[Federal Register Volume 62, Number 101 (Tuesday, May 27, 1997)]
[Proposed Rules]
[Pages 28646-28649]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-13692]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

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 July 2, 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

[[Page 28647]]

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 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-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 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.

[[Page 28648]]

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) 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 U.S.C. 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

[[Page 28649]]

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 
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 May 19, 1997.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-13692 Filed 5-23-97; 8:45 am]
BILLING CODE 4910-13-U