[Federal Register Volume 62, Number 44 (Thursday, March 6, 1997)]
[Proposed Rules]
[Pages 10233-10236]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5471]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-CE-25-AD]
RIN 2120-AA64
Airworthiness Directives; Pilatus Britten-Norman Ltd. (formerly
Britten-Norman) 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
that would apply to Pilatus Britten-Norman Ltd. (Pilatus Britten-
Norman) BN-2A, BN-2B, and BN-2T series airplanes. The proposed AD would
require repetitively inspecting the junction of the torque link lug and
upper case of the main landing gear (MLG) torque link assemblies for
cracks, and replacing any MLG torque link assembly with a Modification
A39 MLG torque link assembly, either immediately when cracks are found
or after a certain period of time if cracks are not found. Replacing
all MLG torque link assemblies with Modification A39 MLG torque link
assemblies would eliminate the need for the repetitive inspections.
These proposed repetitive inspections are currently required by AD 86-
07-02 for the BN-2A, BN-2B, and BN-2T series airplanes, as well as the
BN2A MK. 111 series airplanes. There are no improved design parts for
the BN2A MK. 111 series airplanes. The Federal Aviation Administration
(FAA) is issuing in a separate action a proposed revision to AD 86-07-
02 to retain the repetitive inspection and replacement (if cracked)
requirements for the BN2A MK. 111 series airplanes. The actions
specified in the proposed AD are intended to prevent failure of the
main landing gear caused by cracks in the torque link area, which could
lead to loss of control of the airplane during landing operations.
DATES: Comments must be received on or before May 12, 1997.
ADDRESSES: Submit comments on the proposal in triplicate to the FAA,
Central Region, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 96-CE-25-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.
FOR FURTHER INFORMATION CONTACT: Mr. Tom Rodriguez, Program Officer,
Brussels Aircraft Certification Division, FAA, Europe, Africa, and
Middle East Office, c/o American Embassy, B-1000 Brussels, Belgium;
telephone (32 2) 508.2717; facsimile (32 2) 230.6899; or Mr. S.M.
Nagarajan, Project Officer, Small Airplane Directorate, Airplane
Certification Service, FAA, 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. 96-CE-25-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 Assistant Chief Counsel,
Attention: Rules Docket No. 96-CE-25-AD, Room 1558, 601 E. 12th Street,
Kansas City, Missouri 64106.
Discussion
The FAA has determined that reliance on critical repetitive
inspections on aging commuter-class airplanes carries an unnecessary
safety risk when a design change exists that could eliminate or, in
certain instances, reduce the number of those critical inspections. In
determining what inspections are critical, the FAA considers (1) the
safety consequences if the known problem is not detected during the
inspection; (2) the probability of the problem not being detected
during the inspection; (3) whether the inspection area is difficult to
access; and (4) the possibility of damage to an adjacent structure as a
result of the problem.
These factors have led the FAA to establish an aging commuter-class
aircraft policy that requires incorporating a known design change when
it could replace a critical repetitive inspection. With this policy in
mind, the FAA conducted a review of existing AD's that apply to Pilatus
Britten-Norman BN-2A, BN-2B, BN-2T, and BN2A MK. 111 series airplanes.
Assisting the FAA in this review were (1) Pilatus Britten-Norman; (2)
the Regional Airlines Association (RAA); (3) the Civil Aviation
Authority of the
[[Page 10234]]
United Kingdom; and (4) several operators of the affected airplanes.
From this review, the FAA has identified AD 86-07-02, Amendment 39-
5382, as one which falls under the FAA's aging aircraft policy. AD 86-
07-02 currently requires repetitively inspecting the junction of the
torque link lug and upper case of the main landing gear (MLG) torque
link assemblies for cracks on Pilatus Britten-Norman BN-2A, BN-2B, BN-
2T, and BN2A MK. 111 series airplanes, and replacing any cracked part.
Pilatus Britten-Norman has developed a modification that, when
incorporated, would eliminate the need for the repetitive inspection
requirement of AD 86-07-02 for the Pilatus Britten-Norman BN-2A, BN-2B,
and BN-2T series airplanes. The requirements of AD 86-07-02 should
still apply for the Pilatus Britten-Norman BN2A MK. 111 series
airplanes.
Applicable Service Information
Fairey Hydraulics Limited has issued Service Bulletin (SB) 32-4,
Issue 4, dated January 30, 1990, which applies to the Pilatus Britten-
Norman BN-2A, BN-2B, and BN-2T series airplanes. This SB includes
procedures for inspecting the junction of the torque link lug and upper
case of the MLG torque link assemblies, and installing new Modification
A39 MLG torque link assemblies. Pilatus Britten-Norman SB BN-2/SB.170,
Issue 4, dated November 16, 1990, references Fairey Hydraulic Limited
SB32-4, Issue 4, dated January 30, 1990.
The FAA's Determination
The FAA has examined all available information related to this
subject matter and has determined that:
AD action should be taken for the Pilatus Britten-Norman
BN-2A, BN-2B, and BN-2T series airplanes to require the installation of
Modification A39 MLG torque link assemblies. The repetitive inspections
of the junction of the torque link lug and upper case of the MLG torque
link assemblies would still be required until the improved parts are
installed; and
AD 86-07-02 should be revised to remove the BN-2A BN-2B,
and BN-2T series airplanes from the applicability of that AD, but
retain the actions for the BN2A MK. 111 series airplanes (this is being
proposed in a separate action).
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-2A, BN-2B, and BN-
2T series airplanes of the same type design, the proposed AD would
require repetitively inspecting the junction of the torque link lug and
upper case of the MLG torque link assemblies for cracks, and replacing
any MLG torque link assembly with a Modification A39 MLG torque link
assembly, either immediately when cracks are found or at a certain
period of time if cracks are not found. Installation of the improved
part would eliminate the need for the repetitive inspections.
Accomplishment of the proposed inspections and installation would be in
accordance with Fairey Hydraulics Limited SB 32-4, Issue 4, dated
January 30, 1990.
Cost Impact
The FAA estimates that 112 airplanes in the U.S. registry would be
affected by the proposed AD, that it would take approximately 13
workhours per airplane to accomplish the proposed action (1 workhour
per inspection and 12 workhours for the installation), and that the
average labor rate is approximately $60 an hour. Parts cost
approximately $6,200 per airplane. Based on these figures, the total
cost impact of the proposed AD on U.S. operators is estimated to be
$781,760 or $6,980 per airplane.
The proposed inspections are currently required on the 112 affected
airplanes by AD 86-07-02. The proposed AD would not require any
additional inspection requirements over that already required by AD 86-
07-02. In addition, the cost figures referenced above are based on the
presumption that no affected airplane operator has incorporated the
proposed inspection-terminating installation. Pilatus Britten-Norman
does not know the number of parts distributed to the affected airplane
owners/operators. Numerous sets of parts were sent out to the owners/
operators of the affected airplanes, but over the years Pilatus
Britten-Norman has not retained these records.
The FAA's Aging Commuter Aircraft Policy
The intent of the FAA's aging commuter airplane program is to
ensure safe operation of commuter-class airplanes that are in
commercial service without adversely impacting private operators. Of
the approximately 112 airplanes in the U.S. registry that would be
affected by the proposed AD, the FAA has determined that approximately
25 percent are operated in scheduled passenger service by 11 different
operators. A significant number of the remaining 75 percent are
operated in other forms of air transportation such as air cargo and air
taxi.
The proposed action would allow at least 1,000 hours TIS after the
effective date of the AD before mandatory accomplishment of the design
modification (upon the accumulation of 5,000 hours TIS or within the
next 1,000 hours TIS after the effective date of the AD, whichever is
later). The average utilization of the fleet for those airplanes in
commercial commuter service is approximately 25 to 50 hours TIS per
week. Based on these figures, operators of commuter airplanes involved
in commercial operation would have to accomplish the proposed
modification within 5 to 10 calendar months (at the least) after the
proposed AD would become effective. For private owners, who typically
operate between 100 to 200 hours TIS per year, this would allow 5 to 10
years (at the least) before the proposed modification would be
mandatory. The time it would take those in air cargo/air taxi
operations before the proposed action would be mandatory is unknown
because of the wide variation between each airplane used in this
service. The exact numbers would fall somewhere between the average for
commuter operators and private operators.
Regulatory Flexibility Determination and Analysis
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionally burdened by government regulations. The RFA requires
government agencies to determine whether rules would have a
``significant economic impact on a substantial number of small
entities,'' and, in cases where they would, conduct a Regulatory
Flexibility Analysis in which alternatives to the rule are considered.
FAA Order 2100.14A, Regulatory Flexibility Criteria and Guidance,
outlines FAA procedures and criteria for complying with the RFA. Small
entities are defined as small businesses and small not-for-profit
organizations that are independently owned and operated or airports
operated by small governmental jurisdictions. A ``substantial number''
is defined as a number that is not less than 11 and that is more than
one-third of the small entities subject to a proposed rule, or any
number of small entities judged to be substantial by the rulemaking
official. A ``significant economic impact'' is defined by an annualized
net compliance cost, adjusted for inflation, which is greater than a
threshold cost level for defined entity types.
The entities that would be affected by this AD are mostly in the
portion of Standard Industrial Classification (SIC)
[[Page 10235]]
4512, Operators of Aircraft for Hire, classified as ``unscheduled.''
FAA Order 2100.14A sets the size threshold for small entities operating
aircraft in this category at nine or fewer aircraft owned and the
annualized cost thresholds of at least $4,975 (1996 dollars) for
unscheduled operators. A four-year life for the torque link assembly
and capital cost of 15-percent would establish an annualized cost of
$2,445 (1996 dollars). This is less than 50-percent of the threshold
cost of $4,975 per year. In order to incur costs of at least $4,975, an
entity would have to operate three or more of the airplanes referenced
in the proposed AD. FAA data shows that only five small entities
operate three or more of these airplanes. In addition, this data shows
that approximately 60 entities operate the airplanes referenced in the
proposed AD, but that only 15 of these entities (one-fourth) operate
two or more of these airplanes.
Based on this information, less than one-third of the entities
would incur significant operating costs under FAA Order 2100.14A.
Therefore, the proposed AD would not significantly affect a number of
small entities.
A copy of the full Cost Analysis and Regulatory Flexibility
Determination for the proposed action may be examined at the FAA,
Central Region, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 96-CE-25-AD, Room 1558, 601 E. 12th Street, Kansas City,
Missouri.
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
Pilatus Britten-Norman: Docket No. 96-CE-25-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 (f) 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 after the effective date of
this AD, unless already accomplished.
To prevent failure of the main landing gear caused by cracks in
the torque link assembly area, which could lead to loss of control
of the airplane during landing operations, accomplish the following:
(a) Prior to further flight after the effective date of this AD
or within the next 100 hours time-in-service (TIS) after the last
inspection required by AD 86-07-02, whichever occurs later, and
thereafter at intervals not to exceed 100 hours TIS until the
installations required by paragraph (c) of this AD are accomplished,
inspect the junction of the torque link lug and upper case of all
main landing gear (MLG) torque link assemblies for cracks (using a
10-power magnifying glass or by dye penetrant methods). Accomplish
these inspections in accordance with the ACCOMPLISHMENT INSTRUCTIONS
section of Fairey Hydraulics Limited Service Bulletin (SB) 32-4,
Issue 4, dated January 30, 1990. Pilatus Britten-Norman SB BN-2/
SB.170, Issue 4, November 16, 1990, references this service
bulletin.
Note 2: These inspections were initially a part of AD 86-07-02,
which applied to the BN2A MK. 111 series airplanes as well as the
airplanes affected by this AD. The ``prior to further flight after
the effective date of this AD'' compliance time was the original
initial compliance time of AD 86-07-02, and is being retained to
provide credit and continuity for already-accomplished and future
inspections.
(b) If any cracks are found during any of the inspections
required by this AD, prior to further flight, replace the MLG torque
link assembly with a Modification A39 MLG torque link assembly in
accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Fairey
Hydraulics Limited SB No. 32-4, Issue 4, dated January 30, 1990.
(1) Repetitive inspections are no longer required when all MLG
torque assemblies are replaced with Modification A39 MLG torque link
assemblies.
(2) Repetitive inspections may no longer be required on one MLG
torque assembly, but still be required on another if all haven't
been replaced with a Modification A39 MLG torque link assembly.
(c) Upon the accumulation of 5,000 hours TIS or within the next
1,000 hours TIS after the effective date of this AD, whichever
occurs later, unless already accomplished as specified in paragraph
(b) of this AD, replace each MLG torque link assembly with a
Modification A39 MLG torque link assembly in accordance with of the
ACCOMPLISHMENT INSTRUCTIONS section of Fairey Hydraulics Limited SB
No. 32-4, Issue 4, dated January 30, 1990.
(d) The intervals between the repetitive inspections required by
this AD may be adjusted up to 10 percent of the specified interval
to allow accomplishing these actions along with other scheduled
maintenance on the airplane.
(e) 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 inspection requirements of this AD can be accomplished.
(f) An alternative method of compliance or adjustment of the
initial or repetitive compliance times that provides an equivalent
level of safety may be approved by the Manager, Brussels Aircraft
Certification Division, Europe, Africa, Middle East office, FAA, c/o
American Embassy, 1000 Brussels, Belgium. The request should be
forwarded through an appropriate FAA Maintenance Inspector, who may
add comments and then send it to the Manager, Brussels Aircraft
Certification Division.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Brussels Aircraft Certification Division.
(g) All persons affected by this directive may obtain copies of
the documents referred to herein upon request to Fairey Hydraulics
[[Page 10236]]
Limited, Claverham, Bristol, England; or Pilatus Britten-Norman
Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR, as
applicable; or may examine these documents at the FAA, Central
Region, Office of the Assistant Chief Counsel, Room 1558, 601 E.
12th Street, Kansas City, Missouri 64106.
Issued in Kansas City, Missouri, on February 24, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-5471 Filed 3-5-97; 8:45 am]
BILLING CODE 4910-13-U
