[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