This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

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REGISTER issue of each week.

Rules and Regulations Federal Register

729 

Vol. 77, No. 4 

Friday, January 6, 2012 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1382; Directorate 

Identifier 2011–SW–053–AD; Amendment 

39–16900; AD 2011–26–10] 

RIN 2120–AA64 

Airworthiness Directives; Enstrom 

Helicopter Corporation Helicopters 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule; request for 

comments. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for 

Enstrom Helicopter Corporation 

(Enstrom) Model F–28C, F–28C–2, F– 

28F, 280C, 280F, 280FX TH–28, 480, 

and 480B helicopters with certain trim 

relays to require modifying and testing 

the lateral and longitudinal cyclic trim 

actuator assemblies. This AD was 

prompted by four failures in the cyclic 

trim system on certain Enstrom model 

helicopters that resulted in reduced 

controllability of the helicopter. These 

actions are intended to prevent failure 

of the cyclic trim system and 

subsequent loss of control of the 

helicopter. 

DATES: This AD becomes effective 

January 23, 2012. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain documents listed in this AD 

as of January 23, 2012. 

We must receive comments on this 

AD by March 6, 2012. 

ADDRESSES: You may send comments by 

any of the following methods: 

• Federal eRulemaking Docket: Go to 

http://www.regulations.gov. Follow the 

online instructions for sending your 

comments electronically. 

• Fax: (202) 493–2251. 

• Mail: Send comments to the U.S. 

Department of Transportation, Docket 

Operations, M–30, West Building 

Ground Floor, Room W12–140, 1200 

New Jersey Avenue SE., Washington, 

DC 20590–0001. 

• Hand Delivery: Deliver to the 

‘‘Mail’’ address between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. 

Examining the AD Docket: You may 

examine the AD docket on the Internet 

at http://www.regulations.gov or in 

person at the Docket Operations Office 

between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

The AD docket contains this AD, the 

economic evaluation, any comments 

received, and other information. The 

street address for the Docket Operations 

Office (telephone (800) 647–5527) is in 

the ADDRESSES section. Comments will 

be available in the AD docket shortly 

after receipt. 

For service information identified in 

this AD, contact Enstrom Helicopter 

Corporation, 2209 22nd St., Menominee, 

Michigan, 49858–0490; telephone: (906) 

863–1200; email: customerservice@

enstromhelicopter.com; Web site: 

http://www.enstromhelicopter.com/

enstrom_new/enstrom_support_

tec.html. You may review copies of the 

referenced service information at the 

FAA, Office of the Regional Counsel, 

Southwest Region, 2601 Meacham 

Blvd., Room 663, Fort Worth, Texas 

76137. 

FOR FURTHER INFORMATION CONTACT: 

Gregory J. Michalik, Enstrom Program 

Manager, FAA, Chicago Aircraft 

Certification Office, 2300 East Devon 

Avenue, Room 107, Des Plaines, Illinois 

60018; telephone (847) 294–7135; fax 

(847) 294–7834; email: 

gregory.michalik@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

This AD is a final rule that involves 

requirements affecting flight safety, and 

we did not provide you with notice and 

an opportunity to provide your 

comments prior to it becoming effective. 

However, we invite you to participate in 

this rulemaking by submitting written 

comments, data, or views. We also 

invite comments relating to the 

economic, environmental, energy, or 

federalism impacts that resulted from 

adopting this AD. The most helpful 

comments reference a specific portion of 

the AD, explain the reason for any 

recommended change, and include 

supporting data. To ensure the docket 

does not contain duplicate comments, 

commenters should send only one copy 

of written comments, or if comments are 

filed electronically, commenters should 

submit them only one time. We will file 

in the docket all comments that we 

receive, as well as a report summarizing 

each substantive public contact with 

FAA personnel concerning this 

rulemaking during the comment period. 

We will consider all the comments we 

receive and may conduct additional 

rulemaking based on those comments. 

Discussion 

We are adopting a new AD for the 

Enstrom Model F–28C, F–28C–2, F–28F, 

280C, 280F, 280FX, TH–28, 480, and 

480B helicopters with a trim relay, partnumber (P/N) KUP14D55–472, M83536/ 

10–015M, or M83536/10–024M. This 

AD does not apply to the specified 

helicopters with a reversible trim motor, 

P/N 28–16621 (Ford Motor Company 

C1AZ–14553A) or P/N AD1R–10 (Signal 

Electric). This AD requires modifying 

the lateral and longitudinal trim 

actuator assemblies by replacing the 

actuator and limit switch bracket to 

provide a positive stop for the trim 

actuator. In the event of a trim actuator 

runaway, the new bracket will stop the 

actuator, causing the circuit breaker to 

trip before any significant loss of control 

occurs. After the trim actuator 

assemblies are modified, this AD 

requires performing operational 

(ground) and flight tests to determine 

that the trim relay is working correctly. 

This AD was prompted by reports of 4 

failures in the cyclic trim system in the 

field, 2 that occurred on the Enstrom 

Model 480B helicopter and 2 that 

occurred on the Enstrom Model F28 

helicopter. These failures resulted in 

reduced controllability of the helicopter. 

We are issuing this AD to prevent 

failure of the cyclic trim system and 

subsequent loss of control of the 

helicopter. 

FAA’s Determination 

We are issuing this AD because we 

evaluated all the relevant information 

and determined the unsafe condition 

described previously is likely to exist or 

develop in other products of the same 

type design. 


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730 Federal Register / Vol. 77, No. 4 / Friday, January 6, 2012 / Rules and Regulations 

Related Service Information 

We reviewed Enstrom Service 

Directive Bulletin (SDB) No. 0110, 

Revision 3, dated July 6, 2011 (SDB 

0110), for Model F–28C, F–28C–2, F– 

28F, 280C, 280F, and 280FX helicopters; 

and Enstrom SDB No. T–039, Revision 

3, dated July 6, 2011 (SDB T–039), for 

Model TH–28, 480, and 480B 

helicopters. SDB 0110 specifies, for 

helicopters with a trim relay, P/N 

KUP14D55–472, M83536/10–015M, or 

M83536/10–024M, procedures for 

modifying the lateral and longitudinal 

trim actuator assembly using the cyclic 

trim assembly kit (modification kit), P/ 

N 28–01063–1, and specifies performing 

an operational check and flight test to 

determine the trim is operating correctly 

after the modification. SDB T–039 

specifies, for helicopters with a trim 

relay, P/N M83536/10–024M, 

procedures for modifying the lateral and 

longitudinal trim actuator assembly 

using the modification kit, P/N 

4230045–1, and specifies performing an 

operational check and flight test to 

determine the trim is operating correctly 

after the modification. The SDBs state 

that the modification kits contain the 

upgraded bracket. 

AD Requirements 

This AD requires, within 5 hours 

time-in-service (TIS) or at the next 

annual or 100 hour time-in-service 

inspection, whichever occurs first, the 

following actions: 

• For the Enstrom Model F–28C, F– 

28C–2, F–28F, 280C, 280F, and 280FX 

helicopters with a trim relay, P/N 

KUP14D55–472, M83536/10–015M, or 

M83536/10–024M, modify the lateral 

and longitudinal trim actuator assembly 

using the modification kit, P/N 28– 

01063–1. 

• For the Enstrom Model TH–28, 480, 

and 480B helicopter with a trim relay, 

P/N M83536/10–024M, modify the 

lateral and longitudinal trim actuator 

assembly using the modification kit, P/ 

N 4230045–1. 

• For all affected helicopters, after 

accomplishing the modification of the 

lateral and longitudinal trim actuator 

assemblies and before further flight, 

perform an operational test and flight 

test to determine the trim is operating 

correctly. 

The actions required by this AD are to 

be accomplished by following specified 

portions of the SDBs described 

previously. 

Differences Between This AD and the 

Service Information 

The SDBs specify, before further 

flight, to insert a special addendum into 

the Emergency Procedures section of the 

Flight Manual, and this AD does not 

require this action. 

Costs of Compliance 

We estimate that this AD will affect 

207 helicopters of U.S. Registry. We 

estimate that operators may incur the 

following costs in order to comply with 

this AD. For Model 480, 480B, and TH– 

28, modifying the actuator assembly 

will require 4 work hours at a cost of 

$85 per hour and parts will cost $327; 

the cost per helicopter will be $667. For 

Model 280C, 280F, 280FX, F–28C, F– 

28C–2, and F–28F, modifying the 

actuator assembly will require 4 work 

hours at a cost of $85 per hour; parts 

will cost $383; and the cost per 

helicopter will be $723. 

FAA’s Justification and Determination 

of the Effective Date 

Providing an opportunity for public 

comments prior to adopting these AD 

requirements would delay 

implementing the safety actions needed 

to correct this known unsafe condition. 

Therefore, we find that the risk to the 

flying public justifies waiving notice 

and comment prior to the adoption of 

this rule because the required corrective 

actions must be accomplished within 5 

hours time-in-service, a very short time 

period based on the average flight-hour 

utilization rate of these helicopters. 

Since an unsafe condition exists that 

requires the immediate adoption of this 

AD, we determined that notice and 

opportunity for public comment before 

issuing this AD are impracticable and 

contrary to the public interest and that 

good cause exists for making this 

amendment effective in less than 30 

days. 

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 

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, 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. 

We prepared an economic evaluation 

of the estimated costs to comply with 

this AD and placed it in the AD docket. 

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 AD: 

2011–26–10 Enstrom Helicopter 

Corporation: Amendment 39–16900; 

Docket No. FAA–2011–1382; Directorate 

Identifier 2011–SW–053–AD. 

(a) Applicability 

This AD applies to the Enstrom Model F– 

28C, F–28C–2, F–28F, 280C, 280F, 280FX, 

TH–28, 480, and 480B helicopters with a trim 

relay, part-number (P/N) KUP14D55–472, 

M83536/10–015M, or M83536/10–024M, 

certificated in any category. 

Note 1: This AD does not apply to the 

specified helicopters with a reversible trim 

motor, P/N 28–16621 (Ford Motor Company 

C1AZ–14553A) or P/N AD1R–10 (Signal 

Electric). 


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Federal Register / Vol. 77, No. 4 / Friday, January 6, 2012 / Rules and Regulations 731 

(b) Unsafe Condition 

This AD defines the unsafe condition as a 

failure in the cyclic trim system. This 

condition could result in reduced 

controllability of the helicopter and 

subsequent loss of control of the helicopter. 

(c) Effective Date 

This airworthiness directive (AD) becomes 

effective January 23, 2012. 

(d) Compliance 

You are responsible for performing each 

action required by this AD within the 

specified compliance time unless it has 

already been accomplished prior to that time. 

(e) Required Actions 

Within 5 hours time-in-service (TIS) or at 

the next annual or 100 TIS inspection, 

whichever comes first: 

(1) For the Enstrom Model F–28C, F–28C– 

2, F–28F, 280C, 280F, and 280FX helicopters, 

modify the lateral and longitudinal trim 

actuator assemblies using the cyclic trim 

assembly kit (modification kit), P/N 28– 

01063–1, in accordance with the instructions 

in paragraph 6.1 of the Enstrom Service 

Directive Bulletin (SDB) No. 0110, Revision 

3, dated July 6, 2011 (SDB No. 0110 R3), 

except when the instructions specify using 

‘‘Aeroshell 22 grease’’ or ‘‘VC–3 Vibra-tite 

thread locker,’’ you may use an equivalent 

product. 

(2) For the Enstrom Model TH–28, 480, and 

480B helicopters, modify the lateral and 

longitudinal trim actuator assemblies using 

the modification kit, P/N 4230045–1, in 

accordance with the instructions in 

paragraph 6.1 of the Enstrom SDB No. T–039, 

Revision 3, dated July 6, 2011 (SDB No. T– 

039 R3), except when the instructions specify 

using ‘‘Aeroshell 22 grease’’ or ‘‘VC–3 Vibratite thread locker,’’ you may use an 

equivalent product, and you are not required 

to contact Enstrom Customer Service. 

(3) After modifying the lateral and 

longitudinal trim actuator assemblies in 

accordance with paragraphs (e)(1) or (e)(2) of 

this AD, before further flight, operationally 

test the trim limits in accordance with 

paragraph 6.2. of the SDB for your model 

helicopter, and determine during a flight test 

whether there is appropriate trim authority in 

accordance with paragraph 6.3. of the SDB 

for your model helicopter. 

(f) Special Flight Permits 

A one-time special-flight permit may be 

issued in accordance with 14 CFR 21.197 and 

21.199 provided the helicopter is operated 

with the trim system circuit breaker pulled. 

(g) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Safety Management 

Group, FAA, may approve AMOCs for this 

AD. Send your proposal to: Gregory J. 

Michalik, Enstrom Program Manager, FAA, 

Chicago Aircraft Certification Office, 2300 

East Devon Avenue, Room 107, Des Plaines, 

Illinois 60018; telephone (847) 294–7135; fax 

(847) 294–7834; email: 

gregory.michalik@faa.gov. 

(2) For operations conducted under a Part 

119 operating certificate or under Part 91, 

Subpart K, we suggest that you notify your 

principal inspector or lacking a principal 

inspector, the manager of the local flight 

standards district office or certificate holding 

district office before operating any aircraft 

complying with this AD through an AMOC. 

(h) Subject 

Joint Aircraft Service Component (JASC) 

Code: 6710: Main Rotor Control. 

(i) Material Incorporated by Reference 

You must use the specified portions of the 

following service information to do the 

specified actions required by this AD. The 

Director of the Federal Register approved the 

incorporation by reference of this service 

information under 5 U.S.C. 552(a) and 1 CFR 

part 51. 

(2) Enstrom Service Directive Bulletin No. 

0110, Revision 3, dated July 6, 2011, for the 

Model F–28C, F–28C–2, F–28F, 280C, 280F; 

and 

(3) 280FX or Enstrom Service Directive 

Bulletin No. T–039, Revision 3, dated July 6, 

2011, for the Model TH–28, 480, and 480B. 

(4) For service information identified in 

this AD, contact Enstrom Helicopter 

Corporation, 2209 22nd St., Menominee, 

Michigan 49858–0490; telephone: (906) 863– 

1200; email: customerservice@enstrom

helicopter.com; Web site: 

http://www.enstromhelicopter.com/enstrom_

new/enstrom_support_tec.html. 

(5) You may review copies of the 

referenced service information at the FAA, 

Office of the Regional Counsel, Southwest 

Region, 2601 Meacham Blvd., Room 663, Fort 

Worth, Texas 76137 or 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/code_of_federal_regulations/

ibr_locations.html. 

Issued in Fort Worth, Texas, on December 

14, 2011. 

M. Monica Merritt, 

Acting Manager, Rotorcraft Directorate, 

Aircraft Certification Service. 

[FR Doc. 2011–32895 Filed 1–5–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0415; Directorate 

Identifier 2007–NM–256–AD; Amendment 

39–16904; AD 2011–27–03] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for all 

Model 737 airplanes. This AD was 

prompted by a report of extensive 

corrosion of a ballscrew used in the 

drive mechanism of the horizontal 

stabilizer trim actuator (HSTA). This AD 

requires repetitive inspections, 

lubrications, and repetitive overhauls of 

the ball nut and ballscrew and 

attachment (Gimbal) fittings for the trim 

actuator of the horizontal stabilizer; 

various modification(s); and corrective 

actions if necessary; as applicable. We 

are issuing this AD to prevent an 

undetected failure of the primary load 

path for the ballscrew in the drive 

mechanism of the HSTA and 

subsequent wear and failure of the 

secondary load path, which could lead 

to loss of control of the horizontal 

stabilizer and consequent loss of control 

of the airplane. 

DATES: This AD is effective February 10, 

2012. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in the AD 

as of February 10, 2012. 

ADDRESSES: For Boeing service 

information identified in this AD, 

contact Boeing Commercial Airplanes, 

Attention: Data & Services Management, 

P.O. Box 3707, MC 2H–65, Seattle, 

Washington 98124–2207; telephone 

(206) 544–5000, extension 1; fax (206) 

766–5680; email 

me.boecom@boeing.com; Internet 

https://www.myboeingfleet.com. 

For Skytronics service information 

identified in this AD, contact Skytronics 

Inc., (cage 16553), P.O. Box 807, El 

Segundo, California 90245; telephone 

(310) 322–6284; fax (310) 322–6160; 

Internet http://www.skytronicsinc.com. 

For Linear Motion service information 

identified in this AD, contact Linear 

Motion LLC, 628 North Hamilton Street, 

Saginaw, Michigan 48602; telephone 

(989) 759–8300; Internet http:// 

www.thomsonaerospace.com. 

For Umbra Cuscinetti service 

information identified in this AD, 

contact Umbra Cuscinetti S.p.A., 

Technical Publications Department; Via 

Piave 12, Foligno (PG) 06034, Italy; 

telephone +39 (0742) 348300; fax +39 

(0742) 348277; email 

tech.pubs@umbracus.com. 

You may review copies of the 

referenced service information at the 

FAA, Transport Airplane Directorate, 

1601 Lind Avenue SW., Renton, 

Washington. For information on the 

availability of this material at the FAA, 

call (425) 227–1221. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http:// 


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