[Federal Register: March 19, 1998 (Volume 63, Number 53)]
[Proposed Rules]               
[Page 13379-13381]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19mr98-19]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-112-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pilatus Britten-Norman Ltd. BN-2, BN-
2A, BN-2B, and BN-2T Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Pilatus Britten-Norman Ltd. (Pilatus 
Britten-Norman) BN-2, BN-2A, BN-2B, and BN-2T series airplanes. The 
proposed AD would require replacing the washers on the attachment bolts 
of the lower fitting of the main landing gear (MLG). The proposed AD is 
the result of mandatory continuing airworthiness information (MCAI) 
issued by the airworthiness authority for the United Kingdom. The 
actions specified by the proposed AD are intended to prevent the bolts 
that attach the lower fitting of the MLG to the nacelle from becoming 
threadbound, which could result in structural failure of the MLG with 
consequent loss of control of the airplane during takeoff, taxi, or 
landing operations.

DATES: Comments must be received on or before April 17, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 97-CE-112-AD, Room 1558, 601 E. 12th 
Street, Kansas City, Missouri 64106. Comments may be inspected at this 
location between 8 a.m. and 4 p.m., Monday through Friday, holidays 
excepted.
    Service information that applies to the proposed AD may be obtained 
from Pilatus Britten-Norman Limited, Bembridge, Isle of Wight, United 
Kingdom PO35 5PR; telephone: 44-1983 872511; facsimile: 44-1983 873246. 
This information also may be examined at the Rules Docket at the 
address above.


[[Page 13380]]


FOR FURTHER INFORMATION CONTACT: Mr. Roger Chudy, Aerospace Engineer, 
Small Airplane Directorate, Aircraft Certification Service, 1201 
Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-
6932; facsimile: (816) 426-2169

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 should 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 that summarizes 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 No. 97-CE-112-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, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 97-CE-112-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    The Civil Airworthiness Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain Pilatus Britten-Norman BN-2, BN-2A, BN-
2B, and BN-2T series airplanes. The CAA reports that the attachment 
bolts of the lower fitting of the main landing gear (MLG) may become 
``threadbound''. This condition results because the bolt length may be 
slightly longer than necessary and thus the nut bottoms out of the 
thread. Although all indications show that the bolt is properly 
torqued, the assembled parts may become loose, which could result in 
the MLG fitting separating from the nacelle.
    This condition, if not corrected in a timely manner, could result 
in structural failure of the MLG with consequent loss of control of the 
airplane during takeoff, taxi, and landing operations.

Relevant Service Information

    Pilatus Britten-Norman has issued Service Bulletin (SB) BN-2/
SB.231, Initial Issue, dated October 17, 1996, which specifies 
procedures for replacing the washer on the attachment bolts of the 
lower fitting of the MLG with two thicker washers. This SB also 
includes torque loading specifications for the attachment bolts.
    The CAA classified this service bulletin as mandatory and issued 
British AD No. 008-10-96, dated January 31, 1997, in order to assure 
the continued airworthiness of these airplanes in the United Kingdom.

The FAA's Determination

    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, including the service information referenced 
above; and determined that AD action is necessary for products of this 
type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Pilatus Britten-Norman BN-2, BN-2A, BN-2B, 
and BN-2T series airplanes of the same type design registered in the 
United States, the proposed AD would require replacing the washers on 
the attachment bolts of the lower fitting of the MLG. Accomplishment of 
the proposed installation would be in accordance with the service 
information previously referenced.

Cost Impact

    The FAA estimates that 80 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 3 
workhours per airplane to accomplish the proposed action, and that the 
average labor rate is approximately $60 an hour. Parts cost 
approximately $10 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be $15,200.

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 action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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 has been placed 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 13381]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

Pilatus Britten-Norman Ltd: Docket No. 97-CE-112-AD.

    Applicability: Models BN-2, BN-2A, BN-2A-3, BN-2A-6, BN-2A-8, 
BN-2A-2, BN-2A-9, BN-2A-20, BN-2A-21, BN-2A-26, BN-2A-27, BN-2B-20, 
BN-2B-21, BN-2B-26, BN-2B-27, and BN-2T airplanes (all serial 
numbers), 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 within the next 50 landings after the 
effective date of this AD, unless already accomplished.
    To prevent the bolts that attach the lower fitting of the main 
landing gear (MLG) to the nacelle from becoming threadbound, which 
could result in structural failure of the MLG with consequent loss 
of control of the airplane during takeoff, taxi, or landing 
operations, accomplish the following:
    (a) Replace the washers on the attachment bolts of the lower 
fitting of the MLG in accordance with Pilatus Britten-Norman Service 
Bulletin No. BN-2/SB.231, Initial Issue, dated October 17, 1996.
    (b) 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.
    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Small Airplane Directorate, 1201 Walnut, 
suite 900, Kansas City, Missouri, 64106. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Small Airplane 
Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (d) Questions or technical information related to Pilatus 
Britten-Norman Service Bulletin BN-2/SB.231, initial issue, dated 
October 17, 1996 should be directed to Pilatus Britten-Norman 
Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR; 
telephone: 44-1983 872511; facsimile: 44-1983 873246. This service 
information may be examined at the FAA, Central Region, Office of 
the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri 64106.

    Note 3: The subject of this AD is addressed in British AD No. 
008-10-96, dated January 31, 1997.

    Issued in Kansas City, Missouri, on March 12, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-7091 Filed 3-18-98; 8:45 am]
BILLING CODE 4910-13-U