
[Federal Register: June 21, 2010 (Volume 75, Number 118)]
[Proposed Rules]               
[Page 34956-34958]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21jn10-22]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0632; Directorate Identifier 2010-CE-025-AD]
RIN 2120-AA64

 
Airworthiness Directives; Robert E. Rust, Jr. Model DeHavilland 
DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A Airplanes

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
Robert E. Rust, Jr. Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 
22, and DH.C1 Chipmunk 22A airplanes. This proposed AD would require a 
one-time inspection of the flap operating system for an unauthorized 
latch plate design installation. This proposed AD results from a report 
of a latch plate failing in service that was not made in accordance 
with the applicable de Havilland drawing. We are proposing this AD to 
detect and correct unauthorized latch plate design installation, which 
could result in an un-commanded retraction of the flaps. This failure 
could lead to a stall during a landing approach.

DATES: We must receive comments on this proposed AD by August 5, 2010.

[[Page 34957]]


ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact de 
Havilland Support Limited, Duxford Airfield, Cambridgeshire, CB22 4QR, 
England, phone: +44 (0) 1223 830090; fax: +44 (0) 1223 830085; e-mail: 
info@dhsupport.com; Internet: http://www.dhsupport.com/.

FOR FURTHER INFORMATION CONTACT: Carey O'Kelley, Aerospace Engineer, 
FAA, Atlanta Aircraft Certification Office (ACO), 1701 Columbia Avenue, 
College Park, Georgia 30337; telephone: (404) 474-5543; fax: (404) 474-
5606.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include the docket number, ``FAA-
2010-0632; Directorate Identifier 2010-CE-025-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://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive concerning this proposed AD.

Discussion

    We have received a report of a latch plate supplied under part 
number (P/N) C1-CF-1489 failing in service on a Model DeHavilland DH.C1 
Chipmunk 21, DH.C1 Chipmunk 22, or DH.C1 Chipmunk 22A airplane. The 
part in question was not manufactured to the de Havilland drawing for 
P/N C1-CF-1489. The unapproved latch plate was made of a shaft that was 
pressed into a plate, rather than being machined from bar material as 
one piece. The shaft and plate on the unapproved part can become 
separated or bent, resulting in rapid wear and failure of the part.
    This condition, if not corrected, could result in an un-commanded 
retraction of the flaps. This failure could lead to a stall during a 
landing approach.

Relevant Service Information

    We have reviewed de Havilland Support Limited Technical News Sheet 
(TNS) CT(C1) No 208 Issue 1, dated January 3, 2009. The service 
information describes procedures for inspecting the flap operating 
system latch plate for an unapproved part installation.

FAA's Determination and Requirements of the Proposed AD

    We are proposing this AD because we evaluated all information and 
determined the unsafe condition described previously is likely to exist 
or develop on other products of the same type design. This proposed AD 
would require a one-time inspection of the flap operating system for an 
unauthorized latch plate design installation.

Costs of Compliance

    We estimate that this proposed AD would affect 64 airplanes in the 
U.S. registry.
    We estimate the following costs to do the proposed inspection:

------------------------------------------------------------------------
                                                 Total cost   Total cost
          Labor cost              Parts cost        per        on U.S.
                                                  airplane    operators
------------------------------------------------------------------------
3 work-hours x $85 per hour =  Not Applicable.         $255      $16,320
 $255.
------------------------------------------------------------------------

     We estimate the following costs to do any necessary replacements 
that would be required based on the results of the proposed inspection. 
We have no way of determining the number of airplanes that may need 
this replacement:

------------------------------------------------------------------------
                                                         Total cost per
              Labor cost                  Parts cost        airplane
------------------------------------------------------------------------
.5 work-hour x $85 per hour = $42.50..            $175           $217.50
------------------------------------------------------------------------

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. 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.

[[Page 34958]]

    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

    You may examine the AD docket that contains the proposed AD, the 
regulatory evaluation, any comments received, and other information on 
the Internet at http://www.regulations.gov; or in person at the Docket 
Management Facility between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Office (telephone (800) 647-5527) 
is located at the street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

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

    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 AD:

Robert E. Rust, Jr.: Docket No. FAA-2010-0632; Directorate 
Identifier 2010-CE-025-AD.

Comments Due Date

    (a) We must receive comments on this airworthiness directive 
(AD) action by August 5, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Model DeHavilland DH.C1 Chipmunk 21, 
DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A airplanes, all serial 
numbers, that are certificated in any category.

    Note: These airplanes are also identified as CHIPMUNK 22A, 
CHIPMUNK DHC-1T10, CHIPMUNK T.10 MK-22, DH.C1 MK22A, DHC-1, DHC-1 
CHIPMUNK, DHC-1 CHIPMUNK 22, DHC-1 SERIES 22, or DHC-1 T.MK. 10.

Subject

    (d) Air Transport Association of America (ATA) Code 27: Flight 
Controls.

Unsafe Condition

    (e) This AD results from a report of a latch plate supplied 
under part number C1-CF-1489 failing in service. The part in 
question was not manufactured to the applicable de Havilland 
drawing. The unapproved latch plate was made of a shaft that was 
pressed into a plate, rather than being machined from bar material 
as one piece. The shaft and plate on the unapproved part can become 
separated or bent, resulting in rapid wear and failure of the part. 
This condition, if not corrected, could result in an un-commanded 
retraction of the flaps. This failure could lead to a stall during a 
landing approach.

Compliance

    (f) To address this problem, you must do the following, unless 
already done:

----------------------------------------------------------------------------------------------------------------
               Actions                             Compliance                            Procedures
----------------------------------------------------------------------------------------------------------------
(1) Inspect the flap operating        Within 50 hours time-in-service       Follow de Havilland Support Limited
 system to identify the part number    (TIS) after the effective date of     Technical News Sheet (TNS) CT(C1)
 (P/N) of the latch plate installed.   this AD or within 90 days after the   No 208 Issue 1, dated January 3,
 If latch plate P/N C1-CF-1489 is      effective date of this AD,            2009.
 installed, inspect the latch plate    whichever occurs first.
 to determine if it is in compliance
 with the design standard. An
 unapproved latch plate P/N C1-CF-
 1489 is made from two pieces
 pressed together while one that
 complies with the design standard
 is machined in one piece from bar
 material.
(2) If during the inspection          Before further flight after the       Follow de Havilland Support Limited
 required in paragraph (f)(1) of       inspection where the unapproved       TNS CT(C1) No 208 Issue 1, dated
 this AD an unapproved latch plate P/  latch plate P/N C1-CF-1849 was        January 3, 2009.
 N C1-CF-1489 is found, replace the    found.
 latch plate with a latch plate that
 complies with the design standard.
 The following U.S. standard
 hardware may be substituted for the
 hardware specified in the service
 information:
(i) 1/16'' diameter cotter pin that
 is P/N MS24665-153 (or equivalent)
 in place of split pin P/N SP90/C
 and;
(ii) Washer that is P/N MS15795-806B
 (or equivalent) in place of washer
 P/N SP13/B.
----------------------------------------------------------------------------------------------------------------

Alternative Methods of Compliance (AMOCs)

    (g) The Manager, Atlanta Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. Send information to 
Attn: Carey O'Kelley, Aerospace Engineer, FAA, Atlanta Aircraft 
Certification Office (ACO), 1701 Columbia Avenue, College Park, 
Georgia 30337; telephone: (404) 474-5543; fax: (404) 474-5606. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

Related Information

    (h) To get copies of the service information referenced in this 
AD, contact de Havilland Support Limited, Duxford Airfield, 
Cambridgeshire, CB22 4QR, England, phone: +44 (0) 1223 830090; fax: 
+44 (0) 1223 830085; e-mail: info@dhsupport.com; Internet: http://
www.dhsupport.com/. To view the AD docket, go to U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or 
on the Internet at http://www.regulations.gov.

    Issued in Kansas City, Missouri, on June 14, 2010.
Sandra J. Campbell,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-14989 Filed 6-18-10; 8:45 am]
BILLING CODE 4910-13-P

