AD Amdt-39-10170

[Federal Register Volume 62, Number 203 (Tuesday, October 21, 1997)]
[Rules and Regulations]
[Pages 54577-54579]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 97-27795]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-25-AD; Amendment 39-10170; AD 97-22-01]
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: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive that 
applies to Pilatus Britten-Norman Ltd. (Pilatus Britten-Norman) BN-2A, 
BN-2B, and BN-2T series airplanes. This AD requires 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 
eliminates the need for the repetitive inspections. These 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 revision to AD 86-07-02 to retain the repetitive 
inspection and replacement (if necessary) requirements for the BN2A MK. 
111 series airplanes. The actions specified in this 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: Effective November 28, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 28, 1997.

ADDRESSES: Service information that applies to this AD may be obtained 
from Fairey Hydraulics Limited, Claverham, Bristol, England; or Pilatus 
Britten-Norman Limited, Bembridge, Isle of Wight, United Kingdom PO35 
5PR; telephone 44-1983 872511; facsimile 44-1983 873246. This 
information may also be examined at the FAA, Central Region, Office of 
the Regional Counsel, Attention: Rules Docket 96-CE-25-AD, Room 1558, 
601 E. 12th Street, Kansas City, Missouri 64106; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. S.M. Nagarajan, Aerospace 
Engineer, 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:

Events Leading to the Issuance of This AD

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to Pilatus Britten-
Norman BN-2A, BN-2B, and BN-2T series airplanes was published in the 
Federal Register as a notice of proposed rulemaking (NPRM) on May 27, 
1997 (62 FR 28646). The NPRM proposed to 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 as specified in the NPRM would be in 
accordance with Fairey Hydraulics Limited SB 32-4, Issue 4, dated 
January 30, 1990.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.

The FAA's Aging Commuter-Class Airplane Policy

    This AD applies to the FAA's aging commuter-class airplane policy. 
This policy simply states that reliance on repetitive inspections of 
critical areas on 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. The 
alternative to issuing this AD would be to rely on repetitive 
inspections to detect failure of the MLG torque link assemblies on the 
affected airplanes.
    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 this 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.
    This AD allows 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 will have to accomplish the replacement within 5 to 10 
calendar months (at the least) after this AD becomes effective. For 
private owners, who typically operate between 100 to 200 hours TIS per 
year, this will allow 5 to 10 years (at the least) before the 
replacement becomes mandatory. The time it would take those in air 
cargo/air taxi operations before the replacement becomes 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.

Cost Impact

    The FAA estimates that 112 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 13 workhours per 
airplane to accomplish this AD (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 this AD on 
U.S. operators is

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estimated to be $781,760 or $6,980 per airplane.
    The inspections are currently required on the 112 affected 
airplanes by AD 86-07-02. This 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 
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.

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 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 this 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 this 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 will 
incur significant operating costs under FAA Order 2100.14A. Therefore, 
this AD will not significantly affect a number of small entities.
    A copy of the full Cost Analysis and Regulatory Flexibility 
Determination for this AD may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Attention: Rules Docket No. 96-CE-25-
AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does 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) 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 final 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

97-22-01  Pilatus Britten-Norman: Amendment 39-10170; Docket No. 96-
CE-25-AD.

    Applicability: Models BN-2, BN-2A, BN-2A-2, BN-2A-3, BN-2A-6, 
BN-2A-8, 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 replacement, 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: The inspections required by paragraph (a) of this AD 
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.


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    (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 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, Small Airplane 
Directorate, 1201 Walnut, suite 900, Kansas City, Missouri 64106. 
The request should be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Small Airplane Directorate.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (g) The inspections and replacement required by this AD shall be 
done in accordance with Fairey Hydraulics Limited Service Bulletin 
(SB) 32-4, Issue 4, dated January 30, 1990. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from Fairey Hydraulics Limited, Claverham, Bristol, 
England; or Pilatus Britten-Norman Limited, Bembridge, Isle of 
Wight, United Kingdom PO35 5PR. Copies may be inspected at the FAA, 
Central Region, Office of the Regional Counsel, Room 1558, 601 E. 
12th Street, Kansas City, Missouri, or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (h) This amendment (39-10170) becomes effective on November 28, 
1997.

    Issued in Kansas City, Missouri, on October 14, 1997.
Mary Ellen Schutt,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-27795 Filed 10-20-97; 8:45 am]
BILLING CODE 4910-13-U