[Federal Register Volume 61, Number 225 (Wednesday, November 20, 1996)]
[Rules and Regulations]
[Pages 58981-58983]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29261]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-258-AD; Amendment 39-9817; AD 96-23-12]
RIN 2120-AA64
Airworthiness Directives; Jetstream Model 4101 Airplanes
AGENCY: Federal Aviation Administration, DOT.
[[Page 58982]]
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to certain Jetstream Model 4101 airplanes. This action
requires a one-time check of the left and right main landing gear leg
assemblies to determine whether certain assemblies have been installed;
and the replacement of certain discrepant retaining bolts on these
assemblies with correctly manufactured bolts. This amendment is
prompted by a report indicating that some of these retaining bolts have
failed during the assembly and installation of a main landing gear
unit, due to an incorrect process that was used during the manufacture
of the bolts. The actions specified in this AD are intended to prevent
structural damage to the main landing gear due to failure of the
retaining bolts which, if not corrected, could result in reduced
controllability of the airplane during takeoff, landing, and taxiing.
DATES: Effective December 5, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of December 5, 1996.
Comments for inclusion in the Rules Docket must be received on or
before January 21, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-258-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from
Jetstream Aircraft, Inc., P.O. Box 16029, Dulles International Airport,
Washington, DC 20041-6029. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2148; fax (206) 227-1149.
SUPPLEMENTARY INFORMATION: 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 Jetstream Model
4101 airplanes. The CAA advises that it has received a report
indicating that some of the retaining bolts that secure the uplock
attachment plate to the cylinder of the shock absorber strut on left
and right main landing gear leg assemblies of certain Model 4101
airplanes failed during the assembly and installation of a main landing
gear unit; these failures occurred as these bolts were being tightened
to the torque specified for them.
An investigation revealed that the discrepant bolts were
incorrectly heat-treated during manufacture, which causes them to be
less capable of sustaining required loads. Other incorrectly heat-
treated retaining bolts have been installed on airplanes now in
service. Continued use of these bolts could result in failure of the
bolts and consequent structural damage to the main landing gear. This
condition, if not corrected, could result in reduced controllability of
the airplane during takeoff, landing, and taxiing.
Explanation of Relevant Service Information
Jetstream has issued Service Bulletin J41-32-054, dated July 4,
1996, which describes procedures for a one-time check of the serial
numbers on the left and right main landing gear leg assemblies to
determine whether assemblies with discrepant retaining bolts have been
installed. This service bulletin also describes procedures for
replacing discrepant retaining bolts that secure the uplock attachment
plate to the cylinder of the shock absorber strut on those assemblies.
The replacement bolts have been correctly heat-treated. (The Jetstream
service bulletin references APPH Precision Hydraulics Ltd. Service
Bulletin AIR83090-32-03, dated June 1996, as an additional source of
procedural service information for the one-time check and the
replacement of discrepant bolts.)
The CAA classified this service bulletin as mandatory and issued
CAA airworthiness directive 004-07-96, dated July 23, 1996, in order to
assure the continued airworthiness of these airplanes in the United
Kingdom.
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 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, this AD is being issued to prevent failure of the
retaining bolts and consequent structural damage to the main landing
gear leg assemblies which, if not corrected, could result in reduced
controllability of the airplane during takeoff, landing, and taxiing.
This AD requires a one-time check of the serial numbers of the left and
right main landing gear leg assemblies on certain Jetstream Model 4101
airplanes. It also requires the replacement of discrepant retaining
bolts that secure the uplock attachment plate to the cylinder of the
shock absorber strut on certain main landing gear leg assemblies with
bolts that have been correctly heat-treated. The actions are required
to be accomplished in accordance with the Jetstream service bulletin
described previously.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic,
[[Page 58983]]
environmental, and energy aspects of the rule that might suggest a need
to modify the 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 that summarizes each FAA-
public contact concerned with the substance of this AD will be filed in
the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 96-NM-258-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, may be obtained from the Rules Docket at the
location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 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:
96-23-12 Jetstream Aircraft Limited: Amendment 39-9817. Docket 96-
NM-258-AD.
Applicability: Model 4101 airplanes having constructor numbers
41081 through 41086 inclusive, certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 failure of the retaining bolts and consequent
structural damage to the main landing gear, which could result in
reduced controllability of the airplane during takeoff, landing, and
taxiing, accomplish the following:
(a) Within 60 days after the effective date of this AD, perform
a one-time check of the left and right main landing gear leg
assemblies to determine the serial numbers on these units, in
accordance with Jetstream Service Bulletin J41-32-054, dated July 4,
1996.
Note 2: The Jetstream service bulletin references APPH Precision
Hydraulics Ltd. Service Bulletin AIR83090-32-03, dated June 1996, as
an additional source of procedural service information for the one-
time check and replacement of discrepant bolts.
(1) If the serial number indicates that the unit is not subject
to having discrepant retaining bolts installed, no further action is
required for that unit.
(2) If the serial number indicates that the unit is subject to
having discrepant retaining bolts installed, prior to further
flight, replace each retaining bolt that secures the uplock
attachment plate to the cylinder of the shock absorber strut of that
unit with a bolt that is correctly heat-treated, in accordance with
the Jetstream 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, 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.
(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.
(d) The one-time check and the replacement shall be done in
accordance with Jetstream Service Bulletin J41-32-054, dated July 4,
1996. This incorporation by reference was approved by the Director
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from Jetstream Aircraft, Inc., P.O.
Box 16029, Dulles International Airport, Washington, DC 20041-6029.
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(e) This amendment becomes effective on December 5, 1996.
Issued in Renton, Washington, on November 7, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-29261 Filed 11-19-96; 8:45 am]
BILLING CODE 4910-13-U
