[Federal Register Volume 62, Number 205 (Thursday, October 23, 1997)]
[Rules and Regulations]
[Pages 55156-55157]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-27931]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 84-CE-18-AD; Amendment 39-10172; AD 84-23-06 R1]
RIN 2120-AA64


Airworthiness Directives; Pilatus Britten-Norman Ltd. Models BN-
2, BN-2A, BN-2B, BN-2T, and BN-2A MK. 111 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment revises airworthiness directive (AD) 84-23-06, 
which currently requires repetitively inspecting the upper mounting 
brackets, bolts, and bushings on wing mounted engines for cracks, wear, 
and insufficient fit on certain Pilatus Britten-Norman Ltd. (Pilatus) 
Models BN-2, BN-2A, BN-2B, BN-2T, and BN-2A MK. 111 series airplanes, 
and replacing any cracked, worn, or ill-fitting part. This action 
retains the same action required in AD 84-23-06, except the action is 
only applicable to the BN-2A MK. 111 series airplanes. This action is 
the result of a terminating modification, now available to the Pilatus 
Models BN-2, BN-2A, BN-2B, BN-2T airplanes, which removes them from the 
applicability of AD 84-23-06. The actions specified by this AD are 
intended to prevent failure of the upper mounting brackets on wing 
mounted engines, which could possibly cause structural failure of the 
airplane.

DATES: Effective November 24, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 24, 1997.

ADDRESSES: Service information that applies to this AD may be obtained 
from Pilatus Britten-Norman Limited, Bembridge, Isle of Wight, United 
Kingdom PO35 5PR; telephone 44-19-83-872511; facsimile 44-19-83-873246. 
This information may also be examined at the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket 84-CE-18-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, Project Officer, 
Small Airplane Directorate, Aircraft 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 BN-2, BN-2A, 
BN-2B, BN-2T, and BN-2A MK. 111 series was published in the Federal 
Register on March 10, 1997 (62 FR 10756). The proposed AD would revise 
AD 84-23-06 by deleting the Pilatus BN-2, BN-2A, BN-2B, BN-2T series 
airplanes from the AD, and by retaining the following for the Pilatus 
BN-2A MK. 111 series airplanes:
    (1) Visually inspecting the upper engine mounting bracket lugs for 
cracks extending radially from the bolt holes in the doubler;
    (2) Inspecting for elongation of the bolt holes, distortion, 
delamination, cracks, flaking, and corrosion;
    (3) Inspecting the bolts for correct bearing length, and loose and 
fretted bushings; and
    (4) Correcting any discrepancies found.
    Accomplishment of this action will be in accordance with Pilatus 
Britten-Norman Ltd. Service Bulletin (SB) BN-2/SB.61, Issue 5, dated 
December 9, 1981, which is also referenced in the Notice of Proposed 
Rulemaking (NPRM) Docket 96-CE-17-AD for a terminating action 
applicable to the Pilatus BN-2, BN-2A, BN-2B and BN-2T series 
airplanes.
    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.

Cost Impact

    The FAA estimates that 9 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 2 workhours per 
airplane to accomplish this action and the average labor rate is 
approximately $60 an hour. There are no parts required for the initial 
inspection. Based on these figures, the total cost impact for the 
initial inspection of this AD on U.S. operators is estimated to be 
$1,080 or $120 per airplane. This figure is based on the initial 
inspection cost and does not include workhours for repetitive 
inspections because the FAA does not have the information to determine 
the number of repetitive inspections that would be incurred over the 
life of the airplane.

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

[[Page 55157]]

``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 removing Airworthiness Directive 
(AD) 84-23-06, Amendment 39-4942, (49 FR 43621, October 31, 1984), and 
adding a new AD to read as follows:

84-23-06  R1. Pilatus Britten-Norman LTD.: Amendment 39-10172; 
Docket No. 84-CE-18-AD; Revises AD 84-23-06, Amendment 39-4942.

    Applicability: BN-2A MK. 111 Series 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 (d) 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.
    Note 2: The paragraph structure of this AD is as follows:

Level 1: (a), (b), (c), etc.
Level 2: (1), (2), (3), etc.
Level 3: (i), (ii), (iii), etc.

Level 2 and Level 3 structures are designations of the Level 1 
paragraph they immediately follow.

    Compliance: Required initially upon the accumulation of 500 
hours time-in-service (TIS) or within the next 50 hours TIS after 
the effective date of this AD, whichever occurs later, unless 
already accomplished (compliance with AD 84-23-06), and thereafter 
at intervals not to exceed 500 hours TIS.
    To prevent failure of the upper mounting brackets on both wing 
mounted engines, which could possibly cause structural failure of 
the airplane, accomplish the following:
    (a) Visually inspect the following areas in accordance with 
paragraphs 1 through 6 of the ``Inspection'' section of the Pilatus 
Britten-Norman (Pilatus) Service Bulletin (SB) No. BN-2/SB.61, Issue 
5, dated December 9, 1981:
    (1) The upper engine to wing mounting brackets for:
    (i) Minimum lug bolt hole-to-edge distance, elongation of the 
bolt holes, distortion, delamination, cracks, flaking, and 
corrosion;
    (ii) The bolts for correct bearing length; and
    (iii) Loose and fretted bushings.
    (2) Prior to further flight, correct defects in accordance with 
the following:
    (i) If the lug bolt hole-to-edge distance is less than the 
specified minimum (0.2625-inches), correct in accordance with 
paragraph 3 of the ``Rectification/Modification'' section of Pilatus 
SB No. BN-2/SB.61, Issue 5, dated December 9, 1981;
    (ii) If the bolt holes are elongated, or if any bushings are 
loose or fretted, modify and correct in accordance with paragraph 4 
of the ``Rectification/Modification'' section of Pilatus SB No. BN-
2/SB.61, Issue 5, dated December 9, 1981;
    (iii) If any mounting bracket is cracked, modify both brackets 
on the same engine installation (left side engine or right side 
engine) concurrently (even if only one bracket is defective) in 
accordance with paragraph 1 of the ``Rectification/Modification'' 
section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 
1981;
    (iv) If any lug is distorted or delaminated, replace the 
deficient part in accordance with paragraphs 1 and 2 of the 
``Rectification/Modification'' section of Pilatus SB No. BN-2/SB.61, 
Issue 5, dated December 9, 1981;
    (v) If any inspected part is corroded or flaking, replace the 
part in accordance paragraph 1 with the ``Rectification/
Modification'' section of Pilatus SB No. BN-2/SB.61, Issue 5, dated 
December 9, 1981; and
    (vi) If any of the bolts are of incorrect length or damaged, 
replace with new units of the correct length in accordance with 
paragraphs 1 and 2 of the ``Rectification/Modification'' section of 
Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981.
    (b) The intervals between the repetitive inspections required by 
this AD may be adjusted up to 10 percent of the specified interval 
to allow for accomplishing these inspections concurrent with the 
other scheduled maintenance of the airplane.
    (c) 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.
    (d) 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, Aircraft Certification Service, FAA, 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (e) The inspections, modifications, and replacements, required 
by this AD shall be done in accordance with Pilatus Britten-Norman 
Service Bulletin No. BN-2/SB.61, Issue: 5, Date: December 9, 1981. 
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 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.
    (f) This amendment (39-10172) becomes effective on November 24, 
1997.

    Issued in Kansas City, Missouri, on October 16, 1997.
Mary Ellen A. Schutt,
Acting Manger, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-27931 Filed 10-22-97; 8:45 am]
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