[Federal Register Volume 61, Number 135 (Friday, July 12, 1996)]
[Proposed Rules]
[Pages 36669-36671]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17739]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-08-AD]
RIN 2120-AA64
Airworthiness Directives; Shorts Model SD3-30, -60, and -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 Shorts Model SD3-30, -60, and
-SHERPA series airplanes. This proposal would require a visual
inspection to detect signs of exfoliation corrosion on the brackets of
the flap hydraulic units, and rework or replacement of corroded
brackets. This proposal is prompted by a report that exfoliation
corrosion was found on the brackets of the flap hydraulic units. The
actions specified by the proposed AD are intended to prevent such
corrosion, and consequent reduced structural integrity of the brackets
of the flap hydraulic units, which could result in the loss of the flap
control and consequent reduced controllability of the airplane.
DATES: Comments must be received by August 29, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-08-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 PLC, 2011 Crystal Drive, Suite 713,
Arlington, Virginia 22202-3719.
This information may be examined at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Phil Forde, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2146; fax (206) 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.
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 96-NM-08-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-103, Attention: Rules
Docket No. 96-NM-08-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The Civil Aviation Authority (CAA), which is the airworthiness
authority for the United Kingdom, recently notified the FAA that an
unsafe condition may exist on all Short Brothers Model SD3-30, -60, and
-SHERPA series airplanes. The CAA advises that, during a maintenance
check on a Model SD3-30 series airplane, exfoliation corrosion was
found on the brackets of the flap hydraulic units. The effects of such
corrosion could lead to the reduced structural integrity of the
brackets of the flap hydraulic units. This condition, if not detected
and corrected in a timely manner, could result in the loss of the flap
control and consequent reduced controllability of the airplane.
The brackets of the flap hydraulic units on certain Model SD3-60,
and -SHERPA series airplanes are identical to those on the affected
Model SD3-30 series airplanes. Therefore, all of these models may be
subject to the same unsafe condition.
[[Page 36670]]
Explanation of Relevant Service Information
Shorts has issued Service Bulletin SD330-27-34 (for Model SD3-30
series airplanes), Service Bulletin SD360-27-24 (for Model SD3-60
series airplanes), and Service Bulletin SD3 SHERPA-27-1 (for Model SD3-
SHERPA series airplanes), all dated September 12, 1995. These service
bulletins describe procedures for a visual inspection to detect signs
of exfoliation corrosion on the brackets of the flap hydraulic units,
and rework or replacement of corroded brackets. The CAA classified
these service bulletins as mandatory and issued airworthiness
directives 005-09-95 (for Model SD3-30 series airplanes), 007-09-95
(for Model SD3-60 series airplanes), and 008-09-95 (for Model SD3-
SHERPA series airplanes), in order to assure the continued
airworthiness of these airplanes in the United Kingdom.
FAA's Conclusion
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, the
proposed AD would require a visual inspection to detect signs of
exfoliation corrosion on the brackets of the flap hydraulic units, and
rework or replacement of corroded brackets. The actions would be
required to be accomplished in accordance with the service bulletins
described previously.
Cost Impact
The FAA estimates that 138 airplanes (50 Model SD3-30 series
airplanes, 72 Model SD3-60 series airplanes, and 16 Model SD3-SHERPA
series airplanes) of U.S. registry would be affected by this proposed
AD, that it would take approximately 5 work hours per airplane to
accomplish the proposed actions, 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 $41,400, or $300 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.
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 96-NM-08-AD.
Applicability: All Model SD3-30, -60, and -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 (b) 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 on the brackets of the flap hydraulic
units, and consequent reduced structural integrity of those
brackets, which could result in the loss of the flap control and
consequent reduced controllability of the airplane; accomplish the
following:
(a) Within 90 days after the effective date of this AD, perform
a visual inspection to detect signs of exfoliation corrosion on the
brackets of the flap hydraulic units, in accordance with Shorts
Service Bulletin SD330-27-34 (for Model SD3-30 series airplanes);
Shorts Service Bulletin SD360-27-24 (for Model SD3-60 series
airplanes); or Short Service Bulletin SD3 SHERPA-27-1 (for Model
SD3-SHERPA series airplanes); all dated September 12, 1995; as
applicable.
(1) If no corrosion is detected, accomplish paragraph (a)(1)(i)
or (a)(1)(ii) of this AD, as applicable.
(i) For Model SD3-30 and -60 series airplanes: Repeat the visual
inspection thereafter at intervals not to exceed 2,400 hours or 12
months, whichever occurs first.
(ii) For Model SD3-SHERPA series airplanes: Repeat the visual
inspection thereafter at intervals not to exceed 12 months. -
(2) If any corrosion is detected and it is within the limits
specified in the applicable service bulletin, prior to further
flight, rework the subject area in accordance with the applicable
service bulletin. After accomplishment of the rework, accomplish
paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as applicable. -
(i) For Model SD3-30 and -60 series airplanes: Repeat the visual
inspection thereafter at intervals not to exceed 600 hours or 6
months, whichever occurs first. -
(ii) For Model SD3-SHERPA series airplanes: Repeat the visual
inspection thereafter at intervals not to exceed 6 months.
(3) If any corrosion is detected and it is outside the limits
specified in the applicable service bulletin, prior to further
flight, replace the bracket with a new bracket in accordance with
the applicable service bulletin.
(b) 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, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate. Operators shall submit their
requests through an appropriate FAA Principal Maintenance
[[Page 36671]]
Inspector, who may add comments and then send it to the Manager,
Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(c) 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.
Issued in Renton, Washington, on July 8, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-17739 Filed 7-11-96; 8:45 am]
BILLING CODE 4910-13-U