Airworthiness Directives; CFM International S.A. Turbofan Engines

[Federal Register Volume 80, Number 36 (Tuesday, February 24, 2015)]
[Rules and Regulations]
[Pages 9591-9594]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-03582]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0521; Directorate Identifier 2014-NE-11-AD; 
Amendment 39-18104; AD 2015-04-02]
RIN 2120-AA64


Airworthiness Directives; CFM International S.A. Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all CFM 
International S.A. (CFM) CFM56-7B series turbofan engines. This AD was 
prompted by a dual engine thrust instability event that resulted in the 
overspeed and in-flight shutdown (IFSD) of one engine. This AD requires 
modification of the engine by removing

[[Page 9592]]

full authority digital engine control (FADEC) software, version 7.B.V4 
or earlier, installed in the electronic engine controls (EECs) on 
CFM56-7B engines. 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.

DATES: This AD is effective March 31, 2015.

ADDRESSES: For service information identified in this AD, contact CFM 
International Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 
285, Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-3329; 
email: [email protected]. 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. It is also available on the Internet at 
http://www.regulations.gov by searching for and locating Docket No. 
FAA-2014-0521.

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-2014-
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 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: Kyle Gustafson, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; phone: 781-238-7183; 
fax: 781-238-7199; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to all CFM CFM56-7B series 
turbofan engines. The NPRM published in the Federal Register on October 
2, 2014 (79 FR 59467). The NPRM was prompted by 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 
contamination of the fuel being supplied to the engine which had an 
adverse effect on the response of the fuel metering valve (FMV) in the 
hydro-mechanical unit (HMU). CFM has modified its FADEC software to 
compensate for compromised fuel within the HMU and improved the 
response of the FMV, thereby mitigating these thrust instability 
events. The NPRM proposed to require modification of the engine by 
removing FADEC software, version 7.B.V4 or earlier, installed in the 
EECs on CFM56-7B engines. 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.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM (79 
FR 59467, October 2, 2014) and the FAA's response to each comment.

Request To Change Emphasis From Software Removal to Software 
Installation

    Delta Air Lines (DAL) and American Air Lines (AAL) requested that 
we change wording in the AD to emphasize installation of an eligible 
software standard rather than removal of the ineligible software 
standard. They suggested that we add this sentence to compliance 
paragraph (e): ``Within 6 months of the effective date of this AD, 
modify the engine by installing FADEC software version 7.B.W, released 
by CFM Service Bulletins 73-0203 and 73-0204, or later approved 
software versions.'' DAL and AAL state that the Boeing 737NG Aircraft 
Maintenance Manual does not contain a removal step but rather guides 
how to overwrite previous software with eligible software.
    We disagree. The purpose of this AD is to require removal of 
software standard 7.B.V4, or earlier, to correct the unsafe condition. 
Overwriting a previously installed software standard with a software 
standard eligible for installation is an acceptable method for removing 
an affected software standard. We did not change this AD.

Request To Require Use of Software EEC Software Standard 7.B.W or Later

    DAL and AAL requested that we revise paragraph (h)(2) of FAA AD 
2012-05-02 (77 FR 20511, April 5, 2012) (``AD 2012-05-02'') to state 
that EEC software standard 7.B.W or later is required. AD 2012-05-02 
requires inspection and modification to the Boeing 737NG thrust 
reversers, and also requires, in paragraph (h)(2), installation of 
software standard 7.B.R3 on affected engines. Since AD 2012-05-02 was 
issued, new versions of software have been released, requiring 
alternative methods of compliance (AMOCs) to allow installation of 
versions later than software standard 7.B.R3. The requested change to 
AD 2012-05-02 would bring AD 2012-05-02 and this AD into agreement on 
the required airplane configuration.
    We disagree. The current version of the software standard, 7.B.W, 
also addresses the thrust reverser unsafe condition and is approved as 
an AMOC for AD 2012-05-02. We did not change this AD.

Request To Change Description of the Unsafe Condition

    The Boeing Company (Boeing) and CFM requested that we change the 
wording of the unsafe condition to ``We are proposing this AD to 
mitigate characteristics of a thrust instability event; without 
mitigation, thrust instability events could potentially lead to engine 
overspeed and IFSD of one or more engines, loss of thrust control, and 
damage to the airplane.'' The commenters state that the EEC cannot 
prevent the occurrence of the events, but it can effectively mitigate 
the characteristics of the events.
    We disagree. While the work to prevent the root cause of fuel 
contamination continues, the purpose of the FADEC software and this AD 
is to prevent the events described in the unsafe condition. We did not 
change this AD.

Request To Change Wording in the Description Paragraph

    CFM and Boeing requested that we change the wording of two 
sentences in the Description paragraph to ``These resulted from water-
borne contamination of the fuel being supplied to the engine which had 
an adverse effect on the response of the FMV in the HMU. CFM has 
modified its FADEC software to compensate for compromised fuel within 
the HMU and improve the response of the fuel control valve, thereby 
mitigating these thrust instability events.''
    We agree. We changed the wording of the two sentences in the 
Description paragraph to be more correct and accurate.

[[Page 9593]]

Request To Clarify a Sentence in the Relevant Service Information 
Paragraph

    Boeing requested, for clarity, that in the Relevant Service 
Information paragraph of the preamble we add the words ``post 7.B.V4'' 
to describe the FADEC software. Boeing requested that the changed 
sentence read: ``The SBs describe the procedures for the introduction 
of new FADEC software, post 7.B.V4, for the EECs.''
    We disagree. The information in this AD provides the necessary 
information for compliance. No additional clarification is required. 
Furthermore, the Relevant Service Information paragraph, which appeared 
in the preamble of the NPRM (79 FR 59467, October 2, 2014), does not 
appear in this AD. We did not change this AD.

Request That We Correct Our References to the FADEC Software Standard

    CFM requested that we change all references to the software 
standard throughout this AD from ``7BV4'' to ``7.B.V4'' because that is 
the correct way to reference the software standard.
    We agree. We changed all references to the software standard 
throughout this AD to the correct nomenclature.

Request To Add a Table Specifying the Software Versions To Remove

    Boeing requested that for clarity we include in this AD a table 
that would show the software versions, by part number, that should be 
removed as a result of this AD.
    We disagree. The information in this AD provides the necessary 
information for compliance. No additional clarification is required. We 
did not change this AD.

Additional Changes

    In our review of the NPRM, we found that we failed to include the 
prohibition against operating any aircraft configured with one engine 
with FADEC software version 7.B.V4 or earlier, installed, and the other 
engine with an eligible FADEC software version installed. This 
prohibition is in SB CFM Service Bulletin (SB) No. CFM56-7B S/B 73-
0203, dated June 9, 2014 and CFM No. SB CFM56-7B S/B 73-0204, dated 
June 9, 2014. We added the prohibition to this AD.

Agreement With the Proposed AD

    One anonymous commenter expressed agreement with 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 have determined that 
these minor changes:
    <bullet> [Agr]re consistent with the intent that was proposed in 
the NPRM (79 FR 59467, October 2, 2014) for correcting the unsafe 
condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM (79 FR 59467, October 2, 2014).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

    We estimate that this 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 engine to comply with this AD. The average labor rate 
is $85 per hour. Parts cost is zero. Based on these figures, we 
estimate the cost of this 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.

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) 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.

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

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2015-04-02 CFM International S.A.: Amendment 39-18104; Docket No. 
FAA-2014-0521; Directorate Identifier 2014-NE-11-AD.

(a) Effective Date

    This AD is effective March 31, 2015.

(b) Affected ADs

    None.

(c) Applicability

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

(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 of this AD, modify 
the engine by removing full authority digital engine control (FADEC) 
software, version 7.B.V4 or earlier, installed in the electronic 
engine control (EEC).
    (3) Do not return to service any aircraft configured with one 
engine with FADEC software, version 7.B.V4 or earlier, installed, 
and the other engine with an eligible FADEC software version, 
installed.

[[Page 9594]]

(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. You may email your request to: [email protected].

(g) Related Information

    (1) For more information about this AD, contact Kyle Gustafson, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, MA 
01803; phone: 781-238-7183; fax: 781-238-7199; email: 
[email protected].
    (2) CFM Service Bulletin (SB) No. CFM56-7B S/B 73-0203, dated 
June 9, 2014, and CFM No. SB CFM56-7B S/B 73-0204, dated June 9, 
2014, which are not incorporated by reference in this AD, can be 
obtained from CFM using the contact information in paragraph (g)(3) 
of this AD.
    (3) For service information identified in this AD, contact CFM 
International Inc., Aviation Operations Center, 1 Neumann Way, M/D 
Room 285, Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-
3329; email: [email protected].
    (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.

(h) Material Incorporated by Reference

    None.

    Issued in Burlington, Massachusetts, on February 10, 2015.
Ann C. Mollica,
Acting Directorate Manager, Engine & Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2015-03582 Filed 2-23-15; 8:45 am]
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