[Federal Register Volume 61, Number 133 (Wednesday, July 10, 1996)]
[Proposed Rules]
[Pages 36308-36310]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17536]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-271-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 adoption of a new airworthiness 
directive (AD) that is applicable to certain Jetstream Model 4101 
series airplanes. This proposal would require a high frequency eddy 
current inspection to detect cracks of the boundary angle and joint 
angle of the rear pressure bulkhead, and repair, if necessary. This 
proposal also would require modification of the rear pressure bulkhead 
of the fuselage. This proposal is prompted by a report of fatigue 
cracking in the rear pressure bulkhead of the fuselage. The actions 
specified by the proposed AD are intended to prevent such fatigue 
cracking, which could result in reduced structural integrity of the 
fuselage and, consequently, lead to the rapid decompression of the 
pressurized area of the airplane.

DATES: Comments must be received by August 19, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103,

[[Page 36309]]

Attention: Rules Docket No. 95-NM-271-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 95-NM-271-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. 95-NM-271-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, during fatigue tests on a Model 4101 test 
article, cracking was found in the rear pressure bulkhead of the 
fuselage. Such cracking is attributed to fatigue-related stress. 
Fatigue-related cracking in the rear pressure bulkhead, if not detected 
and correct in a timely manner, could result in reduced structural 
integrity of fuselage and, consequently, lead to the rapid 
decompression of the pressurized area of the airplane.

Explanation of Relevant Service Information -

    Jetstream has issued Service Bulletin J41-53-020-41382A, dated 
September 28, 1995, as revised by Erratum No. 1, dated October 11, 
1995, which describes procedures for a high frequency eddy current 
inspection to detect cracks of the boundary angle and joint angle of 
the rear pressure bulkhead. The service bulletin also describes 
procedures for modification of the rear pressure bulkhead of the 
fuselage. The modification involves installing shear cleats, angles, 
brackets, and stiffeners; and removing and replacing the brackets with 
new brackets. The CAA classified this service bulletin as mandatory in 
order to assure the continued airworthiness of these airplanes in the 
United Kingdom.

FAA's Conclusion -

    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, the 
proposed AD would require a high frequency eddy current inspection to 
detect cracks of the boundary angle and joint angle of the rear 
pressure bulkhead, and repair, if necessary. The proposed AD also would 
require modification of the rear pressure bulkhead of the fuselage. The 
actions would be required to be accomplished in accordance with the 
service bulletin described previously. If any boundary angle or joint 
angle is cracked, the repair would be required to be accomplished in 
accordance with a method approved by the FAA.

Cost Impact -

    The FAA estimates that 26 Model 4101 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
40 work hours per airplane to accomplish the proposed actions, and that 
the average labor rate is $60 per work hour. Required parts would be 
supplied by the manufacturer at no cost to the operators. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $62,400, or $2,400 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.

[[Page 36310]]

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.


39.13  [Amended] -

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Jetstream Aircraft Limited: Docket 95-NM-271-AD.

    -Applicability: Model 4101 airplanes, constructors numbers 41004 
through 41060 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 fatigue-related cracking in the rear pressure 
bulkhead, which could result in reduced structural integrity of the 
fuselage and, consequently, lead to the rapid decompression of the 
pressurized area of the airplane; accomplish the following: -
    (a) Prior to the accumulation of 10,000 total landings, or 
within 6 months after the effective date of this AD, whichever 
occurs later, accomplish paragraphs (a)(1) and (a)(2) of this AD, in 
accordance Jetstream Service Bulletin J41-53-020-41382A, dated 
September 28, 1995, as revised by Erratum No. 1, dated October 11, 
1995. -
    (1) Perform a high frequency eddy current inspection to detect 
cracks of the boundary angle and joint angle of the rear pressure 
bulkhead, in accordance with the service bulletin. If any crack is 
detected, prior to further flight, repair it in accordance with a 
method approved by the Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate. -
    (2) Modify the rear pressure bulkhead of the fuselage (Jetstream 
Modification 41382A), in accordance with the 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, 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.

     -(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.

    Issued in Renton, Washington, on July 3, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-17536 Filed 7-9-96; 8:45 am]
BILLING CODE 4910-13-U