DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administntion 

14 CFR Part 39 

[Docket No. FAA-2012-0913; Directorate Identifier 2012-NE-23-ADI 

RIN 2120-AA64 

Airworthiness Directives; Honeywell International Inc. Turboprop Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking (NPRM). 

[4910-13-Pl 

SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain 

Honeywell International Inc. TPE331-5, -5A, -5AB, -58, -10, -lOR, -IOU, -IOUF, 

-I OUG, -I OUGR, and -I OUR model turboprop engines. This proposed AD was prompted 

by engine propeller shaft coupling failures, leading to unexpected propeller pitch changes 

resulting in high aerodynamic and asymmetric drag on the airplanes using these engines. 

This proposed AD would require removing certain part number (PIN) propeller shaft 

couplings from service. This proposed AD would also require inserting a copy of 

Honeywell International Inc. Operating Information Letter 01331-26, dated March 2, 

20 I 0, into the applicable Airplane Flight Manuals. We are proposing this AD to prevent 

loss of airplane control, leading to an accident. 

DATES: We must receive comments on this proposed AD by [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: You may send comments, using the procedures found in 14 CFR ll.43 

and I 1.45, by any of the fo llowing methods: 

• Federa l eRulemaking Portal: Go to http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202-493-2251. 
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West 

Building Ground Floor, Room Wl2-140, 1200 New Jersey Avenue SE., Washington, DC 

20590. 

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal holidays. 

For service infom1ation identified in this proposed AD, contact Honeywell 

International fnc., 1 I I S. 34111 Street, Phoenix, AZ 85034-2802; phone: 800-601-3099; 

Web site : http://portal.honeywell.com. You may view this service info rmation 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-2012-09 13; or in person at the Docket 

Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federa l 

holidays. The AD docket contains this proposed AD, the regulatory evaluation, any 

comments received, and other information. The street address for the Docket Office 

(phone : 800-647-5527) is in the ADDRESSES section. Comments will be available in the 

AD docket shortly after receipt. 

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer. 

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

Paramount Blvd., Lakewood, CA 907 12-4137; phone: 562-627-5246; fax: 562-627-521 0; 

email: joseph.costa@ faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to send any written relevant data, views, or arguments about this 

proposal. Send your comments to an address listed under the ADDRESSES section. 

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Include "Docket No. r AA-2012-0913; Directorate Identi fi er 2012-NE-23-AD" at the 

beginning of your comments. We specifically invite comments on the overall regulatory, 

economic, environmental, and energy aspects of this proposed AD. We will consider all 

comments received by the closing date and may amend this proposed AD because of 

those comments. 

We will post all comments we receive, without change, to 

http://www.regulations.gov, including any personal information you provide. We will 

also post a report summarizing each substantive verbal contact we receive about this 

proposed AD. 

Discussion 

We have rece ived numerous reports of propeller shaft couplings, PINs 3107065-1 

and 865888-3, faili ng. These propeller shaft couplings experience fatigue cracks at the 

corners of the lubrication slots that may result in separation and fragmentation of the 

propeller shaft coup I in g. That separation causes a sudden loss of drive torque from the 

engine's power section to the propeller shaft (called drivetrain uncoupling). After a 

drivetrain uncoupling, the engine's fuel pump continues to provide fuel to the power 

section, and with no propeller load and no engine control changes by the pilot, the engine 

power section will accelerate to the fuel control's overspced governor set point. Even 

though the propeller drive is uncoupled, the propeller blade pitch is still controlled by the 

propeller governor. During this overspeed condition, the propeller governor is designed 

to move the propeller blades toward higher pitch unti l full feather is reached with the 

propeller not rotating or rotating very slowly. Under certain conditions the power section 

will remain at about I 04% RPM with the propeller blades in feather position and the 

propeller not rotating or rotating very slowly, until the engine is shut down by the pilot. 
Potential Unsafe Failure Scenarios 

After a propell er shaft drivetrain uncoupli ng, the speed of the engine's power 

section may be reduced: (l) from full power, by the pilot retarding the power lever to 

flight idle, which reduces fuel to the power section; (2) at flight idle, because the fuel 

control reduces the fuel supply to the power section and/or; (3) by fragmentation of the 

propeller shaft coupling and secondary damage to the gears in the gearbox. If the 

resulting speed o f the power section falls below the propeller governor set point (set by 

the pilot-controlled condition lever), the propeller governor will move the propeller out of 

feather to a low-pitch, high-drag position. 

Also, after a propeller shaft drivetrain uncoupling, a pilot reacting to the 

overspeed of the power section may inadvertently retard the power lever to flight idle. 

Doing so wi ll cause the propeller governor to move the fea thered propeller to a low-pitch, 

high-drag condition. 

Several reports during maintenance test flights and in-service operations of twinengine airplanes have shown that inadvertent movement of the propeller blade pitch to a 

low blade angle create a high aerodynamic and asymmetric drag with resultant 

uncommanded yaw and roll response on the airplane. Following this unexpected yaw and 

roll response, stabi I ization and control of the airplane may range from unusuall y difficult 

to catastrophic, and pilots may lack sufficient time to properl y assess the engine problem, 

initiate an engine emergency shutdown, and activate the feather valve. 

The dri vetrain uncoupling events described previously lead to loss of thrust, cause 

the propeller blade pitch to go to a low-blade angle, and create a high aerodynamic and 

asymmetric drag on the airplane. The low-blade angle may result in loss of airplane 

control, leading to an accident. After a review o f about 40 years of National 

Transportation Safety Board fatal accident reports of multi-engine airplanes with TPE331 

engines, we determined that certain airplanes are more at risk by engine-failure events 

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than others. There fore, we are proposing compliance times in this AD that address the 

risk by a irplane after a propeller shaft coupli ng fai lure. 

Relevant Service Information 

Allied-Signal Aerospace Company, Garrett Engine Division Service Bulletin No. 

TP£331-72-0873. Revision 1, dated May 20, 1993, describes procedures for replacing the 

affected P/Ns of propeller shaft couplings with a defined redesigned propeller shaft 

coupling. 

Honeywell International lnc. Operating Information Letter 0 133 1-26, dated 

March 2, 20 I 0, describes emergency procedures for aircrew if a propeller shaft coupling 

fai ls. 

FAA's Determination 

We arc proposing this AD because we evaluated all the re levant information and 

determined the unsafe condition described previously is likely to exist or develop in other 

products of the same type design. 

Proposed AD Requirements 

This proposed AD would require removing propeller shaft couplings, PINs 

31 07065-l, 865888-3, 865888-6, and 865888-8, from service. 

This proposed AD would a lso require inserting a copy of Honeywell lnternational 

Inc. Operating Information Letter 01331-26, dated March 2, 20 I 0, into the applicable 

Airplane Flight Manual, Pilot Operating Handbook, or Manufacturer's Operating 

Manual. 

Costs of Compliance 

We estimate that this proposed AD would affect 485 engines installed on 

airplanes ofU.S. registry. We also estimate that it would take about one hour per engine 

to perfom1 the actions required by this proposed AD, if done at next turbine hot section 

scheduled inspection, and 40 hours per engine if done at an unscheduled access of the 

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propeller shaft coupling. We also estimate that 400 engines would have the replacement 

actions done at a scheduled time of next turbine hot section inspection, and 85 engines 

would have the replacement actions done at an unscheduled access of the propeller shaft 

coupling. We also estimate that the average labor rate is $85 per hour. Required parts 

would cost about $ 12,000 per engine. Based on these figures, we estimate the total cost of 

the proposed AD to U.S. operators to be $6, 143,000. 

Authority fo•· this Rulemaking 

Title 49 of the United States Code specifies the FAA's authority to issue rules on 

aviation safety. Subtitle r, section 106, describes the authority of the F /\A Administrator. 

Subtitle VIT: 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 I ll, Section 4470 I : "General requirements." Under that section, Congress 

charges the r AA 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 like ly to exist or develop on products 

identified in this rulcmaking action. 

Regulatory Findings 

We determined that this proposed /\0 would not have federalism implications 

under Executi ve Order 13132. This proposed AD would 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 responsibi lities among the various levels of 

government. 

For the reasons discussed above, I certify this proposed regulation: 

(1) Is not a ·'significant regulatory action" under Executive Order 12866, 

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(2) Is not a ·'significant rule" under the DOT Regulatory Policies and Procedures 

( 44 FR I I 034, 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. 

The Proposed Amendment 

Accordingly, under the authority delegated to me by the Administrator, the FAA 

proposes to amend 14 CFR pa1t 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): 

Honeywelllntem a tionallnc. (Type Certificate previously held by AlliedSignallnc., 

Garrett Engine Division; Garrett Turbine Engine Company; and AiResearch 

Manufacturing Company of Arizona): Docket No. F AA-2012-0913; Directorate 

ldentifier 20 12-NE-23-AO. 

(a) Comments Due Date 

We must receive comments by (INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

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(c) Applicability 

This AD applies to Honeywell International Inc. TPE331-5, -SA, -5AB, -58, -10, 

-I OR,-1 OU, -1 OUF, - 1 OUG, -1 OUGR, and - 1 OUR model turboprop engines, with a 

propeller shafl coupling, part number (P/N) 3 1 07065- 1, 865888-3, 865888-6, or 865888-

8, installed. 

(d) Unsafe Condition 

This AD was prompted by engine propeller shaft coupling failures leading to 

unexpected propell er pitch changes resulting in high aerodynamic and asymmetric drag 

on the airplanes using these engines. We are issuing this AD to prevent loss of airplane 

control, leading to an accident. 

(c) Compliance 

Comply with this AD withi n the compliance times specified, unless a lready done. 

(1) Engines Installed In Mitsubishi MU-2B Series (MU-2 Series) Airplanes 

Remove from service the affected propeller shaft coupling at the earliest of the 

following: 

(i) Next piece-part exposure; or 

(ii) Next turbine (hot) section inspection (HSI); or 

(iii) Before accumulating an additiona l I ,200 cycles after the effective date of this 

AD. 

(2) Engines Installed In Construcciones Aeronauticas, S.A. (CASA) C-212 Series, 

and Twin Commander 690 and 695 Series (Jetprop Commander) Airplanes 

Remove from service the affected propeller shaft coupling at the earliest of the 

followi ng: 

(i) Next piece-part exposure; or 

(ii) Next turbine HSI; or 

(iii) Before accumulating an additional 2,400 cycles after the effective date of this 

AD. 

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(3) Engines Installed In British Aerospace Jetstream 3101 Series, Dornier Luftfahrt 

Dornier 228 Series, and M7 (formerly Fairchild, Swearingen) SA226 and SA227 

Series Airplanes, and All Other Airplanes Not Listed in this AD Using Affected 

Engines 

Remove from service the affected propeller shaft coupling at the earliest of the 

following: 

(i) Next piece-part exposure; or 

(ii) Next turbine HST; or 

(iii) Before accumulating an additional 3,600 cycles after the effective date of this 

AD. 

(4) Inserting a Copy of Honeywell International Inc. Operating Information Letter 

into the FAA-Approved Flight Manual 

Within 60 days after the e1Tective date of this AD, for airplanes with engine 

propeller shaft coupling, PIN 3107065-1 , 865888-3, 865888-6, or 865888-8, installed, 

insert a copy of Honeywell International Inc. Operating Infonnation Letter 0 1331-26, 

dated March 2, 20 I 0, into the Emergency Procedures Section of the applicable Airplane 

Flight Manual, Pilot Operating Handbook, or Manufacturer's Operating Manual. 

(f) Definition 

For the purpose of this AD, next piece-part exposure is when the nose cone 

assembly is removed from the engine. 

(g) Installation Prohibition 

After the effective date of this AD, do not install any propeller shaft coupling, P/N 

3107065- I, 865888-3, 865888-6, or 865888-8, into any engine. 

(h) 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. 

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(i) Related Information 

(I) 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 907 12-4137; phone: 562-627-5246; 

fax: 562-627-521 0; email: joseph.costa@faa.gov. 

(2) Allied-Signal Aerospace Company Service Bulletin No. TPE33 1-72-0873. 

Revision 1, dated May 20, 1993, addresses acceptable replacement parts, and other 

information pertaining to the subject of this AD. 

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

Inc., 111 S. 34111 Street, Phoenix, AZ 85034-2802; phone: 800-601-3099; Web site: 

http://portal.honeywell.com. 

(4) 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, ca ll 781-238-7125. 

Issued in Burlington, Massachusetts, on May 6, 2014. 

Colleen M. D' Alessandro, 

Assistant Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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