DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

14 CFR Part 39

[Docket  No.  FAA-2005-23334;  Directorate  Identifier  2005-CE-53-AD] RIN
2120-AA64

AIRWORTHINESS DIRECTIVES;  General  Machine--Diecron,  Inc.  Actuator  Nut
Assembly for the Right Main Landing Gear

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)  for
General Machine--Diecron,  Inc. (GMD)  actuator nut  assembly, part number
(P/N) GMD115-810029-17  and P/N  GMD115-810029-23, that  are installed  on
certain airplanes.  This proposed  AD would  require you  to determine  by
maintenance  records  check  and/or inspection  whether  any  actuator nut
assembly, P/N  GMD115-810029-17 or  P/N GMD115-810029-23,  is installed on
the  right main  landing gear  (MLG) actuator,  and, if  installed,  would
require you to  replace it with  a new actuator  nut assembly, P/N  GMD115
-810029-23B or FAA-approved equivalent P/N. This proposed AD results  from
several  reports of  failures of  the actuator  nut assembly,  P/N  GMD115
-810029-17 and P/N  GMD115-810029-23. We are  issuing this proposed  AD to
prevent failure of the actuator  nut assembly for the right  MLG actuator,
which could result in failure of  the MLG. This failure could prevent  the
extension or retraction of the MLG.

DATES: We must receive comments on this proposed AD by April 3, 2006.

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: 1-202-493-2251.

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 General  Machine--Diecron, Inc.,  3131 U.S.  Highway 41,  Griffin,
Georgia 30224, telephone: (770)  228-6200; facsimile: (770) 228-6299,  for
the service information identified in this proposed AD.

You may examine the comments on this  proposed AD in the AD docket on  the
Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Don Buckley, Aerospace Engineer, Airframe
and  Propulsion  Branch,  ACE-117A,  FAA,  Atlanta  Aircraft Certification
Office,  One Crown  Center, 1895  Phoenix Boulevard,  Suite 450,  Atlanta,
Georgia 30337-2748, telephone (770) 703-6086; fax (770) 703-6097.

SUPPLEMENTARY INFORMATION:

COMMENTS INVITED

How do I comment on this proposed AD?

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  the   docket  number,  "FAA-2005-23334;   Directorate
Identifier  2005-CE-53-AD"   at  the   beginning  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  rulemaking.  Using  the search
function of the DOT docket Web site, anyone can find and read the comments
received into 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 DOCKETS

Where can I go to view the docket information?

You  may  examine the  docket  that contains  the  proposal, any  comments
received and any final disposition on the Internet at http://dms.dot.gov ,
or in person at the DOT Docket  Offices between 9 a.m. and 5 p.m.,  Monday
through Friday, except  Federal holidays. The  Docket Office (telephone  1
-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  Docket
Management Facility receives them.

DISCUSSION

What events have caused this proposed AD?

The  FAA has  received several  reports of  failure of  the  actuator  nut
assembly, part  numbers (P/N)  GMD115-810029-17 and  P/N GMD115-810029-23,
for the right main landing  gear (MLG) actuator in airplanes  not equipped
with a hydraulic MLG or modified to a hydraulic MLG. One failure  resulted
in the MLG not extending and a "gear-up" landing.

Investigation found the separation of  the threaded nut insert in  the P/N
GMD115-810029-17 and P/N GMD115-810029-23  MLG actuator nut assembly.  The
insert has  internal and  external threads.  The external  threads of  the
insert  screw into  a threaded  steel tube  to complete  the actuator  nut
assembly. The internal threads of  the insert interface with the  Actuator
Screw in the Raytheon MLG Actuator. Rotation of the MLG Actuator Screw  in
the right MLG Actuator transmits load to the insert which tends to unscrew
the insert from the GMD  Actuator Nut Assembly during the  extension cycle
of the  MLG. If  the insert  separates (unscrews)  from the threaded steel
tube, it can prevent the actuator from extending or retracting the MLG  to
the locked position. The separation of the insert only occurs in the right
MLG actuator.

What is the potential impact if FAA took no action?

This  condition,  if  not  corrected,  could  prevent  the  extension   or
retraction of the MLG.

RELEVANT SERVICE INFORMATION

Is there service information that applies to this subject?

We have reviewed General Machine  Diecron, Inc.  Service  Bulletin  GM-D32
-30-01/102505, dated November 21, 2005.

What are the provisions of this service information?

The service information describes procedures for:

Determining by  maintenance records  check and/or  inspection whether  any
actuator nut assembly, P/N  GMD115-810029-17 or P/N GMD115-  810029-23, is
installed on the right MLG actuator; and

If any actuator  nut assembly, P/N  GMD115-810029-17 or P/N  GMD115-810029
-23, is installed, replacing it with a new P/N GMD115-810029-23B  actuator
nut assembly.

FAA'S DETERMINATION AND REQUIREMENTS OF THE PROPOSED AD

Why have we determined AD action is necessary and what would this proposed
AD require?

We are proposing this AD to address an unsafe condition that we determined
is likely to exist or develop on other products of this same type  design.
The proposed  AD would  require you  to determine  by maintenance  records
check  and/or inspection  whether any  actuator nut  assembly, P/N  GMD115
-810029-17  or  P/N  GMD115-810029-23,  is  installed  on  the  right  MLG
actuator, and, if installed,  would require you to  replace it with a  new
actuator nut assembly, P/N  GMD115-810029-23B or FAA- approved  equivalent
P/N. The  proposed AD  would require  you to  use the  service information
described previously to perform these actions.

DIFFERENCES BETWEEN THE PROPOSED AD AND SERVICE INFORMATION

Are there  differences between  the requirements  of this  AD and  what is
contained in the service information?

If any actuator nut assembly,  P/N GMD115-810029-17 or  P/N  GMD115-810029
-23, is installed on the right MLG actuator, this AD would require you  to
replace it  with a  new actuator  nut assembly,  P/N GMD115- 810029-23B or
FAA-equivalent P/N. The requirements of  the proposed AD, if adopted  as a
final  rule, would  take precedence  over the  provisions in  the  service
information.

COSTS OF COMPLIANCE

How many airplanes would this proposed AD impact?

We estimate  that this  proposed AD  affects 1,629  airplanes in  the U.S.
registry.

What would be the cost impact  of this proposed AD on owners/operators  of
the affected airplanes?

We estimate the  following costs to  do this proposed  maintenance records
check and/or inspection  to determine whether  any actuator nut  assembly,
P/N GMD115-810029-17 or  P/N GMD115-810029-23, is  installed on the  right
MLG actuator:

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                               TOTAL COST PER      TOTAL COST ON U.S.
 LABOR COST       PARTS COST      AIRPLANE             OPERATORS
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1 work hour
x $65 = $65     Not Applicable      $65         1,629 x $65 = $105,885
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We estimate the  following costs to  do any necessary  replacements of the
actuator nut assembly that would be required based on the results of  this
proposed inspection. We have no way of determining the number of airplanes
that may need this replacement:

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                                                             TOTAL COST
                 LABOR COST                    PARTS COST   PER AIRPLANE
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4 work hours x $65 = $260...................     $1,700        $1,960
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AUTHORITY FOR THIS RULEMAKING

What authority does FAA have for issuing this rulemaking action?

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

Would this proposed AD impact various entities?

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. 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.

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 adding the  following new airworthiness
   directive: