[Federal Register Volume 61, Number 225 (Wednesday, November 20, 1996)]
[Proposed Rules]
[Pages 59038-59040]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29606]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-97-AD]
RIN 2120-AA64


Airworthiness Directives; Jetstream Model 4101 Airplanes

AGENCY: Federal Aviation Administration, DOT.


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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 Jetstream Model 4101 
airplanes. This proposal would require a one-time inspection for damage 
caused by arcing and overheating of the electrical ground posts 
(``earth posts'') and ground cables for the direct current (DC) power 
generation and propeller de-icing systems of the left and right 
engines; and repair and replacement, if necessary. The proposed AD also 
would require the eventual replacement of earth posts with new posts. 
This proposal is prompted by reports indicating that earth posts on 
some airplanes have failed due to overheating. The actions specified by 
the proposed AD are intended to prevent potential consequences of 
overheating, such as failure of the DC power generation and propeller 
de-icing systems.

DATES: Comments must be received by December 30, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-97-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, 
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-97-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-97-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 Jetstream Model 4101 airplanes. 
The CAA advises that it has received reports indicating that electrical 
ground posts (``earth posts'') for the direct current (DC) power 
generation and propeller de-icing systems of the left and right engines 
have failed on some Model 4101 airplanes due to overheating. Ground 
cables (``earth cables'') from the DC power generation and de-icing 
systems are attached to the earth post, and when the earth post is 
loosened, it can overheat and fail. Overheating of the earth post, if 
not corrected, could have several consequences, such as:

--Failure of the DC power generation and de-icing systems,
--Creation of a fire hazard,
--Incorrect actions by the flight crew who are relying on engine data 
that could be distorted by a discrepant earth post; and
--Structural erosion, which can weaken adjacent structures.

Explanation of Relevant Service Information

    Jetstream has issued Service Bulletin J41-24-033, Revision 2, dated 
January 24, 1996, which describes procedures for a one-time inspection 
to detect damage and signs of overheating of the earth posts, earth 
post brackets, and earth cables of the left and right engines. It also 
describes procedures for repair and replacement of discrepant posts; as 
well as for replacement of discrepant earth cables. The CAA classified 
this service bulletin as mandatory and issued British airworthiness 
directive 007-01-96, dated February 22, 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 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 require a one-time 
inspection to detect damage or signs of overheating of the earth posts 
and earth cables for the DC power generation and propeller de-icing 
systems of the left and right engines. It would require, prior to 
further flight, repair and replacement of damaged earth posts with new 
posts, and replacement of damaged earth cables with new or serviceable 
cables. The proposed AD also would require the eventual replacement of 
all earth posts on all affected airplanes. The repair of damaged earth 
posts would be required to be accomplished in accordance with a method 
approved by the FAA; all other actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Cost Impact

    The FAA estimates that 44 Jetstream Model 4101 airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 8 work hours per airplane to accomplish 
the proposed inspection, at an average labor

[[Page 59040]]

rate of $60 per work hour. Based on these figures, the cost impact of 
the proposed inspection on U.S. operators is estimated to be $21,120, 
or $480 per airplane.
    It would take approximately 8 work hours per airplane to accomplish 
the proposed replacement of earth posts, at an average labor rate of 
$60 per work hour. Required parts would be provided by the manufacturer 
at no charge. Based on these figures, the cost impact of the proposed 
replacement on U.S. operators is estimated to be $21,120, or $480 per 
airplane.
    The cost impact figures discussed above are 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:

Jetstream Aircraft Limited: Docket 96-NM-97-AD.

    Applicability: Model 4101 airplanes having constructor number 
41004 through 41074 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 (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 overheating of the electrical ground posts (``earth 
posts'') for the direct current (DC) power generation and de-icing 
systems of the left and right engines, which could result in such 
things as failure of these systems, accomplish the following:
    (a) Within 300 hours time-in-service after the effective date of 
this AD, accomplish the actions specified in paragraphs (a)(1) and 
(a)(2) of this AD on both the left and right engines:
    (1) Inspect each earth post and earth post bracket to detect 
damage caused by arcing, signs that it has been overheated, and 
lateral movement of the earth post, in accordance with Part A of 
Jetstream Service Bulletin J41-24-033, Revision 2, dated January 24, 
1996. If any discrepancy is detected, prior to further flight, 
accomplish both paragraphs (a)(1)(i) and (a)(1)(ii) of this AD:
    (i) Repair any damage and lateral movement in accordance with a 
method approved by the Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate; and
    (ii) Replace the earth post with a new earth post in accordance 
with Part B of the service bulletin.
    (2) Inspect each ground cable (earth cable) for the DC power 
generation and propeller de-icing systems to detect damage caused by 
arcing, and signs that the terminal tags and cable insulation have 
been overheated, in accordance with Part A of the service bulletin. 
If any discrepancy is detected, prior to further flight, replace the 
earth cable with a new or serviceable cable, in accordance with Part 
A of the service bulletin.
    (b) Within 6 months after the effective date of this AD, replace 
each earth post with a new earth post, in accordance with Part B of 
Jetstream Service Bulletin J41-24-033, Revision 2, dated January 24, 
1996. Any earth post that is replaced in accordance with paragraph 
(a)(1)(ii) of this AD need not be replaced again under the 
requirements of this paragraph.
    (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. 
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 Standardization Branch, ANM-113.

    (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 November 13, 1996.
James V. Devany, Acting Manager,
Transport Airplane Directorate, Dircraft Certification Service.
[FR Doc. 96-29606 Filed 11-19-96; 8:45 am]
BILLING CODE 4910-13-P