[Federal Register Volume 63, Number 156 (Thursday, August 13, 1998)]
[Proposed Rules]
[Pages 43351-43353]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-21714]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-235-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Model Avro 146-RJ85A 
and RJ100A Series 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 Model 
Avro 146-RJ85A and RJ100A series airplanes. This proposal would require 
a one-time inspection for evidence of machining (undercutting) into the 
web of the integral stringers of the bottom skin of the wings, and 
corrective 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 prevent reduced wing strength and stiffness, and the onset 
of premature fatigue cracking, which could result in reduced structural 
integrity of the airplane.

DATES: Comments must be received by September 14, 1998.


[[Page 43352]]


ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-235-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: 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-235-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-235-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 Model Avro 146-RJ85A 
and RJ100A series airplanes. The CAA advises that, during the 
production of certain airplanes, the web of the integral stringers of 
the bottom skin of the wings may have been produced with unnecessary 
undercuts. These unnecessary undercuts may have undersized all the webs 
of the integral stringers between ribs 2 to 18. This condition, if not 
corrected, could result in reduced wing strength and stiffness, and the 
onset of premature fatigue cracking, which could result in reduced 
structural integrity of the airplane.

Explanation of Relevant Service Information

    The manufacturer has issued British Aerospace Service Bulletin 
SB.57-55, dated April 27, 1998, which describes procedures for a one-
time detailed visual inspection for evidence of machining 
(undercutting) into the web of the integral stringers, between ribs 2 
and 18, of the bottom skin of the wings, and corrective actions, if 
necessary. The corrective actions include measuring the web of the 
integral stringers if any machining (undercutting) is detected, and 
repair, if necessary. Accomplishment of the action specified in the 
service bulletin is intended to adequately address the identified 
unsafe condition. The CAA classified this service bulletin as mandatory 
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.

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 bulletin described previously, 
except as described below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for disposition of certain 
machining (undercutting) conditions, this proposal would require the 
repair of those conditions to be accomplished in accordance with a 
method approved by either the FAA, or the CAA (or its delegated agent). 
In light of the type of repair that would be required to address the 
identified unsafe condition, and in consonance with existing bilateral 
airworthiness agreements, the FAA has determined that, for this 
proposed AD, a repair approved by either the FAA or the CAA would be 
acceptable for compliance with this proposed AD.

Cost Impact

    The FAA estimates that 5 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 16 work 
hours 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 
$4,800, or $960 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

[[Page 43353]]

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 British Aerospace 
Regional Aircraft Limited, Avro International Aerospace Division; 
British Aerospace, PLC; British Aerospace Commercial Aircraft 
Limited): Docket 98-NM-235-AD.

    Applicability: Model Avro 146-RJ85A and RJ100A series airplanes, 
as listed in British Aerospace Service Bulletin SB.57-55, dated 
April 27, 1998, 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 prevent reduced wing strength and stiffness, and the onset of 
premature fatigue cracking, 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 
a one-time detailed visual inspection for evidence of machining 
(undercutting) into the web of the integral stringers of the bottom 
skin of the wings, in accordance with British Aerospace Service 
Bulletin SB.57-55, dated April 27, 1998.
    (1) If no machining into the web is detected, no further action 
is required by this AD.
    (2) If any machining into the web is detected, prior to further 
flight, measure the thickness of the web of the integral stringer in 
accordance with the service bulletin.
    (i) If the web thickness is 0.099 inch or more, no further 
action is required by this AD.
    (ii) If the web thickness is less than 0.099 inch, prior to 
further flight, repair in accordance with a method approved by 
either the Manager, International Branch, ANM-116, FAA, Transport 
Directorate, or the Civil Aviation Authority (or its delegated 
agent).
    (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.

    Issued in Renton, Washington, on August 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-21714 Filed 8-12-98; 8:45 am]
BILLING CODE CODE 4910-13-U