[Federal Register Volume 63, Number 76 (Tuesday, April 21, 1998)]
[Proposed Rules]
[Pages 19680-19682]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10483]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-86-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace (Jetstream) Model 
4100 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 4100 airplanes. This proposal would require an eddy 
current conductivity test to measure the conductivity of the upper 
splice plate of the wing, and follow-on actions, 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 correct corrosion of the 
upper splice plate of the wing, which could result in reduced 
structural integrity of the airplane.

DATES: Comments must be received by May 21, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-86-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.


[[Page 19681]]


FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
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 98-NM-86-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. 98-NM-86-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 4100 
airplanes. The CAA advises that it has received reports of exfoliation 
corrosion of the upper splice plate of the wing on certain airplanes. 
Investigation has revealed that the susceptibility to corrosion of the 
upper splice plate is related to the conductivity of the material. 
Because the manufacturer finds that such corrosion may be related to a 
material batch problem, the corrosion is likely to be present or 
develop on other airplanes with an upper splice plate made from the 
same material. Corrosion on the upper splice plate of the wing, if not 
corrected, could result in reduced structural integrity of the 
airplane.

Explanation of Relevant Service Information

    British Aerospace has issued Regional Aircraft Service Bulletin 
J41-57-019, Revision 1, dated November 26, 1997, including Appendix 1, 
which describes procedures for performing an eddy current conductivity 
test to measure the conductivity of the upper splice plate of the wing. 
If the conductivity of the upper splice plate of the wing is less than 
35% of the International Aluminum and Copper Standards (IACS), follow-
on actions are required. The CAA approved this service bulletin.
    British Aerospace also has issued Regional Aircraft Service 
Bulletin J41-57-020, dated March 20, 1997, including Appendix 1 and 
Appendix 2, which describes procedures for performing repetitive 
detailed visual inspections, using a boroscope, to detect corrosion 
along the full length of the upper splice plate of the wing; repairing 
damage that is found to be within certain specified limits; and 
replacing the existing upper splice plate with a new upper splice 
plate, if necessary. Such replacement eliminates the need for the 
repetitive inspections. The CAA classified this service bulletin as 
mandatory and issued British airworthiness directive 005-03-97 
(undated), 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 accomplishment of 
the actions specified in the service bulletins described previously, 
except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although British Aerospace Regional 
Aircraft Service Bulletin J41-57-020 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.

Cost Impact

    The FAA estimates that 54 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 eddy current conductivity 
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 $3,240, or $60 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 19682]]

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 
98-NM-86-AD.

    Applicability: Jetstream Model 4100 airplanes, constructor's 
numbers 41004 through 41096 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 (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 correct corrosion of the upper splice plate of the wing, 
which could result in reduced structural integrity of the airplane, 
accomplish the following:
    (a) Within 6 months after the effective date of this AD, perform 
an eddy current conductivity test to measure the conductivity of the 
upper splice plate of the wing, in accordance with British Aerospace 
Regional Aircraft Service Bulletin J41-57-019, Revision 1, dated 
November 26, 1997, including Appendix 1. If the conductivity 
measurement is greater than or equal to 35.0% of the International 
Aluminum and Copper Standards (IACS), no further action is required 
by this AD.
    (b) During the inspection required by paragraph (a) of this AD, 
if the conductivity measurement is less than 35.0% of the IACS: 
Prior to further flight, use a boroscope to perform a detailed 
visual inspection to detect corrosion along the full length of the 
upper splice plate of the wing, in accordance with British Aerospace 
Regional Aircraft Service Bulletin J41-57-020, dated March 20, 1997, 
including Appendix 1 and Appendix 2. Thereafter, repeat the 
inspection at intervals not to exceed 1 year.
    (1) During any inspection required by paragraph (b) of this AD, 
if any corrosion is detected that is within the allowable limits 
specified in the service bulletin: Accomplish the actions required 
by paragraphs (b)(1)(i) and (b)(1)(ii) of this AD, at the times 
specified in those paragraphs.
    (i) Prior to further flight, repair the upper splice plate of 
the wing in accordance with Appendix 2 of the service bulletin. And
    (ii) Within 3 years after the detection of corrosion, replace 
the upper splice plate of the wing with a new upper splice plate in 
accordance with the service bulletin. Such replacement constitutes 
terminating action for the requirements of this AD.
    (2) During any inspection required by paragraph (b) of this AD, 
if any corrosion is detected that is outside the allowable limits 
specified in the service bulletin: Prior to further flight, repair 
in accordance with a method approved by the Manager, International 
Branch, ANM-116, FAA, Transport Airplane Directorate.
    (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, 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.

    (d) Special flight permits may be issued in accordance with 
Secs. 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 005-03-97 (undated).

    Issued in Renton, Washington, on April 15, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-10483 Filed 4-20-98; 8:45 am]
BILLING CODE 4910-13-U