[Federal Register Volume 64, Number 120 (Wednesday, June 23, 1999)]
[Proposed Rules]
[Pages 33439-33441]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-15930]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-137-AD]
RIN 2120-AA64
Airworthiness Directives; Short Brothers Model SD3-30, SD3-60,
SD3 SHERPA, and SD3-60 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 all Short Brothers Model SD3-30,
SD3-60, SD3 SHERPA, and SD3-60 SHERPA series airplanes. This proposal
would require a one-time borescope inspection to detect corrosion of
the shear decks and ribs of the left and right stub wings, follow-on
corrective actions, if necessary; and drilling of new drain holes in
the lower shear decks. This proposal is prompted by issuance of
mandatory continuing airworthiness information by a foreign civil
airworthiness authority. The actions specified by the proposed AD are
intended to prevent corrosion of the stub wing shear decks and ribs,
which could result in cracking or failure of the stub wing structure.
DATES: Comments must be received by July 23, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-137-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
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 be examined at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager,
International Branch, ANM-116, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
227-2110; 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 notice may be changed in
light of the comments received.
[[Page 33440]]
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 notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 98-NM-137-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. 98-NM-137-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 all Short Brothers Model SD3-30, SD3-60, SD3
SHERPA, and SD3-60 SHERPA series airplanes. The CAA advises that
corrosion has been found in the area of the upper and lower shear
decks, and on the outer and inner ribs of the left and right stub
wings. The corrosion is believed to have been caused by the ingress of
water and debris into the area from the main landing gear wheels, and
lack of follow-on maintenance in ensuring that the area is dry and
clean. Corrosion of the stub wing shear decks and ribs, if not
corrected, could result in cracking or failure of the stub wing
structure.
Explanation of Relevant Service Information
Shorts has issued the following service bulletins, all dated
November 27, 1998:
SD330-53-68 (for Model SD3-30 series airplanes);
SD360-53-43, Revision 1 (for Model SD3-60 series
airplanes);
SD3 Sherpa-53-4 (for Model SD3 SHERPA series airplanes);
and
SD360-Sherpa-53-4 (for Model SD3-60 SHERPA series
airplanes).
These service bulletins describe procedures for a one-time
borescope inspection to detect corrosion of the shear decks and ribs of
the left and right stub wings, in the areas of the inner and outer
ribs, front and rear web plates, strut support bracket, and upper and
lower shear decks; and corrective actions, if necessary. The corrective
actions include additional inspections for corrosion in other areas;
removal of corrosion within acceptable limits; replacement of certain
components with new components; and, follow-on repetitive inspections
if corrosion is found. The service bulletins also describe procedures
for drilling of new drain holes in the lower shear decks. Additionally,
the service bulletins specify that operators are to report the results
of the initial inspection to the manufacturer.
Accomplishment of the actions specified in these service bulletins
is intended to adequately address the identified unsafe condition. The
CAA classified these service bulletins as mandatory and issued British
airworthiness directives 006-11-97, 006-11-98, 007-11-98, and 008-11-98
in order to assure the continued airworthiness of these airplanes in
the United Kingdom.
FAA's Conclusions
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. 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 the service bulletins described previously,
except as discussed below.
Differences Between Proposed Rule and Service Bulletins
Operators should note that, although the service bulletins specify
that the manufacturer may be contacted for disposition of certain
corrosion conditions, this proposal would require the repair of those
conditions to be accomplished in accordance with 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 identified unsafe
condition, and in consonance with existing bilateral airworthiness
agreements, the FAA has determined that, for this proposed AD, a repair
approved by either the FAA or the CAA would be acceptable for
compliance with this proposed AD.
Cost Impact
The FAA estimates that 112 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 100 work
hours per airplane to accomplish the proposed inspection, and that the
average labor rate is $60 per work hour.
Based on these figures, the cost impact of the proposed AD on U.S.
operators is estimated to be $672,000, or $6,000 per airplane.
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.
Regulatory Impact
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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.
[[Page 33441]]
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 98-NM-137-AD.
Applicability: All Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60
SHERPA series airplanes, certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (e) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent corrosion of the stub wing shear decks and ribs,
which could result in cracking or failure of the stub wing
structure, accomplish the following:
Inspection and Corrective Actions
(a) Within 6 months after the effective date of this AD, perform
a borescope inspection in the areas of the stub wing shear decks and
ribs to detect corrosion, and drill new drain holes in the lower
shear decks, in accordance with Part A of the Accomplishment
Instructions of the applicable Shorts Service Bulletin specified
below, all dated November 27, 1998 (hereinafter referred to as the
applicable service bulletin):
SD330-53-68 (for Model SD3-30 series airplanes);
SD360-53-43, Revision 1 (for Model SD3-60 series
airplanes);
SD3 Sherpa-53-4 (for Model SD3 SHERPA series
airplanes); and
SD360-Sherpa-53-4 (for Model SD3-60 SHERPA series
airplanes).
Note 2: In the case where no corrosion is detected during the
inspection described in Part A of the Accomplishment Instructions of
the applicable service bulletin, the service bulletin specifies
accomplishment of follow-on repetitive inspections of this area as
specified in Short Brothers Aircraft Maintenance Programme, Chapter
5-26-57.
(b) Except as provided by paragraph (c) of this AD: If any
corrosion is detected during the inspection required by paragraph
(a) of this AD, prior to further flight, accomplish corrective
actions (i.e., additional inspections, removal of corrosion,
replacement of components), as applicable, in accordance with Part B
of the Accomplishment Instructions of the applicable service
bulletin. Thereafter, repeat the inspection required by paragraph
(a) of this AD at intervals not to exceed 12 months.
(c) If any corrosion condition is found for which the applicable
service bulletin specifies that Short Brothers is to be contacted
for an appropriate repair action: Prior to further flight, repair in
accordance with a method approved by either the Manager,
International Branch, ANM-116, FAA, Transport Airplane Directorate,
or the Civil Aviation Authority (CAA) of the United Kingdom (or its
delegated agent).
Reporting Requirement
(d) Within 10 days after accomplishment of the initial
inspection required by paragraph (a) of this AD, or within 30 days
after the effective date of this AD, whichever occurs later, submit
a report of the inspection findings (positive or negative) to: Team
Leader, Service Engineering-Aerospace Customer Support Short
Brothers plc, Belfast, N. Ireland. Information collection
requirements contained in this regulation have been approved by the
Office of Management and Budget (OMB) under the provisions of the
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have
been assigned OMB Control Number 2120-0056.
Alternative Methods of Compliance
(e) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, International Branch, ANM-116.
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, International Branch, ANM-116.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the International Branch, ANM-116.
Special Flight Permits
(f) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Note 4: The subject of this AD is addressed in British
airworthiness directives 006-11-97, 006-11-98, 007-11-98, and 008-
11-98.
Issued in Renton, Washington, on June 17, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-15930 Filed 6-22-99; 8:45 am]
BILLING CODE 4910-13-U
