### DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [4910-13-P]

[Docket No. FAA-2009-0776; Directorate Identifier 2009-NE-32-AD; Amendment 39-17481; AD 2010-17-11R1] RIN 2120-AA64 Airworthiness Directives; Dowty Propellers Propellers AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are revising an existing airworthiness directive (AD) that applies to all Dowty Propellers R408/6-123-F117 model propellers. That AD currently requires initial applications of sealant between the bus bar assembly and the backplate assembly of certain line-replaceable units, and repetitive applications of sealant on all R408/6-123- F117 model propellers. This new AD requires the same actions and allows the use ofan equivalent sealant as prescribed in revised service information. This AD was prompted by the need to add an optional terminating action to the applications of sealant. We are issuing this AD to prevent an in-flight double generator failure, which could result in reduced control ofthe airplane. DATES: This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. The Director ofthe Federal Register approved the incorporation by reference ofa certain publication listed in the AD as of [INSERT DATE 35 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. ADDRESSES: For service information identified in this AD , contact Dowty Propellers, AnsonBusiness Park, Cheltenham Road East, Gloucester GL2 9QN, UK; phone: 44 (0) 1452 716000 ; fax : 44 (0) 1452 716001. You may view this service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA

. For information on the availability ofthis material at the FAA, call 781-23 8-7125

. 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: Michael Schwetz, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803 ; phone: 781-238-7761; fax 781-238-7170 ; email: michael. schwetz@faa

.gov. SUPPLEMENTARY INFORMATION: Discussion We issued a notice ofproposed rulemaking (NPRM) to amend 14 CFR part 39 to revise AD 2010-17-11 , Amendment 39-16403 (75 FR 51656, August 23 , 2010). That AD applies to the specified products. The NPRM published in the Federal Register on February 7, 2013 (78 FR 9005). That NPRM proposed to add an optional terminating action to the applications of sealant.

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### 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. Request to Add Revised Service Information Horizon Air requested that we reference the latest revision ofDowty Alert Service Bulletin (ASB) No. D8400-61-A66, which is Revision 7, dated December 1, 2011 in the Compliance and the Credit for Previous Actions sections ofthe final rule. We partially agree. We changed paragraph (e)(l)(ii) ofthe Compliance section to read, "Use paragraph 3 ofthe Accomplishment Instructions ofDowty Propellers Alert Service Bulletin (ASB) No. D8400-61-A66, Revision 7, dated December 1, 2011 to apply the sealant. " We do not agree with the change to the Credit for Previous Actions paragraph because referencing the ASB in the Compliance paragraph satisfies this request by directing the use ofthe latest revision as stated

. Request to Add Equivalent Sealant Horizon Air requested that we allow the use of 3M 4200 sealant as an equivalent replacement for the 3M 5300 sealant listed in the Accomplishment Instructions ofDowty Propellers Service Bulletin (SB) No. D8400-61-94, Revision 3, dated October 23 , 2012. We agree. We changed the AD by modif ying references to " sealant" to " 3M 5300

or 3M 4200 sealant" in the Compliance and Installation Prohibition paragraphs

. 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 minor changes:

3• Are consistent with the intent that was proposed in the NPRM (78 FR 9005, February 7, 2013 ) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (78 FR 9005 , February 7, 2013)

. 

### Differences Between This AD and the Service Information Dowty Propellers SB No. D8400-61-94, Revision 3, dated October 23 , 2012 requires the application of3M 5300 sealant between the bus bar assembly and the backplate assembly ofDowty Propeller R408/6-123-F/ 17. This AD also permits use of 3M 4200 sealant as an acceptable equivalent to the 3M 5300 sealant. 

### Costs of Compliance We estimate that this AD will affect about 104 propellers installed on airplanes of U.S. registry. We also estimate that it will take about 3 hours per propeller to apply the sealant and that required sealant will cost about $20 per propeller. We also estimate that it will take about 3 hours to replace the bus bar with a de-icer slip ring harness and that required parts will cost about $1,200 per propeller. The average labor rate is $85 per hour. Based on these figures, we estimate the cost ofthe AD on U.S. operators to be $171,080. 

### Authority for this Rulemaking Title 49 ofthe United States Code specifies the FAA' s authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority ofthe FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope ofthe 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 ofcivil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds

4necessary for safety in air commerce. This regulation is within the scope ofthat authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. 

### Regulatory Findings We have determined that this AD will not have federalism implications under Executive Order 13132

. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels ofgovernment. For the reasons discussed above, I certify that this AD: (1) Is not a " significant regulatory action" under Executive Order 12866, (2) Is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will not affect intrastate aviation in Alaska to the extent that itjustifies making a regulatory distinction, and (4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria ofthe 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.



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### § 39.13 [Amended] 2. The FAA amends§ 39.13 by removing airworthiness directive (AD) 2010-17-11, Amendment 39-16403 (75 FR 51656, August 23, 2010), and adding the following new AD: 

### 2010-17-11R1 Dowty Propellers: Amendment 39-17481; Docket No. FAA-2009-0776; Directorate Identifier 2009-NE-32-AD. 

### (a) Effective Date This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

### (b) Affected ADs This AD revises AD 2010-17-11, Amendment 39-16403 (75 FR 51656, August 23, 2010). 

### (c) Applicability This AD applies to Dowty Propellers R408/6-123-F/17 model propellers. 

### (d) Unsafe Condition This AD was prompted by the need to add an optional terminating action to the applications of sealant. We are issuing this AD to prevent an in-flight double generator failure, which could result in reduced control ofthe airplane. (e) 

### Compliance Comply with this AD within the compliance times specified, unless already done. (1) 

### For R408/6-123-F/17 model propellers with a hub, actuator, and backplate assembly line-replaceable unit serial number below DAP0347, do the following initial sealant application within 5,000 flight hours (FHs) after September 27,2010, or within 100 FHs from the effective date ofthis AD, whichever occurs later: (i) Apply 3M 5300 or 3M 4200 sealant between the bus bar assemblies and the backplate assembly.

6(ii) Use paragraph 3 ofthe Accomplishment Instructions ofDowty Propellers Alert Service Bulletin (ASB) No. D8400-61-A66, Revision 7, dated December 1, 2011 , to apply the sealant. (2) Thereafter, for all R408/6-123-F/17 model propellers, re-apply sealant as specified in paragraphs (e)(1)(i) through (e)(1)(ii) ofthis AD within every additional 10,000 FHs. (f) 

### Installation Prohibition After the effective date ofthis AD , do not install any Dowty Propellers R408/6- 123-F/17 model propeller unless 3M 5300 or 3M 4200 sealant has been applied between the bus bar assembly and the backplate assembly as specified by this AD , or unless the optional terminating action as specified in paragraph (h) ofthis AD has been performed. (g) 

### Credit for Previous Actions Sealant applications performed before the effective date ofthis AD that followed Dowty Propellers Service Bulletin (SB) No. D8400-61-66, dated February 9, 2007, Revision 1, dated May 4, 2007; ASB No. D8400-61-A66, Revision 2, dated August 19, 2009; Revision 3, dated November 10, 2009; Revision 4, dated January 19, 2010; Revision 5, dated June 16, 2010, or Revision 6, dated August 17, 2011 satisfy the initial sealant application requirement ofthis AD. 

### (h) Optional Terminating Action As optional terminating action to the sealant application requirements ofthis AD, replace the bus bar assembly with a slip ring de-icer harness. Use paragraph 3.A. ofthe Accomplishment Instructions ofDowty Propellers SB No. D8400-61-94, Revision 2, dated August 29, 2012, or Revision 3, dated October 23 , 2012, to do the replacement. 

### (i) Alternative Methods of Compliance (AMOCs) The Manager, Boston Aircraft Certification Office, FAA, may approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request.

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### U) Related Information (1) Refer to European Aviation Safety Agency AD 2009-0114R1 (correction: dated December 12, 2012) for related information. (2) For more information about this AD, contact Michael Schwetz, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7761; fax 781- 238-7170; email: michael.schwetz01faa.gov. (k) Material Incorporated 

### by Reference (1) 

### The Director ofthe Federal Register approved the incorporation by reference (IBR) ofthe 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. (3) The following service information was approved for IBR on [INSERT DATE 35 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. (i) Dowty Propellers Alert Service Bulletin No. D8400-61-A66, Revision 7, dated December 1, 2011. (ii) Reserved. (4) For service information identified in this AD, contact Dowty Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL 29QN, UK; phone: 44 (0) 1452 716000; fax: 44 (0) 1452 716001. (5) You may view this service information at the FAA, Engine & 

### Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability ofthis material at the FAA, call 781-238-7125. (6) You may view this service information at the National Archives and Records Administration (NARA). For information on the availability ofthis material at NARA, 

### 8call 202-741-6030, or go to: http: //www.archives.gov/federal-register/cfr /ibrlocations

.html.

Robert Ganl y, Acting Assistant Manager, Engine & Propeller Directorate, Aircraft Certification Service.

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