[Federal Register Volume 63, Number 53 (Thursday, March 19, 1998)]
[Proposed Rules]
[Pages 13379-13381]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7091]
-----------------------------------------------------------------------
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).
-----------------------------------------------------------------------
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
