[Docket No. FAA-2014-0521; Directorate Identifier 2014-NE-11-AD] 

RIN 2120-AA64 

Airworthiness Directives; CFM International S.A. Turbofan Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking (NPRM). 

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

International (CFM) S.A. CFM56-7B series turbofan engines. This proposed AD was 

prompted by a dual engine thrust instability event that resulted in the overspeed and inflight shutdown (IFSD) of one engine. This proposed AD would require modification of 

the engine by removing full authority digital engine control (F ADEC) software, version 

7BV4 or earlier, installed in the electronic engine controls (EECs) on CFM56-7B 

engines. We are proposing this AD to prevent a thrust instability event, which could lead 

to overspeed and IFSD of one or more engines, loss of thrust control, damage to the 

engine, and damage to the airplane. 

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 11.43 

and 11.45, by any ofthe following methods: 

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

instructions for submitting comments. 

• Fax: 202-493-2251. 
Monday through Friday, except Federal holidays. 

For service information identified in this AD, contact CFM International Inc., 

Aviation Operations Center, 1 Neumann Way, MID Room 285, Cincinnati, OH 45125; 

phone: 877-432-3272; fax: 877-432-3329; email: geae.aoc@ge.com. 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. F AA-20 14-0521; 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 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: Barbara Caufield, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7146; fax: 781-238-

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

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Include 

Docket No. FAA-2014-0521; Directorate Identifier 2014-NE-11-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 received reports of dual engine thrust instability events on CFM56-7B 

turbofan engines that resulted in overspeed and IFSD of one engine. These resulted from 

water-borne fuel contamination of the fuel supply causing a lag in the response of the 

control valve in the fuel metering unit (FMU). CFM has improved its FADEC software to 

help prevent the lag in the response of the FMU control valve, thereby mitigating these 

thrust instability events. This condition, if not corrected, could lead to overs peed and 

IFSD of one or more engines, loss of thrust control, damage to the engine, and damage to 

the airplane. 

Relevant Service Information 

We reviewed CFM Service Bulletin (SB) No. CFM56-7B SIB 73-0203, dated 

June 9, 2014, and CFM SB No. CFM56-7B SIB 73-0204, dated June 9, 2014. The SBs 

describe procedures for the introduction of new F ADEC software for the EECs. 

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Proposed AD Requirements 

This proposed AD would require modification of the engine by removing FADEC 

software, version 7BV 4 or earlier, installed in the EECs on CFM56-7B engines. 

Costs of Compliance 

We estimate that this proposed AD would affect about 2,921 engines installed on 

airplanes of U.S. registry. We also estimate that it would take about 1 hour per product to 

comply with this proposed AD. The average labor rate is $85 per hour. Based on these 

figures, we estimate the cost of the proposed AD on U.S. operators to be $248,285. 

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. 

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o

the distribution of power and responsibilities 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, 

(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. 

The Proposed Amendment 

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

proposes to amend 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): 

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PUBLICATION IN THE Federal Register]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all CFM International (CFM) S.A. CFM56-7B series turbofan 

engmes. 

(d) Unsafe Condition 

This AD was prompted by a dual engine thrust instability event that resulted in 

the overspeed and in-flight shutdown (IFSD) of one engine. We are issuing this AD to 

prevent a thrust instability event, which could lead to overspeed and IFSD of one or more 

engines, loss of thrust control, damage to the engine, and damage to the airplane. 

(e) Compliance 

(1) Comply with this AD within the compliance times specified, unless already 

done. 

(2) Within 6 months after the effective date ofthis AD, modify the engine by 

removing full authority digital engine control (F ADEC) software, version 7BV 4 or 

earlier, installed in the electronic engine controls. 

(f) 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. 

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(2) CFM Service Bulletin (SB) No. CFM56-7B SIB 73-0203, dated June 9, 2014, 

and CFM No. SB CFM56-7B SIB 73-0204, dated June 9, 2014, which are not 

incorporated by reference in this proposed AD, can be obtained from CFM using the 

contact information in paragraph (g)(3) of this proposed AD. 

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

International Inc., Aviation Operations Center, 1 Neumann Way, MID Room 285, 

Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-3329; email: 

geae.aoc@ge.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, call 781-238-7125. 

Issued in Burlington, Massachusetts, on September 25, 2014. 

Ann C. Mollica, 

Acting Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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