[Federal Register Volume 62, Number 31 (Friday, February 14, 1997)]
[Proposed Rules]
[Pages 6888-6890]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3691]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-168-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 
airplanes. This proposal would require repetitive detailed visual 
inspections to detect cracks on frame 179 at the attachment bracket for 
the door restraint cable, and various follow-on actions. This proposal 
also would require installation of new doublers and stress pads on 
frame 179, which would terminate the repetitive inspections. This 
proposal is prompted by reports of cracks in frame 179 of the fuselage 
at the attachment bracket for the door restraint cable on in-service 
airplanes due to improper rigging of the door restraint system. The 
actions specified by the proposed AD are intended to prevent such 
cracking, which could result in structural failure of the fuselage and 
consequent rapid decompression of the pressurized section of the 
fuselage.

DATES: Comments must be received by March 27, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-168-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

[[Page 6889]]

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-168-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-168-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 of cracks in frame 179 of 
the fuselage at the attachment bracket for the door restraint cable on 
these in-service airplanes. The existing design of the door restraint 
cable will not withstand continuous high loads that are induced by 
improper rigging of the door restraint system. Cracking in frame 179 of 
the fuselage, if not detected and corrected, could result in structural 
failure of the fuselage and consequent rapid decompression of the 
pressurized section of fuselage.

Explanation of Relevant Service Information

    Jetstream has issued Alert Service Bulletin J41-A53-024, dated 
April 26, 1996, which describes procedures for performing repetitive 
detailed visual inspections to detect cracks on frame 179 at the 
attachment bracket for the door restraint cable, and various follow-on 
actions. (These follow-on actions include performing a test to verify 
proper adjustment of the restraint cable, and correcting any 
discrepancy.) For cases where no cracks are detected during inspection, 
the alert service bulletin also describes procedures for installation 
of new doublers and stress pads on frame 179, which would eliminate the 
need for repetitive inspections. The CAA classified this alert service 
bulletin as mandatory and issued British airworthiness directive 004-
04-96 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 Sec. 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 repetitive detailed 
visual inspections to detect cracks on frame 179 at the attachment 
bracket for the door restraint cable, and various follow-on actions. 
The proposed AD also would require installation of new doublers and 
stress pads on frame 179, which would constitute terminating action for 
the repetitive inspection requirements. The inspection, various follow-
on actions, and installation would be required to be accomplished in 
accordance with the alert service bulletin described previously. If any 
crack is detected during any visual inspection, the repair would be 
required to be accomplished in accordance with a method approved by the 
FAA.

Cost Impact

    The FAA estimates that 49 Jetstream Model 4101 airplanes of U.S. 
registry would be affected by this proposed AD.
    The proposed inspection would take approximately 2 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection proposed by 
this AD on U.S. operators is estimated to be $5,880, or $120 per 
airplane, per inspection cycle.
    The proposed installation would take approximately 8 work hours per 
airplane to accomplish, at an average labor rate of $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 installation 
proposed by this AD on U.S. operators is estimated to be $23,520, 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.

[[Page 6890]]

Sec. 39.13  [Amended]

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

Jetstream Aircraft Limited: Docket 96-NM-168-AD.

    Applicability: Model 4101 airplanes, constructors numbers 41004 
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 
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 cracking in frame 179 of the fuselage, which could 
result in structural failure of the fuselage and consequent rapid 
decompression of the pressurized section of the fuselage, accomplish 
the following:
    (a) Prior to the accumulation of 3,000 total flight cycles, or 
within 300 flight cycles after the effective date of this AD, 
whichever occurs later, perform a detailed visual inspection to 
detect cracks on frame 179 at the attachment bracket for the door 
restraint cable, in accordance with Part 1 of the Accomplishment 
Instructions of Jetstream Alert Service Bulletin J41-A53-024, dated 
April 26, 1996.
    (1) If no crack is detected, repeat the visual inspection 
thereafter at intervals not to exceed 1,000 flight cycles. After 
each inspection, perform the actions specified in paragraph (c) of 
this AD.
    (2) 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. After repair, 
perform the actions specified in paragraph (c) of this AD.
    (b) Within 24 months after the effective date of this AD, 
perform the visual inspection specified in paragraph (a) of this AD 
in accordance with Part 2 of the Accomplishment Instructions of 
Jetstream Alert Service Bulletin J41-A53-024, dated April 26, 1996; 
and accomplish the applicable follow-on actions specified in 
paragraph (b)(1) or (b)(2) of this AD.
    (1) If no crack is detected, prior to further flight, install 
new doublers and stress pads on frame 179 in accordance with the 
alert service bulletin. Immediately after installation, perform the 
actions specified in paragraph (c) of this AD. Accomplishment of 
these actions constitutes terminating action for the repetitive 
inspection requirements of paragraphs (a)(1) of this AD.
    (2) If any crack is detected, prior to further flight, repair it 
in accordance with a method approved by the Manager, Standardization 
Branch. Prior to further flight following accomplishment of the 
repair, install new doublers and stress pads on frame 179 in 
accordance with the alert service bulletin; and then perform the 
actions specified in paragraph (c) of this AD. Accomplishment of 
these actions constitutes terminating action for the repetitive 
inspection requirements of paragraphs (a)(1) of this AD.
    (c) Prior to further flight following accomplishment of the 
actions as specified in paragraph (a)(1), (a)(2), (b)(1), or (b)(2) 
of this AD, perform a test to verify proper adjustment of the 
restraint cable, in accordance with the alert service bulletin. If 
the restraint cable has been improperly adjusted, prior to further 
flight, correct the discrepancy in accordance with the alert service 
bulletin.
    (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. 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.

    (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 February 5, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3691 Filed 2-13-97; 8:45 am]
BILLING CODE 4910-13-U