[4910-13-P] 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA-2015-4866; Directorate Identifier 2015-NE-33-AD; Amendment 

39-18648; AD 2016-18-17] 

RIN 2120-AA64 

Airworthiness Directives; Honeywell International Inc. Turboprop and Turboshaft 

Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new airworthiness directive (AD) for certain Honeywell 

International Inc. (Honeywell) TPE331 model turboprop engines and TSE331-3U model 

turboshaft engines. This AD was prompted by the discovery of cracks in a 2nd stage 

compressor impeller during a routine shop visit. This AD requires removal of the 2nd 

stage compressor impeller. We are issuing this AD to prevent failure of the compressor 

impeller, uncontained part release, damage to the engine, and damage to the airplane. 

DATES: This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

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. F AA-20 15-4866; 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: Joseph Costa, Aerospace Engineer, 

Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 

Paramount Blvd., Lakewood, CA 90712-4137; phone: 562-627-5246; fax: 562-627-5210; 

email: joseph.costa@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 3 9 by 

adding an AD that would apply to certain Honeywell TPE331 model turboprop engines 

and TSE331-3U model turboshaft engines. The NPRM published in the Federal Register 

on March 15, 2016 (81 FR 13764) ("the NPRM"). The NPRM was prompted by the 

discovery of cracks in a 2nd stage compressor impeller during a routine shop visit. The 

NPRM proposed to require removal of the 2nd stage compressor impeller. We are issuing 

this AD to prevent failure of the compressor impeller, uncontained part release, damage 

to the engine, and damage to the airplane. 

Comments 

We gave the public the opportunity to participate in developing this AD. The 

following presents the comments received on the NPRM and the FAA's response to each 

comment. 

Request to Change Compliance 

Bearskin Airlines and Turbine Standard, LTD requested that the compliance time 

interval be changed because many TPE3 31 engine operators are on a Continuous 

Airworthiness Maintenance (CAM) program: This program does not require impeller 

inspections per the overhaul manual and the impeller is not considered as "overhauled". 

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AD compliance under CAM may be interpreted as being within 200 cycles or 30 to 45 

days. 

Other commenters requested that the compliance time be changed to a less 

aggressive time interval appropriate to the unsafe condition. Many high-usage operators 

have suspect impellers that currently exceed 7,000 cycles since the last compressor 

inspection. 

We agree. We changed compliance interval in paragraph (e)(1) of this AD. 

Request to Allow Other Inspection Facilities to Return Impellers to Service 

Turbine Standard, LTD requested that this AD allow other inspection facilities to 

return impellers to service. There are many inspection facilities that are capable of 

inspecting the 2nd stage compressor impeller. 

We partially agree. We agree that many inspection facilities are capable of 

performing a focused inspection of the 2nd stage compressor impeller. We disagree with 

allowing other inspection and regrinding facilities to return impellers to service. This AD 

does not address inspection or regrinding of the curvic area of the 2nd stage compressor 

impeller. Regrinding of the curvic area of the 2nd stage compressor impeller involves 

machining of a critical rotating part, which must be approved by the FAA. We did not 

change this AD. 

Request to Change Costs of Compliance 

Honeywell; Perimeter Aviation, LP; and Intercontinental Jet Service Corp. 

requested that the costs of compliance be changed because the NPRM is not 

representative of the impeller's replacement costs. Honeywell quotes the cost of a new 

2nd stage compressor impeller at $11,922.50. 

We partially agree. We agree with the comment because the costs were not clearly 

defined. We disagree with the comment because replacement costs are based on pro-rated 

costs that are estimated at 50% of new parts costs. Since issuing the NPRM, the FAA 

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estimated that 30% of impellers will be scrapped; therefore, we changed the costs of 

compliance accordingly. 

Request to Include Service Information 

The European Aviation Safety Agency, Honeywell, and Candler & Associates, 

Inc. requested that service information be included in this AD. Having the service 

information available would aid in understanding any differences between this AD and 

the service information. 

We agree. We added Honeywell Service Bulletin (SB) TPE331-72-2208, dated 

July 29, 2014, as related information in this AD. 

Conclusion 

We reviewed the relevant data, considered the comments received, and 

determined that air safety and the public interest require adopting this AD with the 

changes described previously. 

We also determined that these changes will not increase the economic burden on 

any operator or increase the scope of this AD. 

Related Service Information 

We reviewed Honeywell SB TPE331-72-2208, dated July 29,2014. The SB 

describes procedures for replacing the 2nd stage compressor impeller. 

Costs of Compliance 

We estimate that this AD will affect 4,000 engines installed on airplanes of U.S. 

registry. We estimate that it will take 2 hours per engine to comply with this AD. The 

average labor rate is $85 per hour. We also estimate that required parts will cost about 

$4,404 per engine. Based on these figures, we estimate the total cost of this AD on U.S. 

operators to be $18,298,000. 

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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 44 701: "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 

This AD will not have federalism implications under Executive Order 1313 2. 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 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. 

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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): 

2016-18-1 7 Honeywell International Inc. (Type Certificate previously held by 

AlliedSignal Inc., Garrett Engine Division; Garrett Turbine Engine Company; and 

AiResearch Manufacturing Company of Arizona): Amendment 39-18648; Docket 

No. FAA-2015-4866; Directorate Identifier 2015-NE-33-AD. 

(a) Effective Date 

This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Honeywell International Inc. (Honeywell) TPE331-3U, -3UW, 

-5, -SA, -5AB, -5B, -6, -6A, -8, -10, -lOAV, -lOGP, -lOGT, -ION, -lOP, -lOR, -lOT, 

-lOU, -lOU A, -lOUF, -lOUG, -lOUGR, -lOUR, and -11 U model turboprop engines, and 

TSE331-3U model turboshaft engines, with a 2nd stage compressor impeller, part number 

(PIN) 893482-1 through -5, inclusive, or PIN 3107056-1 or PIN 3107056-2, installed. 

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(d) Unsafe Condition 

This AD was prompted by the discovery of cracks in a 2nd stage compressor 

impeller during a routine shop visit. We are issuing this AD to prevent failure of the 

compressor impeller, uncontained part release, damage to the engine, and damage to the 

airplane. 

(e) Compliance 

Comply with this AD within the compliance times specified, unless already done. 

(1) Remove from service the 2nd stage compressor impeller at next removal of the 

2nd stage compressor impeller from the engine or before exceeding 11,500 cycles in 

service after the effective date of this AD, whichever occurs first. 

(2) Reserved. 

(f) Installation Prohibition 

After the effective date of this AD, do not install a 2nd stage compressor impeller, 

part number (PIN) 893482-1 through -5, inclusive, or PIN 3107056-1 or PIN 3107056-2, 

into any engine. 

(g) Alternative Methods of Compliance (AMOCs) 

The Manager, Los Angeles Aircraft Certification Office, FAA, may approve 

AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request. 

(h) Related Information 

(1) For more information about this AD, contact Joseph Costa, Aerospace 

Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane 

Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; phone: 562-627-5246; 

fax: 562-627-5210; email: joseph.costa@faa.gov. 

(2) Honeywell SB TPE331-72-2208, dated July 29, 2014, which is not 

incorporated by reference in this AD, can be obtained from Honeywell, using the contact 

information in paragraph (h)(3) of this AD. 

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(3) For Honeywell service information identified in this AD, contact Honeywell 

International Inc., 111 S 34th Street, Phoenix, AZ 85034-2802; phone: 800-601-3099; 

Internet: https:/ /myaerospace.honeywell.com/wps/portal/! uti. 

( 4) You may view this service information at FAA, Engine & Propeller 

Directorate, 1200 District A venue, Burlington, MA. For information on the availability of 

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

(i) Material Incorporated by Reference 

None. 

Issued in Burlington, Massachusetts, on August 26, 2016. 

Colleen M. D' Alessandro, 

Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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