[Federal Register Volume 63, Number 5 (Thursday, January 8, 1998)]
[Proposed Rules]
[Pages 1074-1075]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-475]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-141-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace (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 British Aerospace 
(Jetstream) Model 4101 airplanes. This proposal would require 
repetitive detailed visual inspections to detect cracking or other 
damage of certain diaphragm support structures of the forward equipment 
compartment; and repair, if necessary. This proposal is prompted by 
issuance of mandatory continuing airworthiness information by a foreign 
civil airworthiness authority. The actions specified by the proposed AD 
are intended to detect and correct failure of the two diaphragms that 
support the upper structure of the forward equipment compartment, which 
could accelerate fatigue damage in adjacent structure and result in 
reduced structural integrity of the airframe.

DATES: Comments must be received by February 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-141-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 AI(R) American Support, Inc., 13850 Mclearen Road, 
Herndon, Virginia 20171. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: International Branch, ANM-116, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2110; fax (425) 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 97-NM-141-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-114, Attention: Rules 
Docket No. 97-NM-141-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA),which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain British Aerospace (Jetstream) Model 4101 
airplanes. The CAA advises that, during fatigue testing, cracks were 
found in the two diaphragms that support the upper structure of the 
forward equipment compartment. This condition, if not detected and 
corrected in a timely manner, could accelerate fatigue damage in 
adjacent structure and result in reduced structural integrity of the 
airframe.

Explanation of Relevant Service Information

    The manufacturer has issued Jetstream Alert Service Bulletin J41-
A53-023, dated December 2, 1996, which describes procedures for 
repetitive detailed visual inspections to detect cracking or other 
damage of certain diaphragms that support the upper structure of the 
forward equipment compartment; and repair, if necessary. The CAA 
classified this alert service bulletin as mandatory and issued British 
airworthiness directive 007-12-96, 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 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.

[[Page 1075]]

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 accomplishment of 
the actions specified in the alert service bulletin described 
previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike the procedures described in 
Jetstream Alert Service Bulletin J41-A53-023, dated December 2, 1996, 
this proposed AD would not permit further flight if cracks are detected 
in certain diaphragms that support the upper structure of the forward 
equipment compartment. The FAA has determined that, because of the 
safety implications and consequences associated with such cracking, any 
subject diaphragm that is found to be cracked must be repaired or 
modified prior to further flight.
    Operators should also note that, although the alert service 
bulletin specifies that the manufacturer may be contacted for 
disposition of certain repair conditions, this proposal would require 
the repair of those conditions to be accomplished in accordance with a 
method approved by the FAA.
    The proposed AD also would differ from the alert service bulletin 
in that it would continue to require repetitive inspections after a 
repair to cracked or damaged diaphragms is accomplished. The alert 
service bulletin considers the accomplishment of the repair as 
terminating action for the repetitive inspections. The FAA requires 
further evidence that the repair will be effective in preventing 
further cracking or damage.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    The FAA estimates that 55 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 1 work 
hour per airplane to accomplish the proposed inspection, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$3,300, or $60 per airplane, per inspection cycle.
    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:

British Aerospace Regional Aircraft [Formerly Jetstream Aircraft 
Limited; British Aerospace (Commercial Aircraft) Limited]: Docket 
97-NM-141-AD.

    Applicability: Jetstream Model 4101 airplanes, constructors 
numbers 41004 through 41098 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 (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 detect and correct failure of the two diaphragms that support 
the upper structure of the forward equipment compartment, which 
could accelerate fatigue damage in adjacent structure and result in 
reduced structural integrity of the airframe, accomplish the 
following:
    (a) Prior to the accumulation of 4,500 total landings, or within 
300 landings after the effective date of this AD, whichever occurs 
later: Perform a detailed visual inspection to detect cracking or 
other damage of the diaphragms installed between station 4 and 
station 8 of the forward fuselage, in accordance with Jetstream 
Alert Service Bulletin J41-A53-023, dated December 2, 1996.
    (1) If no cracking or other damage is detected, repeat the 
inspection thereafter at intervals not to exceed 3,000 landings.
    (2) If any cracking or other damage is detected, prior to 
further flight, repair the diaphragm in accordance with a method 
approved by the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate. Thereafter, repeat the inspection at 
intervals not to exceed 3,000 landings.
    (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, International Branch, ANM-116. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, International Branch, ANM-116.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (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.

    Note 3: The subject of this AD is addressed in British 
airworthiness directive 007-12-96.

    Issued in Renton, Washington, on January 2, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-475 Filed 1-7-98; 8:45 am]
BILLING CODE 4910-13-P