[Federal Register Volume 80, Number 84 (Friday, May 1, 2015)]
[Proposed Rules]
[Pages 24856-24858]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-09930]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0277; Directorate Identifier 2015-NE-05-AD]
RIN 2120-AA64


Airworthiness Directives; CFM International S.A. Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain CFM International S.A. (CFM) CFM56-7B series turbofan engines. 
This proposed AD was prompted by reports of uncommanded in-flight 
shutdowns (IFSDs) on CFM CFM56-7B engines following rupture of the 73-
tooth gearshaft located in the engine accessory gearbox (AGB). This 
proposed AD would require magnetic chip detector (MCD) inspection of 
the affected gearshafts until removal. We are proposing this AD to 
prevent failure of certain engine AGB gearshafts, which could lead to 
failure of one or more engines, loss of thrust control, and damage to 
the airplane.

DATES: We must receive comments on this proposed AD by June 30, 2015.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal 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 W12-140, 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 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.

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-2015-
0277; 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: 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: 

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. Include ``Docket No. FAA-2015-0277; 
Directorate Identifier 2015-NE-05-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 uncommanded IFSDs on CFM CFM56-7B 
engines following rupture of the 73-tooth gearshaft located in the 
engine AGB. CFM has identified an affected population of 73-tooth 
gearshafts that show premature wear on the teeth due to inadequate shot 
peening. In the process of its investigation, CFM identified an 
additional population of 41-tooth gearshafts that is subject to the 
same premature wear. The affected population of 73-tooth and 41-tooth 
gearshafts exhibit a surface finish that leads to loss in oil film 
effectiveness, causing micro-pitting which eventually

[[Page 24857]]

leads to material separating from the gearshaft and its eventual 
failure.
    The proposed AD requires enhanced MCD inspection until removal of 
the gearshaft. This enhanced inspection requires that any material, 
including fuzz, be sent to the particles lab for analysis to determine 
the source of the material. We are allowing affected engines to 
continue to operate for 75 flight hours (FHs) after the MCD inspection 
to provide sufficient time to determine the source of the material and 
to remove the affected gearshaft if the particles lab analysis finds 
that the source of the material is from an affected 73-tooth or 41-
tooth gearshaft. The enhanced MCD inspection and particles lab analysis 
is repeated every 500 FHs after the initial MCD inspection until the 
affected gearshaft is removed from service. This condition, if not 
corrected, could result in failure of certain engine AGB gearshafts, 
which could lead to failure of one or more engines, loss of thrust 
control, and damage to the airplane.

Relevant Service Information Under 1 CFR Part 51

    We reviewed CFM Service Bulletin (SBs) CFM56-7B S/B 72-0964, 
Revision 1, dated December 15, 2014, and CFM56-7B S/B 72-0965, dated 
December 16, 2014. The SBs describe procedures for removal of affected 
73-tooth and 41-tooth gearshafts. This service information is 
reasonably available; see ADDRESSES for ways to access this service 
information.

FAA's Determination

    We are proposing 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.

Proposed AD Requirements

    This proposed AD would require an MCD inspection within 250 FHs 
since last inspection or within 25 FHs after the effective date of this 
AD, whichever comes later. The proposed AD would also require that the 
MCD inspection be repeated every 500 FHs after the initial MCD 
inspection until removal of the affected gearshaft. The proposed AD 
would also require as terminating action that the affected gearshafts 
be removed.

Differences Between This Proposed AD and the Service Information

    This proposed AD would require an MCD inspection 250 FHs since last 
inspection or within 25 FHs after the effective date of this AD, 
whichever comes later. CFM SB CFM56-7B S/B 72-0964, Revision 1, dated 
December 15, 2014, recommends performing a MCD inspection 250 FHs since 
last inspection or as soon as possible if the inspection was done more 
than 250 FHs ago.
    In this proposed AD, we are not requiring that operators send the 
particles to CFM for analysis. We are, however, requiring that 
operators determine if the particles are 73-tooth gearshaft or 41-tooth 
gearshaft material. CFM56-7B S/B 72-0964 recommends that if any 
magnetic particles, including fuzz are seen, operators send the 
inspection results and lab analysis to CFM for disposition.

Costs of Compliance

    We estimate that this proposed AD would affect about 67 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 1 hour per engine to do the inspection and 8 hours per 
engine to replace each affected gearshaft. We estimate thirty-six 73-
tooth gearshafts and forty 41-tooth gearshafts will need replacement at 
a cost of $12,480 and $7,680 per part, respectively. 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 $813,855.

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 proposed AD would not have federalism 
implications under Executive 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 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

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):

CFM International S.A.: Docket No. FAA-2015-0277; Directorate 
Identifier 2015-NE-05-AD.

(a) Comments Due Date

    We must receive comments by June 30, 2015.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to CFM International S.A. (CFM) CFM56-7B engines 
with accessory gearboxes (AGBs), with 73-tooth gearshafts or 41-
tooth gearshafts, identified in Appendix A and Appendix B of CFM 
Service Bulletin (SB) CFM56-7B S/B 72-0964, Revision 1, dated 
December 15, 2014.

(d) Unsafe Condition

    This AD was prompted by reports of uncommanded in-flight 
shutdowns on CFM CFM56-7B engines following rupture of the 73-tooth 
gearshaft located in the engine AGB. We are issuing this AD to 
prevent failure of certain AGB gearshafts, which could lead to 
failure of one or more engines, loss of thrust control, and damage 
to the airplane.

[[Page 24858]]

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) Initial Magnetic Chip Detector (MCD) Inspection and 
Analysis. (i) For affected 73-tooth gearshafts, perform an MCD 
inspection within 250 flight hours (FHs) since last inspection, 
within 25 FHs from the effective date of this AD, or when the 
gearshaft accumulates 3,000 FHs since new, whichever comes later.
    (ii) For affected 41-tooth gearshafts, perform an MCD inspection 
within 250 FHs since last inspection, within 25 FHs from the 
effective date of this AD, or when the gearshaft accumulates 6,000 
FHs since new, whichever comes later.
    (iii) If any magnetic particles, including fuzz, are seen, 
determine with particles lab analysis if the particles are 73-tooth 
or 41-tooth gearshaft material.
    (iv) If the particles are 73-tooth or 41-tooth gearshaft 
material, remove the affected gearshaft(s) within 75 FHs since the 
MCD inspection.
    (2) Repetitive MCD Inspection and Analysis. (i) For affected 73-
tooth gearshafts, perform an MCD inspection and particles lab 
analysis within every 500 FHs since the last MCD inspection until 
affected gearshaft is removed.
    (ii) For affected 41-tooth gearshafts, perform an MCD inspection 
and particles lab analysis within every 500 FHs since the last MCD 
inspection until affected gearshaft is removed.
    (iii) If any magnetic particles, including fuzz, are seen, 
determine with particles lab analysis if the particles are 73-tooth 
or 41-tooth gearshaft material.
    (iv) If the particles are 73-tooth or 41-tooth gearshaft 
material, remove the affected gearshaft(s) within 75 FHs since the 
MCD inspection.

(f) Mandatory Terminating Action

    (1) Remove the affected 73-tooth gearshaft prior to the 
gearshaft accumulating 6,000 FHs since new or within 50 FHs after 
the effective date of this AD, whichever comes later.
    (2) Remove the affected 41-tooth gearshaft prior to the 
gearshaft accumulating 9,000 FHs since new or within 50 FHs after 
the effective date of this AD, whichever comes later.

(g) Installation Prohibition

    After the effective date of this AD, do not install an affected 
gearshaft into an AGB.

(h) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures found in 14 CFR 39.19 to make your 
request. You may email your request to: [email protected].

(i) 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 SBs CFM56-7B S/B 72-0964, Revision 1, dated December 15, 
2014, and CFM56-7B S/B 72-0965, dated December 16, 2014, can be 
obtained from GE using the contact information in paragraph (i)(3) 
of this proposed 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.

    Issued in Burlington, Massachusetts, on April 17, 2015.
Thomas A. Boudreau,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-09930 Filed 4-30-15; 8:45 am]
 BILLING CODE 4910-13-P