52172 Federal Register / Vol. 79, No. 170 / Wednesday, September 3, 2014 / Rules and Regulations 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2013–0766; Directorate 

Identifier 2013–NE–26–AD; Amendment 39– 

17961; AD 2014–17–08] 

RIN 2120–AA64 

Airworthiness Directives; Pratt & 

Whitney Canada Corp. Turboprop 

Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for all Pratt 

& Whitney Canada Corp. (P&WC) PT6A– 

114 and PT6A–114A turboprop engines. 

This AD requires initial and repetitive 

borescope inspection (BSI) of 

compressor turbine (CT) blades, and the 

removal from service of blades that fail 

inspection. This AD was prompted by 

several incidents of CT blade failure, 

causing power loss, and engine failure. 

We are issuing this AD to prevent 

failure of CT blades, which could result 

in damage to the engine and damage to 

the airplane. 

DATES: This AD becomes effective 

October 8, 2014. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of October 8, 2014. 

ADDRESSES: For service information 

identified in this AD, contact Pratt & 

Whitney Canada Corp., 1000 MarieVictorin, Longueuil, Quebec, Canada, 

J4G 1A1; phone: 800–268–8000; fax: 

450–647–2888; Internet: www.pwc.ca. 

You may view this service information 

at the FAA, Engine & Propeller 

Directorate, 12 New England Executive 

Park, Burlington, MA. For information 

on the availability of this material at the 

FAA, call 781–238–7125. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http://

www.regulations.gov by searching for 

and locating Docket No. FAA–2013– 

0766; 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 mandatory 

continuing airworthiness information 

(MCAI), 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: 

Robert Morlath, Aerospace Engineer, 

Engine Certification Office, FAA, Engine 

& Propeller Directorate, 12 New England 

Executive Park, Burlington, MA 01803; 

phone: 781–238–7154; fax: 781–238– 

7199; email: robert.c.morlath@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a supplemental notice of 

proposed rulemaking (SNPRM) to 

amend 14 CFR part 39 by adding an AD 

that would apply to the specified 

products. The SNPRM was published in 

the Federal Register on May 12, 2014 

(79 FR 26901). The SNPRM proposed to 

correct an unsafe condition for the 

specified products. The MCAI states: 

There have been a number of reported 

incidents where Compressor Turbine (CT) 

blade failures have caused power loss on 

PT6A–114 & PT6A–114A engines, resulting 

in in-flight shutdown (IFSD). Investigation by 

engine manufacturer Pratt & Whitney Canada 

(P&WC) has determined that when operated 

at high power and high temperature settings, 

the subject CT blades are prone to crack/

fracture as a result of creep and/or 

sulfidation. 

P&WC issued Service Bulletin (SB) 1669 

that introduces a newly designed CT blade 

which has proven to be far less affected by 

the blade ‘‘Creep’’ phenomenon. 

Additionally, to help prevent IFSD by 

identifying pending creep induced blade 

failure of the pre-SB 1669 configuration 

blades, P&WC has revised SB 1669 to include 

specific inspection/maintenance 

requirements for engines with pre-SB 1669 

configuration CT blade installation. 

An engine power loss or IFSD on a single 

engine powered aeroplane such as Cessna 

208 could result in an unsafe condition. AD 

CF–2013–21 was issued on 1 August 2013 to 

mandate compliance with SB 1669R9 

requirements to inspect and replace the 

existing CT blades on PT6A–114 & PT6A– 

114A engines with a new type of post SB 

1669 configuration CT blades. P&WC, 

through SB 1727, has now introduced a new 

version of the post SB 1669 configuration CT 

blade that features a tighter tolerance on the 

platform width. This enhances the ability of 

the maintainer to achieve the required interplatform gap. 

Comments 

We gave the public the opportunity to 

participate in developing this AD. We 

considered the comments received. 

Request To Remove Mandatory 

Upgrade 

One commenter requested that we 

remove the mandatory terminating 

action requirement to install P&WC 

single crystal CT blades, part numbers 

(P/Ns) 3072791–01 and 3072791–02. 

The commenter states that mandating 

the installation of an unproven 

replacement CT blade is not prudent 

and could be costly. The post-SB blade 

has a questionable operating history 

including failure. This blade has been 

identified for removal in the PT6A–34 

and –36 engines, so it should not be 

made mandatory for installation in the 

PT6A–114 engine. 

We do not agree. P&WC single crystal 

CT blades, P/Ns 3072791–01 and 

3072791–02, are proven replacement CT 

blades for the PT6A–114 and PT6A– 

114A engines. These single crystal CT 

blades have successfully performed over 

2 million flight hours in service and 

have displayed a lower rate of failure 

than older CT blade designs. An 

ongoing investigation into blade failures 

on other PT6A series engines has shown 

that the root cause of those failures does 

not impact the PT6A–114 and PT6A– 

114A fleets. Therefore, P&WC single 

crystal CT blades, P/Ns 3072791–01 and 

3072791–02, have not been identified 

for removal from the PT6A–114 and 

PT6A–114A series engines. We did not 

change this AD. 

Request To Change Mandatory 

Terminating Action 

One commenter suggested that the 36- 

month compliance time for the 

mandatory terminating action is not 

appropriate. The commenter states that 

mandating replacement of the complete 

set of single crystal CT blades with 

P/N 3072791–02 blades within 36 

months is an undue cost burden for 

certain operators and that the 

availability of CT blade, P/N 3072791– 

02, is unreliable. The operator will not 

reach the next scheduled hot section 

interval prior to 36 months, thereby 

causing the performance of the next hot 

section inspection (HSI) sooner than 

necessary. 

We do not agree. The 36-month 

compliance time for installing single 

crystal CT blades, P/Ns 3072791–01 and 

3072791–02, adequately addresses the 

unsafe condition without imposing 

undue burden on operators. P&WC 

single crystal CT blades, P/Ns 3072791– 

01 and 3072791–02 are currently 

available from P&WC both as 

replacement parts and installed in new 

production engines. We did not change 

this AD. 

Request To Change Mandatory 

Terminating Action 

Hawkins Aero Engineering, Inc. 

(Hawkins Aero) requested that the 

mandatory terminating action be 

changed to allow for installation of CT 


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Federal Register / Vol. 79, No. 170 / Wednesday, September 3, 2014 / Rules and Regulations 52173 

blade P/Ns approved by the FAA in the 

future. The reason for this request is that 

P&WC and various parts manufacturer 

approval companies may develop new 

blade designs. Adding language that 

would allow for installation of newly 

approved blades in the future would 

avoid having to revise this AD. 

We do not agree. We cannot approve 

P/Ns that do not exist. We did not 

change this AD. 

Request To Change Referenced SB and 

P/N 

One commenter requested that we 

remove P&WC SB No. PT6A–72–1669 

and CT blade, P/N 3072791–01, from 

this AD. The commenter states that this 

SB introduces CT blade, P/N 3072791– 

01, which is no longer available. The 

commenter suggests that in this AD, to 

avoid confusion when an operator 

reviews engine repair records to 

determine SB compliance, we should 

mention only P&WC SB No. PT6A–72– 

1727, which introduces single crystal 

CT blade, P/N 3072791–02. 

We partially agree. We agree that 

referencing P&WC SB No. PT6A–72– 

1669 in this AD may introduce some 

confusion as to what P/Ns are mandated 

for installation. 

We disagree with removing all 

references to P&WC SB No. PT6A–72– 

1669 from this AD because this SB 

contains instructions on performing the 

optional metallurgical examination 

cited in paragraph (e)(1)(iii)(B) of this 

AD. 

We disagree with removing all 

references to single crystal CT blade, P/ 

N 3072791–01, because it is still 

acceptable for installation even though 

it is no longer in production. 

We made the following change to the 

Credit for Previous Actions paragraph of 

this AD: ‘‘If you performed a 

metallurgical examination of single 

crystal CT blades in accordance with 

P&WC SB No. PT6A–72–1669, Revision 

9, dated June 28, 2013, or earlier 

versions, you met the initial inspection 

requirements of paragraph (e)(1)(i) of 

this AD. However, you must still 

comply with the repetitive BSI 

requirement of paragraph (e)(1)(ii) of 

this AD.’’ 

Request To Change the Number of 

Stated Fatalities 

Hawkins Aero requested that we reevaluate the stated number of fatalities 

that have been associated with CT blade 

failures. Hawkins Aero then provided a 

brief synopsis of recent fatal incidents 

involving CT blade failures and 

associated forced landings that provide 

a different number than what was 

published in the SNPRM (79 FR 26901, 

May 12, 2014). 

We partially agree. We agree that we 

should be accurate in what we report. 

We disagree that we must identify 

fatalities to demonstrate the need for the 

AD. We changed the justification 

statement in the Summary and Unsafe 

Condition paragraphs to state that ‘‘This 

AD was prompted by several incidents 

of CT blade failure, causing power loss, 

and engine failure.’’ 

Request To Change the Costs of 

Compliance 

One commenter requested that we reevaluate the costs of compliance. The 

commenter states that the cost of 

performing the HSI, other than the cost 

of the blades, was not considered. The 

commenter also indicated that the 

hidden cost of installing the post-SB 

blades has not been revealed. The 

replacement single crystal CT blades 

have a hard time life limit of 10,000 

hours, whereas the CT blades that are 

being replaced do not. The post-SB 

blades have a lower stretch inspection 

interval of 4,000 hours compared to 

5,000 for pre-SB blades. 

We do not agree. The cost of 

compliance calculation includes the 

initial work and parts costs associated 

with removing the unsafe condition. It 

does not include costs associated with 

normal scheduled maintenance. We did 

not change this AD. 

Request To Approve Alternate Methods 

of Compliance (AMOCs) 

Hawkins Aero requested that we 

approve AMOCs to this AD. 

We do not agree. This AD sets forth 

our required method of compliance to 

correct the specified unsafe condition. 

Operators may request AMOCs to this 

AD using the procedures below. We did 

not change this AD. 

Request To Change Nomenclature 

Hawkins Aero requested that each 

time we reference the single crystal CT 

blades in this AD we use the 

nomenclature ‘‘P&WC single crystal CT 

blade P/N’s 3072791–01 and 3072791– 

02.’’ The commenter states that ‘‘In 

several locations within the SNPRM the 

FAA has referred to: ‘single crystal CT 

blades P/Ns 3072791–01 or 3072791– 

02,’ ‘CT blades, part numbers P/Ns 

3072791–01 or 3072791–02,’ and ‘P&WC 

single crystal CT blades P/Ns 3072791– 

01 or 3072791–02’.’’ 

We agree. We changed this AD by 

replacing all references to the single 

crystal CT blades with the nomenclature 

‘‘P&WC single crystal CT blades, P/Ns 

3072791–01 and 3072791–02.’’ 

Request To Clarify Compliance 

Language 

One commenter requested that we 

clarify the language in paragraph 

(e)(1)(iii)(A) of this AD with a specific 

P/N. 

We do not agree. Operators may 

install any P/N single crystal CT blade 

eligible for installation. We did not 

change this AD. 

Request To Clarify Assumptions 

One commenter requested that we reevaluate the 1,800 hour assumption for 

a typical hot section interval. The 

commenter states, ‘‘Assuming that 1,800 

hours is the normal interval for all 

operators is incorrect; some operators 

have extended intervals up to and 

including On Condition; therefore, 

stating to perform the AD at next HSI 

could be much longer than the expected 

1,800 hours.’’ 

We do not agree. We did not assume 

1,800 hours as a typical HSI interval. 

This AD requires blade examination or 

replacement at next HSI, and not at 

specific flight-hour or cycles-inoperation intervals, precisely due to the 

wide variety of approved inspection 

intervals that exist for these engines. We 

did not change this AD. 

Conclusion 

We reviewed the available data, 

including the comments received, and 

determined that air safety and the 

public interest require adopting this AD 

with the changes described previously. 

We determined that these changes will 

not increase the economic burden on 

any operator or increase the scope of 

this AD. 

Costs of Compliance 

We estimate that this AD affects 300 

engines installed on airplanes of U.S. 

registry. We also estimate that it will 

take about 4 hours per engine to perform 

the required inspection and 8 hours to 

replace the blades. The average labor 

rate is $85 per hour. Required parts cost 

about $59,334 per engine. Based on 

these figures, we estimate the cost of 

this AD on U.S. operators to be 

$18,106,200, if all blades are replaced. 

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: 


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52174 Federal Register / Vol. 79, No. 170 / Wednesday, September 3, 2014 / Rules and Regulations 

General requirements.’’ Under that 

section, Congress charges the FAA with 

promoting safe flight of civil aircraft in 

air commerce by prescribing regulations 

for practices, methods, and procedures 

the Administrator finds necessary for 

safety in air commerce. This regulation 

is within the scope of that authority 

because it addresses an unsafe condition 

that is likely to exist or develop on 

products identified in this rulemaking 

action. 

Regulatory Findings 

We determined that this AD will not 

have federalism implications under 

Executive Order 13132. This AD will 

not have a substantial direct effect on 

the States, on the relationship between 

the national government and the States, 

or on the distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify this AD: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Is not a ‘‘significant rule’’ under 

the DOT Regulatory Policies and 

Procedures (44 FR 11034, February 26, 

1979), 

(3) Will not affect intrastate aviation 

in Alaska to the extent that it justifies 

making a regulatory distinction, and 

(4) Will 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): 

2014–17–08 Pratt & Whitney Canada Corp.: 

Amendment 39–17961; Docket No. 

FAA–2013–0766; Directorate Identifier 

2013–NE–26–AD. 

(a) Effective Date 

This AD becomes effective October 8, 2014. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all Pratt & Whitney 

Canada Corp. (P&WC) PT6A–114 and PT6A– 

114A turboprop engines. 

(d) Unsafe Condition 

This AD was prompted by several 

incidents of compressor turbine (CT) blade 

failure, causing power loss, and engine 

failure. We are issuing this AD to prevent 

failure of CT blades, which could lead to 

damage to the engine and damage to the 

airplane. 

(e) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(1) For engines that have CT blades 

installed other than P&WC single crystal CT 

blades, part numbers (P/Ns) 3072791–01 or 

3072791–02, perform the following actions: 

(i) Within 150 operating hours after the 

effective date of this AD, perform a borescope 

inspection (BSI) of CT blades for engines 

with 500 or more hours time-since-new that 

have not been previously inspected or timesince-last-inspection (TSLI). 

(ii) Thereafter, repeat the inspection in 

paragraph (e)(1)(i) of this AD within 500 

flight hours TSLI. 

(iii) During the next hot section inspection 

(HSI) after the effective date of this AD, and 

each HSI thereafter, replace the complete set 

of CT blades with any of the following: 

(A) New CT blades; 

(B) CT blades that have passed a two-blade 

metallurgical examination in accordance 

with paragraph 3.B., Accomplishment 

Instructions, of P&WC Service Bulletin (SB) 

No. PT6A–72–1669, Revision 9, dated June 

28, 2013; or 

(C) P&WC single crystal CT blades, P/Ns 

3072791–01 or 3072791–02. 

(2) Reserved. 

(f) Mandatory Terminating Action 

Within 36 months after the effective date 

of this AD, replace the complete set of CT 

blades with P&WC single crystal CT blades, 

P/Ns 3072791–01 or 3072791–02. 

(g) Credit for Previous Action 

If you performed a metallurgical 

examination of single crystal CT blades 

before the effective date of this AD in 

accordance with P&WC SB No. PT6A–72– 

1669, Revision 8, dated January 17, 2013, or 

earlier versions, all of which are not 

incorporated by reference, you have met the 

initial inspection requirements of paragraph 

(e)(1)(i) of this AD. However, you must still 

comply with the repetitive BSI requirement 

of paragraph (e)(1)(ii) of this AD. 

(h) Alternative Methods of Compliance 

(AMOCs) 

The Manager, Engine Certification Office, 

FAA, may approve AMOCs to this AD. Use 

the procedures found in 14 CFR 39.19 to 

make your request. 

(i) Related Information 

(1) For more information about this AD, 

contact Robert Morlath, Aerospace Engineer, 

Engine Certification Office, FAA, Engine & 

Propeller Directorate, 12 New England 

Executive Park, Burlington, MA 01803; 

phone: 781–238–7154; fax: 781–238–7199; 

email: robert.c.morlath@faa.gov. 

(2) Refer to Transport Canada Civil 

Aviation AD CF–2013–21R1, dated 

November 13, 2013, for more information. 

You may examine the MCAI in the AD 

docket on the Internet at http:// 

www.regulations.gov/ 

#!documentDetail;D=FAA-2013-0766-0008. 

(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) Pratt & Whitney Canada Service Bulletin 

No. PT6A–72–1669, Revision 9, dated June 

28, 2013. 

(ii) Reserved. 

(3) For P&WC service information 

identified in this AD, contact Pratt & Whitney 

Canada Corp., 1000 Marie-Victorin, 

Longueuil, Quebec, Canada, J4G 1A1; phone: 

800–268–8000; fax: 450–647–2888; Internet: 

www.pwc.ca. 

(4) You may view this service information 

at FAA, Engine & Propeller Directorate, 12 

New England Executive Park, Burlington, 

MA. For information on the availability of 

this material at the FAA, call 781–238–7125. 

(5) You may view this service information 

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 Burlington, Massachusetts, on 

August18, 2014. 

Richard P. Warren, 

Acting Assistant Directorate Manager, Engine 

& Propeller Directorate, Aircraft Certification 

Service. 

[FR Doc. 2014–20453 Filed 9–2–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2014–0137; Directorate 

Identifier 2013–NM–135–AD; Amendment 

39–17960; AD 2014–17–07] 

RIN 2120–AA64 

Airworthiness Directives; Airbus 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 


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