The FAA proposed to amend 14 CFR part 39 with a proposed airworthiness directive (AD). The proposed AD applies to certain Lycoming Engines (L)O-360, (L)IO-360, AEIO-360, O-540, IO- 540, AEIO-540, (L)TIO-540, IO-580, AEIO-580, and IO-720 series reciprocating engines. We published the proposed AD in the Federal Register on May 25, 2006 (71 FR 30078, May 19, 2006). That action proposed to require replacing certain crankshafts.
Examining the AD Docket
You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
Suggest to Only Reference 360-Series Engines
One private citizen suggests that since Lycoming Mandatory Service Bulletin (MSB) No. 569A, referenced in the proposed AD, only applies to 360-series engines with counterweighted crankshafts, the AD should do the same.
We agree. The commenter is correct that MSB No. 569A refers only to counterweighted (L)O-360 engines. We changed paragraph (c) to limit the applicability of this AD to only those engines listed in the tables in Lycoming MSB No. 569A. The MSB lists the specific engine models and serial numbers (SNs) for engines that have a suspect crankshaft. The MSB also lists the specific crankshaft SNs installed on engines after the engine entered service. We have made this change to limit the AD's applicability to only those engines with a suspect crankshaft.
Need To Correct the Table of Engine Models and AircraftOne private citizen states that we need to correct the table in paragraph (c), "Applicability." The Lycoming O-540-J3C5D engine listed is actually used in the normally-aspirated Cessna R182, not the turbocharged TR182, as currently listed. The engine in the TR182 is the O-540-L3C5D.
We agree, and have corrected the table. We need to note, however, that the table is provided for information only and does not control whether the AD applies to a listed engine/aircraft combination. As we have noted in paragraph (c), the affected engines may or may not be installed in the listed aircraft models.
12-Year Overhaul Limit Not in Lycoming Engines Service Instruction (SI) No. 1009AR
One private citizen states that the 12-year overhaul limit referred to in the proposed rule is not in Lycoming Engines SI No. 1009AR, as we stated.
We do not agree. The Lycoming Engines service instruction states that engines that do not reach the recommended overhaul hours specified in that publicationshould be overhauled in the twelfth year. We note that this AD does not require an engine overhaul. We have incorporated Lycoming Engines SI No. 1009AS, dated May 25, 2006, only for the purpose of providing a maximum time by which crankshaft replacement must occur, if the engine has not required earlier maintenance that involves separating the crankcase. Therefore, crankshaft removal must occur at the earliest of maintenance involving crankcase separation, the time-in-service specified in Lycoming Engines SI No. 1009AS for engine overhaul, or 12 years from the time the crankshaft first entered service. For clarification, we have added to the AD new sub-paragraphs (j)(3) and (k)(3) that now directly specify the 12-year compliance end time for crankshaft removal.
Engine Model Included in Error in MSB
One commenter, Lycoming Engines, states that engine model TIO-540- U2A, SN L-4641-61A, was included in MSB No. 569A in error and it is not affected by the MSB and should not be included in this AD. We agree and added new paragraph (i) in the AD that states that no action is required for this engine model. We have also added a new sub-paragraph (f)(5) to clarify that if the AD applies to an engine, but no action is required because the crankshaft on that engine is not identified as one needing replacement, the owner or operator of the aircraft may make an entry in the AD status log required by 14 CFR 91.417(a)(2)(v) that the AD required no action.
Engine Model Included in Error in Proposed AD
Since we issued the proposed AD, we have identified the engine model AEIO-580 as not type certified for operation in the United States. Although this engine is listed in Table 3 of MSB No. 569A, we have removed this engine model from the AD applicability.
Consider an Additional 100 Hours Operation
One private citizen suggests that for aircraft that are already beyond Lycoming's time-between-overhaul (TBO) that we provide an additional 100 hours of operation from the effective date of the AD, as this would give people time to get new crankshafts or overhauls lined up.
We do not agree. This final rule will not become effective until 35 days after it is published in the Federal Register. That should be ample time to prepare for compliance with the AD for those operators with engines that have operated past the Lycoming recommended TBO. If an operator needs additional time, that operator may request an alternative method of compliance (AMOC), using the procedures found in 14 CFR 39.19. We note that the AD does not require an engine overhaul, but only replacement of an identified crankshaft.
Deadline for Crankshaft Replacement Needs To Be at the Next Overhaul
One private citizen, states that the deadline for crankshaft replacement needs to be at the next overhaul.
We do not agree. The AD requires replacement of identified crankshafts at the earliest of the next time maintenance requires splitting the crankcase, or the time specifiedfor the next engine overhaul listed in Lycoming Engines SI No. 1009AS, or 12 years from when the crankshaft entered service. An operator may request additional time through a request for an AMOC using the procedures found in 14 CFR 39.19. Note that the AD does not require the engine to be overhauled. It only requires replacing the affected crankshaft, which can be done with other maintenance.
Remove Calendar Time Compliance
One commenter, Cessna Pilots Association, states that there should be no calendar time mandated, and that compliance should be determined by the appropriate Federal Aviation Regulations for the type of operations for which the aircraft is used.
Another commenter, Aircraft Owners and Pilots Association, states that aircraft owners should be allowed to continue to operate their engine until reaching time-for-overhaul based on hours without any calendar end time.
We do not agree. We re-evaluated the risk that this unsafe condition presents to aircraft and have determined that adequate risk mitigation can only be achieved by establishing an end limit for crankshaft removal based on years since a crankshaft enters service. The variability of the size and orientation of the metallurgical anomalies present in the identified crankshafts, results in variation in the operating times at which failures could occur. Therefore, while we stated in the proposal that the unsafe condition was unrelated to calendar time, a compliance end-time is necessary to minimize the probability of a crankshaft failure at operating times less than the specified overhaul interval. The 12-year calendar end time was selected to provide the necessary risk mitigation while minimizing the burden on owners and operators. We fully expect that few crankshafts will be replaced solely because of the 12-year calendar end time because crankshafts must be replaced earlier if maintenance requires splitting the crankcase or operations accumulate enough hours to meet the engine TBO.
However, if an owner (or) operator has data to justify an extension of the hourly limit and (or) the calendar end-limit, the owner (or) operator can request an AMOC using the procedures found in 14 CFR 39.19.
Determining crankshaft removal times by the type of operation would impose an overly complex record-keeping requirement on owners and operators. The identified crankshafts are installed in engines that are engaged in multiple types of operations ranging from personal use to commercial operations. We note that for some commercial operators the recommended TBO times may be mandated as a necessary component of their approved maintenance programs. For these operators, then, crankshaft replacement will be a part of the required engine overhaul unless earlier maintenance requires splitting the crankcase.
Evidence for AD Is Not Convincing Enough
One private citizen states that the evidence used to justify the proposed AD is not convincing enough to require parts replacement, and the lengthy compliance time (12 years) implies crankshaft replacement is not urgent, and, if it is urgent, the crankshafts should be replaced in a shorter time.
We do not agree. While we determined that the risk to safety of flight was not urgent enough to warrant publishing an emergency AD that would become effective immediately upon publication, we have sufficient data on which to conclude that an unsafe condition exists and that it is likely to exist or develop on other products of the same type design. We selected the compliance times in this AD because:
The same metallurgical flaw that was found in 23 confirmed crankshaft failures in different groups of Lycoming 360 and 540 engines has been found in the crankshafts in this group of engines; and
Because of the presence of the flaw, this group of crankshafts has a higher potential for failure than other crankshaft groups that do not have the flaw, and it may only take longer to fail; and
The overhaul may be the first opportunity that the crankshaft is removed from the engine and the first opportunity to replace the crankshaft. As previously stated in another comment, we do not have the data to support an hourly or calendar time extension beyond the hourly times contained in Lycoming Engines SI No. 1009AS, or the 12-year compliance end-time.
Suggest Crankshaft Fractures Noted Are From an As-Yet Unidentified Cause
Three private citizens suggest that the 23 crankshaft fractures noted are from an as-yet unidentified cause, or causes, within the engine, which results in crankshaft fracture.
We do not agree. The proposal referred to 23 confirmed failures of similar crankshafts in Lycoming 360 and 540 series reciprocating engines. These are 23 crankshafts that exhibited the same, subsurface material flaw that progress to a fatigue failure. There were several other crankshaft failures that exhibited most of the same failure characteristics as the 23 confirmed failures, but the fracture surface was too badly damaged for a complete examination to confirm that they were the same. The two examples of crankshaft failures mentioned by the commenters were not examined by the Lycoming Materials Laboratory, or any of the other Materials Laboratories that participated in this investigation.
One is an Australian Transport Safety Bureau report of a Lycoming O-540 crankshaft failure, that is known to the FAA, but was not included in the 23 confirmed failures. The other example is the failure of a crankshaft identified as being from a Lycoming O-360 series engine. However, the laboratory failure report did not identify the engine model or SN. This crankshaft failed in two locations and neither of the locations are the same as the single failure location of the crankshafts in this investigation (the 23 confirmed failures and the unconfirmed failures all failed in the same location.) In addition, the report does not contain the engine type, type of engine operation, crankshaft partnumber, serial number, heat code, overhaul rework data, or overhaul assembly data. This makes it impossible to determine if the crankshaft was a Lycoming part or a PMA part, when the part was manufactured, or if the crankshaft was installed in an aerobatic engine and operated at a higher than certified horsepower. Based on the above, we cannot accept these examples as data to support their position that we have inadequate data on which to conclude that an unsafe condition exists and that it is likely to either exist or develop on other products of the same type design.
No Reason To Change Lycoming Engines Current Compliance Conditions
One commenter, Lycoming Engines, sees no reason to change its current compliance conditions, as there is no data to suggest any adjustment to the compliance terms.
We do not agree. Crankshafts from the group listed in Lycoming Engines MSB No. 569A have been found to have the same material flaws as those in the groups that were addressed by previous Lycoming Engines MSBs and FAA ADs. We selected a crankshaft replacement schedule that minimizes the burden on owners and operators by requiring replacement of the crankshaft only when accessible during engine maintenance or overhaul, but contains a compliance end-time of 12 years after the crankshaft enters service to provide the necessary risk mitigation. There is no current data to support an accelerated removal of the crankshafts, so we determined that the crankshafts can continue in service until the next engine overhaul as specified in Lycoming Engines SI No. 1009AS. However, if new data becomes available at a later date, we will re-evaluate our conclusion.
Lycoming Engines Should Pay Regardless of Calendar Time
Six commenters, the Cessna Pilots Association, the Aircraft Owners and Pilots Association, and four private citizens state that Lycoming Engines should pay for the complete replacement cost or extend the $2,000 crankshaft kit price, regardless of when an owner replaces the crankshaft required to be removed to comply with this AD.
We view this comment as beyond the scope of this rulemaking. We have no authority to regulate when or by how much a manufacturer reimburses an owner for actions required as a result of compliance with an AD.
Update to Lycoming Engines SI No. 1009AR
We updated the references of Lycoming Engines SI No. 1009AR, dated June 22, 2004, to Lycoming Engines SI No. 1009AS, dated May 25, 2006, in this AD.
Conclusion
We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
We estimate that this AD will affect 3,774 engines installed on airplanes of U.S. registry. Because the AD compliance interval coincides with engine overhaul or other engine maintenance, we estimate no additional labor hours will be needed to comply with this AD. Parts will cost about $16,000 per engine. Based on these figures, we estimate the total cost of the AD to be $60,384,000. Lycoming said it may provide the parts for $2,000, until February 21, 2009, but will not extend the parts price beyond that date. In addition, since we issued the NPRM, Lycoming Engines has provided additional information on their Web site, explaining that engines affected by MSB No. 569 or MSB No. 569A, which get overhauled at the Lycoming factory at any time within the FAA mandated 12-year limit, will receive a replacement crankshaft during overhaul at no additional charge.
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 Findings
We have determined that 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 thisAD:
(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); and
(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.
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 Federal Aviation Administration amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: