DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

14 CFR Part 39

[Docket No. FAA-2010-0026; Directorate Identifier 2010-NE-03-AD]
RIN 2120-AA64

AIRWORTHINESS DIRECTIVES; CFM International, S.A. CFM56-5, -5B,
and -7B Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)  for
CFM International,  S.A. CFM56-5,  -5B, and  -7B series  turbofan engines.
This proposed  AD would  require removing  from service,  nine stage 3 low
-pressure turbine  (LPT) disks,  identified by  serial number  (S/N). This
proposed  AD  results  from  the  discovery  of  a  material nonconformity
requiring removal of  the disk before  the certified disk  life of certain
stage 3 LPT disks. We are proposing this AD to prevent uncontained failure
of the stage 3 LPT disk and damage to the airplane.

DATES: We must receive any comments on this proposed AD by May 17, 2010.

ADDRESSES: Use one of the following addresses to comment on this  proposed
AD.

Federal eRulemaking Portal: Go  to http:// www.regulations.gov and  follow
the instructions for sending your comments electronically.

Mail: Docket Management Facility, U.S. Department of Transportation,  1200
New  Jersey  Avenue,  SE.,  West  Building  Ground  Floor,  Room  W12-140,
Washington, DC 20590-0001.

Hand Delivery: Deliver to  Mail address above between  9 a.m. and 5  p.m.,
Monday through Friday, except Federal holidays.

Fax: (202) 493-2251.

FOR FURTHER INFORMATION CONTACT: Antonio Cancelliere, Aerospace  Engineer,
Engine Certification Office, FAA,  Engine & Propeller Directorate,  12 New
England     Executive    Park,     Burlington,    MA    01803;     e-mail:
antonio.cancelliere@faa.gov; telephone (781) 238-7751; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

COMMENTS INVITED

We invite you to  send us any written  relevant data, views, or  arguments
regarding this  proposal. Send  your comments  to an  address listed under
ADDRESSES. Include "Docket No. FAA-2010-0026; Directorate Identifier  2010
-NE-03-AD" in the  subject line of  your comments. We  specifically invite
comments on  the overall  regulatory, economic,  environmental, and energy
aspects of the proposed AD. We will consider all comments received by  the
closing date and may amend the proposed AD in light 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  with
FAA personnel concerning  this proposed AD.  Using the search  function of
the Web site, anyone can find and read the comments in any of our dockets,
including, if provided,  the name of  the individual who  sent the comment
(or signed the comment on behalf of an association, business, labor union,
etc.). You  may review  the DOT's  complete Privacy  Act Statement  in the
Federal Register published on April 11, 2000 (65 FR 19477-78).

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 proposed AD, the regulatory evaluation, any  comments
received,  and  other  information.  The  street  address  for  the Docket
Operations  office (telephone  (800) 647-5527)  is the  same  as  the Mail
address provided in the ADDRESSES  section. Comments will be available  in
the AD docket shortly after receipt.

DISCUSSION

In February 2009, we were made aware by CFM International, S.A. of stage 3
LPT  disks,  part  number (P/N)  336-002-006-0,  S/Ns  DE255844, DE256388,
DE256622, DE256623, DE256625, DE256627, DE256628, DE256631, and  DE256637,
being suspect of material non-conformity. This batch of parts was  subject
to a quality problem during manufacturing. CFM International, S.A.  states
that the  manufacturing process  has since  been revised  to eliminate the
quality problem. The non-conformity  requires removal from service  of the
suspect disks before their  certified life limits. Operating  engines with
these  affected  disks  to  the  certified  life  limit  could  result  in
uncontained failure of the stage 3 LPT disk and damage to the airplane.

FAA'S DETERMINATION AND REQUIREMENTS OF THE PROPOSED AD

We  have  evaluated all  pertinent  information and  identified  an unsafe
condition that is  likely to exist  or develop on  other products of  this
same type design. This proposed AD would require removing from service any
affected stage 3 LPT disks from engines before their certified life limit.
We are proposing this AD, which would require removing the affected  stage
3 LPT disks from service before accumulating 9,500 cycles-since-new.

COSTS OF COMPLIANCE

We estimate that  this proposed AD  would affect two  engines installed on
airplanes of U.S. registry. The pro-rated cost of the replacement parts is
$40,375 per engine.  We estimate that  no additional labor  costs would be
incurred to perform the required disk removals, because the removals would
be done at time of engine shop visit. Based on these figures, we  estimate
the total cost of the proposed AD to U.S. operators to be $80,750.

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  have  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 that the proposed AD:

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); and

3. Would 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 a regulatory evaluation of the estimated costs to comply  with
this proposed AD. You may get a copy of this summary at the address listed
under ADDRESSES.

LIST OF SUBJECTS IN 14 CFR PART 39

Air transportation, Aircraft, Aviation safety, Safety.

THE PROPOSED AMENDMENT

Under the  authority delegated  to me  by the  Administrator, the  Federal
Aviation Administration 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.

SEC.  39.13  [AMENDED]

2. The FAA  amends Sec.  39.13  by adding the  following new airworthiness
directive: