Airworthiness Directives; Piper Aircraft, Inc. Airplanes, 56993-57001 [2012-22529]

Download as PDF Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations (3) If any damage or leakage is found as a result of any inspection required in paragraph (f)(2) of this AD, before further flight, do the applicable corrective actions following the instructions in Costruzioni Aeronautiche TECNAM P2006T Aircraft Maintenance Manual, Document No. 2006/ 045, 2nd Edition—Revision 1, dated April 27, 2011. tkelley on DSK3SPTVN1PROD with RULES (g) Other FAA AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Albert Mercado, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329–4119; fax: (816) 329– 4090; email: albert.mercado@faa.gov. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. (2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service. (3) Reporting Requirements: For any reporting requirement in this AD, a federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120–0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave. SW., Washington, DC 20591, Attn: Information Collection Clearance Officer, AES–200. (h) Related Information Refer to MCAI European Aviation Safety Agency (EASA) AD No.: 2012–0043, dated March 19, 2012; Costruzioni Aeronautiche Tecnam Service Bulletin SB 80–CS, dated January 2, 2012; and Costruzioni Aeronautiche Tecnam P2006T Maintenance Manual, 2nd Edition, Revision 1, dated April 7, 2011, for related information. For service information related to this AD, contact Costruzioni Aeronautiche TECNAM Airworthiness Office, Via Maiorise—81043 Capua (CE) Italy; telephone: +39 0823 620134; fax: +39 0823 622899; email: VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 m.oliva@tecnam.com, or g.paduano@tecnam.com; Internet: www.tecnam.com. You may review copies of the referenced service information at the FAA, Small Airplane Directorate, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329–4148. (i) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) Costruzioni Aeronautiche TECNAM Service Bulletin SB 80–CS, dated January 2, 2012; and (ii) Costruzioni Aeronautiche TECNAM P2006T Aircraft Maintenance Manual, Document No. 2006/045, 2nd Edition— Revision 1, dated April 27, 2011. (3) For Costruzioni Aeronautiche TECNAM service information identified in this AD, contact Costruzioni Aeronautiche TECNAM Airworthiness Office, Via Maiorise—81043 Capua (CE) Italy; telephone: +39 0823 620134; fax: +39 0823 622899; email: m.oliva@tecnam.com, or g.paduano@tecnam.com; Internet: www.tecnam.com. (4) You may review copies of the service information at the FAA, Small Airplane Directorate, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329–4148. (5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http:// www.archives.gov/federal-register/cfr/ibrlocations.html. Issued in Kansas City, Missouri, on August 29, 2012. Earl Lawrence, Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 2012–21927 Filed 9–14–12; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2011–0639; Directorate Identifier 2011–CE–016–AD; Amendment 39–17169; AD 2012–17–06] RIN 2120–AA64 Airworthiness Directives; Piper Aircraft, Inc. Airplanes Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: PO 00000 Frm 00007 Fmt 4700 Sfmt 4700 56993 We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA–24, PA– 24–250, and PA–24–260 airplanes. This AD was prompted by reports of cracks developing in the stabilator horn assembly. This AD requires replacement of the stabilator horn assembly and/or repetitive inspections of the stabilator horn assembly for corrosion or cracks, as applicable. Corrosion or cracks could lead to failure of the stabilator horn. Consequently, failure of the stabilator horn could lead to a loss of pitch control in flight. We are issuing this AD to correct the unsafe condition on these products. DATES: This AD is effective October 22, 2012. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of October 22, 2012. ADDRESSES: For service information identified in this AD, contact Piper Aircraft, Inc., 2926 Piper Drive, Vero Beach, Florida 32960; telephone: (772) 567–4361; fax: (772) 978–6573; Internet: http://www.newpiper.com/company/ publications.asp. You may review copies of the referenced service information at the FAA, Small Airplane Directorate, 901 Locust St., Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329–4148. SUMMARY: Examining the AD Docket You may examine the AD docket on the Internet at http:// www.regulations.gov; 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: Gregory K. Noles, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, 1701 Columbia Avenue, College Park, Georgia 30337; phone: (404) 474– 5551; fax: (404) 474–5606; email: gregory.noles@faa.gov. SUPPLEMENTARY INFORMATION: Discussion We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That E:\FR\FM\17SER1.SGM 17SER1 56994 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations NPRM published in the Federal Register on June 22, 2011 (76 FR 36395). That NPRM proposed to require replacement of the stabilator horn assembly and/or repetitive inspections of the stabilator horn assembly for corrosion or cracks, as applicable. Comments We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA’s response to each comment. Support for the Proposed Initial Inspection Comments from Kristin Amelia Winter, Charles Parker, Carl Schoolcraft, Dave Fitzgerald for the International Comanche Society (ICS), Hans Neubert for the ICS, Brian Kotso, and John F. Murray were supportive of the AD’s requirement for an initial inspection. We did not change this final rule AD action based on these comments. tkelley on DSK3SPTVN1PROD with RULES Request FAA To Withdraw NPRM (76 FR 36395, June 22, 2011) Due to Adequacy of External Inspections Phil Ciholas requested we reconsider the NPRM (76 FR 36395, June 22, 2011) requirements and noted that even the most severe horn cracking reported (propagated through the part to an exterior surface and was visually detectable without disassembly) had not resulted in complete horn failure or the severity of loss of control postulated in the justification for the AD. The commenter stated that no loss of control incidents or accidents have ever been documented that can be attributed to this failure mode. Given the statistical distribution of cracks reported, the ability of existing external inspections to detect cracks prior to complete failure of the horn, and the lack of any actual complete failures; the commenter felt the internal inspection requiring disassembly is unwarranted on most aircraft, especially recent serial number aircraft, unless there is other evidence of potential issues observed on a particular aircraft. We infer the commenter requested to withdraw the current proposal. We disagree with the request to withdraw the NPRM (76 FR 36395, June 22, 2011). A cracked stabilator horn coupled with the aircraft flight envelope conditions could create an unsafe scenario even though there has not been an in-flight event. A cracked stabilator horn reduces the aircraft’s structural load limits. We did not change this final rule AD action based on these comments. VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 Request To Clarify Applicability (Affected Part Numbers (P/Ns) and Configurations) David Ray Fitzgerald, Robert (no last name given), Patrick D. Donovan, Edward P. Horan, Steven Fischer, Phil Ciholas, Dave Fitzgerald for ICS, Daniel Jacob Katz, Arthur John Beyer, Hans Neubert for the ICS, Brian Kotso, John F. Murray, and Dennis Boykin requested we clarify the applicability to clearly state the affected horn P/Ns and clarify whether other current and future horns (supplemental type certificates (STC), and so forth) are/will be affected. The commenters noted that the text of the proposed AD did not clearly state the affected part numbers. Robert (no last name given), Steven Fischer, Daniel Jacob Katz, Hans Neubert for ICS, and John F. Murray also requested we address the configuration of Models PA–24, PA–24– 250, and PA–24–260 airplanes using the same horn but installed with thicker torque tubes used on the Models PA– 24–400, PA–30, and PA–39 airplanes as the proposed AD did not currently make mention of this configuration. They requested we consider excluding the airplanes configured with the thicker torque tubes from the applicability or including them as terminating action. Phil Ciholas, Arthur John Beyer, and Dennis Boykin requested we address potential material and process changes during production of the Models PA–24, PA–24–250, and PA–24–260 airplanes, amending the NPRM (76 FR 36395, June 22, 2011) to apply to only those aircraft that have experienced issues. Dennis Boykin noted that the manufacturing cycle between the original castings (about 1957) and the final production in 1972 of the Model PA–24–260 airplane precluded the requirement to ensure that similar castings, raw materials, and processes were in place, not just a similar design. Dennis Boykin was not aware of any Model PA–24–260 airplane’s stabilator horn that has been separated, inspected, and found deficient. We partially agree with the commenters. We agree with clarifying the affected P/Ns because the issue is specific to the combination of the P/N and models in the original NPRM (76 FR 36395, June 22, 2011). However, we disagree with excluding aircraft with the thicker torque tube installed or making the installation of the thicker torque tube a terminating action. No documentation has been supplied to provide approval for the installation of thicker torque tubes on the Models PA– 24, PA–24–250, or PA–24–260 airplanes, and the torque tube is not the PO 00000 Frm 00008 Fmt 4700 Sfmt 4700 only contributing factor to the unsafe condition. The FAA has determined the condition is likely to exist or develop in other products of the same type design. We have insufficient data to show that airplanes modified with the thicker torque tube do not have the unsafe condition. We also disagree with excluding stabilator horns manufactured later in the production cycle. We have no record of castings, raw materials, and/or processes changing significantly enough to provide justification to exclude those airplanes from this AD action. If an owner/operator submits substantiating data to support the installation of the thicker torque tube as an alternative method of compliance (AMOC) to this requirement, the FAA will review and consider all AMOC requests we receive provided they follow the procedures in 14 CFR 39.19 and this AD. We changed the AD’s applicability in this final rule AD action to include the horn P/N. Request To Lower Torque Value for Horn Installation Lawrence La Beau, Charles Parker, Eric Paul, Tom Veatch, Ivan R. Wilson, Patrick D. Donovan, Ken E. Shaffer, Patric Barry, John Trudel, Carl Schoolcraft, Phil Ciholas, Dave Fitzgerald for the ICS, Andrew Detsch, Hans Neubert for the ICS, Brian Kotso, John F. Murray, and Allan H. Bieck requested that the AD state an appropriate lower shear nut torque value for the bolts common to the stabilator horn and torque tube. Phil Ciholas requested we add horn deformation limits as a way to control the installation torque and related stress corrosion cracking. Charles Parker, Eric Paul, Tom Veatch, Ivan R. Wilson, Patric Barry, John Trudel, Dave Fitzgerald for the ICS, Hans Neubert for the ICS, and Brian Kotso requested we consider an initial inspection and reinstallation with the lower torque value as terminating action for the AD. Eric Paul and John F. Murray requested we lower the torque value of the stop collar bolts. Phil Ciholas requested we consider switching to shear nuts when any work is done on the joint. The commenters stated over-torque is the root cause of the stress corrosion condition and the procedure does not clearly require a lower torque value. None of the commenters provided justification for the use of stop collar bolts separate from the horn bolts or for the shear nuts. We agree with adding the installation torque value for the bolts common to the horn and torque tube into the AD E:\FR\FM\17SER1.SGM 17SER1 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations tkelley on DSK3SPTVN1PROD with RULES procedures because it is a factor in mitigating the unsafe condition. We will also coordinate with the airplane’s manufacturer on clarifying the airplane maintenance manual procedures for torque of these bolts. However, we disagree with adding an initial inspection and reinstallation of the torque tube with the lower torque value as terminating action for the AD. Although the torque value is a contributing factor, it is not the only factor (others are balance arm interference fit, basic material susceptibility, and corrosion potential). No sufficient correlation has been established between the torque value and deformation and subsequent stress corrosion cracking. Consequently, we disagree with adding horn deformation limits as a way to control the installation torque and related stress corrosion cracking. We disagree with mandating a lower torque value of the stop collar bolts or mandating a switch to shear nuts when any work is done on the joint. The stop collar bolts did not contribute to the unsafe condition, and we cannot mandate actions through an AD that are unnecessary to correct the unsafe condition. There is no current data for approval to change the configuration to shear nuts. We changed the AD by adding the installation torque value for the bolts common to the horn and torque tube into the AD procedures. Request To Use Thicker Torque Tube With Horn Lawrence La Beau, Randy Black, Anonymous, Donald Dummer, Albert Powers, Steven Fischer, Stewart Campbell, Miller Duffield Einsel, Robert, Eric Paul, Tom Veatch, Patric Barry, John Trudel, Edward P. Horan, Carl Schoolcraft, Steven Fischer, Phil Ciholas, Dave Fitzgerald for the ICS, Daniel Jacob Katz, Hans Neubert for the ICS, Lawrence E. Pride, Jim Ritter, Brian Kotso, and John F. Murray noted thicker torque tubes discovered during the ICS’ survey targeted inspections at the horn. This survey was beyond the current maintenance program. The commenters cited the thicker torque tube could lessen the potential for stress corrosion cracking due to horn deformation. Robert, Steven Fischer, Daniel Jacob Katz, Hans Neubert for ICS, and John F. Murray requested we address the configuration of Models PA–24, PA–24– 250, and PA–24–260 airplanes with the subject horn but installed with thicker torque tubes. We do not agree with the commenters. We disagree with authorizing the installation of the thicker torque tube. VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 No documentation has been supplied to provide approval for installation of the thicker torque tube configuration on any airplanes affected by this AD. The FAA will review and consider any AMOC to support the installation of the thicker tube provided it follows the procedures in 14 CFR 39.19 and this AD. We did not change this final rule AD action based on these comments. Request To Provide for a Terminating Action to the Repetitive Inspections Kristin Amelia Winter, Lawrence Zubel, Charles Parker, Randy Black, Donald Dummer, Steven Fischer, Stewart Campbell, Miller Duffield Einsel, Eric Paul, Tom Veatch, Ivan R. Wilson, Patric Barry, Steven Fischer, Phil Ciholas, Dave Fitzgerald for the ICS, Daniel Jacob Katz, Hans Neubert for the ICS, Jim Ritter, Brian Kotso, and John F. Murray requested a terminating action to the repetitive inspections. All the commenters proposed various actions (that is, use of lower installation torque value, installation of a thicker torque tube, installation of replacement horn by way of Australian Civil Aviation Safety Authority (CASA) CASA Supplemental Type Certificate (STC) SVA 532, and terminating action based on additional data collected during the inspections) with varying levels of supporting data. We disagree because no proposed terminating action eliminates all the contributing factors to the unsafe condition. The individual proposed actions have been addressed in other requested changes to the AD. The inspection or replacement programs will manage the issue to an acceptable level of risk. We will consider proposals for a terminating action as an AMOC provided the procedures of 14 CFR 39.19 and this AD are followed. We did not change this final rule AD action based on these comments. Request To Credit for Previous Compliance Commenters David Charles Meigs, Randy Black, Steven Fischer, Hans Neubert for the ICS, and Brian Kotso noted that operators have typically been allowed credit for previous compliance in AD actions. All commenters requested provision for credit when compliance to the requirements has already been accomplished. We agree that credit should be given when compliance to the requirements has already been done. The AD already allows for such credit by stating ‘‘unless already done’’ in paragraph (f) of the AD. As long as the requirements of the PO 00000 Frm 00009 Fmt 4700 Sfmt 4700 56995 AD are followed, credit is available. Any other actions taken would need to be submitted as an AMOC following paragraph (h) of the AD. We did not change this final rule AD action based on these comments. Request To Clarify the AD Applicability to Replacement Parts Commenters David Charles Meigs, Randy Black, Steven Fischer, Hans Neubert for the ICS, Brian Kotso stated that the AD applicability is not clearly defined in terms of both the susceptible horn part number and the affected models. Several commenters request clarification of the AD applicability to replacement parts, particularly the horn in CASA STC SVA 532. We partially agree with clarification on the applicability because the focus of this AD is the horn P/N as discussed in the previous issue ‘‘Request To Clarify Applicability.’’ We disagree with specifically addressing the CASA STC because the STC is still under review for FAA validation and not all design issues have been addressed at this point. Any action relating the STC to the AD will be documented during the FAA review of the CASA STC. As discussed previously, we changed the AD’s applicability to include the horn P/N. Request To Increase Initial Compliance Time Patric Barry and Phil Ciholas expressed concerns with the availability of parts and shop capacity. The commenters requested an increase in the initial compliance time. We disagree with the commenters. The unsafe condition must be addressed in a timely manner. The FAA will consider AMOCs following the procedures in 14 CFR 39.19 and this AD to address any potential parts availability or shop capacity issues. We did not change this final rule AD action based on these comments. Request To Change Units of Compliance Times Commenters Randy Black, Patrick D. Donovan, Carl Schoolcraft, Hans Neubert for the ICS, John F. Murray, and Allan H. Bieck requested changing compliance time criteria. Patrick D. Donovan, Hans Neubert for the ICS, and John F. Murray asked that only calendar time be used for compliance times. Carl Schoolcraft and Allan H. Bieck requested that only TIS be used for compliance times. The commenters noted that stress corrosion cracking (SCC) is a time-related function and not TIS. Carl Schoolcraft noted the calendar time limit to be arbitrary and to have no E:\FR\FM\17SER1.SGM 17SER1 56996 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations tkelley on DSK3SPTVN1PROD with RULES bearing on the condition of the horn. Allan H. Bieck commented TIS is what puts strain on the horn, not idle calendar time while the aircraft sits in a hangar. We disagree with eliminating the calendar time compliance. Calendar time is a key factor in SCC. We also disagree with removing the operational time (TIS) requirement as corrosion in the torque tube is a contributing factor, and the established actions for the corrosion currently have both a calendar and TIS requirement. We will retain our compliance time using both calendar time and TIS. We did not change this final rule AD action based on these comments. Request To Eliminate the Repetitive Inspection Requirement Kristin Amelia Winter, Charles Parker, Albert Powers, Ken E. Shaffer, John Trudel, Dave Fitzgerald for the ICS, Phil Ciholas, and Brian Kotso requested eliminating the repetitive inspection requirement. Commenters justify eliminating the repetitive inspections by stating the cracks do not appear to be time or use related, there is low or no history of cracking in the fleet, there have been no catastrophic horns failures in service, and there is potential for terminating action. We do not agree because SCC is inherently time-related and indirectly driven by operational usage. Not all aircraft will crack, and those that do will not crack at the same time. SCC has several contributing factors that add to the variability. For instance, typical fatigue cracking includes scatter factors on the order of four to determine the appropriate intervals to take action. While high-time aircraft with no cracking is useful data, it does not eliminate the need for action. As for the volume of findings, the quantity compared to the entire fleet size is low. However, when measured against the quantity of valid inspections performed, the find rate is as high as 20 percent. It is also true that no parts have failed catastrophically in flight and the findings have been during the ICS’ survey targeted at the horn. Note that this survey was beyond the current required maintenance program. A cracked horn coupled with the aircraft flight envelope conditions could still create an unsafe scenario even though there has not been an in-flight event. In fact, the service history provides evidence of extensive cracking on both sides of the torque tube bore leading to the potential unsafe condition. As discussed in other responses to commenter requests, no proposed terminating action eliminates all the VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 contributing factors to the unsafe condition. The inspection or replacement programs will manage the issue to an acceptable level of risk. We did not change this final rule AD action based on these comments. Request To Change Inspection Intervals Eric Paul, Ivan R. Wilson, Patrick D. Donovan, Patric Barry, Carl Schoolcraft, Phil Ciholas, Dave Fitzgerald for the ICS, Andrew Detsch, John F. Murray, and Allan H. Bieck requested an increased repetitive interval from 100 hours to 200 hours, 500 hours, 1,000 hours, or 2,000 hours. Patrick D. Donovan, Patric Barry, and Dave Fitzgerald for the ICS noted that taking half of the average discovery time (stated as 4,000 hours TIS) should be a reasonable approach to establish a repetitive interval. Ivan R. Wilson and Jim Ritter also referenced the long service history of the fleet (approximately 50 years and several thousand hours). Andrew Detsch asserted that the cracks occurred later in the service life or did not grow. Arthur John Beyer provided information that they inspected the component twice near 4,000 TIS at an interval of 4 years and 264 hours with no cracking observed at either inspection. Han Neubert recommended establishing intervals based on a study of 2014–T6 behavior under stress corrosion to define stress and environment thresholds similar to a provided report about stress corrosion susceptibility, Time Exposure Studies on Stress Corrosion Cracking of Aluminum 2014– T6, 2219–T87, 2014–T651, 7075–T651, and Titanium 6Al–4V, dated June 1, 1973 (http://ntrs.nasa.gov/archive/nasa/ casi.ntrs.nasa.gov/19730009798_ 1973009798.pdf). Charles Parker, Arthur John Beyer, and Jim Ritter requested justification for the current intervals. We partially agree with adjusting the repetitive interval from 3 years to 5 years because it would align with the rationale for the existing 10-year or 1,000-hour interval and other guidance used to establish the intervals. There is no need to decrease the interval to 200 hours as the AD provides an interval of 500 hours. We disagree with increasing the repetitive interval beyond 500 hours for several reasons. We must consider many factors to define an appropriate inspection interval. The first factor, the design safety requirement, does not allow strength degradation below design ultimate value or stiffness degradation for flutter. Advisory Circular (AC) 23–13A, Fatigue, Fail-Safe, and Damage Tolerance Evaluation of Metallic Structure for PO 00000 Frm 00010 Fmt 4700 Sfmt 4700 Normal, Utility, Acrobatic, and Commuter Category Airplanes, dated September 29, 2005, (http://rgl.faa.gov/ Regulatory_and_Guidance_Library/ rgAdvisoryCircular.nsf/list/AC%202313A/$FILE/ac23-13A.pdf) describes how ensuring no detectable cracks within the operational life of the aircraft through an appropriate inspection interval meets the design requirement. The existing findings of cracks do not meet these requirements. Simply, the aircraft is not certificated to meet airworthiness standards with a known crack. A ‘‘detectable’’ size for a crack is a value established for the specific inspection method in a specific application. The discovered cracks had far exceeded detectable size before they were found during the targeted inspections. This is due in part to no targeted inspections until discovery of corrosion issues on the attached torque tube several years ago. Following the approach in AC 23–13A, the estimated service history would provide a test life of approximately 4,000 hours, then apply a scatter factor of approximately 4, yielding 1,000 hours. Again, this should be for detectable cracks that do not degrade the strength and stiffness. An additional factor of 2 (providing two inspection opportunities) could be applied to cover that portion, yielding an inspection at 500 hours. Note, this is only an example to show the reasonableness of the proposed interval based on service data. The interval is driven primarily by calendar time using a similar approach. The second factor is the probabilistic nature of cracking. While some hightime or aged aircraft do not exhibit cracking, we expect this in the distribution and is insufficient rationale to shorten the interval. For example, the data point of a 4-year/264-hour interval is useful, but many more data points would be necessary to support an increased interval. The third factor is associated with service history and the existing intervals for related issues on the stabilator control system. For the attached torque tube, Piper Aircraft, Inc. Service Bulletin No. 1160, dated December 26, 2005, specifies a 10-year repetitive inspection for corrosion. Also for the tube, Special Airworthiness Information Bulletin CE–04–88, dated September 15, 2004, (http://rgl.faa.gov/Regulatory_ and_Guidance_Library/rgSAIB.nsf/0/ 77fc29bb15c8a85b8625721f0052ecb4/ $FILE/CE-04-88.pdf) specifies a 3-year or 500-hour repetitive inspection, and AD 74–13–03 (41 FR 17371, April 26, 1976) requires a 3-year or 500-hour repetitive inspection. These issues are E:\FR\FM\17SER1.SGM 17SER1 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations tkelley on DSK3SPTVN1PROD with RULES corrosion-related and corrosion is a factor in the SCC of the horn. The assertion that cracks occurred later or early in service and then did not grow has no supporting data to use in establishing intervals. The FAA reviewed the report provided by Hans Neubert, Time Exposure Studies on Stress Corrosion Cracking of Aluminum 2014–T6, 2219– T87, 2014–T651, 7075–T651, and Titanium 6Al–4V, dated June 1, 1973, (http://ntrs.nasa.gov/archive/nasa/casi. ntrs.nasa.gov/19730009798_ 1973009798.pdf). While additional work could be coordinated if funding is available, we must first manage the known condition. The report already alludes to the fact that aluminum 2014– T6 is particularly susceptible to SCC which invalidates the assumption that aluminum 2014–T6 would have equivalent behavior to other test material. There is no true stress corrosion threshold (similar to a fatigue endurance limit) for aluminum 2014– T6. Additional work would be required to validate the stresses from all contributing factors once any type of threshold was tested. We changed the repetitive interval for inspected parts in paragraph (g)(1) of the AD from 3 years to 5 years. Request To Reconsider the Requirement for Repetitive Inspection of the Assembly Kristin Amelia Winter, Steven Fischer, George Edward White, Patric Barry, Carl Schoolcraft, Dave Fitzgerald for the ICS, Andrew Detsch, Arthur John Beyer, Jim Ritter, and John F. Murray requested we reconsider the requirement for repetitive, intrusive inspection of the assembly. The commenters were concerned that repetitive disassembly and re-assembly of the structure could introduce new risks from wear, assembly errors, etc. We disagree with the commenters. While we agree that there are potential risks with the repeated inspection, the current issue is a higher risk and we must address the known unsafe condition. The need for a repetitive inspection has been addressed elsewhere in this final rule AD action. Installation of the new parts would minimize the stated risk of repeated disassembly and reassembly and achieve the maximum interval of 10 years or 1,000 hours. We did not change this final rule AD action based on these comments. Request To Allow Alternative Inspection Methods George Edward White, Patrick D. Donovan, Patric Barry, Phil Ciholas, and VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 Dave Fitzgerald for the ICS requested allowance for alternative, less intrusive, inspection methods such as X-ray, magnetic particle inspection, or bolt torque and measured torque tube deformation. The commenters reasoned that the alternative inspection methods could avoid disassembly and reassembly. We do not agree with this request because: • X-ray does not provide a sufficiently high probability (reliability) of detection for cracks at sizes needed to control the unsafe condition. • Magnetic particle inspection is for magnetic materials and would not be appropriate for the aluminum horn. • While the bolt torque value or torque tube deformation could be a partial indicator, it is not a full measure of all the contributing factors. The viability of such a method would also be affected by manufacturing variability (machining, drawing tolerances, and so forth) making it difficult to build an appropriate model to ensure an adequate inspection method. We did not change this final rule AD action based on these comments. Request To Clarify What the AD Requires Dave Fitzgerald for the ICS requested we clarify the statement in the summary of the NPRM (76 FR 36395, June 22, 2011) of what parts are being replaced. We agree with the commenter that it is important to clearly state what parts are required in the AD action. We changed the summary of the final rule to require replacement of the stabilator horn assembly and/or repetitive inspection of the stabilator horn assembly, as applicable. Request To Allow Re-Use of Inspected Horns Ivan R. Wilson, Patrick D. Donovan, Carl Schoolcraft, Andrew Detsch, and John F. Murray requested a change in compliance time to allow inspected parts to have the same inspection interval as new replacement parts. Carl Schoolcraft also requested the option of installing serviceable parts in lieu of new parts. We agree with allowing used parts as replacement parts provided they have been inspected before installation and found free of cracks (serviceable) and they continue the repetitive inspection option in this AD. However, we disagree with allowing the same interval on used inspected replacement parts as on new replacement parts because a single penetrant inspection method does not provide the same confidence level for a crack-free part as a new part does. Such PO 00000 Frm 00011 Fmt 4700 Sfmt 4700 56997 an inspection could not reliably detect sufficiently small cracks; therefore, an approach similar to damage tolerance requiring multiple inspections is warranted. We added language to: • Clarify compliance and procedures for the replacement of the stabilator horn assembly with a serviceable stabilator horn assembly, provided it is inspected before installation and found free of cracks or corrosion and continues with the repetitive inspections required for a used part; and • Clarify the initial inspection for owner/operators who may have already installed a used serviceable stabilator horn assembly on their airplane. Request To Validate and/or Revise the Cost Estimate Randy Black and Arthur John Beyer requested we validate and/or revise the cost estimate. One commenter ordered parts including a new horn, new torque tube, new bearings, and new hardware estimated at $1,500 for only the parts cost. Another commenter noted the cost on U.S. operators does not include subsequent inspections. We do not agree with this request because the parts cost only includes those parts required by the AD actions (the horn assembly). Optional parts, such as the tube, are not mandated and not required in the associated cost. Repetitive inspections are not included in AD cost estimates as it cannot be determined which option an owner/ operator may choose, or the number of times the action(s) may be executed on an individual aircraft. We did not change this final rule AD action based on these comments. Request To Have Manufacturer Show Ability To Meet Parts Demand Commenters Bob Rosansky, Patrick D. Donovan, Patric Barry, John Trudel, and Phil Ciholas are associated with this request. Some commenters requested that the airplane manufacturer demonstrate the ability to meet the parts demand before the AD is issued. One commenter requested time to create a parts supply for the replacement horn from the Australian CASA STC SVA 532. Several commenters estimated that it might require one year or more for the manufacturer to provide the required parts and are concerned that the manufacturer’s parts ordering system will be unable to meet the demand. The request for the CASA-approved horn is to alleviate the AD actions. We do not agree because the manufacturer has told the FAA they can support the parts requirements for this AD. This AD is necessary to address an E:\FR\FM\17SER1.SGM 17SER1 56998 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations unsafe condition. If parts availability becomes a problem, the FAA will consider AMOC requests and determine whether they provide an acceptable level of safety when they are submitted following the procedures in 14 CFR 39.19 and this AD. The AD initial compliance time should provide sufficient time to create a parts supply. The AD is not addressing the CASAapproved horn since the horn is not FAA-approved at this time. We did not change this final rule AD action based on these comments. Request To Change Compliance Time Because Quality Issues Might Occur Patrick D. Donovan, Patric Barry, and John Trudel requested changes to the compliance time based on possible quality issues in manufacturing or delivering required parts. The commenters referenced instances where the manufacturer supplied parts that did not meet/specifications or delivered the wrong part numbers. We do not agree because if nonconforming parts or the wrong parts are distributed by the manufacturer, then the problem will be addressed through the current regulations, including potential AD action. The FAA cannot address this problem unless it occurs and is appropriately reported. We did not change this final rule AD action based on these comments. tkelley on DSK3SPTVN1PROD with RULES Request To Have Manufacturer Provide Parts Kit Randy Black suggested the manufacturer combine the replacement horn into a kit with the torque tube and noted that a combined kit would provide a convenience to owners/ operators. We disagree because the additional parts beyond the horn assembly are not required by this AD because they are not necessary to address the unsafe condition. We did not change this final rule AD action based on these comments. Request To Have FAA Directly Notify Owners/Operators of the NPRM (76 FR 36395, June 22, 2011) Dennis Boykin stated the FAA failed to send the NPRM (76 FR 36395, June 22, 2011) to him. The commenter stated he was not notified of the NPRM by the FAA, but by the type club. We conclude that the commenter requested direct notification of the NPRM. We disagree with the request. The FAA does not mail NPRMs. Effective March 1, 2010, the FAA stopped mailing paper copies of ADs. We have continued to fax and/or use the US Postal Service to mail Emergency ADs. VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 To continue receiving ADs at no cost, please subscribe to our GovDelivery email service by visiting the Regulatory and Guidance Library home page (http://rgl.faa.gov). For those desiring paper copies, we will continue to provide the AD Biweekly, which is a paid subscription of all ADs issued in the Federal Register over the previous 2-week period. The AD Biweekly is printed and mailed by the Government Printing Office (GPO). Contact the GPO directly at phone: (202) 512–1806 to subscribe. We did not change this final rule AD action based on these comments. Request To Include Reporting Requirement and Analysis of Data To Refine AD Kristin Amelia Winter, George Edward White, Patrick D. Donovan, Arthur John Beyer, Hans Neubert for the ICS, and Dennis Boykin requested adding a reporting requirement with subsequent use of the data to evaluate (or eliminate) the inspection intervals and to evaluate potential terminating actions. Two of the commenters requested the reporting be provided to both the FAA and ICS. One commenter also requested a provision for rescinding the AD or extending the inspection intervals based on the number of nonfindings, especially if a new part is installed. Finally, one commenter proposed to exclude the Model PA–24– 260 and evaluate it at a later date. The commenters noted that the initial inspection cycle would provide three years of time to collect and evaluate the data which would allow the FAA and interested parties an opportunity to formulate a more narrowly targeted AD that would better balance the cost with the hoped for improvement in airworthiness and hence safety. Lastly, it would provide the data necessary to design and obtain approval of an AMOC or STC that effectively addresses this unsafe condition and terminates any final recurring AD. We disagree with adding a reporting requirement. Based on the Paperwork Reduction Act, a reporting requirement must meet the following conditions: • Help develop a corrective action; • Determine the scope of the problem and how adequate the Design Approval Holder’s corrective actions are; and • Avoid unsafe consequences if we do not collect the information. To eliminate the repetitive inspections and develop a terminating action depends on a combination of factors. The following three factors would require a re-design to eliminate the repetitive inspections: Balance arm interference fit, basic material PO 00000 Frm 00012 Fmt 4700 Sfmt 4700 properties, and use of a thicker torque tube previously discussed. Lowering the installation torque value was addressed earlier. Reduction of corrosion potential is currently addressed via repetitive inspections as discussed below. As all major contributing factors are not eliminated, reporting would not provide sufficient information to eliminate the inspections or directly provide terminating action. Any individual or group is free to work independently to coordinate data collection supporting a potential concept as an AMOC or design change (STC). We also disagree with evaluating the Model PA–24–260 airplane only in the future because that model meets the regulatory requirement where the unsafe condition is likely to exist or develop in other products of the same type design. We did not change this final rule AD action based on these comments. Request To Have FAA Determine Status of Type Certificate Holder Patric Barry and John Trudel expressed concern that the manufacturer ’s engineering/design work on the corrective action and parts supply issues are evidence of abandonment of the responsibilities of a type certificate holder. We conclude the commenters requested the FAA determine the status of the type certificate holder. We disagree with this request. The manufacturer met its obligation as a type certificate holder by working with the FAA and industry to generate a corrective action program addressing the unsafe condition. Based on these comments, we made no change to the AD action. Request To Require Inspection of the Torque Tube Assembly/Control Horn Hans Neubert for the ICS commented that the reason that the torque tube assembly/control horn has not been previously inspected for cracks is due to the fact there is no prior manufacturer requirement to inspect. We infer the commenter requested the FAA require inspection of the torque tube assembly/ control horn. We agree with the commenter. There was not a known need for inspection of the assembly. With discovery of the unsafe condition, a program is now being put into place. Based on these comments, we made no change to the AD action. E:\FR\FM\17SER1.SGM 17SER1 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations Request To Make Piper Aircraft, Inc. Service Bulletin No. 1189, dated April 29, 2010, Only Advisory for the AD Hans Neubert for the ICS recommended that this service information be considered as advisory only to the corrective action. The commenter stated that the preliminary and final versions of the service information were based on an industry magazine article and were without substantiating data, field service history, or engineering evaluation. We disagree because the FAA independently evaluated all available data. We incorporated the intent of this service information into the AD, with the exception of adjustments to the applicability and compliance time. We did not change this final rule AD action based on these comments. Request To Incorporate Corrosion Preventive Measures in the AD George Edward White recommended incorporation of corrosion preventive measures into the AD. The commenter noted known corrosion issues on the adjacent torque tube. We disagree because corrosion preventive measures are already covered by the following documents and are not necessary to address the unsafe condition identified in this AD: • Piper Aircraft, Inc. Service Bulletin No. 1160, dated December 26, 2005, at http://www.piper.com/Company/ Publications/SB%201160%20Stab%20 Torque%20Tube%20Assy%20Insp.pdf; • Special Airworthiness Information Bulletin CE–04–88, dated September 15, 2004, at http://rgl.faa.gov/Regulatory_ and_Guidance_Library/rgSAIB.nsf/0/ 77fc29bb15c8a85b8625721f0052ecb4/ $FILE/CE-04-88.pdf; • AD 74–13–03, Amendment 39–2588 (41 FR 17371, April 26, 1976), at http://rgl.faa.gov/Regulatory_and_ Guidance_Library/rgAD.nsf/0/ 5CBFDEAB5E2AC41586256E12004 98F02?OpenDocument&Highlight=7413-03; • AC 43.13–1B, Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair, at http://www. faa.gov/regulations_policies/advisory_ circulars/index.cfm/go/document. information/documentID/99861; and • AC 43–4A, Corrosion Control for Aircraft, at http://rgl.faa.gov/ Regulatory_and_Guidance_Library/ rgAdvisoryCircular.nsf/list/AC%20434A/$FILE/AC%2043-4a%20.pdf. Based on these comments, we made no change to the AD action. Request To Require Inspection of the Tail of the Aircraft Patric Barry stated that periodically opening up the tail of the aircraft for inspection may be beneficial, suggesting that routine servicing of the entire area should be included in this AD. Dave Fitzgerald for the ICS stated that opening up the tail area for service of the trim drum, torque tube bearings, and associated areas is beneficial as part of normal maintenance, but is not part of 56999 this AD since the AD addresses the horn and torque tube and not associated components. We agree that maintenance of the trim drum, torque tube bearings, and associated areas is important but disagree with including it in this AD action. These components are not directly related to the unsafe condition so are not part of this AD. We did not change this final rule AD action based on these comments. Conclusion We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these changes: • Are consistent with the intent that was proposed in the NPRM (76 FR 36395, June 22, 2011) for correcting the unsafe condition; and • Do not add any additional burden upon the public than was already proposed in the NPRM (76 FR 36395, June 22, 2011) We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. Costs of Compliance We estimate that this AD affects 3,100 airplanes of U.S registry. We estimate the following costs to comply with this AD: ESTIMATED COSTS Action Labor cost Parts cost Cost per product Cost on U.S. operators Stabilator horn assembly inspection 12 work-hours × $85 per hour = $1,020 Not applicable ................................ $1,020 $3,162,000 We estimate the following costs to do any necessary replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that might need this replacement: ON-CONDITION COSTS Labor cost Parts cost Cost per product Stabilator horn assembly replacement ......................... tkelley on DSK3SPTVN1PROD with RULES Action 12 work-hours × $85 per hour = $1,020 ...................... $572 $1,592 According to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate. VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 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. PO 00000 Frm 00013 Fmt 4700 Sfmt 4700 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 E:\FR\FM\17SER1.SGM 17SER1 57000 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. Regulatory Findings This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. For the reasons discussed above, I certify that this AD: (1) Is not a ‘‘significant regulatory action’’ under Executive Order 12866, (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, and (4) 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. 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 1. The authority citation for part 39 continues to read as follows: ■ Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD): ■ 2012–17–06 Piper Aircraft, Inc.: Amendment 39–17169; Docket No. FAA–2011–0639; Directorate Identifier 2011–CE–016–AD. tkelley on DSK3SPTVN1PROD with RULES (a) Effective Date This AD is effective October 22, 2012. (b) Affected ADs None. (c) Applicability This AD applies to the following Piper Aircraft, Inc. airplanes, certificated in any category: (1) Model PA–24, serial numbers (S/Ns) 24–1 through 24–3687, with horn part VerDate Mar<15>2010 16:41 Sep 14, 2012 Jkt 226001 number (P/N) 20397–00 (assembly P/N 20399) installed; (2) Model PA–24–250, S/Ns 24–1 and 24– 103 through 24–3687, with horn P/N 20397– 00 (assembly P/N 20399) installed; and (3) Model PA–24–260, S/Ns 24–3642 and 24–4000 through 24–5034, with horn P/N 20397–00 (assembly P/N 20399) installed. (d) Subject Joint Aircraft System Component (JASC)/ Air Transport Association (ATA) of America Code 27: Flight Controls. (e) Unsafe Condition This AD was prompted by reports of cracks developing in the stabilator horn assembly. We are issuing this AD to detect and correct corrosion or cracks in the stabilator horn assembly. Corrosion or cracks could lead to failure of the stabilator horn. Consequently, failure of the stabilator horn could lead to a loss of pitch control in flight. (f) Compliance Comply with this AD following Piper Aircraft, Inc. Service Bulletin No. 1189, dated April 29, 2010, within the compliance times specified in this AD, unless already done (does not eliminate the repetitive actions of this AD). (g) Inspection/Replacement (1) When a new stabilator horn assembly has been installed (during production or replacement) and the stabilator horn assembly reaches a total of 1,000 hours timein-service (TIS) or 10 years after installation, or within the next 100 hours TIS after October 22, 2012 (the effective date of this AD), whichever occurs later, do one of the following actions: (i) Initially inspect the stabilator horn assembly for corrosion or cracks. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first. (ii) Replace the stabilator horn assembly with a new stabilator horn assembly. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD. (iii) Replace the stabilator horn assembly with a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first. (2) When a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion has been installed and the stabilator horn assembly reaches a total of 500 hours TIS or 5 years after installation, or within the next 100 hours TIS after October 22, 2012 (the effective date of this AD), whichever occurs later, do one of the following actions: (i) Initially inspect the stabilator horn assembly for corrosion or cracks. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first. PO 00000 Frm 00014 Fmt 4700 Sfmt 4700 (ii) Replace the stabilator horn assembly with a new stabilator horn assembly. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD. (iii) Replace the stabilator horn assembly with a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first. (3) If you do not know the total hours TIS on the stabilator horn assembly, within the next 100 hours TIS after October 22, 2012 (the effective date of this AD) do one of the actions required in paragraph (g)(1)(i), (g)(1)(ii), (g)(1)(iii), (g)(2)(i), (g)(2)(ii), or (g)(2)(iii) of this AD. (4) If any corrosion or cracks are found during any of the inspections required in paragraph (g)(1)(i), (g)(1)(iii), (g)(2)(i), or (g)(2)(iii) of this AD, before further flight, you must replace the stabilator horn assembly as specified in paragraph (g)(1)(ii), (g)(1)(iii). (g)(2)(ii), or (g)(2)(iii) of this AD, as applicable. (5) For the bolts common to the torque tube and stabilator horn, install the nuts using a torque of 120–145 in.-lbs. for the actions required by paragraphs (g)(1), (g)(2), or (g)(3) of this AD. Note 1 to paragraph (g) of this AD: The stated torque value of 120–145 in.-lbs. includes friction drag from the nut’s locking element, which is assumed to be 60 in.-lbs. The installation torque can be adjusted according to the actual, measured friction drag. For example, if the friction-drag torque is measured to be 40 in.-lbs. (20 in.-lbs. less than the assumed value of 60 in.-lbs.), then the installation torque will be adjusted to be 100–125 in.-lbs. of torque. (6) You may at any time replace the stabilator horn assembly with a new stabilator horn assembly, provided no corrosion or cracks were found during an inspection that would require replacement before further flight. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD. Note 2 to paragraph (g) of this AD: Piper Aircraft, Inc. Service Bulletin No. 1160, dated December 26, 2005; Special Airworthiness Information Bulletin CE–04–88, dated September 15, 2004, at http://rgl.faa.gov/ Regulatory_and_Guidance_Library/ rgSAIB.nsf/0/ 77fc29bb15c8a85b8625721f0052ecb4/$FILE/ CE-04-88.pdf; and AD 74–13–03, Amendment 39–2588 (41 FR 17371, April 26, 1976), are related to this AD action. For the attached torque tube, you may consider combining that inspection with the requirements of this AD. (h) Alternative Methods of Compliance (AMOCs) (1) The Manager, Atlanta Aircraft Certification Office (ACO), FAA, has the E:\FR\FM\17SER1.SGM 17SER1 Federal Register / Vol. 77, No. 180 / Monday, September 17, 2012 / Rules and Regulations authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/ certificate holding district office. (i) Related Information For more information about this AD, contact Gregory K. Noles, Aerospace Engineer, FAA, Atlanta ACO, 1701 Columbia Avenue, College Park, Georgia 30337; phone: (404) 474–5551; fax: (404) 474–5606; email: gregory.noles@faa.gov. (j) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) Piper Aircraft, Inc. Service Bulletin No. 1189, dated April 29, 2010. (ii) Reserved. (3) For Piper Aircraft, Inc. service information identified in this AD, contact Piper Aircraft, Inc., 2926 Piper Drive, Vero Beach, Florida 32960; telephone: (772) 567– 4361; fax: (772) 978–6573; Internet: http:// www.piper.com/company/publications.asp. (4) You may view this service information at the FAA, Small Airplane Directorate, 901 Locust St., Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329–4148. (5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741–6030, or go to: http:// www.archives.gov/federal-register/cfr/ibrlocations.html. Issued in Kansas City, Missouri, on August 20, 2012. John Colomy, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 2012–22529 Filed 9–14–12; 8:45 am] tkelley on DSK3SPTVN1PROD with RULES BILLING CODE 4910–13–P VerDate Mar<15>2010 16:41 Sep 14, 2012 DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2012–0071; Directorate Identifier 2012–NE–05–AD; Amendment 39– 17191; AD 2012–18–14] RIN 2120–AA64 Airworthiness Directives; Pratt & Whitney Canada, Auxiliary Power Units Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: We are adopting a new airworthiness directive (AD) for certain serial numbers of Pratt & Whitney Canada (P&WC) PW901A auxiliary power units (APUs) approved under Technical Standard Order TSO–C77A and installed on, but not limited to, Boeing 747–400 series airplanes. This AD requires modifications of the rear gas generator case, exhaust duct support, and turbine exhaust duct flanges. This AD was prompted by several events of high-pressure turbine blade fracture leading to separation of the rear gas generator case and release of high energy debris. We are issuing this AD to prevent separation of the rear gas generator case and release of high energy debris, which could result in injury and damage to the airplane. DATES: This AD becomes effective October 22, 2012. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of October 22, 2012. ADDRESSES: The Docket Operations office is located at Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue SE., West Building Ground Floor, Room W12–140, Washington, DC 20590–0001. FOR FURTHER INFORMATION CONTACT: Mazdak Hobbi, Aerospace Engineer, New York Aircraft Certification Office, FAA, Engine & Propeller Directorate, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516–228– 7330; fax: 516–794–5531; email: mazdak.hobbi@faa.gov. SUPPLEMENTARY INFORMATION: SUMMARY: Discussion We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on February 27, 2012 (77 FR 11421). That NPRM proposed to correct Jkt 226001 PO 00000 Frm 00015 Fmt 4700 Sfmt 4700 57001 an unsafe condition for the specified products. Transport Canada, which is the aviation authority for Canada, has issued AD CF–2011–40, dated October 26, 2011 (referred to after this as ‘‘the MCAI’’), to correct an unsafe condition for the specified products. The MCAI states: The PW901A Auxiliary Power Units have experienced several events of High Pressure Turbine (HPT) blade fracture, some of which have resulted in the separation of the rear gas generator case, exhaust duct support, the turbine exhaust duct flanges and the release of high energy debris. Subsequent investigation revealed the turbine exhaust duct can separate under excessive load conditions resulting from extreme engine distress such as HPT blade fractures. You may obtain further information by examining the MCAI in the AD docket. Comments We gave the public the opportunity to participate in developing this AD. We considered the comments received. The following presents the comments received on the proposal and the FAA’s response to each comment. Support for the NPRM The Boeing Company indicated it supported the content of the proposed rule. Request To Increase Compliance Time Several commenters believed the compliance time in the AD should be extended. Atlas Air requested that the compliance time be increased from 42 to 60 months. Atlas Air noted that the 42month requirement would force them to remove APUs prior to their 8,000 hours soft time threshold which is based on their budget and operating experience and reliability. This threshold would increase the maintenance burden and cost to Atlas Air. KLM Royal Dutch Airlines (KLM) also requested that the compliance date be extended. KLM indicated that requiring all the affected APUs be modified in 42 months would require forced unscheduled replacements. United Airlines (UAL) also requested that the compliance time be extended from 42 to 48 months. United indicated that the 42-month compliance time would require engines to be removed prematurely and cause capacity problems for repair shops. We do not agree. We have no data that justifies extending the compliance time to 48 months. Operators who want to a longer compliance interval may request an AMOC using the procedures in 14 CFR part 39. Operators contemplating an AMOC request are reminded that they must show that their extension will E:\FR\FM\17SER1.SGM 17SER1

Agencies

[Federal Register Volume 77, Number 180 (Monday, September 17, 2012)]
[Rules and Regulations]
[Pages 56993-57001]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-22529]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0639; Directorate Identifier 2011-CE-016-AD; 
Amendment 39-17169; AD 2012-17-06]
RIN 2120-AA64


Airworthiness Directives; Piper Aircraft, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Piper Aircraft, Inc. Models PA-24, PA-24-250, and PA-24-260 airplanes. 
This AD was prompted by reports of cracks developing in the stabilator 
horn assembly. This AD requires replacement of the stabilator horn 
assembly and/or repetitive inspections of the stabilator horn assembly 
for corrosion or cracks, as applicable. Corrosion or cracks could lead 
to failure of the stabilator horn. Consequently, failure of the 
stabilator horn could lead to a loss of pitch control in flight. We are 
issuing this AD to correct the unsafe condition on these products.

DATES: This AD is effective October 22, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of October 22, 
2012.

ADDRESSES: For service information identified in this AD, contact Piper 
Aircraft, Inc., 2926 Piper Drive, Vero Beach, Florida 32960; telephone: 
(772) 567-4361; fax: (772) 978-6573; Internet: http://www.newpiper.com/company/publications.asp. You may review copies of the referenced 
service information at the FAA, Small Airplane Directorate, 901 Locust 
St., Kansas City, Missouri 64106. For information on the availability 
of this material at the FAA, call (816) 329-4148.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; 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: Gregory K. Noles, Aerospace Engineer, 
FAA, Atlanta Aircraft Certification Office, 1701 Columbia Avenue, 
College Park, Georgia 30337; phone: (404) 474-5551; fax: (404) 474-
5606; email: gregory.noles@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That

[[Page 56994]]

NPRM published in the Federal Register on June 22, 2011 (76 FR 36395). 
That NPRM proposed to require replacement of the stabilator horn 
assembly and/or repetitive inspections of the stabilator horn assembly 
for corrosion or cracks, as applicable.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
and the FAA's response to each comment.

Support for the Proposed Initial Inspection

    Comments from Kristin Amelia Winter, Charles Parker, Carl 
Schoolcraft, Dave Fitzgerald for the International Comanche Society 
(ICS), Hans Neubert for the ICS, Brian Kotso, and John F. Murray were 
supportive of the AD's requirement for an initial inspection.
    We did not change this final rule AD action based on these 
comments.

Request FAA To Withdraw NPRM (76 FR 36395, June 22, 2011) Due to 
Adequacy of External Inspections

    Phil Ciholas requested we reconsider the NPRM (76 FR 36395, June 
22, 2011) requirements and noted that even the most severe horn 
cracking reported (propagated through the part to an exterior surface 
and was visually detectable without disassembly) had not resulted in 
complete horn failure or the severity of loss of control postulated in 
the justification for the AD. The commenter stated that no loss of 
control incidents or accidents have ever been documented that can be 
attributed to this failure mode. Given the statistical distribution of 
cracks reported, the ability of existing external inspections to detect 
cracks prior to complete failure of the horn, and the lack of any 
actual complete failures; the commenter felt the internal inspection 
requiring disassembly is unwarranted on most aircraft, especially 
recent serial number aircraft, unless there is other evidence of 
potential issues observed on a particular aircraft. We infer the 
commenter requested to withdraw the current proposal.
    We disagree with the request to withdraw the NPRM (76 FR 36395, 
June 22, 2011). A cracked stabilator horn coupled with the aircraft 
flight envelope conditions could create an unsafe scenario even though 
there has not been an in-flight event. A cracked stabilator horn 
reduces the aircraft's structural load limits.
    We did not change this final rule AD action based on these 
comments.

Request To Clarify Applicability (Affected Part Numbers (P/Ns) and 
Configurations)

    David Ray Fitzgerald, Robert (no last name given), Patrick D. 
Donovan, Edward P. Horan, Steven Fischer, Phil Ciholas, Dave Fitzgerald 
for ICS, Daniel Jacob Katz, Arthur John Beyer, Hans Neubert for the 
ICS, Brian Kotso, John F. Murray, and Dennis Boykin requested we 
clarify the applicability to clearly state the affected horn P/Ns and 
clarify whether other current and future horns (supplemental type 
certificates (STC), and so forth) are/will be affected. The commenters 
noted that the text of the proposed AD did not clearly state the 
affected part numbers.
    Robert (no last name given), Steven Fischer, Daniel Jacob Katz, 
Hans Neubert for ICS, and John F. Murray also requested we address the 
configuration of Models PA-24, PA-24-250, and PA-24-260 airplanes using 
the same horn but installed with thicker torque tubes used on the 
Models PA-24-400, PA-30, and PA-39 airplanes as the proposed AD did not 
currently make mention of this configuration. They requested we 
consider excluding the airplanes configured with the thicker torque 
tubes from the applicability or including them as terminating action.
    Phil Ciholas, Arthur John Beyer, and Dennis Boykin requested we 
address potential material and process changes during production of the 
Models PA-24, PA-24-250, and PA-24-260 airplanes, amending the NPRM (76 
FR 36395, June 22, 2011) to apply to only those aircraft that have 
experienced issues.
    Dennis Boykin noted that the manufacturing cycle between the 
original castings (about 1957) and the final production in 1972 of the 
Model PA-24-260 airplane precluded the requirement to ensure that 
similar castings, raw materials, and processes were in place, not just 
a similar design. Dennis Boykin was not aware of any Model PA-24-260 
airplane's stabilator horn that has been separated, inspected, and 
found deficient.
    We partially agree with the commenters. We agree with clarifying 
the affected P/Ns because the issue is specific to the combination of 
the P/N and models in the original NPRM (76 FR 36395, June 22, 2011). 
However, we disagree with excluding aircraft with the thicker torque 
tube installed or making the installation of the thicker torque tube a 
terminating action. No documentation has been supplied to provide 
approval for the installation of thicker torque tubes on the Models PA-
24, PA-24-250, or PA-24-260 airplanes, and the torque tube is not the 
only contributing factor to the unsafe condition. The FAA has 
determined the condition is likely to exist or develop in other 
products of the same type design. We have insufficient data to show 
that airplanes modified with the thicker torque tube do not have the 
unsafe condition.
    We also disagree with excluding stabilator horns manufactured later 
in the production cycle. We have no record of castings, raw materials, 
and/or processes changing significantly enough to provide justification 
to exclude those airplanes from this AD action.
    If an owner/operator submits substantiating data to support the 
installation of the thicker torque tube as an alternative method of 
compliance (AMOC) to this requirement, the FAA will review and consider 
all AMOC requests we receive provided they follow the procedures in 14 
CFR 39.19 and this AD.
    We changed the AD's applicability in this final rule AD action to 
include the horn P/N.

Request To Lower Torque Value for Horn Installation

    Lawrence La Beau, Charles Parker, Eric Paul, Tom Veatch, Ivan R. 
Wilson, Patrick D. Donovan, Ken E. Shaffer, Patric Barry, John Trudel, 
Carl Schoolcraft, Phil Ciholas, Dave Fitzgerald for the ICS, Andrew 
Detsch, Hans Neubert for the ICS, Brian Kotso, John F. Murray, and 
Allan H. Bieck requested that the AD state an appropriate lower shear 
nut torque value for the bolts common to the stabilator horn and torque 
tube. Phil Ciholas requested we add horn deformation limits as a way to 
control the installation torque and related stress corrosion cracking. 
Charles Parker, Eric Paul, Tom Veatch, Ivan R. Wilson, Patric Barry, 
John Trudel, Dave Fitzgerald for the ICS, Hans Neubert for the ICS, and 
Brian Kotso requested we consider an initial inspection and 
reinstallation with the lower torque value as terminating action for 
the AD. Eric Paul and John F. Murray requested we lower the torque 
value of the stop collar bolts. Phil Ciholas requested we consider 
switching to shear nuts when any work is done on the joint.
    The commenters stated over-torque is the root cause of the stress 
corrosion condition and the procedure does not clearly require a lower 
torque value. None of the commenters provided justification for the use 
of stop collar bolts separate from the horn bolts or for the shear 
nuts.
    We agree with adding the installation torque value for the bolts 
common to the horn and torque tube into the AD

[[Page 56995]]

procedures because it is a factor in mitigating the unsafe condition. 
We will also coordinate with the airplane's manufacturer on clarifying 
the airplane maintenance manual procedures for torque of these bolts. 
However, we disagree with adding an initial inspection and 
reinstallation of the torque tube with the lower torque value as 
terminating action for the AD. Although the torque value is a 
contributing factor, it is not the only factor (others are balance arm 
interference fit, basic material susceptibility, and corrosion 
potential).
    No sufficient correlation has been established between the torque 
value and deformation and subsequent stress corrosion cracking. 
Consequently, we disagree with adding horn deformation limits as a way 
to control the installation torque and related stress corrosion 
cracking.
    We disagree with mandating a lower torque value of the stop collar 
bolts or mandating a switch to shear nuts when any work is done on the 
joint. The stop collar bolts did not contribute to the unsafe 
condition, and we cannot mandate actions through an AD that are 
unnecessary to correct the unsafe condition. There is no current data 
for approval to change the configuration to shear nuts.
    We changed the AD by adding the installation torque value for the 
bolts common to the horn and torque tube into the AD procedures.

Request To Use Thicker Torque Tube With Horn

    Lawrence La Beau, Randy Black, Anonymous, Donald Dummer, Albert 
Powers, Steven Fischer, Stewart Campbell, Miller Duffield Einsel, 
Robert, Eric Paul, Tom Veatch, Patric Barry, John Trudel, Edward P. 
Horan, Carl Schoolcraft, Steven Fischer, Phil Ciholas, Dave Fitzgerald 
for the ICS, Daniel Jacob Katz, Hans Neubert for the ICS, Lawrence E. 
Pride, Jim Ritter, Brian Kotso, and John F. Murray noted thicker torque 
tubes discovered during the ICS' survey targeted inspections at the 
horn. This survey was beyond the current maintenance program. The 
commenters cited the thicker torque tube could lessen the potential for 
stress corrosion cracking due to horn deformation. Robert, Steven 
Fischer, Daniel Jacob Katz, Hans Neubert for ICS, and John F. Murray 
requested we address the configuration of Models PA-24, PA-24-250, and 
PA-24-260 airplanes with the subject horn but installed with thicker 
torque tubes.
    We do not agree with the commenters. We disagree with authorizing 
the installation of the thicker torque tube. No documentation has been 
supplied to provide approval for installation of the thicker torque 
tube configuration on any airplanes affected by this AD.
    The FAA will review and consider any AMOC to support the 
installation of the thicker tube provided it follows the procedures in 
14 CFR 39.19 and this AD.
    We did not change this final rule AD action based on these 
comments.

Request To Provide for a Terminating Action to the Repetitive 
Inspections

    Kristin Amelia Winter, Lawrence Zubel, Charles Parker, Randy Black, 
Donald Dummer, Steven Fischer, Stewart Campbell, Miller Duffield 
Einsel, Eric Paul, Tom Veatch, Ivan R. Wilson, Patric Barry, Steven 
Fischer, Phil Ciholas, Dave Fitzgerald for the ICS, Daniel Jacob Katz, 
Hans Neubert for the ICS, Jim Ritter, Brian Kotso, and John F. Murray 
requested a terminating action to the repetitive inspections. All the 
commenters proposed various actions (that is, use of lower installation 
torque value, installation of a thicker torque tube, installation of 
replacement horn by way of Australian Civil Aviation Safety Authority 
(CASA) CASA Supplemental Type Certificate (STC) SVA 532, and 
terminating action based on additional data collected during the 
inspections) with varying levels of supporting data.
    We disagree because no proposed terminating action eliminates all 
the contributing factors to the unsafe condition. The individual 
proposed actions have been addressed in other requested changes to the 
AD. The inspection or replacement programs will manage the issue to an 
acceptable level of risk.
    We will consider proposals for a terminating action as an AMOC 
provided the procedures of 14 CFR 39.19 and this AD are followed.
    We did not change this final rule AD action based on these 
comments.

Request To Credit for Previous Compliance

    Commenters David Charles Meigs, Randy Black, Steven Fischer, Hans 
Neubert for the ICS, and Brian Kotso noted that operators have 
typically been allowed credit for previous compliance in AD actions. 
All commenters requested provision for credit when compliance to the 
requirements has already been accomplished.
    We agree that credit should be given when compliance to the 
requirements has already been done. The AD already allows for such 
credit by stating ``unless already done'' in paragraph (f) of the AD. 
As long as the requirements of the AD are followed, credit is 
available. Any other actions taken would need to be submitted as an 
AMOC following paragraph (h) of the AD.
    We did not change this final rule AD action based on these 
comments.

Request To Clarify the AD Applicability to Replacement Parts

    Commenters David Charles Meigs, Randy Black, Steven Fischer, Hans 
Neubert for the ICS, Brian Kotso stated that the AD applicability is 
not clearly defined in terms of both the susceptible horn part number 
and the affected models. Several commenters request clarification of 
the AD applicability to replacement parts, particularly the horn in 
CASA STC SVA 532.
    We partially agree with clarification on the applicability because 
the focus of this AD is the horn P/N as discussed in the previous issue 
``Request To Clarify Applicability.'' We disagree with specifically 
addressing the CASA STC because the STC is still under review for FAA 
validation and not all design issues have been addressed at this point. 
Any action relating the STC to the AD will be documented during the FAA 
review of the CASA STC.
    As discussed previously, we changed the AD's applicability to 
include the horn P/N.

Request To Increase Initial Compliance Time

    Patric Barry and Phil Ciholas expressed concerns with the 
availability of parts and shop capacity. The commenters requested an 
increase in the initial compliance time.
    We disagree with the commenters. The unsafe condition must be 
addressed in a timely manner. The FAA will consider AMOCs following the 
procedures in 14 CFR 39.19 and this AD to address any potential parts 
availability or shop capacity issues.
    We did not change this final rule AD action based on these 
comments.

Request To Change Units of Compliance Times

    Commenters Randy Black, Patrick D. Donovan, Carl Schoolcraft, Hans 
Neubert for the ICS, John F. Murray, and Allan H. Bieck requested 
changing compliance time criteria. Patrick D. Donovan, Hans Neubert for 
the ICS, and John F. Murray asked that only calendar time be used for 
compliance times. Carl Schoolcraft and Allan H. Bieck requested that 
only TIS be used for compliance times. The commenters noted that stress 
corrosion cracking (SCC) is a time-related function and not TIS. Carl 
Schoolcraft noted the calendar time limit to be arbitrary and to have 
no

[[Page 56996]]

bearing on the condition of the horn. Allan H. Bieck commented TIS is 
what puts strain on the horn, not idle calendar time while the aircraft 
sits in a hangar.
    We disagree with eliminating the calendar time compliance. Calendar 
time is a key factor in SCC. We also disagree with removing the 
operational time (TIS) requirement as corrosion in the torque tube is a 
contributing factor, and the established actions for the corrosion 
currently have both a calendar and TIS requirement. We will retain our 
compliance time using both calendar time and TIS.
    We did not change this final rule AD action based on these 
comments.

Request To Eliminate the Repetitive Inspection Requirement

    Kristin Amelia Winter, Charles Parker, Albert Powers, Ken E. 
Shaffer, John Trudel, Dave Fitzgerald for the ICS, Phil Ciholas, and 
Brian Kotso requested eliminating the repetitive inspection 
requirement. Commenters justify eliminating the repetitive inspections 
by stating the cracks do not appear to be time or use related, there is 
low or no history of cracking in the fleet, there have been no 
catastrophic horns failures in service, and there is potential for 
terminating action.
    We do not agree because SCC is inherently time-related and 
indirectly driven by operational usage. Not all aircraft will crack, 
and those that do will not crack at the same time. SCC has several 
contributing factors that add to the variability. For instance, typical 
fatigue cracking includes scatter factors on the order of four to 
determine the appropriate intervals to take action. While high-time 
aircraft with no cracking is useful data, it does not eliminate the 
need for action. As for the volume of findings, the quantity compared 
to the entire fleet size is low. However, when measured against the 
quantity of valid inspections performed, the find rate is as high as 20 
percent.
    It is also true that no parts have failed catastrophically in 
flight and the findings have been during the ICS' survey targeted at 
the horn. Note that this survey was beyond the current required 
maintenance program. A cracked horn coupled with the aircraft flight 
envelope conditions could still create an unsafe scenario even though 
there has not been an in-flight event. In fact, the service history 
provides evidence of extensive cracking on both sides of the torque 
tube bore leading to the potential unsafe condition. As discussed in 
other responses to commenter requests, no proposed terminating action 
eliminates all the contributing factors to the unsafe condition. The 
inspection or replacement programs will manage the issue to an 
acceptable level of risk.
    We did not change this final rule AD action based on these 
comments.

Request To Change Inspection Intervals

    Eric Paul, Ivan R. Wilson, Patrick D. Donovan, Patric Barry, Carl 
Schoolcraft, Phil Ciholas, Dave Fitzgerald for the ICS, Andrew Detsch, 
John F. Murray, and Allan H. Bieck requested an increased repetitive 
interval from 100 hours to 200 hours, 500 hours, 1,000 hours, or 2,000 
hours.
    Patrick D. Donovan, Patric Barry, and Dave Fitzgerald for the ICS 
noted that taking half of the average discovery time (stated as 4,000 
hours TIS) should be a reasonable approach to establish a repetitive 
interval. Ivan R. Wilson and Jim Ritter also referenced the long 
service history of the fleet (approximately 50 years and several 
thousand hours). Andrew Detsch asserted that the cracks occurred later 
in the service life or did not grow. Arthur John Beyer provided 
information that they inspected the component twice near 4,000 TIS at 
an interval of 4 years and 264 hours with no cracking observed at 
either inspection. Han Neubert recommended establishing intervals based 
on a study of 2014-T6 behavior under stress corrosion to define stress 
and environment thresholds similar to a provided report about stress 
corrosion susceptibility, Time Exposure Studies on Stress Corrosion 
Cracking of Aluminum 2014-T6, 2219-T87, 2014-T651, 7075-T651, and 
Titanium 6Al-4V, dated June 1, 1973 (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730009798_1973009798.pdf). Charles Parker, Arthur 
John Beyer, and Jim Ritter requested justification for the current 
intervals.
    We partially agree with adjusting the repetitive interval from 3 
years to 5 years because it would align with the rationale for the 
existing 10-year or 1,000-hour interval and other guidance used to 
establish the intervals. There is no need to decrease the interval to 
200 hours as the AD provides an interval of 500 hours.
    We disagree with increasing the repetitive interval beyond 500 
hours for several reasons. We must consider many factors to define an 
appropriate inspection interval.
    The first factor, the design safety requirement, does not allow 
strength degradation below design ultimate value or stiffness 
degradation for flutter. Advisory Circular (AC) 23-13A, Fatigue, Fail-
Safe, and Damage Tolerance Evaluation of Metallic Structure for Normal, 
Utility, Acrobatic, and Commuter Category Airplanes, dated September 
29, 2005, (http://rgl.faa.gov/Regulatory--and--Guidance--Library/
rgAdvisoryCircular.nsf/list/AC%2023-13A/$FILE/ac23-13A.pdf) describes 
how ensuring no detectable cracks within the operational life of the 
aircraft through an appropriate inspection interval meets the design 
requirement. The existing findings of cracks do not meet these 
requirements. Simply, the aircraft is not certificated to meet 
airworthiness standards with a known crack.
    A ``detectable'' size for a crack is a value established for the 
specific inspection method in a specific application. The discovered 
cracks had far exceeded detectable size before they were found during 
the targeted inspections. This is due in part to no targeted 
inspections until discovery of corrosion issues on the attached torque 
tube several years ago. Following the approach in AC 23-13A, the 
estimated service history would provide a test life of approximately 
4,000 hours, then apply a scatter factor of approximately 4, yielding 
1,000 hours. Again, this should be for detectable cracks that do not 
degrade the strength and stiffness. An additional factor of 2 
(providing two inspection opportunities) could be applied to cover that 
portion, yielding an inspection at 500 hours. Note, this is only an 
example to show the reasonableness of the proposed interval based on 
service data. The interval is driven primarily by calendar time using a 
similar approach.
    The second factor is the probabilistic nature of cracking. While 
some high-time or aged aircraft do not exhibit cracking, we expect this 
in the distribution and is insufficient rationale to shorten the 
interval. For example, the data point of a 4-year/264-hour interval is 
useful, but many more data points would be necessary to support an 
increased interval.
    The third factor is associated with service history and the 
existing intervals for related issues on the stabilator control system. 
For the attached torque tube, Piper Aircraft, Inc. Service Bulletin No. 
1160, dated December 26, 2005, specifies a 10-year repetitive 
inspection for corrosion. Also for the tube, Special Airworthiness 
Information Bulletin CE-04-88, dated September 15, 2004, (http://
rgl.faa.gov/Regulatory--and--Guidance--Library/rgSAIB.nsf/0/
77fc29bb15c8a85b8625721f0052ecb4/$FILE/CE-04-88.pdf) specifies a 3-year 
or 500-hour repetitive inspection, and AD 74-13-03 (41 FR 17371, April 
26, 1976) requires a 3-year or 500-hour repetitive inspection. These 
issues are

[[Page 56997]]

corrosion-related and corrosion is a factor in the SCC of the horn.
    The assertion that cracks occurred later or early in service and 
then did not grow has no supporting data to use in establishing 
intervals.
    The FAA reviewed the report provided by Hans Neubert, Time Exposure 
Studies on Stress Corrosion Cracking of Aluminum 2014-T6, 2219-T87, 
2014-T651, 7075-T651, and Titanium 6Al-4V, dated June 1, 1973, (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730009798_1973009798.pdf). While additional work could be coordinated if funding 
is available, we must first manage the known condition. The report 
already alludes to the fact that aluminum 2014-T6 is particularly 
susceptible to SCC which invalidates the assumption that aluminum 2014-
T6 would have equivalent behavior to other test material. There is no 
true stress corrosion threshold (similar to a fatigue endurance limit) 
for aluminum 2014-T6. Additional work would be required to validate the 
stresses from all contributing factors once any type of threshold was 
tested.
    We changed the repetitive interval for inspected parts in paragraph 
(g)(1) of the AD from 3 years to 5 years.

Request To Reconsider the Requirement for Repetitive Inspection of the 
Assembly

    Kristin Amelia Winter, Steven Fischer, George Edward White, Patric 
Barry, Carl Schoolcraft, Dave Fitzgerald for the ICS, Andrew Detsch, 
Arthur John Beyer, Jim Ritter, and John F. Murray requested we 
reconsider the requirement for repetitive, intrusive inspection of the 
assembly. The commenters were concerned that repetitive disassembly and 
re-assembly of the structure could introduce new risks from wear, 
assembly errors, etc.
    We disagree with the commenters. While we agree that there are 
potential risks with the repeated inspection, the current issue is a 
higher risk and we must address the known unsafe condition. The need 
for a repetitive inspection has been addressed elsewhere in this final 
rule AD action. Installation of the new parts would minimize the stated 
risk of repeated disassembly and reassembly and achieve the maximum 
interval of 10 years or 1,000 hours.
    We did not change this final rule AD action based on these 
comments.

Request To Allow Alternative Inspection Methods

    George Edward White, Patrick D. Donovan, Patric Barry, Phil 
Ciholas, and Dave Fitzgerald for the ICS requested allowance for 
alternative, less intrusive, inspection methods such as X-ray, magnetic 
particle inspection, or bolt torque and measured torque tube 
deformation. The commenters reasoned that the alternative inspection 
methods could avoid disassembly and reassembly.
    We do not agree with this request because:
     X-ray does not provide a sufficiently high probability 
(reliability) of detection for cracks at sizes needed to control the 
unsafe condition.
     Magnetic particle inspection is for magnetic materials and 
would not be appropriate for the aluminum horn.
     While the bolt torque value or torque tube deformation 
could be a partial indicator, it is not a full measure of all the 
contributing factors. The viability of such a method would also be 
affected by manufacturing variability (machining, drawing tolerances, 
and so forth) making it difficult to build an appropriate model to 
ensure an adequate inspection method.
    We did not change this final rule AD action based on these 
comments.

Request To Clarify What the AD Requires

    Dave Fitzgerald for the ICS requested we clarify the statement in 
the summary of the NPRM (76 FR 36395, June 22, 2011) of what parts are 
being replaced.
    We agree with the commenter that it is important to clearly state 
what parts are required in the AD action.
    We changed the summary of the final rule to require replacement of 
the stabilator horn assembly and/or repetitive inspection of the 
stabilator horn assembly, as applicable.

Request To Allow Re-Use of Inspected Horns

    Ivan R. Wilson, Patrick D. Donovan, Carl Schoolcraft, Andrew 
Detsch, and John F. Murray requested a change in compliance time to 
allow inspected parts to have the same inspection interval as new 
replacement parts. Carl Schoolcraft also requested the option of 
installing serviceable parts in lieu of new parts.
    We agree with allowing used parts as replacement parts provided 
they have been inspected before installation and found free of cracks 
(serviceable) and they continue the repetitive inspection option in 
this AD. However, we disagree with allowing the same interval on used 
inspected replacement parts as on new replacement parts because a 
single penetrant inspection method does not provide the same confidence 
level for a crack-free part as a new part does. Such an inspection 
could not reliably detect sufficiently small cracks; therefore, an 
approach similar to damage tolerance requiring multiple inspections is 
warranted.
    We added language to:
     Clarify compliance and procedures for the replacement of 
the stabilator horn assembly with a serviceable stabilator horn 
assembly, provided it is inspected before installation and found free 
of cracks or corrosion and continues with the repetitive inspections 
required for a used part; and
     Clarify the initial inspection for owner/operators who may 
have already installed a used serviceable stabilator horn assembly on 
their airplane.

Request To Validate and/or Revise the Cost Estimate

    Randy Black and Arthur John Beyer requested we validate and/or 
revise the cost estimate. One commenter ordered parts including a new 
horn, new torque tube, new bearings, and new hardware estimated at 
$1,500 for only the parts cost. Another commenter noted the cost on 
U.S. operators does not include subsequent inspections.
    We do not agree with this request because the parts cost only 
includes those parts required by the AD actions (the horn assembly). 
Optional parts, such as the tube, are not mandated and not required in 
the associated cost. Repetitive inspections are not included in AD cost 
estimates as it cannot be determined which option an owner/operator may 
choose, or the number of times the action(s) may be executed on an 
individual aircraft.
    We did not change this final rule AD action based on these 
comments.

Request To Have Manufacturer Show Ability To Meet Parts Demand

    Commenters Bob Rosansky, Patrick D. Donovan, Patric Barry, John 
Trudel, and Phil Ciholas are associated with this request. Some 
commenters requested that the airplane manufacturer demonstrate the 
ability to meet the parts demand before the AD is issued. One commenter 
requested time to create a parts supply for the replacement horn from 
the Australian CASA STC SVA 532. Several commenters estimated that it 
might require one year or more for the manufacturer to provide the 
required parts and are concerned that the manufacturer's parts ordering 
system will be unable to meet the demand. The request for the CASA-
approved horn is to alleviate the AD actions.
    We do not agree because the manufacturer has told the FAA they can 
support the parts requirements for this AD. This AD is necessary to 
address an

[[Page 56998]]

unsafe condition. If parts availability becomes a problem, the FAA will 
consider AMOC requests and determine whether they provide an acceptable 
level of safety when they are submitted following the procedures in 14 
CFR 39.19 and this AD. The AD initial compliance time should provide 
sufficient time to create a parts supply.
    The AD is not addressing the CASA-approved horn since the horn is 
not FAA-approved at this time.
    We did not change this final rule AD action based on these 
comments.

Request To Change Compliance Time Because Quality Issues Might Occur

    Patrick D. Donovan, Patric Barry, and John Trudel requested changes 
to the compliance time based on possible quality issues in 
manufacturing or delivering required parts. The commenters referenced 
instances where the manufacturer supplied parts that did not meet/
specifications or delivered the wrong part numbers.
    We do not agree because if non-conforming parts or the wrong parts 
are distributed by the manufacturer, then the problem will be addressed 
through the current regulations, including potential AD action. The FAA 
cannot address this problem unless it occurs and is appropriately 
reported.
    We did not change this final rule AD action based on these 
comments.

Request To Have Manufacturer Provide Parts Kit

    Randy Black suggested the manufacturer combine the replacement horn 
into a kit with the torque tube and noted that a combined kit would 
provide a convenience to owners/operators.
    We disagree because the additional parts beyond the horn assembly 
are not required by this AD because they are not necessary to address 
the unsafe condition.
    We did not change this final rule AD action based on these 
comments.

Request To Have FAA Directly Notify Owners/Operators of the NPRM (76 FR 
36395, June 22, 2011)

    Dennis Boykin stated the FAA failed to send the NPRM (76 FR 36395, 
June 22, 2011) to him. The commenter stated he was not notified of the 
NPRM by the FAA, but by the type club. We conclude that the commenter 
requested direct notification of the NPRM.
    We disagree with the request. The FAA does not mail NPRMs. 
Effective March 1, 2010, the FAA stopped mailing paper copies of ADs. 
We have continued to fax and/or use the US Postal Service to mail 
Emergency ADs. To continue receiving ADs at no cost, please subscribe 
to our GovDelivery email service by visiting the Regulatory and 
Guidance Library home page (http://rgl.faa.gov). For those desiring 
paper copies, we will continue to provide the AD Biweekly, which is a 
paid subscription of all ADs issued in the Federal Register over the 
previous 2-week period. The AD Biweekly is printed and mailed by the 
Government Printing Office (GPO). Contact the GPO directly at phone: 
(202) 512-1806 to subscribe.
    We did not change this final rule AD action based on these 
comments.

Request To Include Reporting Requirement and Analysis of Data To Refine 
AD

    Kristin Amelia Winter, George Edward White, Patrick D. Donovan, 
Arthur John Beyer, Hans Neubert for the ICS, and Dennis Boykin 
requested adding a reporting requirement with subsequent use of the 
data to evaluate (or eliminate) the inspection intervals and to 
evaluate potential terminating actions. Two of the commenters requested 
the reporting be provided to both the FAA and ICS. One commenter also 
requested a provision for rescinding the AD or extending the inspection 
intervals based on the number of non-findings, especially if a new part 
is installed. Finally, one commenter proposed to exclude the Model PA-
24-260 and evaluate it at a later date.
    The commenters noted that the initial inspection cycle would 
provide three years of time to collect and evaluate the data which 
would allow the FAA and interested parties an opportunity to formulate 
a more narrowly targeted AD that would better balance the cost with the 
hoped for improvement in airworthiness and hence safety. Lastly, it 
would provide the data necessary to design and obtain approval of an 
AMOC or STC that effectively addresses this unsafe condition and 
terminates any final recurring AD.
    We disagree with adding a reporting requirement. Based on the 
Paperwork Reduction Act, a reporting requirement must meet the 
following conditions:
     Help develop a corrective action;
     Determine the scope of the problem and how adequate the 
Design Approval Holder's corrective actions are; and
     Avoid unsafe consequences if we do not collect the 
information.
    To eliminate the repetitive inspections and develop a terminating 
action depends on a combination of factors. The following three factors 
would require a re-design to eliminate the repetitive inspections: 
Balance arm interference fit, basic material properties, and use of a 
thicker torque tube previously discussed. Lowering the installation 
torque value was addressed earlier. Reduction of corrosion potential is 
currently addressed via repetitive inspections as discussed below. As 
all major contributing factors are not eliminated, reporting would not 
provide sufficient information to eliminate the inspections or directly 
provide terminating action.
    Any individual or group is free to work independently to coordinate 
data collection supporting a potential concept as an AMOC or design 
change (STC).
    We also disagree with evaluating the Model PA-24-260 airplane only 
in the future because that model meets the regulatory requirement where 
the unsafe condition is likely to exist or develop in other products of 
the same type design.
    We did not change this final rule AD action based on these 
comments.

Request To Have FAA Determine Status of Type Certificate Holder

    Patric Barry and John Trudel expressed concern that the 
manufacturer 's engineering/design work on the corrective action and 
parts supply issues are evidence of abandonment of the responsibilities 
of a type certificate holder. We conclude the commenters requested the 
FAA determine the status of the type certificate holder.
    We disagree with this request. The manufacturer met its obligation 
as a type certificate holder by working with the FAA and industry to 
generate a corrective action program addressing the unsafe condition.
    Based on these comments, we made no change to the AD action.

Request To Require Inspection of the Torque Tube Assembly/Control Horn

    Hans Neubert for the ICS commented that the reason that the torque 
tube assembly/control horn has not been previously inspected for cracks 
is due to the fact there is no prior manufacturer requirement to 
inspect. We infer the commenter requested the FAA require inspection of 
the torque tube assembly/control horn.
    We agree with the commenter. There was not a known need for 
inspection of the assembly. With discovery of the unsafe condition, a 
program is now being put into place.
    Based on these comments, we made no change to the AD action.

[[Page 56999]]

 Request To Make Piper Aircraft, Inc. Service Bulletin No. 1189, dated 
April 29, 2010, Only Advisory for the AD

    Hans Neubert for the ICS recommended that this service information 
be considered as advisory only to the corrective action. The commenter 
stated that the preliminary and final versions of the service 
information were based on an industry magazine article and were without 
substantiating data, field service history, or engineering evaluation.
    We disagree because the FAA independently evaluated all available 
data. We incorporated the intent of this service information into the 
AD, with the exception of adjustments to the applicability and 
compliance time.
    We did not change this final rule AD action based on these 
comments.

 Request To Incorporate Corrosion Preventive Measures in the AD

    George Edward White recommended incorporation of corrosion 
preventive measures into the AD. The commenter noted known corrosion 
issues on the adjacent torque tube.
    We disagree because corrosion preventive measures are already 
covered by the following documents and are not necessary to address the 
unsafe condition identified in this AD:
     Piper Aircraft, Inc. Service Bulletin No. 1160, dated 
December 26, 2005, at http://www.piper.com/Company/Publications/SB%201160%20Stab%20Torque%20Tube%20Assy%20Insp.pdf;
     Special Airworthiness Information Bulletin CE-04-88, dated 
September 15, 2004, at http://rgl.faa.gov/Regulatory--and--Guidance--
Library/rgSAIB.nsf/0/77fc29bb15c8a85b8625721f0052ecb4/$FILE/CE-04-
88.pdf;
     AD 74-13-03, Amendment 39-2588 (41 FR 17371, April 26, 
1976), at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/5CBFDEAB5E2AC41586256E1200498F02?OpenDocument&Highlight=74-13-03;
     AC 43.13-1B, Acceptable Methods, Techniques, and 
Practices--Aircraft Inspection and Repair, at http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/99861; and
     AC 43-4A, Corrosion Control for Aircraft, at http://
rgl.faa.gov/Regulatory--and--Guidance--Library/rgAdvisoryCircular.nsf/
list/AC%2043-4A/$FILE/AC%2043-4a%20.pdf.
    Based on these comments, we made no change to the AD action.

 Request To Require Inspection of the Tail of the Aircraft

    Patric Barry stated that periodically opening up the tail of the 
aircraft for inspection may be beneficial, suggesting that routine 
servicing of the entire area should be included in this AD. Dave 
Fitzgerald for the ICS stated that opening up the tail area for service 
of the trim drum, torque tube bearings, and associated areas is 
beneficial as part of normal maintenance, but is not part of this AD 
since the AD addresses the horn and torque tube and not associated 
components.
    We agree that maintenance of the trim drum, torque tube bearings, 
and associated areas is important but disagree with including it in 
this AD action. These components are not directly related to the unsafe 
condition so are not part of this AD.
    We did not change this final rule AD action based on these 
comments.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously and minor editorial 
changes. We have determined that these changes:
     [Agr]re consistent with the intent that was proposed in 
the NPRM (76 FR 36395, June 22, 2011) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 36395, June 22, 2011)
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of the AD.

Costs of Compliance

    We estimate that this AD affects 3,100 airplanes of U.S registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
              Action                     Labor cost            Parts cost           product         operators
----------------------------------------------------------------------------------------------------------------
Stabilator horn assembly            12 work-hours x $85   Not applicable......          $1,020       $3,162,000
 inspection.                         per hour = $1,020
----------------------------------------------------------------------------------------------------------------

     We estimate the following costs to do any necessary replacements 
that would be required based on the results of the proposed inspection. 
We have no way of determining the number of airplanes that might need 
this replacement:

                                               On-condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Stabilator horn assembly replacement.........  12 work-hours x $85 per hour =             $572           $1,592
                                                $1,020.
----------------------------------------------------------------------------------------------------------------

     According to the manufacturer, some of the costs of this AD may be 
covered under warranty, thereby reducing the cost impact on affected 
individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

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

[[Page 57000]]

safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (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, and
    (4) 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.

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):

2012-17-06 Piper Aircraft, Inc.: Amendment 39-17169; Docket No. FAA-
2011-0639; Directorate Identifier 2011-CE-016-AD.

(a) Effective Date

    This AD is effective October 22, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the following Piper Aircraft, Inc. airplanes, 
certificated in any category:
    (1) Model PA-24, serial numbers (S/Ns) 24-1 through 24-3687, 
with horn part number (P/N) 20397-00 (assembly P/N 20399) installed;
    (2) Model PA-24-250, S/Ns 24-1 and 24-103 through 24-3687, with 
horn P/N 20397-00 (assembly P/N 20399) installed; and
    (3) Model PA-24-260, S/Ns 24-3642 and 24-4000 through 24-5034, 
with horn P/N 20397-00 (assembly P/N 20399) installed.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 27: Flight Controls.

(e) Unsafe Condition

    This AD was prompted by reports of cracks developing in the 
stabilator horn assembly. We are issuing this AD to detect and 
correct corrosion or cracks in the stabilator horn assembly. 
Corrosion or cracks could lead to failure of the stabilator horn. 
Consequently, failure of the stabilator horn could lead to a loss of 
pitch control in flight.

(f) Compliance

    Comply with this AD following Piper Aircraft, Inc. Service 
Bulletin No. 1189, dated April 29, 2010, within the compliance times 
specified in this AD, unless already done (does not eliminate the 
repetitive actions of this AD).

(g) Inspection/Replacement

    (1) When a new stabilator horn assembly has been installed 
(during production or replacement) and the stabilator horn assembly 
reaches a total of 1,000 hours time-in-service (TIS) or 10 years 
after installation, or within the next 100 hours TIS after October 
22, 2012 (the effective date of this AD), whichever occurs later, do 
one of the following actions:
    (i) Initially inspect the stabilator horn assembly for corrosion 
or cracks. Repetitively thereafter inspect at intervals not to 
exceed 500 hours TIS or 5 years, whichever occurs first.
    (ii) Replace the stabilator horn assembly with a new stabilator 
horn assembly. When the new stabilator horn assembly reaches a total 
of 1,000 hours TIS after replacement or within 10 years after 
replacement, whichever occurs first, you must do one of the actions 
in paragraph (g)(1) of this AD.
    (iii) Replace the stabilator horn assembly with a used 
serviceable stabilator horn assembly that has been inspected before 
installation and found free of cracks or corrosion. Repetitively 
thereafter inspect at intervals not to exceed 500 hours TIS or 5 
years, whichever occurs first.
    (2) When a used serviceable stabilator horn assembly that has 
been inspected before installation and found free of cracks or 
corrosion has been installed and the stabilator horn assembly 
reaches a total of 500 hours TIS or 5 years after installation, or 
within the next 100 hours TIS after October 22, 2012 (the effective 
date of this AD), whichever occurs later, do one of the following 
actions:
    (i) Initially inspect the stabilator horn assembly for corrosion 
or cracks. Repetitively thereafter inspect at intervals not to 
exceed 500 hours TIS or 5 years, whichever occurs first.
    (ii) Replace the stabilator horn assembly with a new stabilator 
horn assembly. When the new stabilator horn assembly reaches a total 
of 1,000 hours TIS after replacement or within 10 years after 
replacement, whichever occurs first, you must do one of the actions 
in paragraph (g)(1) of this AD.
    (iii) Replace the stabilator horn assembly with a used 
serviceable stabilator horn assembly that has been inspected before 
installation and found free of cracks or corrosion. Repetitively 
thereafter inspect at intervals not to exceed 500 hours TIS or 5 
years, whichever occurs first.
    (3) If you do not know the total hours TIS on the stabilator 
horn assembly, within the next 100 hours TIS after October 22, 2012 
(the effective date of this AD) do one of the actions required in 
paragraph (g)(1)(i), (g)(1)(ii), (g)(1)(iii), (g)(2)(i), (g)(2)(ii), 
or (g)(2)(iii) of this AD.
    (4) If any corrosion or cracks are found during any of the 
inspections required in paragraph (g)(1)(i), (g)(1)(iii), (g)(2)(i), 
or (g)(2)(iii) of this AD, before further flight, you must replace 
the stabilator horn assembly as specified in paragraph (g)(1)(ii), 
(g)(1)(iii). (g)(2)(ii), or (g)(2)(iii) of this AD, as applicable.
    (5) For the bolts common to the torque tube and stabilator horn, 
install the nuts using a torque of 120-145 in.-lbs. for the actions 
required by paragraphs (g)(1), (g)(2), or (g)(3) of this AD.

    Note 1 to paragraph (g) of this AD: The stated torque value of 
120-145 in.-lbs. includes friction drag from the nut's locking 
element, which is assumed to be 60 in.-lbs. The installation torque 
can be adjusted according to the actual, measured friction drag. For 
example, if the friction-drag torque is measured to be 40 in.-lbs. 
(20 in.-lbs. less than the assumed value of 60 in.-lbs.), then the 
installation torque will be adjusted to be 100-125 in.-lbs. of 
torque.

    (6) You may at any time replace the stabilator horn assembly 
with a new stabilator horn assembly, provided no corrosion or cracks 
were found during an inspection that would require replacement 
before further flight. When the new stabilator horn assembly reaches 
a total of 1,000 hours TIS after replacement or within 10 years 
after replacement, whichever occurs first, you must do one of the 
actions in paragraph (g)(1) of this AD.

    Note 2 to paragraph (g) of this AD: Piper Aircraft, Inc. Service 
Bulletin No. 1160, dated December 26, 2005; Special Airworthiness 
Information Bulletin CE-04-88, dated September 15, 2004, at http://
rgl.faa.gov/Regulatory--and--Guidance--Library/rgSAIB.nsf/0/
77fc29bb15c8a85b8625721f0052ecb4/$FILE/CE-04-88.pdf; and AD 74-13-
03, Amendment 39-2588 (41 FR 17371, April 26, 1976), are related to 
this AD action. For the attached torque tube, you may consider 
combining that inspection with the requirements of this AD.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Atlanta Aircraft Certification Office (ACO), 
FAA, has the

[[Page 57001]]

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

(i) Related Information

    For more information about this AD, contact Gregory K. Noles, 
Aerospace Engineer, FAA, Atlanta ACO, 1701 Columbia Avenue, College 
Park, Georgia 30337; phone: (404) 474-5551; fax: (404) 474-5606; 
email: gregory.noles@faa.gov.

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Piper Aircraft, Inc. Service Bulletin No. 1189, dated April 
29, 2010.
    (ii) Reserved.
    (3) For Piper Aircraft, Inc. service information identified in 
this AD, contact Piper Aircraft, Inc., 2926 Piper Drive, Vero Beach, 
Florida 32960; telephone: (772) 567-4361; fax: (772) 978-6573; 
Internet: http://www.piper.com/company/publications.asp.
    (4) You may view this service information at the FAA, Small 
Airplane Directorate, 901 Locust St., Kansas City, Missouri 64106. 
For information on the availability of this material at the FAA, 
call (816) 329-4148.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Kansas City, Missouri, on August 20, 2012.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-22529 Filed 9-14-12; 8:45 am]
BILLING CODE 4910-13-P