[Federal Register Volume 69, Number 73 (Thursday, April 15, 2004)]
[Proposed Rules]
[Pages 19956-19958]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-8534]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-235-AD]
RIN 2120-AA64


Airworthiness Directives; Short Brothers Model SD3-SHERPA Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Short Brothers Model SD3-
SHERPA series airplanes. This proposal would require a repetitive 
detailed inspection of the stub wing shear decks for corrosion and 
abnormal wear on and around the retaining pin in the main landing gear 
(MLG) forward pintle pin; and corrective action, if necessary. This 
proposed AD also provides an optional terminating action. These actions 
are necessary to detect and correct corrosion and abnormal wear to the 
top and bottom shear decks, which could result in damage to the MLG and 
consequent reduced controllability of the airplane on landing. This 
action is intended to address the identified unsafe condition.

DATES: Comments must be received by May 17, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-235-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2003-NM-235-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Short Brothers, Airworthiness & Engineering Quality, P.O. 
Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. This 
information may

[[Page 19957]]

be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, 
discuss a request to change the compliance time and a request to change 
the service bulletin reference as two separate issues.
     For each issue, state what specific change to 
the proposed AD is being requested.
     Include justification (e.g., reasons or data) 
for each request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2003-NM-235-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2003-NM-235-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain Short Brothers Model SD3-SHERPA series 
airplanes. The CAA advises that a report has been received stating that 
corrosion and abnormal wear to the top and bottom shear decks was found 
on and around the retaining pin in the main landing gear (MLG) forward 
pintle pin, due to loss of the retaining pin circlip, which allowed 
migration of the retaining pin. This condition, if not corrected, could 
result in damage to the MLG and consequent reduced controllability of 
the airplane on landing.

Explanation of Relevant Service Information

    Short Brothers has issued Short Brothers Service Bulletin SD3 
SHERPA-53-6, dated May 2003, which describes procedures for repetitive 
detailed inspections of the stub wing shear decks for corrosion and 
abnormal wear on and around the retaining pin in the MLG forward pintle 
pin; and corrective action, if necessary. The corrective action 
involves blending out corrosion, installing bushings in the affected 
shear deck, performing a visual inspection of the MLG pintle pin and 
sleeve for defects, and repairing any defects, as applicable. 
Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition. The CAA 
classified this service bulletin as mandatory and issued airworthiness 
directive 004-05-2003, dated August 2003, to ensure the continued 
airworthiness of these airplanes in the United Kingdom.
    Short Brothers has also issued Service Bulletin SD3 SHERPA-32-4, 
dated July 2003. That service bulletin describes procedures for 
replacement of the retaining pin and circlip with a new retaining pin, 
washer, castellated nut, and cotter pin, which would eliminate the need 
for repetitive detailed inspections of that retaining pin.

FAA's Conclusions

    This airplane model is manufactured in the United Kingdom and is 
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. The FAA has examined the 
findings of the CAA, 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.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require accomplishment of 
the actions specified in Short Brothers Service Bulletin SD3 SHERPA-53-
6 described previously, except as discussed below.

Differences Among Proposed Rule, British Airworthiness Directive, and 
Referenced Service Bulletin

    Although Service Bulletin SD3 SHERPA-53-6 specifies that operators 
may contact the manufacturer for disposition of certain corrective 
actions, this proposal would require operators to perform those actions 
per a method approved by either the FAA or the CAA or its delegated 
agent. In light of the type of repair that would be required to address 
the unsafe condition, and consistent with existing bilateral 
airworthiness agreements, we have determined that, for this proposed 
AD, a repair approved by either the FAA or the CAA (or its delegated 
agent) would be acceptable for compliance with this proposed AD.
    Operators should note that, although the referenced service 
bulletin describes procedures for reporting inspection results to the 
manufacturer, this proposed AD would not require that action. The FAA 
does not need this information from operators.
    Operators should note that the British airworthiness directive 
specifies that initial inspection of the stub wing shear decks for 
corrosion and abnormal wear on and around the retaining pin in the MLG 
forward pintle pin should be accomplished no later than October 31, 
2003 (which equates to a compliance time of 3 months after the 
effective date of the British airworthiness directive). In developing 
an appropriate compliance time for this proposed AD, the FAA considered 
not only the safety implications and the CAA's recommendations, but 
also the manufacturer's recommendations. In light of all of these 
factors, the FAA finds that the initial inspection must be accomplished 
within 6 months after the effective date of this AD, which represents 
an appropriate interval of time allowable for affected airplanes to

[[Page 19958]]

continue to operate without compromising safety.

Cost Impact

    The FAA estimates that 16 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 13 work 
hours per airplane per inspection to accomplish the proposed repetitive 
inspections, and that the average labor rate is $65 per work hour. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $13,520, or $845 per airplane, per 
inspection.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted. The cost impact figures 
discussed in AD rulemaking actions represent only the time necessary to 
perform the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.
    If an operator chooses to accomplish the optional terminating 
action rather than continue the repetitive detailed inspections, it 
would take about 12 work hours per stub wing (2 stub wings per 
airplane) to accomplish the replacement of the retaining pin and 
circlip with a new retaining pin with castellated nut and cotter pin; 
at an average labor rate of $65 per work hour. Required parts would 
cost about $2,400 per stub wing. Based on these figures, we estimate 
the cost of this optional terminating action to be $6,360 per airplane.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

Short Brothers PLC: Docket 2003-NM-235-AD.
    Applicability: Model SD3-SHERPA series airplanes, except those 
which have embodied Short Brothers Service Bulletin SD3 SHERPA-32-4, 
dated July 2003; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct corrosion and abnormal wear to the top and 
bottom shear decks, which could result in damage to the main landing 
gear (MLG) and consequent reduced controllability of the airplane on 
landing, accomplish the following:

Repetitive Inspections

    (a) Within 6 months after the effective date of this AD, and 
continuing at intervals not to exceed 6 months, perform a detailed 
inspection of the stub wing shear decks to detect corrosion and/or 
abnormal wear according to the Accomplishment Instructions of Short 
Brothers Service Bulletin SD3 SHERPA-53-6, dated May 2003.

    Note 1: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available 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.''


Repair

    (b) If any corrosion and/or abnormal wear is discovered during 
the inspection required by paragraph (a) of this AD, before further 
flight, perform corrective actions in accordance with the 
Accomplishment Instructions of Short Brothers Service Bulletin SD3 
SHERPA-53-6, dated May 2003, Part B and/or Part C as applicable; 
except where the service bulletin specifies that operators should 
contact the manufacturer for disposition of certain repair 
conditions, before further flight, repair those conditions per a 
method approved by the Manager, International Branch, ANM116, 
Transport Airplane Directorate, FAA; or the UK-CAA or its delegated 
agent.

Optional Terminating Action

    (c) Performance of the optional terminating action, which 
includes replacement of the retaining pin and circlip with a new 
retaining pin, washer, castellated nut and cotter pin per the 
Accomplishment Instructions of Short Brothers Service Bulletin SD3 
SHERPA-32-4, dated July 2003, terminates the requirement for 
repetitive detailed inspections specified in paragraph (a) of this 
AD.

No Reporting Requirement

    (d) Operators should note that, although Short Brothers Service 
Bulletin SD3 SHERPA-53-6, dated May 2003, describes procedures for 
reporting inspection results to the manufacturer, this AD does not 
require that action.

Alternative Methods of Compliance

    (e) In accordance with 14 CFR 39.19, the Manager, International 
Branch, ANM116, FAA, Transport Airplane Directorate, is authorized 
to approve alternative methods of compliance for this AD.

    Note 2: The subject of this AD is addressed in British 
airworthiness directive 004-05-2003, dated August 2003.


    Issued in Renton, Washington, on April 1, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-8534 Filed 4-14-04; 8:45 am]
BILLING CODE 4910-13-P