37226 Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 

(g) Required Actions 

Except as specified by paragraph (h) of this 

AD: At the applicable times specified in the 

‘‘Compliance’’ paragraph of Boeing Special 

Attention Requirements Bulletin 747–25– 

3725 RB, dated October 27, 2020, do all 

applicable actions identified in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Special Attention 

Requirements Bulletin 747–25–3725 RB, 

dated October 27, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Special Attention 

Service Bulletin 747–25–3725, dated October 

27, 2020, which is referred to in Boeing 

Special Attention Requirements Bulletin 

747–25–3725 RB, dated October 27, 2020. 

(h) Exception to Service Information 

Specifications 

Where Boeing Special Attention 

Requirements Bulletin 747–25–3725 RB, 

dated October 27, 2020, uses the phrase 

‘‘after the Original Issue date of Requirements 

Bulletin 747–25–3725 RB,’’ this AD requires 

using ‘‘the effective date of this AD.’’ 

(i) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Seattle ACO Branch, 

FAA, has the authority to approve AMOCs 

for this AD, if requested using the procedures 

found in 14 CFR 39.19. In accordance with 

14 CFR 39.19, send your request to your 

principal inspector or responsible Flight 

Standards Office, as appropriate. If sending 

information directly to the manager of the 

certification office, send it to the attention of 

the person identified in paragraph (j) of this 

AD. Information may be emailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the responsible Flight Standards Office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair, 

modification, or alteration required by this 

AD if it is approved by The Boeing Company 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, Seattle ACO Branch, FAA, to make 

those findings. To be approved, the repair 

method, modification deviation, or alteration 

deviation must meet the certification basis of 

the airplane, and the approval must 

specifically refer to this AD. 

(j) Related Information 

(1) For more information about this AD, 

contact Julie Linn, Aerospace Engineer, 

Cabin Safety and Environmental Systems 

Section, FAA, Seattle ACO Branch, 2200 

South 216th St., Des Moines, WA 98198; 

phone and fax: 206–231–3584; email: 

Julie.Linn@faa.gov. 

(2) Service information identified in this 

AD that is not incorporated by reference is 

available at the addresses specified in 

paragraphs (k)(3) and (4) of this AD. 

(k) 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) Boeing Special Attention Requirements 

Bulletin 747–25–3725 RB, dated October 27, 

2020. 

(ii) [Reserved] 

(3) For service information identified in 

this AD, contact Boeing Commercial 

Airplanes, Attention: Contractual & Data 

Services (C&DS), 2600 Westminster Blvd., 

MC 110–SK57, Seal Beach, CA 90740–5600; 

telephone 562–797–1717; internet https://

www.myboeingfleet.com. 

(4) You may view this service information 

at the FAA, Airworthiness Products Section, 

Operational Safety Branch, 2200 South 216th 

St., Des Moines, WA. For information on the 

availability of this material at the FAA, call 

206–231–3195. 

(5) You may view this service information 

that is incorporated by reference at the 

National Archives and Records 

Administration (NARA). For information on 

the availability of this material at NARA, 

email fedreg.legal@nara.gov, or go to: https:// 

www.archives.gov/federal-register/cfr/ibrlocations.html. 

Issued on June 25, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–15027 Filed 7–14–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–1025; Project 

Identifier MCAI–2020–00757–E; Amendment 

39–21630; AD 2021–14–03] 

RIN 2120–AA64 

Airworthiness Directives; Rolls-Royce 

Deutschland Ltd & Co KG (Type 

Certificate Previously Held by BMW 

Rolls-Royce GmbH and BMW RollsRoyce Aero Engines) Turbofan 

Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

Rolls-Royce Deutschland Ltd. & Co KG 

(RRD) BR700–715A1–30, BR700– 

715B1–30, and BR700–715C1–30 model 

turbofan engines. This AD was 

prompted by reports of HPT stage 1 

blades failing in service due to 

sulphidation and subsequent crack 

initiation. This AD requires removal and 

replacement of the HPT stage 1 blade 

and HPT stage 1 blade damper. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective August 19, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of August 19, 2021. 

ADDRESSES: For service information 

identified in this final rule, contact 

Rolls-Royce Deutschland Ltd. & Co KG, 

Eschenweg 11, 15827 BlankenfeldeMahlow, Germany; phone: +49 (0) 33 

708 6 0; email: rrd.techhelp@rolls-royce; 

website: https://www.rolls-royce.com/ 

contact-us.aspx. You may view this 

service information at the FAA, 

Airworthiness Products Section, 

Operational Safety Branch, 1200 District 

Avenue, Burlington, MA 01803. For 

information on the availability of this 

material at the FAA, call (781) 238– 

7759. It is also available at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2020– 

1025. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2020–1025; or in person at Docket 

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

Monday through Friday, except Federal 

holidays. The AD docket contains this 

final rule, any comments received, and 

other information. The address for 

Docket Operations is 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: 

Barbara Caufield, Aviation Safety 

Engineer, ECO Branch, FAA, 1200 

District Avenue, Burlington, MA 01803; 

phone: (781) 238–7146; fax: (781) 238– 

7199; email: barbara.caufield@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to certain RRD BR700–715A1–30, 

BR700–715B1–30, and BR700–715C1– 

30 model turbofan engines. The NPRM 

published in the Federal Register on 

November 13, 2020 (85 FR 72608). The 

NPRM was prompted by reports of HPT 

stage 1 blades failing in service due to 

sulphidation and subsequent crack 

initiation, due to contamination of the 

blade shank passing by the blade 

damper. In the NPRM, the FAA 

proposed to require removal and 

replacement of the HPT stage 1 blade 

and HPT stage 1 blade damper. The 


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FAA is issuing this AD to address the 

unsafe condition on these products. 

The European Aviation Safety Agency 

(EASA), which is the Technical Agent 

for the Member States of the European 

Community, has issued EASA AD 2018– 

0194, dated September 4, 2018 (referred 

to after this as ‘‘the MCAI’’), to address 

the unsafe condition on these products. 

The MCAI states: 

Occurrences have been reported on RRD 

BR700–715 engines where certain HP turbine 

stage 1 blades failed in service. Investigation 

of these events showed that these were 

caused by sulphidation and subsequent crack 

initiation, due to contamination of the blade 

shank passing by the blade damper. 

This condition, if not corrected, could lead 

to further HP turbine stage 1 blade failures, 

possibly resulting in engine in-flight shutdown and consequent reduced control of the 

aeroplane. To address this potential unsafe 

condition, RRD published the NMSB to 

provide instructions to replace the affected 

assembly. 

For the reasons described above, this 

[EASA] AD requires determination of the 

engine configuration and, depending on 

findings, removal of the engine from service 

to replace the affected assembly. 

You may obtain further information 

by examining the MCAI in the AD 

docket at https://www.regulations.gov 

by searching for and locating Docket No. 

FAA–2020–1025. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

one commenter. The commenter was 

Delta Airlines (Delta). The following 

presents the comments received on the 

NPRM and the FAA’s response to each 

comment. 

Request To Revise Definition of ‘‘Parts 

Eligible for Installation’’ 

Delta requested that the FAA revise 

the definition of ‘‘parts eligible for 

installation’’ to avoid the necessity of an 

alternate method of compliance (AMOC) 

request each time Rolls-Royce 

introduces a new part number for the 

HPT stage 1 blade or HPT stage 1 

damper. 

The FAA agrees and revised the 

definition of ‘‘parts eligible for 

installation’’ to allow installation of 

HPT stage 1 blades and HPT stage 1 

dampers approved as eligible for 

installation in accordance with certain 

RRD service information. 

Request To Clarify Compliance Time 

Language 

Delta requested that the FAA revise 

paragraph (g)(1)(i) in the Required 

Actions section of this AD to refer to 

‘‘flight cycles since new’’ instead of 

‘‘flight cycles since first installation,’’ as 

proposed in the NPRM. Delta noted that 

the proposed language could be 

misinterpreted as referring to any 

affected HPT stage 1 blade, regardless of 

whether the affected HPT stage 1 blade 

is currently installed on an engine. 

The FAA partially agrees. The FAA 

agrees to update this reference to avoid 

possible misinterpretation, but disagrees 

with the specific language proposed by 

the commenter. The FAA has updated 

paragraph (g)(1)(i) of this AD to read: 

‘‘Before an affected HPT stage 1 blade 

exceeds 10,000 flight cycles (FCs) since 

first installation . . .’’ 

Conclusion 

The FAA reviewed the relevant data, 

considered any comments received, and 

determined that air safety requires 

adopting this AD as proposed. 

Accordingly, the FAA is issuing this AD 

to address the unsafe condition on these 

products. Except for minor editorial 

changes and any other changes 

described previously, this AD is 

adopted as proposed in the NPRM. 

None of the changes will increase the 

economic burden on any operator. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed RRD BR700 Series 

Alert Non-Modification Service Bulletin 

(NMSB) SB–BR700–72–A900640, 

Revision 1, dated August 31, 2018. The 

Alert NMSB describes procedures for 

removing and replacing the HPT stage 1 

blade and HPT stage 1 blade damper. 

This service information is reasonably 

available because the interested parties 

have access to it through their normal 

course of business or by the means 

identified in ADDRESSES. 

Other Related Service Information 

The FAA reviewed RRD Service 

Bulletin (SB) SB–BR700–72–102005, 

dated March 20, 2018; RRD NMSB SB– 

BR700–72–900118, dated June 6, 2017; 

and RRD SB SB–BR700–72–101671, 

dated January 29, 2010. RRD SB SB– 

BR700–72–102005, dated March 20, 

2018, introduces a new HPT stage 1 

blade damper with a front restrictor that 

reduces the average airflow into the 

blade shank cavity, thereby reducing 

deposition of particles in the cavity. 

RRD NMSB SB–BR700–72–900118, 

dated June 6, 2017, describes 

procedures for recording the serial 

numbers of the cleaned, crack tested, 

and examined HPT stage 1 blades. RRD 

SB SB–BR700–72–101671, dated 

January 29, 2010, introduces a 

redesigned HPT stage 1 blade that 

improves robustness and stress 

characteristics. 

Costs of Compliance 

The FAA estimates that this AD 

affects 222 engines installed on 

airplanes of U.S. registry. The agency 

estimates that the service life of both the 

HPT stage 1 blade and HPT stage 1 

blade damper are 5.5 years. Based on 

this life estimate, the agency is 

providing an estimated annual cost to 

replace these parts. 

The FAA estimates the following 

costs to comply with this AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Annualized 

cost on U.S. 

operators 

Replace HPT stage 1 blade and HPT stage 1 

blade damper.

20 work-hours × $85 per hour = $1,700 ........ $692,000 $693,700 $28,000,524 

The FAA has included all known 

costs in its cost estimate. According to 

the manufacturer, however, all of the 

costs of this AD may be covered under 

warranty, thereby reducing the cost 

impact on affected individuals. 

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. 

The FAA is issuing this rulemaking 

under the authority described in 

Subtitle VII, Part A, Subpart III, Section 

44701: General requirements. Under 


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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 

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 that this AD: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Will not affect intrastate aviation 

in Alaska, and 

(3) 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 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: 

2021–14–03 Rolls-Royce Deutschland Ltd & 

Co KG (Type Certificate previously held 

by BMW Rolls-Royce GmbH and BMW 

Rolls-Royce Aero Engines): Amendment 

39–21630; Docket No. FAA–2020–1025; 

Project Identifier MCAI–2020–00757–E. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective August 19, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all Rolls-Royce 

Deutschland Ltd. & Co KG (Type Certificate 

previously held by BMW Rolls-Royce GmbH 

and BMW Rolls-Royce Aero Engines) (RRD) 

BR700–715A1–30, BR700–715B1–30, and 

BR700–715C1–30 model turbofan engines 

with high-pressure turbine (HPT) stage 1 

blade, part number (P/N) BRH17133, 

BRH19984, BRH20011, BRH20237, 

BRH20351, FW35594, FW45914, FW64379, 

or FW75735, and with HPT stage 1 blade 

damper, 

P/N BRH10943, BRH20353, or FW45770, 

installed. 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 7250, Turbine Section. 

(e) Unsafe Condition 

This AD was prompted by reports of HPT 

stage 1 blades failing in service due to 

sulphidation and subsequent crack initiation. 

The FAA is issuing this AD to prevent failure 

of the HPT stage 1 blade. The unsafe 

condition, if not addressed, could result in 

the release of the HPT stage 1 blade, failure 

of the engine, in-flight shutdown, and loss of 

the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

(1) For affected engines that have not 

operated exclusively under the Hawaiian 

Flight Mission: 

(i) Before an affected HPT stage 1 blade 

exceeds 10,000 flight cycles (FCs) since first 

installation of that affected HPT stage 1 

blade, or within 50 FCs after the effective 

date of this AD, whichever occurs later, 

remove the affected HPT stage 1 blade and 

the affected HPT stage 1 blade damper from 

service and replace with parts eligible for 

installation using the Accomplishment 

Instructions, paragraph 3.R. through T., of 

RRD Alert Non-Modification Service Bulletin 

(NMSB) SB–BR700–72–A900640, Revision 1, 

dated August 31, 2018 (NMSB SB–BR700– 

72–A900640). 

(ii) If an HPT stage 1 blade has been 

cleaned and examined before the effective 

date of this AD using RRD NMSB SB–BR700– 

72–900118, dated June 6, 2017, within 1,500 

FCs from the last cleaning and examination, 

or within 10 FCs after the effective date of 

this AD, whichever occurs later, remove the 

affected HPT stage 1 blade and affected HPT 

stage 1 blade damper from service and 

replace with parts eligible for installation 

using Accomplishment Instructions, 

paragraph 3.R. through T., of RRD NMSB SB– 

BR700–72–A900640. 

(2) For affected engines operated 

exclusively under the Hawaiian Flight 

Mission: 

(i) At the next change of the flight mission 

after the effective date of this AD, replace the 

affected HPT stage 1 blade and affected HPT 

stage 1 blade damper in accordance with 

paragraphs (g)(1)(i) and (ii) of this AD. 

(ii) [Reserved] 

(h) Installation Prohibition 

After the effective date of this AD, do not 

install any HPT stage 1 blade, P/N 

BRH17133, BRH19984, BRH20011, 

BRH20237, BRH20351, FW35594, FW45914, 

FW64379, or FW75735, with any HPT stage 

1 blade damper, P/N BRH10943, BRH20353, 

or FW45770, in any engine. 

(i) Definitions 

(1) For the purpose of this AD, ‘‘parts 

eligible for installation’’ are an HPT stage 1 

blade, P/N FW75735, or a P/N approved for 

installation in accordance with paragraph 2.C 

of RRD NMSB SB–BR700–72–A900640, 

installed with HPT stage 1 blade damper, 

P/N KH82098, or a P/N approved for 

installation in accordance with paragraph 2.C 

of RRD NMSB SB–BR700–72–A900640. 

(2) For the purpose of this AD, the 

‘‘Hawaiian Flight Mission’’ are flights 

operated by Hawaiian Airlines. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, ECO Branch, FAA, has 

the authority to approve AMOCs for this AD, 

if requested using the procedures found in 14 

CFR 39.19. In accordance with 14 CFR 39.19, 

send your request to your principal inspector 

or local Flight Standards District Office, as 

appropriate. If sending information directly 

to the manager of the certification office, 

send it to the attention of the person 

identified in Related Information. You may 

email your request to: ANE-AD-AMOC@

faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the local flight standards district office/ 

certificate holding district office. 

(k) Related Information 

(1) Barbara Caufield, Aviation Safety 

Engineer, ECO Branch, FAA, 1200 District 

Avenue, Burlington, MA 01803; phone: (781) 

238–7146; fax: (781) 238–7199; email: 

barbara.caufield@faa.gov. 

(2) Refer to European Aviation Safety 

Agency (EASA) AD 2018–0194, dated 

September 4, 2018, for more information. 

You may examine the EASA AD in the AD 

docket at https://www.regulations.gov by 

searching for and locating it in Docket No. 

FAA–2020–1025. 

(l) 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) Rolls-Royce Deutschland Ltd. & Co KG 

(RRD) BR700 Series Alert Non-Modification 

Service Bulletin SB–BR700–72–A900640, 

Revision 1, dated August 31, 2018. 

(ii) [Reserved] 

(3) For RRD service information identified 

in this AD, contact Rolls-Royce Deutschland 

Ltd. & Co KG, Eschenweg 11, 15827 

Blankenfelde-Mahlow, Germany; phone: +49 

(0) 33 708 6 0; email: rrd.techhelp@rollsVerDate Sep<11>2014 15:50 Jul 14, 2021 Jkt 253001 PO 00000 Frm 00016 Fmt 4700 Sfmt 4700 E:\FR\FM\15JYR1.SGM 15JYR1

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Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 37229 

royce; website: https://www.rolls-royce.com/ 

contact-us.aspx. 

(4) You may view this service information 

at FAA, Airworthiness Products Section, 

Operational Safety Branch, 1200 District 

Avenue, Burlington, MA 01803. For 

information on the availability of this 

material at the FAA, call (781) 238–7759. 

(5) You may view this service information 

that is incorporated by reference at the 

National Archives and Records 

Administration (NARA). For information on 

the availability of this material at NARA, 

email: fedreg.legal@nara.gov, or go to: 

https://www.archives.gov/federal-register/cfr/ 

ibr-locations.html. 

Issued on June 21, 2021. 

Gaetano A. Sciortino, 

Deputy Director for Strategic Initiatives, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–15055 Filed 7–14–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0100; Project 

Identifier MCAI–2020–00309–E; Amendment 

39–21613; AD 2021–13–08] 

RIN 2120–AA64 

Airworthiness Directives; Safran 

Helicopter Engines, S.A. (Type 

Certificate Previously Held by 

Turbomeca, S.A.) Turboshaft Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for all 

Safran Helicopter Engines, S.A. Arriel 

2C and Arriel 2S1 model turboshaft 

engines. This AD was prompted by 

reports of error messages on the full 

authority digital engine control (FADEC) 

B digital engine control unit (DECU), 

caused by blistering of the varnish on 

the DECU circuit board. This AD 

requires the replacement of certain 

FADEC B DECUs. The FAA is issuing 

this AD to address the unsafe condition 

on these products. 

DATES: This AD is effective August 19, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of August 19, 2021. 

ADDRESSES: For service information 

identified in this final rule, contact 

Safran Helicopter Engines, S.A., Avenue 

du 1er Mai, 40220 Tarnos, France; 

phone: +33 (0) 5 59 74 40 00. You may 

view this service information at the 

FAA, Airworthiness Products Section, 

Operational Safety Branch, 1200 District 

Avenue, Burlington, MA 01803. For 

information on the availability of this 

material at the FAA, call (781) 238– 

7759. It is also available at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0100. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0100; or in person at Docket 

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

Monday through Friday, except Federal 

holidays. The AD docket contains this 

final rule, the mandatory continuing 

airworthiness information (MCAI), any 

comments received, and other 

information. The address for Docket 

Operations is 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: 

Wego Wang, Aviation Safety Engineer, 

ECO Branch, FAA, 1200 District 

Avenue, Burlington, MA 01803; phone: 

(781) 238–7134; fax: (781) 238–7199; 

email: wego.wang@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to all Safran Helicopter Engines, 

S.A. Arriel 2C and Arriel 2S1 model 

turboshaft engines. The NPRM 

published in the Federal Register on 

February 26, 2021 (86 FR 11662). The 

NPRM was prompted by reports of error 

messages on the FADEC B DECU, 

caused by blistering of the varnish on 

the DECU circuit board. In the NPRM, 

the FAA proposed to require the 

replacement of certain FADEC B DECUs. 

The FAA is issuing this AD to address 

the unsafe condition on these products. 

The European Union Aviation Safety 

Agency (EASA), which is the Technical 

Agent for the Member States of the 

European Community, has issued EASA 

AD 2020–0046, dated March 4, 2020 

(referred to after this as ‘‘the MCAI’’), to 

address the unsafe condition on these 

products. The MCAI states: 

Occurrences have been reported of FADEC 

B DECU error messages, which were found to 

be caused by blistering of the varnish on the 

DECU circuit board. Subsequent 

investigation determined that the use of a 

non-compliant primer is related to the 

blistering effect which, in wet conditions, 

can cause malfunction of the stepper motor. 

This condition, if not corrected, could lead 

to loss of automatic control on both engines 

concurrently, possibly resulting in reduced 

control of the helicopter. 

To address this potentially unsafe 

condition, SAFRAN issued the MSB, as 

defined in this [EASA] AD, to provide 

instructions for identification and 

replacement of affected parts. For the reason 

described above, this [EASA] AD requires 

replacement of affected parts with 

serviceable parts. This [EASA] AD also 

prohibits (re-installation of affected parts. 

You may obtain further information 

by examining the MCAI in the AD 

docket on at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0100. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received no comments on 

the NPRM or on the determination of 

the costs. 

Conclusion 

The FAA reviewed the relevant data 

and determined that air safety requires 

adopting this AD as proposed. 

Accordingly, the FAA is issuing this AD 

to address the unsafe condition on these 

products. This AD is adopted as 

proposed in the NPRM. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed Safran Helicopter 

Engines Note Technique AA187866, 

Version A, dated 18 Octobre 2019 

[October 18, 2019]. This service 

information identifies the serial 

numbers (S/Ns) of certain FADEC B 

DECUs installed on Arriel 2C and Arriel 

2S1 model turboshaft engines. This 

service information is reasonably 

available because the interested parties 

have access to it through their normal 

course of business or by the means 

identified in ADDRESSES. 

Other Related Service Information 

The FAA reviewed Safran Helicopter 

Engines Mandatory Service Bulletin 

(MSB) No. 292 73 2872, Version A, 

dated October 17, 2019. This MSB 

describes procedures for identifying the 

S/Ns of certain FADEC B DECUs and 

replacing certain FADEC B DECUs on 

Arriel 2C and Arriel 2S1 model 

turboshaft engines. 

Costs of Compliance 

The FAA estimates that this AD 

affects 148 engines installed on 

helicopters of U.S. registry. 

The FAA estimates the following 

costs to comply with this AD: 


khammond on DSKJM1Z7X2PROD with RULES