[Federal Register Volume 69, Number 140 (Thursday, July 22, 2004)]
[Proposed Rules]
[Pages 43779-43783]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-16682]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18661; Directorate Identifier 2003-NM-273-AD]
RIN 2120-AA64


Airworthiness Directives; Short Brothers Model SD3-60, SD3-
SHERPA, and SD3-60 SHERPA Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for certain Short Brothers Model SD3-60, SD3-SHERPA, and 
SD3-60 SHERPA series airplanes. That AD currently requires a one-time 
inspection to detect cracks and/or corrosion of the gland nut on the 
shock absorber of the main landing gear (MLG), and follow-on actions. 
That AD also requires repair or replacement of any cracked/corroded 
gland nut with a new nut. This proposed AD would add airplanes to the 
applicability; add repetitive inspections and corrective actions; and 
provide an optional action that would end the repetitive inspections. 
This proposed AD is prompted by reports of cracked aluminum alloy gland 
nuts that had been inspected previously using the existing AD. We are 
proposing this AD to prevent failure of the aluminum alloy gland nut on 
the MLG shock absorber, which could cause the MLG to collapse.

DATES: We must receive comments on this proposed AD by August 23, 2004.

ADDRESSES: Use one of the following addresses to submit comments 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

[[Page 43780]]

Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
     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. You can get 
the service information identified in this proposed AD from Short 
Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport 
Road, Belfast BT3 9DZ, Northern Ireland.
    You may examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Todd Thompson, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 
227-1175; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-18661; 
Directorate Identifier 2003-NM-273-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://
http://dms.dot.gov">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 our 
docket 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.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You may examine the AD docket in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the DOT street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after the DMS 
receives them.

Discussion

    On October 18, 1996, we issued AD 96-22-09, amendment 39-9797 (61 
FR 57311, November 6, 1996), for certain Short Brothers Model SD3-60 
and SD3-SHERPA series airplanes. That AD requires a one-time inspection 
to detect cracks and/or corrosion of the gland nut on the shock 
absorber of the main landing gear (MLG), and follow-on actions. That AD 
also requires repair or replacement of any cracked/corroded gland nut 
with a new nut. That AD was prompted by a report indicating that, due 
to stress corrosion and cracking of the gland nut on the shock 
absorber, the MLG collapsed on an in-service airplane. We issued that 
AD to detect and correct such stress corrosion or cracking in a timely 
manner and consequent reduced structural integrity of the gland nut, 
which could result in separation of the shock absorber cylinder from 
the MLG shock absorber body and, consequently, lead to the collapse of 
the MLG during landing.

Actions Since Existing AD Was Issued

    Since we issued AD 96-22-09, the Civil Aviation Authority (CAA), 
which is the airworthiness authority for the United Kingdom, notified 
us of cracked aluminum alloy gland nuts on the MLG shock absorber of a 
Short Brothers Model SD3-60 and an SD3-SHERPA series airplane. These 
airplanes had been inspected using AD 96-22-09. The cracks were caused 
by corrosion around the inner shoulder radius of the gland nut. This 
condition, if not corrected, could cause the aluminum alloy gland nut 
on the MLG shock absorber to fail. A failed gland nut could cause the 
MLG to collapse.
    The gland nut that is installed on certain Short Brothers Model 
SD3-60 SHERPA series airplanes is almost identical to that on the Model 
SD3-60 and SD3-SHERPA series airplanes that had the cracked gland nuts. 
Therefore, the Model SD3-60 SHERPA series airplanes may be subject to 
the same unsafe condition that occurred on the Model SD3-60 and SD3-
SHERPA series airplanes.

Relevant Service Information

    Short Brothers has issued the following service bulletins:
     Service Bulletin SD360 SHERPA-32-1, dated June 30, 2003, 
for Model SD3-60 SHERPA series airplanes;
     Service Bulletin SD360-32-34, Revision 1, dated June 30, 
2003, for Model SD3-60 series airplanes; and
     Service Bulletin SD3 SHERPA-32-2, Revision 1, dated June 
30, 2003, for Model SD3-SHERPA series airplanes.
    These service bulletins describe procedures for doing a detailed 
inspection for corrosion and/or cracks of the aluminum alloy gland nut, 
part number (P/N) 200920604, on the MLG shock absorber, and procedures 
for doing any necessary corrective actions. The corrective actions 
include the following:
     Repairing the gland nut if only corrosion is found. The 
repair involves machining the inner faces and radius of the gland nut 
to remove the corrosion. If the gland nut is machined to a certain 
limit and the corrosion has not been removed, the gland nut must be 
replaced with a new gland nut.
     Replacing the gland nut with a new aluminum alloy gland 
nut having the same part number if any cracking is found or if the 
repair does not remove the corrosion.
    The Short Brothers service bulletins refer to Messier-Dowty Service 
Bulletin 32-78SD, Revision 1, dated December 9, 2002. This Messier-
Dowty service bulletin gives additional information about how to do the 
inspection and corrective actions.
    Accomplishing the actions specified in these service bulletins will 
address

[[Page 43781]]

the unsafe condition adequately. The CAA mandated Short Brothers 
Service Bulletin SD360 SHERPA-32-1 and Messier-Dowty Service Bulletin 
32-78SD, and issued British airworthiness directive 008-06-2003, to 
ensure the continued airworthiness of these airplanes in the United 
Kingdom.
    The Short Brothers service bulletins also refer to Messier-Dowty 
Service Bulletin 32-80SD, dated August 31, 2000, which describes 
procedures for installing a new steel gland nut that has improved 
resistance to corrosion. Accomplishing this Messier-Dowty service 
bulletin eliminates the need to repeat the inspections described in the 
Short Brothers service bulletins.

FAA's Determination and Requirements of the Proposed AD

    These airplane models are manufactured in the United Kingdom 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. Pursuant 
to this bilateral airworthiness agreement, the CAA has kept the FAA 
informed of the situation described above. We have examined the CAA's 
findings, evaluated all pertinent information, and determined that AD 
action is necessary for airplanes of this type design that are 
certificated for operation in the United States.
    Therefore, we are proposing to supersede AD 96-22-09 to continue to 
require a one-time inspection to detect cracks and/or corrosion of the 
gland nut on the shock absorber of the MLG, and follow-on actions. This 
proposed AD would also:

 Add airplanes to the applicability;
 Add repetitive inspections and corrective actions; and
 Provide an optional action that would end the repetitive 
inspections.
    The proposed AD would require you to use the service information 
described previously to perform these actions, except as discussed 
under ``Difference Between the Proposed AD and the British 
Airworthiness Directive.''

Difference Between the Proposed AD and the British Airworthiness 
Directive

    The British airworthiness directive applies only to Short Brothers 
Model SD3-60 SHERPA series airplanes; however, the unsafe condition 
also exists on Short Brothers Model SD3-60 and SD3-SHERPA series 
airplanes. Therefore, this proposed AD would apply to any of these 
three airplane models with an aluminum alloy gland nut, P/N 200920604, 
on the MLG shock absorber. This difference has been coordinated with 
the CAA.

Change to Applicability of Existing AD

    We have changed the way the airplane models are listed in the 
Applicability section of the proposed AD. This change identifies the 
airplane models as they are published in the most recent type 
certificate data sheet.

Additional Change to Existing AD

    This proposed AD would retain all requirements of AD 96-22-09. 
Since AD 96-22-09 was issued, the AD format has been revised, and 
certain paragraphs have been rearranged. As a result, the corresponding 
paragraph identifiers have changed in this proposed AD, as listed in 
the following table:

                      Revised Paragraph Identifiers
------------------------------------------------------------------------
                                            Corresponding requirement in
        Requirement in AD 96-22-09                this proposed AD
------------------------------------------------------------------------
paragraph (a).............................  paragraph (g)
paragraph (b).............................  paragraph (h)
paragraph (c).............................  paragraph (k)
------------------------------------------------------------------------

Change to Labor Rate

    We have reviewed the figures we have used over the past several 
years to calculate AD costs to operators. We have increased the labor 
rate used in these calculations from $60 per work hour to $65 per work 
hour. This new figure accounts for various inflationary costs in the 
airline industry. The cost information, below, reflects this increase 
in the hourly labor rate.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this proposed AD.

                                                 Estimated Costs
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                                             Average                                     Number of
                                    Work      labor                          Cost per      U.S.-
             Action                hours     rate per         Parts          airplane    registered   Fleet cost
                                               hour                                      airplanes
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Inspections required by AD 96-           5        $65  N/A...............         $325           58      $18,850
 22-095.
Proposed inspections (per                5         65  N/A...............          325           85       26,625
 inspection cycle).
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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.
    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 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 removing amendment 39-9797 (61 FR 
57311, November 6, 1996) and adding the following new airworthiness 
directive (AD):


[[Page 43782]]


Short Brothers PLC: Docket No. FAA-2004-18661; Directorate 
Identifier 2003-NM-273-AD.

Comments Due Date

    (a) The Federal Aviation Administration must receive comments on 
this AD action by August 23, 2004.

Affected ADs

    (b) This AD supersedes AD 96-22-09, amendment 39-9797.

Applicability

    (c) This AD applies to Short Brothers Model SD3-60, SD3-SHERPA, 
and SD3-60 SHERPA series airplanes, that are equipped with aluminum 
alloy gland nuts, part number (P/N) 200920604, on the main landing 
gear (MLG) shock absorber; certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of cracked aluminum alloy 
gland nuts on the MLG shock absorber that had been previously 
inspected using AD 96-22-09. We are issuing this AD to prevent 
failure of the aluminum alloy gland nut on the MLG shock absorber, 
which could cause the MLG to collapse.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Service Bulletin Reference

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of the applicable service bulletin or 
service bulletins listed in the following paragraphs:
    (1) For the requirements specified in paragraphs (g) and (h) of 
this AD, which are restated from AD 96-22-09, use the applicable 
service bulletin in Table 1 of this AD.

                      Table 1.--Short Brothers Service Bulletins for Restated Requirements
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                Model                     Service bulletin             Revision                   Date
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SD3-60 series airplanes.............  SD360-32-34............  Original...............  September 22, 1995.
SD3-60 series airplanes.............  SD360-32-34............  1......................  June 30, 2003.
SD3-SHERPA series airplanes.........  SD3 SHERPA-32-2........  Original...............  September 22, 1995.
SD3-SHERPA series airplanes.........  SD3 SHERPA-32-2........  1......................  June 30, 2003.
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    (2) For the new requirements specified in paragraphs (i) and (j) 
of this AD, use the applicable service bulletin in Table 2 of this 
AD.

                         Table 2.--Short Brothers Service Bulletins for New Requirements
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                Model                     Service bulletin             Revision                   Date
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SD3-60 SHERPA series airplanes......  SD360 SHERPA-32-1......  Original...............  June 30, 2003.
SD3-SHERPA series airplanes.........  SD3 SHERPA-32-2........  1......................  June 30, 2003.
SD3-60 series airplanes.............  SD360-32-34............  1......................  June 30, 2003.
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    Note 1: The Messier-Dowty service bulletins listed in Table 3 of 
this AD are additional sources of service information for certain 
actions in the Short Brothers Service Bulletins.


           Table 3.--Additional Sources of Service Information
------------------------------------------------------------------------
                                   Is an additional source of service
  This Messier-Dowty service      information for these Short Brothers
          bulletin--                      service bulletins--
------------------------------------------------------------------------
32-78SD, dated July 19, 1995.  SD360-32-34, dated July 19, 1995.
                               SD3 SHERPA-32-2, dated July 19, 1995.
32-78SD, Revision 1, dated     SD 360-32-34, Revision 1, dated June 30,
 December 9, 2002.              2003.
                               SD3 SHERPA-32-1, dated June 30, 2003.
32-80SD, dated August 31,      SD3 SHERPA-32-1, dated June 30, 2003.
 2000.                         SD3 SHERPA-32-2, Revision 1, dated June
                                30, 2003.
                               SD360-32-34, Revision 1, dated June 30,
                                2003.
------------------------------------------------------------------------

Restatement of the Requirements of AD 96-22-09

    (g) For Model SD3-60 series airplanes and Model SD3-SHERPA 
series airplanes: Within 90 days after December 11, 1996 (the 
effective date AD 96-22-09), perform a one-time visual and 
fluorescent dye penetrant inspection to detect cracks and/or 
corrosion of the gland nut on the shock absorber of the MLG, in 
accordance with the applicable service bulletin.
    (1) If no crack and/or corrosion is detected, no further action 
is required by paragraph (g) of this AD.
    (2) If no crack is detected, but corrosion is detected that is 
within the limits specified in the service bulletin, prior to 
further flight, repair the gland nut in accordance with the 
applicable service bulletin.
    (3) If any crack is detected, or if any corrosion is detected 
that is outside the limits specified in the applicable service 
bulletin, prior to further flight, replace the gland nut with a new 
gland nut, in accordance with the applicable service bulletin.
    (h) Following accomplishment of paragraph (g) of this AD, prior 
to further flight, apply grease to the threads of the cylinder, and 
apply sealant to the inner radius of the gland nut, in accordance 
with the applicable service bulletin.

New Requirements of this AD

Detailed Inspection and Corrective Action

    (i) For all airplanes: Within 4 months after the effective date 
of this AD, do a detailed inspection of the P/N 200920604 gland nut 
on the MLG shock absorber for corrosion and/or cracking, and do any 
applicable corrective action before further flight, in accordance 
with the applicable service bulletin. Repeat the inspection at 
intervals not to exceed 12 months.

    Note 2: For the purposes of this AD, a detailed inspection is: 
``An intensive visual examination of a specific structural area, 
system, installation, or assembly to detect damage, failure, or 
irregularity. Available

[[Page 43783]]

lighting is normally supplemented with a direct source of good 
lighting at intensity deemed appropriate by the inspector. 
Inspection aids such as mirror, magnifying lenses, etc., may be 
used. Surface cleaning and elaborate access procedures may be 
required.''

Optional Terminating Action

    (j) Replacing the aluminum alloy gland, P/N 200920604, with a 
new steel gland nut, P/N 200920639, in accordance with the 
applicable service bulletin, terminates the requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (k) The Manager, International Branch, ANM-116, Transport 
Airplane Directorate, FAA, has the authority to approve AMOCs for 
this AD, if requested in accordance with the procedures found in 14 
CFR 39.19.

Related Information

    (l) British airworthiness directive 008-06-003 also addresses 
the subject of this AD.

    Issued in Renton, Washington, on July 9, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-16682 Filed 7-21-04; 8:45 am]
BILLING CODE 4910-13-P