[Federal Register Volume 61, Number 212 (Thursday, October 31, 1996)]
[Proposed Rules]
[Pages 56169-56170]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27925]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

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: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Jetstream Model 4101 series 
airplanes, that would have required a high frequency eddy current 
(HFEC) inspection to detect cracks of the boundary angle and joint 
angle of the rear pressure bulkhead, and repair, if necessary. That 
action also proposed to require modification of the rear pressure 
bulkhead of the fuselage. That proposal was prompted by a report of 
fatigue cracking in the rear pressure bulkhead of the fuselage. This 
action revises the proposed rule by referencing a new service bulletin 
that includes new technical procedures for accomplishing the HFEC 
inspection, and removing airplanes having certain constructor numbers. 
The actions specified by this 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 November 19, 1996.

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

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Jetstream Model 4101 series airplanes, was published as a 
notice of proposed rulemaking (NPRM) in the Federal Register on July 
10, 1996 (61 FR 36308). That NPRM would have required 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. 
That NPRM also would have required modification of the rear pressure 
bulkhead of the fuselage. That NPRM was prompted by a report of fatigue 
cracking in the rear pressure bulkhead of the fuselage. That condition, 
if not detected and corrected in a timely manner, could result in 
reduced structural integrity of the fuselage and, consequently, lead to 
the rapid decompression of the pressurized area of the airplane.

Actions Since Issuance of Previous Proposal

    Since the issuance of that NPRM, Jetstream has issued Revision 1 of 
Service Bulletin J41-53-020 (the original version of this service 
bulletin was referenced as Service Bulletin J41-53-020-41382A in the 
NPRM), dated June 4, 1995. This revision revises certain technical 
procedures specified in the Accomplishment Instructions. In addition, 
airplanes having constructors numbers 41048 through 41060, inclusive, 
are removed from the effectivity listing of the service bulletin, since 
those planes have been identified as not being subject to the addressed 
unsafe condition. 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

    The FAA has examined the findings of the CAA and reviewed the new 
service information. The FAA has determined that, in order to 
effectively address the unsafe condition presented by the problems 
associated with fatigue cracking in the subject area, the proposed rule 
must be revised to reference Revision 1 of Jetstream Service Bulletin 
J41-53-020 as the appropriate source of service information. In 
addition, the applicability of the proposed rule must be revised by 
removing Model 4101 airplanes having constructors numbers 41048 through 
41060, inclusive.
    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

[[Page 56170]]

Cost Impact

    The FAA estimates that 40 Model 4101 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 40 work 
hours per airplane to accomplish the actions, and that the average 
labor rate is $60 per work hour. Required parts will be supplied by the 
manufacturer at no cost to the operators. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $96,000, 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.

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 95-NM-271-AD.

    Applicability: Model 4101 airplanes, constructors numbers 41004 
through 41047 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, Revision 1, dated 
June 4, 1996.
    (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 JM41382A), 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 October 24, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-27925 Filed 10-30-96; 8:45 am]
BILLING CODE 4910-13-P