DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

14 CFR Part 39

[Docket No. FAA-2005-20856; Directorate Identifier 2004-NE-25-AD]
RIN 2120-AA64

AIRWORTHINESS DIRECTIVES; MT-Propeller Entwicklung GmbH
Propellers

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness directive
(AD) for certain  MT-Propeller Entwicklung GmbH  variable pitch and  fixed
pitch propellers manufactured  before 1995 which  had not been  overhauled
since April  1994. That  AD currently  requires overhauling  the propeller
blades  and  performing  initial  and  repetitive  visual  inspections  of
affected propeller blades.  That AD also  requires removing all  propeller
blades from service with damaged  erosion sheath bonding or loose  erosion
sheaths  and installing  any missing  or  damaged  polyurethane protective
strips. This proposed AD would require the same actions. This proposed  AD
results from  the need  to clarify  the population  of affected propellers
previously listed in  AD 2006-05-05. We  are proposing this  AD to prevent
erosion sheath separation leading to damage of the airplane.

DATES: We must receive  any comments on this  proposed AD by February  12,
2007.

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

DOT Docket Web site: Go to http://dms.dot.gov and follow the  instructions
for sending your comments electronically.

Government-wide rulemaking Web site: Go to http://www.regulations.gov  and
follow the instructions for sending your comments electronically.

Mail: Docket Management Facility;  U.S. Department of Transportation,  400
Seventh Street, SW.,  Nassif Building, Room  PL-401, Washington, DC  20590
-0001.

Fax: (202) 493-2251.

Hand Delivery: Room PL-401 on the plaza level of the Nassif Building,  400
Seventh Street,  SW., Washington,  DC, between  9 a.m.  and 5 p.m., Monday
through Friday, except Federal holidays.

Contact MT-Propeller USA,  Inc., 1180 Airport  Terminal Drive, Deland,  FL
32724;   telephone   (386)   736-7762,  fax   (386)   736-7696   or  visit
http://www.mt-propeller.com for the service information identified in this
proposed AD.

FOR FURTHER INFORMATION CONTACT:  Frank Walsh, Aerospace Engineer,  Boston
Aircraft Certification Office, FAA,  Engine and Propeller Directorate,  12
New England  Executive Park,  Burlington, MA  01803-5299; telephone  (781)
238-7158, fax (781) 238-7170.

SUPPLEMENTARY INFORMATION:

COMMENTS INVITED

We  invite you  to send  any written  relevant data,  views, or  arguments
regarding this  proposal. Send  your comments  to an  address listed under
ADDRESSES.  Include  "Docket  No.  FAA-2005-20856;  Directorate Identifier
2004-NE-25-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://dms.dot.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 DMS  Web site,  anyone can  find and  read the  comments in any of our
dockets, including  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) or you  may
visit http://dms.dot.gov.

EXAMINING THE AD DOCKET

You  may  examine the  docket  that contains  the  proposal, any  comments
received and  any final  disposition in  person at  the DMS  Docket Office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
The Docket Office (telephone (800) 647-5227) is located on the plaza level
of the Department of Transportation Nassif Building at the street  address
stated in ADDRESSES. Comments will  be available in the AD  docket shortly
after the DMS receives them.

DISCUSSION

On February 24, 2006, we  issued AD 2006-05-05, Amendment 39-14502  (71 FR
11151, March 6, 2006). That AD requires overhaul of models MT, MTV-1,  MTV
-2, MTV-3, MTV-5,  MTV-6, MTV-7, MTV-9,  MTV-10, MTV-11, MTV-  12, MTV-14,
MTV-15,  MTV-17,  MTV-18,  MTV-20,  MTV-21,  MTV-22,  MTV-24,  and  MTV-25
propellers  with serial  numbers (SNs)  below 95000,  which  had  not been
overhauled since April  1994, within 30  days after the  effective date of
the AD. That action also required performing initial and repetitive visual
inspections of those propeller blades. That action also required  removing
all propeller blades from service  with damaged erosion sheath bonding  or
loose erosion sheaths and to  install any missing or damaged  polyurethane
protective strips. The  European Aviation Safety  Agency (EASA), which  is
the airworthiness authority  for the European  Union, notified us  that an
unsafe  condition  may  exist  on  certain  MT-Propeller  Entwicklung GmbH
propellers.

ACTIONS SINCE AD 2006-05-05 WAS ISSUED

Since AD 2006-05-05 was  issued, MT-Propeller Entwicklung GmbH  Propellers
and EASA have clarified the population of affected propellers. AD  2006-05
-05 described the  affected propellers as  variable pitch and  fixed pitch
propellers with serial numbers (SNs) below 95000. Because propellers  with
SNs starting with 00, 01, 02, 03, 04, 05, and 06, were manufactured in the
years 2000,  2001, 2002,  2003, 2004,  2005, and  2006 respectively,  some
operators are confused  as to whether  their propeller SN  is part of  the
affected  population. For  example,  propeller  SN 00246,  manufactured in
2000,  would appear  to be  part of  the affected  population because  the
number is below 95000. For clarification, we are proposing to identify the
affected  population  as  variable   pitch  and  fixed  pitch   propellers
manufactured before 1995 which had  not been overhauled since April  1994.
Also, since AD 2006-05-05 was  issued, we discovered that propeller  model
MTV-25 was erroneously listed in the AD.

RELEVANT SERVICE INFORMATION

We have  reviewed and  approved the  technical contents  of MT-  Propeller
Service  Bulletin  (SB) No.  8B,  dated March  8,  2006, which  lists  the
affected propeller population  as models MT,  MTV-1, MTV-2, MTV-3,  MTV-5,
MTV-6, MTV-7, MTV-9, MTV-10, MTV-11, MTV-12, MTV-14, MTV- 15, MTV-17,  MTV
-18, MTV-20,  MTV-21, MTV-22,  and MTV-24  propellers, manufactured before
1995 which have  not been overhauled  since April 1994.  This SB describes
the visual inspections, removals,  and installations proposed by  this AD.
EASA classified this  SB as mandatory  and issued AD  No. 2006-0345, dated
November  14, 2006,  in order  to ensure  the airworthiness  of  these  MT
-Propeller Entwicklung GmbH propellers in Europe.

BILATERAL AGREEMENT INFORMATION

These  propeller  models  are   manufactured  in  Germany  and   are  type
certificated for operation  in the United  States under the  provisions of
Section 21.29 of the Federal  Aviation Regulations (14 CFR 21.29)  and the
applicable  bilateral  airworthiness   agreement.  Under  this   bilateral
airworthiness agreement, EASA kept us informed of the situation  described
above.  We have  examined the  findings of  EASA,  reviewed  all available
information, and determined  that AD action  is necessary for  products of
this type design that are certificated for operation in the United States.

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. We are proposing this AD, which would require you to:

Overhaul  all  installed  propeller blades  of  propellers  listed in  the
applicability, within 30 days after the effective date of this AD,  unless
previously done per AD 2006-05-05.

Visually inspect certain MT-Propeller Entwicklung GmbH variable pitch  and
fixed pitch propellers manufactured before 1995.

Remove from service, certain MT-Propeller Entwicklung GmbH variable  pitch
and  fixed  pitch propellers  manufactured  before 1995  if  the propeller
blades have damaged erosion sheath bonding or loose erosion sheaths.

Install  polyurethane protective  strips  onto  propeller blades  that are
missing these strips or have damaged strips.

COSTS OF COMPLIANCE

We estimate that 103 of these MT-Propeller Entwicklung GmbH variable pitch
and fixed pitch propellers installed on aircraft of U.S. registry would be
affected by this proposed AD. We also estimate that it would take about  2
work-hours to  inspect and  install the  polyurethane protective  strip of
each affected propeller, and 4 work- hours to remove a propeller requiring
overhaul. The average labor rate  is $80 per work-hour. Required  parts to
inspect and  install the  polyurethane protective  strip of  each affected
propeller would cost  about $20. Based  on these figures,  we estimate the
total cost of the  proposed AD to U.S.  operators, to inspect and  install
protective strips to be $18,540.

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 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); 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. See the ADDRESSES section for a location to examine  the
regulatory evaluation.

LIST OF SUBJECTS IN 14 CFR PART 39

Air transportation, Aircraft, Aviation safety, Safety.

THE PROPOSED AMENDMENT

Accordingly, 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 removing Amendment 39-14502 (71 FR 11151,
March 6, 2006)  and by adding  a new airworthiness  directive, to read  as
follows: