[Federal Register Volume 61, Number 146 (Monday, July 29, 1996)]
[Proposed Rules]
[Pages 39364-39366]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-19150]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 61, No. 146 / Monday, July 29, 1996 /
Proposed Rules
[[Page 39364]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-09-AD]
RIN 2120-AA64
Airworthiness Directives; Shorts Model SD3-60 and 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 Shorts Model SD3-60 and
SD3-SHERPA series airplanes. This proposal would require 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.
The proposal also would require repair or replacement of any cracked/
corroded gland nut with a new nut. This proposal is prompted by a
report that, due to stress corrosion and cracking of the gland nut on
the shock absorber, the MLG collapsed on an in-service airplane. The
actions specified by the proposed AD are intended to prevent such
stress corrosion or cracking 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.
DATES: Comments must be received by September 9, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-09-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-09-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-09-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 certain Shorts Model SD3-60 and Model
SD3-SHERPA series airplanes. The CAA advises that it has received a
report indicating that the right-hand main landing gear (MLG) collapsed
on a Model SD3-60 series airplane. The cause of this failure has been
attributed to stress corrosion and cracking around the inner shoulder
radius of the gland nut on the shock absorber of the MLG. The effects
of such stress corrosion and cracking could lead to reduced structural
integrity of the gland nut. This condition, if not detected and
corrected in a timely manner, 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. -
The gland nut on the shock absorber of the MLG on certain Model
SD3-SHERPA series airplanes is identical to that on the affected Model
SD3-60 series airplanes. Therefore, Model SD3-SHERPA series airplanes
may be subject to the same unsafe condition revealed on Model SD3-60
series airplanes.
Explanation of Relevant Service Information -
Shorts has issued Service Bulletin SD360-32-34 (for Model SD3-60
series airplanes), and Service Bulletin SD3 SHERPA-32-2 (for Model SD3-
SHERPA series airplanes), both dated September 22, 1995. These service
bulletins describe procedures for 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, and repair or replacement of the
gland nut with a new nut, if necessary. Following accomplishment of the
inspection, these service bulletins also describe procedures for
applying grease to the threads of the cylinder and applying sealant to
the inner radius of the gland nut; these procedures will prevent stress
corrosion and cracking of the subject gland nut. The CAA classified
these service bulletins as mandatory and issued airworthiness
directives 010-09-95 (for Model SD3-60 series airplanes)
[[Page 39365]]
and 009-09-95 (for Model SD3-SHERPA series airplanes), 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, the
proposed AD would require 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, and repair or replacement of the
gland nut with a new nut, if necessary. Following the accomplishment of
the inspection, the proposed AD also would require applying grease to
the threads of the cylinder and applying sealant to the inner radius of
the gland nut. The actions would be required to be accomplished in
accordance with the service bulletins described previously.
Cost Impact -
The FAA estimates that 88 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
$26,400, 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-09-AD.
-Applicability: Model SD3-60 and Model SD3-SHERPA series
airplanes, as listed in Shorts Service Bulletin SD360-32-34 (for
Model SD3-60 series airplanes), and Shorts Service Bulletin SD3
SHERPA-32-2 (for Model SD3-SHERPA series airplanes), both dated
September 22, 1995; 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 (c) 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 stress corrosion or cracking of the gland nut on the
shock absorber of the main landing gear (MLG) and consequent reduced
structural integrity of the 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;
accomplish the following: -
(a) Within 90 days after the effective date of this AD, 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 Shorts Service Bulletin SD360-32-34 (for
Model SD3-60 series airplanes), and Shorts Service Bulletin SD3
SHERPA-32-2 (for Model SD3-SHERPA series airplanes), both dated
September 22, 1995, as applicable.
-Note 2: Shorts Service Bulletins SD360-32-34 and SD3 SHERPA-32-
2 reference Messier-Dowty Service Bulletin 32-78SD, dated July 19,
1995, as an additional source of service information.
-(1) If no crack and/or corrosion is detected, no further action
is required by paragraph (a) 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 service bulletin, prior
to further flight, replace the gland nut with a new gland nut, in
accordance with the applicable service bulletin. -
(b) Following accomplishment of paragraph (a) 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 Shorts Service Bulletin SD360-32-34 (for Model SD3-60 series
airplanes), and Shorts Service Bulletin SD3 SHERPA-32-2 (for Model
SD3-SHERPA series airplanes), both dated September 22, 1995, as
applicable. -
(c) 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 Inspector,
who may add comments and then send it to the Manager,
Standardization Branch, ANM-113. -
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113. -
[[Page 39366]]
(d) 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 23, 1996.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-19150 Filed 7-26-96; 8:45 am]
BILLING CODE 4910-13-P
