[Federal Register Volume 61, Number 83 (Monday, April 29, 1996)]
[Proposed Rules]
[Pages 18707-18709]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-10505]



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DEPARTMENT OF AGRICULTURE
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-49-AD]
RIN 2120-AA64


Airworthiness Directives; Jetstream Model 4101 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Jetstream Model 
4101 airplanes, that currently requires inspection to determine the 
number of hours time-in-service on the landing gear control unit, and 
modification of the cable (electrical wiring circuit) of the landing 
gear control unit. That AD was prompted by a report of failure of a 
micro-switch in the landing gear control unit. This action would 
require installation of a new landing gear control unit. This action 
also would expand the applicability of the existing AD to include 
additional airplanes. The actions specified by the proposed AD are 
intended to prevent uncommanded retraction of a landing gear, which 
could adversely affect airplane controllability.

DATES: Comments must be received by June 10, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-49-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 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.

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

[[Page 18708]]

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2148; 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-49-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-49-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On May 18, 1995, the FAA issued AD 95-09-03, amendment 39-9241 (60 
FR 28035, May 30, 1995), applicable to certain Jetstream Model 4101 
airplanes, to require inspection to determine the number of hours time-
in-service on the landing gear control unit, and modification of the 
cable (electrical wiring circuit) of the landing gear control unit. 
That action was prompted by a report of failure of a micro-switch in 
the landing gear control unit. The requirements of that AD are intended 
to prevent uncommanded retraction of a landing gear, which could 
adversely affect airplane controllability.
    In the preamble to AD 95-09-03, the FAA indicated that modification 
(Jetstream Modification JM41490) of the cable (electrical wiring 
circuit) of the landing gear control unit was considered ``interim 
action'' and that further rulemaking action was being considered. As a 
follow-on action from that determination, the FAA is now proposing 
additional, final action.

Explanation of Relevant Service Information

    Since the issuance of AD 95-09-03, Jetstream has issued Service 
Bulletin J41-32-044, dated September 22, 1995, which describes 
procedures for installation of a new improved landing gear control 
unit, identified as Modification JM41501. The procedures involve 
installing a new landing gear control unit that has revised switching. 
The new switching will prevent uncommanded landing gear retractions 
caused by spurious signals from single switch failures.
    The installation also involves revising certain wiring, which 
includes removing cables installed in accordance with Jetstream 
Modification JM41490. Additionally, the installation involves 
reallocating a spare pin in the airplane connector to prevent the 
operation of the old landing gear control unit in the event that one is 
inadvertently installed.
    Accomplishment of Modification JM41501 will positively address the 
unsafe condition identified as uncommanded retraction of a main landing 
gear.
    In addition, the effectivity listing of this service bulletin 
includes additional airplanes that were not previously affected by AD 
95-09-03, and removes certain others.
    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, classified this service bulletin as 
mandatory 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 the Requirements of the 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 supersede AD 95-09-03. For 
those airplanes subject to AD 95-09-03, it would continue to require an 
inspection to determine the number of hours time-in-service on the 
landing gear control unit, and modification of the cable (electrical 
wiring circuit) of the landing gear control unit. For those airplanes 
and certain others, it would require installation of a new improved 
landing gear control unit. The actions would be required to be 
accomplished in accordance with the Jetstream service bulletin 
described previously.
    The applicability of the proposed AD would include additional 
airplanes that have been identified to be subject to the same unsafe 
condition (an included in the effectivity listing of the Jetstream 
service bulletin).

Cost Impact

    There are approximately 44 Jetstream Model 4101 airplanes of U.S. 
registry that would be affected by this proposed AD.
    The actions that are currently required by AD 95-09-03, and 
retained in this proposed AD, take approximately 7 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
The required parts are provided by the manufacturer at no cost to the 
operator. Based on these figures, the cost impact on U.S. operators of 
the actions currently required is estimated to be $18,480, or $420 per 
airplane. The FAA has been advised that all affected U.S. operators 
have accomplished these requirements; therefore, there is no future 
cost impact of these requirements on current U.S. operators of these 
airplanes.
    The new installation that would be required by this proposed AD 
would take approximately 6 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Required parts would be 
provided at no cost to the operator. Based on these figures, the cost 
impact on U.S. operators of the proposed requirements of this AD is 
estimated to be $15,840, or $360 per airplane. This cost impact figure 
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.

[[Page 18709]]

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 removing amendment 39-9241 (60 FR 
28035, May 30, 1995), and by adding a new airworthiness directive (AD), 
to read as follows:

Jetstream Aircraft Limited: Docket 96-NM-49-AD. Supersedes AD 95-09-
03, Amendment 39-9241.

    Applicability: Model 4101 airplanes, constructor numbers 41001 
through 41073 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 (d) 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 uncommanded retraction of the landing gear, which can 
adversely affect airplane controllability, accomplish the following: 
-
    (a) For airplanes having constructor numbers 41001 through 41046 
inclusive, and 41048 through 41052 inclusive; equipped with either 
landing gear control unit part number 717701-1 or 717701-1 Mod A: 
Within 8 hours time-in-service after June 14, 1995 (the effective 
date of AD 95-09-03, amendment 39-9241), perform an inspection to 
determine the number of hours time-in-service on the landing gear 
control unit, in accordance with Jetstream Alert Service Bulletin 
J41-A32-042, dated April 13, 1995. -
    (1) For those airplanes on which the control unit has 
accumulated less than 200 hours time-in-service: Prior to further 
flight, modify the cable (electrical wiring circuit) of the landing 
gear control unit in accordance with the alert service bulletin. -
    (2) For those airplanes on which the control unit has 
accumulated 200 hours or more time-in-service: Within 50 hours time-
in-service or within 7 days after June 14, 1995 (the effective date 
of AD 95-09-03, amendment 39-9241), whichever occurs earlier, modify 
the cable (electrical wiring circuit) of the landing gear control 
unit in accordance with the alert service bulletin. -
    (b) For airplanes having constructor numbers 41001 through 41073 
inclusive: Within 6 months after the effective date of this AD, 
install a new improved landing gear control unit and modify the 
wiring, in accordance with Jetstream Service Bulletin J41-32-044, 
dated September 22, 1995. -
    (c) As of the effective date of this AD, no person shall install 
a landing gear control unit having part number 717701-1 or 717701-1 
Mod A, on any airplane. -
    (d) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Manager, Standardization Branch, ANM-113. -
    (e) 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 April 23, 1996.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-10505 Filed 4-26-96; 8:45 am]
BILLING CODE 4910-13-P