocating engine cylinder assemblies that failed due to fatigue cracking that initiated in the root of the cylinder head thread, eventually resulting in loss of compression and/or separation of the cylinder head into two pieces.1 These failures involved new assemblies installed on Lycoming and Teledyne Continental Motors (TCM)2 engines, and many resulted in fatal accidents. Although the Federal Aviation Administration (FAA) has issued several airworthiness directives (AD) applicable to certain new ECi cylinder assemblies used on Lycoming and TCM engines to address this issue, similar fatigue failures in other new ECi cylinder assemblies installed on TCM engines have been identified but are not covered by an existing AD. Because fatigue cracking and separation of cylinder assemblies in piston-engine aircraft is a serious safety issue, this letter recommends corrective action for certain new ECi cylinders used on TCM engines.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require repetitive inspection of Engine Components, Inc. cylinder assemblies produced between May 2003 and October 2009 (serial numbers 7709 through 52884) installed on Teledyne Continental Motors model 520 and 550 engines and removal of these cylinder assemblies once they reach the engine manufacturer’s recommended normal time (hours) in service between overhauls.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Hoganas Airfield, OF, Sweden
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: ENG07WA032
Accident Reports:
Report #: None
Accident Date: 7/14/2006
Issue Date: 2/24/2012
Date Closed: 3/29/2017
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: FAA
To: NTSB
Date: 3/29/2017
Response: We note that, on August 28, 2015, you published a supplemental notice of proposed rulemaking (SNPRM) that proposed issuing an airworthiness directive (AD) applicable to the affected ECi cylinder assemblies. In our September 24, 2015, comments on this SNPRM, we said that the proposed AD would satisfy the recommendation. We further note that, on August 11, 2016, you issued AD 2016-16-12, which mandates the actions proposed in the SNPRM. Consequently, Safety Recommendation A-12-7 is classified CLOSED--ACCEPTABLE ACTION.

From: FAA
To: NTSB
Date: 1/25/2017
Response: -From Michael P. Huerta, Administrator: On August 28, 2015, the Federal Aviation Administration (FAA) published a supplemental notice of proposed rulemaking (SNPRM) airworthiness directive (AD). Directorate Identifier 20 11-NE-42-AD (80 FR 52212), applicable to the affected Engine Components. Inc. cylinder assemblies. This SNPRM proposed to: notify the schedule for removal of the affected cylinder assemblies, eliminate a reporting requirement, remove a requirement for initial and repetitive inspections, and clarify that overhauled affected cylinder assemblies should be removed within 80 hours. The Board submitted a comment on September 24, 2015. Indicating that our proposed compliance actions in this SNPRM would satisfy the intent of this recommendation. We subsequently adopted these compliance actions in our final rule AD 2016-16-12, published on August 11, 2016 (81 FR 52975). I believe that the FAA has effectively addressed this recommendation and consider our actions complete.

From: NTSB
To: FAA
Date: 3/29/2016
Response: We note that, on August 5, 2013, you issued a notice of proposed rulemaking (NPRM) for an airworthiness directive (AD) to require both a periodic visual and compression test to detect any cracked or leaking cylinder assemblies and the scheduled removal and replacement of certain ECi cylinder assemblies. After you received over 500 comments regarding this NPRM, and many of them voiced concerns with the issuance of the proposed AD, you reviewed the related technical information and public comments. On January 8, 2015, you published a supplemental notice of proposed rulemaking (SNPRM) that proposed to reduce the severity of compliance by modifying the schedule for removal of the affected cylinder assemblies, eliminating a reporting requirement, removing the requirement for initial and repetitive inspections, and clarifying that overhauled affected cylinders assemblies be removed within 80 hours after the effective date of the AD. On February 11, 2015, we submitted comments about this SNPRM, repeating what we had said in our comments about the 2013 NPRM, including that the proposed revised rule would exceed the action we had recommended in Safety Recommendation A-12-7 by addressing many more cylinder assemblies and by requiring the removal of cylinder assemblies before the engine manufacturer’s recommended normal time in service between overhauls. On June 9, 2015, we met with your staff to discuss your actions related to the safety recommendation and the proposed AD. You published a second SNPRM on August 28, 2015, that allowed for the public to comment on additional supporting information that you added to the AD docket, including your risk analysis supporting the AD. In our September 24, 2015, comments on this second SNPRM, we said that the proposed AD would satisfy the recommendation. Pending issuance of the proposed AD, Safety Recommendation A-12-7 remains classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 2/11/2016
Response: -From Michael P. Huerta, Administrator: On August 5, 20 13, the Federal Aviation Administration (FAA) issued a notice of proposed rulemaking (NPRM) airworthiness directive (AD) applicable to certain Airmotive Engineering Corp. replacement parts manufacturer approval cylinder assemblies marketed by Engine Components International Division (78 FR 48828). The NPRM AD proposed to require both a periodic visual inspection and compression test to detect any cracked or leaking cylinder assemblies, and the scheduled removal and replacement of those cylinder assemblies. The NPRM AD also proposed to remove all cylinder assemblies from service at or before accumulating 1,000 operating hours. The FAA received over 500 comments regarding this NPRM AD. Due to the large number of comments that disagreed with the issuance of the NPRM AD, the FAA assembled a multi-disciplinary team to review the related technical information and public comments. As a result of this review, the FAA published a supplemental notice of proposed rulemaking (SNPRM) AD on January 8, 20 15 (80 FR 1008). This SNPRM AD would reduce the severity of compliance by modifying the schedule for removal of the affected cylinder assemblies, eliminating a reporting requirement, removing the requirement for initial and repetitive inspections, and clarifying that overhauled affected cylinders assemblies be removed within 80 hours after the effective date of this AD. This does not remove the recurring inspections already required by other regulations to provide an adequate level of safety. In addition, there is no direct correlation between the 1,000 hours removal requirement that was proposed in the NPRM AD and the requirement to remove overhauled affected cylinder assemblies within 80 hours as stated in the SNPRM AD. The FAA subsequently met with NTSB staff on June 9, 2015 to provide them with additional technical information that suppo11s the issuance or this AD. We also published a second SNPRM on August 28, 2015 (80 FR 52212) to allow the public to comment on additional supplementing information, including our risk analysis supporting the AD that we have added to the AD docket. I will keep the Board informed of the FAA's progress on this safety recommendation and provide an updated response no later than September 30, 2016.

From: NTSB
To: FAA
Date: 9/24/2015
Response: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) supplemental notice of proposed rulemaking (SNPRM) titled “Airworthiness Directives (AD); Continental Motors, Inc. Reciprocating Engines,” which was published in 80 Federal Register 52212 on August 28, 2015. The proposed AD revises an earlier proposed AD for certain Airmotive Engineering Corp. replacement parts manufacturer approval (PMA) cylinder assemblies marketed by Engine Components International Division (ECi). The original proposed AD would require initial and repetitive inspections, replacement of cracked cylinders, and replacement of cylinder assemblies at reduced times-in-service (TIS) for certain ECi cylinder assemblies installed on Continental Motors, Inc. (CMI) engines. The original proposed AD would also prohibit the installation of affected cylinder assemblies into any engine. The proposed revision modifies the schedule for removal of the affected cylinder assemblies, stipulates that overhauled affected cylinder assemblies be removed within 80 hours after the effective date of the AD, eliminates a reporting requirement, and removes the requirement for initial and repetitive inspections. The SNPRM is intended to prevent failure of the cylinder assemblies, which could lead to engine failure, in-flight shutdown, and loss of airplane control. The NTSB has worked with ECi and the FAA for many years concerning failures of cylinder assemblies installed on reciprocating aircraft engines. After much research into the failure modes and root causes for certain cylinder head separations on ECi-manufactured cylinder assemblies installed on CMI 520 and 550 series engines, on February 24, 2012, the NTSB issued Safety Recommendation A-12-7, stated below, to the FAA. Require repetitive inspection of Engine Components, Inc., cylinder assemblies produced between May 2003 and October 2009 (serial numbers 7709 through 52884) installed on Teledyne Continental Motors model 520 and 550 engines and removal of these cylinder assemblies once they reach the engine manufacturer’s recommended normal time (hours) in service between overhauls. This recommendation was issued to address findings from our investigations and data supplied by ECi in which fatigue cracking of an ECi aluminum cylinder head had initiated in the root of a thread and propagated outward to the point where a majority of the cylinder head separated from a minor portion that remained attached to the cylinder barrel. This head separation causes a significant drop in engine power and can result in engine failure. The NTSB believes that, if implemented, the proposed AD will satisfy the intent of Safety Recommendation A-12-7. The applicability of the proposed AD exceeds that of our recommendation; however, the NTSB notes that the FAA has considered additional failure mechanisms such as dome radius failures in determining the serial number range of affected cylinder assemblies. Thank you for the opportunity to comment on this SNPRM.

From: NTSB
To: FAA
Date: 2/11/2015
Response: CC# 201500049: NTSB Comments on Docket No. FAA-2012-0002; Directorate Identifier: 2011-NE-42-AD The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) supplemental notice of proposed rulemaking (SNPRM) titled “Airworthiness Directives (AD); Continental Motors, Inc. Reciprocating Engines,” which was published in 80 Federal Register 1008 on January 8, 2015. The proposed AD revises an earlier proposal for certain Airmotive Engineering Corp. (AEC) replacement parts manufacturer approval cylinder assemblies marketed by Engine Components International Division (ECi). The original proposed AD would have required initial and repetitive inspections, replacement of cracked cylinders, and replacement of cylinder assemblies at reduced times-in-service (TIS) for certain ECi cylinder assemblies installed on Continental Motors, Inc. (CMI) engines. The original proposed AD would also prohibit the installation of affected cylinder assemblies into any engine. The proposed revision modifies the schedule for removal of the affected cylinder assemblies, stipulates that overhauled affected cylinder assemblies be removed within 80 hours after the effective date of the AD, eliminates a reporting requirement, and removes the requirement for initial and repetitive inspections. The SNPRM is intended to prevent failure of the cylinder assemblies, which could lead to engine failure, in-flight shutdown, and loss of airplane control. The FAA received numerous comments on the original proposed AD, including from the NTSB, with a vast majority of those comments being against the AD’s implementation for various reasons. As stated in our November 5, 2013, comments about the original proposed AD, the NTSB has worked with ECi and the FAA for many years concerning failures of cylinder assemblies installed on reciprocating aircraft engines. After much research into the failure modes and root causes for certain cylinder head separations on ECi-manufactured cylinder assemblies installed on CMI 520 and 550 series engines, the NTSB issued Safety Recommendation A-12-7, shown below, to the FAA on February 24, 2012. Require repetitive inspection of Engine Components, Inc., cylinder assemblies produced between May 2003 and October 2009 (serial numbers 7709 through 52884) installed on Teledyne Continental Motors model 520 and 550 engines and removal of these cylinder assemblies once they reach the engine manufacturer’s recommended normal time (hours) in service between overhauls. This recommendation was issued to address findings from our investigations and data supplied by ECi in which fatigue cracking of an ECi aluminum cylinder head had initiated in the root of a thread and propagated outward to the point where a majority of the cylinder head separated from a minor portion that remained attached to the cylinder barrel. This head separation causes a significant drop in engine power and possibly engine failure. In our November 5, 2013, comments about the original proposed AD, we commented that the proposal affected many more cylinder assemblies than was supported by our investigations. The NTSB has not investigated any cases involving engines with cylinder assemblies ranging from serial number (S/N) 1 through S/N 1043, and concerns about this group of cylinders did not arise during meetings between the NTSB, the FAA, and ECi to discuss findings related to any cylinder assemblies. In the SNPRM, the FAA did not agree with our comment. The FAA stated that based on service failure data and known implementation of design improvements, the proposed AD must apply to cylinder assemblies with S/Ns 1 through 61176. We continue to believe that to be a much larger number of affected cylinder assemblies than is supported by our investigations. ECi cylinder assemblies ranging from S/N 1044 through S/N 7708 installed on CMI 520 and 550 series engines were identified for required replacement before further flight in AD 2004-08-10, which was issued on May 5, 2004, and remains in effect. According to AD 2004-08-10, ECi identified a manufacturing discrepancy that occurred between September 2002 and May 2003 affecting S/N 1044 through S/N 7708 assemblies, which resulted in an inadequate cylinder head wall thickness and an over-hardened condition that would reduce the fatigue strength of the aluminum cylinder head. Because the requirements of AD 2004-08-10 are more stringent and affect some of the same cylinders in the proposed AD, we continue to believe that cylinder assemblies with S/N 1044 through S/N 7708 should not be included in the proposed AD. Following the release of Safety Recommendation A-12-7, ECi reported manufacturing data to the NTSB showing the seal band interference fit for all cylinder assemblies from S/N 36210 through S/N 61176. A list of 165 cylinder assemblies by specific serial number with interference fit values below the minimum acceptable limit was provided to the FAA at a February 14, 2013, meeting between staff from ECi, the FAA, and the NTSB. Therefore, the cases investigated by the NTSB do not provide a basis for including cylinder assemblies with S/N 1 through S/N 7708 in the proposed AD, and we believe that our previously issued Safety Recommendation A-12-7 is still valid for all cylinder assemblies with serial numbers 7709 through 36209. In addition, based on our review of the additional seal band interference fit manufacturing data provided by ECi, the NTSB believes that for serial numbers above 36209, safety action is only needed for the 165 cylinder assemblies specifically identified by ECi between S/N 36210 through S/N 61176. In the SNPRM, the FAA stated that the rate of separation for the affected ECi cylinder assemblies was at least 32 times greater than that of CMI cylinder assemblies over the same period. However, comparison of the failure rates between the ECi and CMI cylinder assemblies as presented in the proposed AD is misleading with regard to fatigue capability because the comparison involves cylinder heads of substantially different design. We disagree with the SNPRM’s removal of the repetitive inspection requirements from all cylinder assemblies in the proposed revised AD because, according to the FAA, the inspection apparently did not detect cracks in two cases about which it was aware. The NTSB notes that repetitive inspection procedures are not perfect, but they are effective in detecting cracks that have propagated through the cylinder wall and provide an added level of safety during the time between the issuance of the final AD and the required removal of the cylinder assembly. The NTSB also notes that removing the inspection requirements because they are not wholly effective is not consistent with previous FAA guidance published in Special Airworthiness Information Bulletin (SAIB) NE-07-09R1 and approved by the FAA in ECi Mandatory Service Bulletin (MSB) 06-2. Cylinders with S/N 7709 through S/N 33696 are currently subject to ECi MSB 06-2, which calls for repetitive inspections every 50 hours TIS once the assemblies accumulate 500 hours TIS and replacement of any discrepant cylinder assemblies. The inspections include a standard cylinder compression check and a soap solution bubble test. The FAA approved this MSB and also issued SAIB NE-07-09R1, detailing the importance of performing the inspections noted in MSB 06-2. The SAIB indicates that cylinder head cracking in these cylinders occurred between 253 hours and 1,483 hours TIS with an average time to crack of 891 hours TIS. The SAIB also states that the cracking causes a loss of cylinder compression but is unlikely to result in a cylinder/head separation. Requiring that operators implement a repetitive inspection approach is also needed to address the concerns identified in Safety Recommendation A-12-7. In Safety Recommendation A-12-7, the NTSB recommended that the affected cylinder assemblies be subjected to repetitive inspection and removal once they reach the engine manufacturer’s recommended normal TIS between overhauls. Instead, the SNPRM proposes a reduced compliance time by specifying that affected cylinders that have never been overhauled be removed between 1,000 and 1,160 hours TIS and overhauled affected cylinder assemblies be removed within 80 hours after the effective date of the AD. We continue to believe that the repetitive inspection and removal approach described in Safety Recommendation A-12-7 is appropriate. In summary, we note that the proposed revised rule would exceed NTSB Safety Recommendation A-12-7 by addressing many more cylinder assemblies and by requiring the removal of cylinder assemblies before the engine manufacturer’s recommended normal time (hours) in service between overhauls. However, it would also remove the repetitive inspection requirements requested in our recommendation. The NTSB continues to believe that the AD should require repetitive inspections and removal at the manufacturer-recommended TIS only for cylinder assemblies with serial numbers 7709 through 36209 and for the 165 cylinder assemblies that the manufacturer identified by specific serial number from 36210 through 61176. Thank you for the opportunity to comment on this SNPRM.

From: NTSB
To: FAA
Date: 7/11/2014
Response: We note that on August 5, 2013, you issued a notice of proposed rulemaking (NPRM) for an airworthiness directive (AD) to require both a periodic visual and compression test to detect any cracked or leaking cylinder assemblies and the scheduled removal and replacement of certain ECi cylinder assemblies. The NPRM also proposed to remove all cylinder assemblies from service at, or before accumulating, 1,000 operating hours. In our November 5, 2013, comments about this NPRM, we said that the proposed AD would affect many more cylinder assemblies than we had included in our recommendation, and we therefore proposed a reduced compliance time. Because we were not aware of information to support the expanded scope and decrease in compliance time contained in the proposed AD, we supported an action more consistent with our recommendation. If there were additional data to warrant expanding the scope, we asked you to provide those data and information supporting an expanded scope and compliance time changes. You said in your letter that the public comment phase had closed on December 11, 2013, and that you were currently reviewing comments submitted about the NPRM, including our comments. We look forward to reviewing the final AD when it is issued, and a description of the additional data beyond that referenced in our recommendation letter that is the basis for the greatly expanded scope of the NPRM. The NPRM proposes an AD that appears to respond to Safety Recommendation A-12-7 which, pending issuance of an AD consistent with the recommendation, remains classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 5/9/2014
Response: -From Michael P. Huerta, Administrator: On August 5, 2013, the Federal Aviation Administration (FAA) issued a notice of proposed rulemaking (NPRM) Airworthiness Directive (A D), Continental Motors, Inc. Reciprocating Engines (78 FR 48828, August 12. 2013). This NPRM AD is applicable to: • Certain ECi Parts Manufacturer Approval (PMA) cylinder assemblies used on Continental Motors, Inc. (CMI) 520 and 550 series engines; and • All other engine models approved for the use of CMI models 520 and 550 cylinder assemblies when modified by supplemental type certificate. This NPRM AD is available at the following Web address: http://www.gpo.gov/fdsys/pkg/FR-2013-08-12/pdf/20 13-19414.pdf. The NPRM AD proposes to require both a periodic visual and compression test to detect any cracked or leaking cylinder assemblies and the scheduled removal and replacement of those cylinder assemblies. The NPRM also proposes to remove all cylinder assemblies from service at or before accumulating 1,000 operating hours. Detection or a leaking cylinder assembly would result in its removal before the metal fatigue process leads to a fracture and a head-to-barrel separation. The public comment phase closed on December 11, 2013. We are currently in the process of reviewing these comments, including the comment from the NTSB. I will keep the Board informed of the FAA's progress on this safety recommendation and provide an updated response by December 31, 2014.

From: NTSB
To: FAA
Date: 11/5/2013
Response: CC# 201301009: What follows is an abbreviated version of the NTSB's comments on the FAA's Notice of Proposed Rulemaking: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM) titled “Airworthiness Directives (AD); Continental Motors, Inc. Reciprocating Engines,” which was published at 78 Federal Register (FR) 48828 on August 12, 2013. The proposed AD would require initial and repetitive inspections, replacement of cracked cylinders, and replacement of cylinder assemblies at reduced times-in-service (TIS) for certain Engine Components International Division (ECi) cylinder assemblies installed on Continental Motors, Inc. (CMI) engines. This proposed AD would also prohibit the installation of affected cylinder assemblies into any engine. The NTSB has worked with ECi and the FAA for many years concerning failures of cylinder assemblies installed on reciprocating aircraft engines. After much research into the failure modes and root causes for certain cylinder head separations on ECi-manufactured cylinder assemblies installed on CMI 520 and 550 series engines, the NTSB issued Safety Recommendation A-12-7, shown below, to the FAA on February 24, 2012. We note that the NPRM’s proposal to remove Group A cylinder assemblies with fewer than 500 hours TIS or more than 1,000 hours TIS within 25 hours TIS does not appear to be based on an existing MSB; findings from known events; discussions between the NTSB, the FAA, and ECi in the meetings cited in the NPRM; or any additional information discussed in the body of the NPRM itself. Accordingly, we are uncertain about the data and information on which the required removal as proposed in the NPRM is based and do not understand the foreseeable safety benefit of the FAA’s proposed action. While we acknowledge that the FAA may have obtained such data or information separately from our investigations, without visibility of the information, we cannot comment on the need for the Group A actions cited above. Based on NTSB Recommendation A-12-7, Group A cylinder assemblies with S/N 7709 through S/N 33696 should be subjected to repetitive inspection and removal once they reach the engine manufacturer’s recommended normal TIS between overhauls. Therefore, the proposed requirement to repetitively inspect Group A cylinder assemblies with 500 to 1,000 hours TIS every 50 hours TIS should apply to all Group A cylinder assemblies with S/N 7709 through S/N 33696, regardless of TIS. In summary, we note that the proposed rule would affect many more cylinder assemblies than the NTSB included in our recommendation letter. Because we are not aware of information to support the expanded scope and decrease in compliance time contained in the FAA’s proposed AD, we support FAA action more consistent with NTSB Safety Recommendation A-12-7. If there is additional data to warrant expanding the scope, we encourage the FAA to provide that data and information supporting an expanded scope and compliance time changes in this proposed action.

From: NTSB
To: FAA
Date: 9/16/2013
Response: THIS LETTER WAS SENT TO DANBURY AEROSPACE, NOT THE ADDRESSEE. THE ADDRESSEE IS FAA (FEDERAL AVIATION ADMINISTRATION): In our February 24, 2012, letter to the FAA issuing this recommendation (the safety recommendation letter), we discussed at least 29 cylinder head fatigue failures that had been reported and confirmed by ECi for ECi cylinder assemblies installed on TCM engines. We are not aware of similar problems with assemblies manufactured by other organizations. In the safety recommendation letter, we also documented ECi’s extensive technical assistance in developing the basis for this recommendation, including supplying, for our analysis, failed cylinder heads submitted to ECi, and designing and developing a fatigue test fixture that simulates the cylinder head temperature and pressure cycles experienced by a cylinder on an operating engine. That letter also described a January 2011 meeting among ECi, the FAA, and the NTSB, at which ECi produced data on the cylinder assembly failures and recommended that the FAA issue an airworthiness directive (AD) to mandate inspection and replacement of any discrepant cylinders. Because the FAA had not acted on ECi’s recommendation, we issued Safety Recommendation A-12-7 and affirmed our support for ECi’s earlier recommendation. The safety recommendation letter also described ECi’s August 2006 Mandatory Service Bulletin 06-2, which recommends that owners and operators of some of the cylinder heads that are the subject of our recommendation (1) perform repetitive inspections for leaks and cracks on the cylinder assemblies and (2) replace any discrepant cylinders found during these inspections. In October 2009, ECi changed the manufacturing process for its cylinder assemblies; since that process change, there have been no reported cylinder head fatigue failures on ECi cylinder assemblies installed on TCM model 520 and 550 engines. We issued Safety Recommendation A-12-7 because, although the results of ECi’s testing demonstrate that the revised manufacturing process increased the fatigue resistance of new production cylinder heads, many cylinder assemblies susceptible to fatigue failure remain in service with no corrective action currently being required. Staff from ECi and the NTSB met again on November 27, 2012, and reviewed in detail the information discussed in DAS’s September 5, 2012, letter. We continue to believe that, as stated in Safety Recommendation A-12-7, the cylinder assemblies need to be subject to repetitive inspections and removed from service once they reach the normal time in service between overhauls. However, new evidence that ECi has gathered since the recommendation was issued may lessen the specific cylinder assembly applicability. Therefore, our recommendation may be satisfied if the repetitive inspections and removal from service are performed on cylinder assemblies with serial numbers that are a subset of the serial numbers listed in our recommendation. After the FAA issues an AD in response to our recommendation, we will evaluate that document and determine whether it satisfies Safety Recommendation A 12 7. If it does, we will close the recommendation. We emphasize that, because the FAA has the regulatory authority to mandate the action in Safety Recommendation A-12-7, we issued our recommendation to that agency. In response to our recommendation, on August 12, 2013, the FAA published a notice of proposed rulemaking (NPRM) that proposed issuance of an AD that would affect a much greater number of ECi cylinder assemblies than would be affected by the action we recommended. We believe that DAS’s comments about our recommendation should be submitted to the FAA as comments regarding the NPRM. We will also submit comments to the FAA regarding the details of the proposed requirement. We believe that the FAA’s consideration of all these comments is the most appropriate way for these concerns to be addressed. During our July 15, 2013, meeting, you indicated that data showing an industry-wide problem with cylinder head separations existed, and that running these cylinders at higher temperatures than anticipated in the design of the assemblies may be the cause of this problem. We understand that you and DAS are gathering and organizing information on catastrophic failures related to cylinder head?to?barrel separations in assemblies manufactured by other organizations. We would be interested in reviewing the information that you are collecting; however, we have not seen any trends in our accident or incident investigations that would support our issuing a safety recommendation to the FAA to perform a thorough study of cylinder failures from all manufacturers. We strongly encourage DAS to share this information with the FAA as well, so that appropriate action can be taken to prevent future accidents and incidents associated with this problem. In summary, we have thoroughly reviewed the information presented by your firm and by DAS. Although some of the details of the affected assemblies may vary, we believe the need for the action by the FAA specified in Safety Recommendation A-12-7 remains, and that, now that the FAA has issued an NPRM, the submission of public comments about the proposed requirement is the most appropriate process for further discussion of these issues.

From: NTSB
To: FAA
Date: 8/12/2013
Response: Correspondence control #201300872 was closed early. No letter was sent using this number.

From: NTSB
To: FAA
Date: 4/12/2013
Response: THIS LETTER WAS SENT TO DANBURY AEROSPACE, NOT THE ADDRESSEE. THE ADDRESSEE IS FAA (FEDERAL AVIATION ADMINISTRATION): Although this recommendation was issued to the FAA, it concerns an important product of ECi, and the FAA’s response may substantially impact DAS. In your December 19, 2012, letter, you provided information about why you believe the NTSB should classify Safety Recommendation A-12-7 “Closed—Reconsidered.” We have considered the information that you and your staff presented, both in your letters and during our meetings, and we acknowledge that, based on additional information and analysis generated after the recommendation was issued, taking action on the specific cylinder assemblies you identified may satisfy the intent of the recommendation. However, we continue to believe that the recommended action is needed for the affected assemblies and that these cylinder assemblies need to be subject to repetitive inspections and removed from service once they reach the normal time in service between overhauls. Accordingly, Safety Recommendation A-12-7 remains classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 12/19/2012
Response: -From Ty Stoller, President of Danbury Aerospace: THIS LETTER IS FROM DANBURY AEROSPACE, NOT THE FAA, THIS LETTER IS NOT FROM THE RECIPIENT OF THIS RECOMMENDATION: Closed-Reconsidered: Recipient rejects the safety recommendation and supports this rejection with a rationale with which the Board concurs. While the Federal Aviation Administration (FAA) is the technical recipient of the Safety Recommendation, this company is directly and immediately impacted by the Board's action. Indeed, the FAA is currently processing a notice of proposed rulemaking (NPRM), which could bankrupt this company; the proposed Airworthiness Directive (AD) is being justified by Safety Recommendation A-12-7. The company provided evidence in the referenced letter and during the meeting of November 27, 2012 that controverted the recommendation's technical assumptions, thus jeopardizing the validity of the actions prescribed for ECi cylinders. Specifically, it rejects the safety recommendation and Board representatives have acknowledged: • The safety objective of the recommendation is to reduce or even eliminate head-to cylinder separations in reciprocating engines. • The test results and root-cause analysis presented by the company during the November 2012 meeting were valid; the condition is caused by over-temperature conditions. Since the company believes it meets the burden established by the Board's procedures, the safety recommendation should be closed. In the alternative, the Board should place the recommendation in a "reconsidered" status. The standard is: Reasons for the "Reconsidered" status would include situations where the recipient is able to convince the Board that the proposed action would not be effective or that it might create other problems. This status is also assigned when the recipient of a recommendation was in compliance before the recommendation was issued or when the recipient was incorrectly chosen and cannot perform the recommended action. The proposed action would not be effective ECi's design and production of reciprocating engine cylinders meets more than the minimum standards established by the FAA; the integrity of the design is maximized by strict production methodologies. Any further action by the company is futile; to decrease head-to-barrel separations, operating parameters must be strictly enforced. The proposed action might create other problems The Board's action has created other problems because the FAA is processing a NPRM that will directly impact this company's viability, particularly if it is released as last indicated by the agency. Board recommendations based upon problematic assumptions are detrimental to its responsibility for improving safety. The recipient has provided good engineering data that refutes the assumption that the problem of head-to-barrel separation is solved by "more" design and/or production improvements. Although improved design analysis and production methodologies have continuously improved the safety margins, the cylinder's design is ultimately dictated by the engine design and operation. The reliability of the cylinder is driven by the engine installation and operation; the underlying cause of head-to-barrel separations is unacceptable practices, i.e., improper break-in and overtemperature engine operations. The Board's recommendation was based upon information that was available to it at the time it was drafted, but new information, including comprehensive test results, has been presented to NTSB technical personnel. They have agreed that the new information is persuasive. The Board is responsible for making objective technically supportable determinations, and we conclude that the Board's continued support of the recommendations in A-12-07 is not in the best interests of operational safety. Improvements to design and/or production standards or requirements will not produce a significant improvement in operational safety as documented from verified and validated engineering tests and analysis. The only way to significantly improve operational safety related to the structural fatigue failures of aircraft piston engine cylinders is to address the operational environment in which these cylinders operate. We believe that changing the emphasis of the Safety Recommendations from the hardware to the operating parameters will enhance the Board's credibility and help insure meaningful changes that have a positive effect on flight safety. The recipient of a recommendation was in compliance before it was issued ECi has continually made design and production changes that ensure the largest margin of safety available for reciprocating engine pistons. Indeed, even before its latest design and production enhancements, the company was in compliance with the standards established for the design of the product. The recipient was incorrectly chosen and cannot perform the recommended action ECi acknowledges that the technical recipient, the FAA, was correctly chosen. However: • The ultimate aim of the recommendation is to address head-to-barrel separations in reciprocating engine cylinders. • The original report is based upon problematic data and engineering analysis. • The ultimate recipient of the recommendation (ECi) provided technically sound information (based upon Board representatives' recommendations) that the ultimate cause of the safety issue (head-to-barrel separations) is over-temperature either due to improper maintenance at break-in or operations of the engine. • The recommended action is misdirected o Break-in is a maintenance action accomplished when the cylinder is installed in the engine; break-in must be done in accordance with 14 CFR part 43. ECi does not control the maintenance of aircraft engines, but does provide information to help operators break-in their cylinders correctly. o Likewise, ECi has no control of the operation of the engine once it is installed in an aircraft. If an aircraft owner operates in over-temperature conditions overlong or repetitively, the reliability of all reciprocating engine cylinders declines rapidly. 14 CFR part 91 controls deliberate operations that endanger the aircraft or its passengers. To ensure operators are aware of unsafe operating conditions, appropriate changes to mandatory installation requirements would accomplish the safety objective. Therefore, while the correct recipient of the recommendation may remain the FAA, correction of the root cause must be directed at operations. To decrease head-to-barrel separations, operating parameters must be strictly enforced by requiring reliable cylinder head temperature gauge installation. ECI has requested a meeting with the FAA and NTSB representatives in January to discuss the safety issue of over-temperature operation and glazed bores and their effect on our product and flight safety. Conclusion Based upon valid and verifiable engineering data available to the Board, it should close Safety Recommendation A-12-7. Alternatively, the Board should: • Amend its recommendation as was suggested in the September 5, 2012 letter. • Place the recommendation in "reconsider" status. Please understand the urgency of this request; if the FAA proceeds with its NPRM based on a problematic safety recommendation, it would be contrary to safety. Further it will result in the demise of this 70-year old American manufacturing company and the livelihood of two hundred (200) employees as the company lacks the resources to withstand the potential AD's scope. Additionally, as noted in the attached article entitled "Separation Anxiety" by Mike Busch, published in the November 2012 volume of Cessna Pilots Association Magazine, the ultimate costs will be borne directly by the flying public. Please act expeditiously on our request; if we need a formal meeting to discuss the details, please contact us at your earliest convenience. We look forward to your reply.

From: NTSB
To: FAA
Date: 7/12/2012
Response: We note that the FAA is developing, and will soon issue, a notice of proposed rulemaking for an airworthiness directive (AD) to require the recommended action. Pending issuance of the AD, Safety Recommendation A-12-7 is classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 5/8/2012
Response: -From Michael P. Huerta, Acting Administrator: From 2006 through 2012, the Federal Aviation Administration (FAA) Engine and Propeller Directorate has investigated continued operational safety issues with new parts manufacturer approval (PMA) reciprocating engine cylinder assemblies manufactured by ECi. We have received 33 reports of head-to-barrel separations in new replacement ECi PMA cylinder assemblies for Continental Motors 520 and 550 series engines. The FAA has undertaken a series of actions to prevent accidents caused by cylinder head separations. On March 21, 2007, we issued Special Airworthiness Information Bulletin (SAI13) NE-07-09R I for certain ECi PMA cylinder assemblies for Continental Motors 520 and 550 series engines. This SAIB recommended periodic visual and compression tests for ECi part number AEC631397 and serial numbers 7709 through 33696. On December 31, 2009, we issued Airworthiness Directive (AD) 2009-26-12 for certain ECi PMA cylinder assemblies for Lycoming Engines 320, 360, and 540 series engines. This AD required periodic cylinder inspections with removal at the normal Time Between Overhaul recommended by Lycoming Engines. We plan to issue an AD notice of proposed rulemaking (NPRM) for Eei PMA cylinder assemblies for Continental Motors 520 and 550 series engines, with Part umber AEC631397 and Serial numbers 7709 through 61176. This NPRM will require both a periodic visual and compression lest to detect any cracked or leaking cylinder assemblies and the scheduled removal and replacement of those cylinder assemblies. Detection of a leaking cylinder assembly will allow its removal before the metal fatigue process results in a fracture and a head-to-barrel separation. We plan to issue the PRM by August 31. 2012. I will keep the Board informed of the FAA's progress on this safety recommendation, and provide an update by December 31, 2012.