[Federal Register Volume 62, Number 46 (Monday, March 10, 1997)]
[Proposed Rules]
[Pages 10756-10758]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5840]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 84-CE-18-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to revise 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) BN-2, BN-2A, BN-
2B, BN-2T, and BN-2A Mk 111 series airplanes, and replacing any 
cracked, worn, or ill-fitting part. The proposed action would retain 
the same action required in AD 84-23-06, except the action would only 
be applicable to the BN-2A Mk 111 series airplanes. The proposed action 
is prompted by a terminating modification only applicable to the 
Pilatus BN-2, BN-2A, BN-2B, BN-2T series airplanes that would remove 
them from the applicability of AD 84-23-06. The actions specified by 
the proposed 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: Comments must be received on or before May 12, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 84-CE-18-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 (322) 508-2715; facsimile 
(322) 230-6899;
    or
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:

Comments Invited

    Interested persons are invited to participate in the making of the

[[Page 10757]]

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. 84-CE-18-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. 84-CE-18-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 (UK), notified the FAA that an unsafe 
condition may exist on certain Pilatus BN-2A Mk 111 series airplanes. 
The CAA reports that several incidents have revealed cracking, wear, 
and ill-fitting parts in the upper wing mount brackets on the wing 
mounted engines which could eventually result in structural failure of 
the wing. This condition, if not detected and corrected, could result 
in failure of the engine mounting brackets of the wing mounted engines 
and possible structural failure and loss of control of the airplane. 
Pilatus has issued service bulletin BN-2/SB.61, Issue 5, dated December 
9, 1981, which specifies inspecting for cracked, worn, or ill-fitting 
parts, and if found, repair and continue to repetitively inspect.
    This service bulletin is also referenced in AD 84-23-06. The 
proposed action would be a revision to AD 84-23-06 to remove the 
Pilatus BN-2, BN-2A, BN-2B and BN-2T series airplanes from the 
applicability of AD 84-23-06. Since publication of this AD, a 
modification terminating the repetitive inspections became available to 
the Pilatus BN-2, BN-2A, BN-2B and BN-2T series airplanes that is not 
applicable to the BN-2A Mk 111 series airplanes. The terminating 
modification is proposed in a Notice for Proposed Rulemaking (NPRM) 
Docket No. 96-CE-17-AD. The Pilatus Service Bulletin (SB) BN-2/SB.61, 
Issue 5, dated December 9, 1981, is also referenced in this NPRM for 
the terminating action applicable to the Pilatus BN-2, BN-2A, BN-2B and 
BN-2T series airplanes.
    The UK CAA classified this service bulletin as mandatory and issued 
AD No. 0619 in order to assure the continued airworthiness of these 
airplanes in the United Kingdom.
    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 UK CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the UK CAA, reviewed all available information, and 
determined that AD action is necessary for products of this type design 
that are certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop in other Pilatus BN-2A Mk 111 series airplanes of the 
same type design registered for operation in the United States, the 
proposed AD would revise AD 84-23-06 to eliminate Pilatus BN-2, BN-2A, 
BN-2B, BN-2T series airplanes from the applicability of this AD and 
would retain the Pilatus BN-2A Mk 111 series airplanes in the 
applicability section of the proposed AD, and would also retain the 
requirement for:
    (1) Visually inspecting the upper engine to wing mounting brackets 
for minimum lug bolt hole-to-edge distance (0.2625 inches),
    (2) Inspecting for elongation of the bolt holes, distortion, 
delamination, cracks, flaking, and corrosion, and
    (3) Inspecting the bolts for correct bearing length, and loose and 
fretted bushings.
    If the lug bolt hole-to-edge distance is less than the specified 
minimum, prior to further flight, correct the defects. If the bolt 
holes are elongated, or if any bushings are loose or fretted, modify 
and correct. 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). If any lug is 
distorted or delaminated, replace the deficient part. If any part is 
corroded or flaking, replace the part. If any of the bolts are of 
incorrect length or damaged, replace with new units of the correct 
length and continue to repetitively inspect.

Cost Impact

    The FAA estimates that 9 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 2 
workhours per airplane to accomplish the proposed 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 the proposed AD on U.S. 
operators is estimated to be $1,080 or $120 per airplane. This figure 
is based on the proposed initial inspection cost and does not include 
workhours for repetitive inspections. The FAA has no way to determine 
how many of these airplanes have already accomplished this action.

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.

[[Page 10758]]

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 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:

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

    Applicability: BN-2T 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, 
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 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 the following areas:
    (1) The upper engine to wing mounting brackets for:
    (i) Minimum lug bolt hole-to-edge distance (0.2625 inches), 
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, 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 with paragraph 1 of 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, Brussels Aircraft 
Certification Division, FAA, Europe, Africa, and Middle East Office, 
c/o American Embassy, B-1000 Brussels, Belgium; telephone (322) 
508.2715; facsimile(322) 230.6899; or Mr. S. M. Nagarajan, Project 
Officer, 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, 
Brussels Aircraft Certification Office or 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 Brussels Aircraft Certification Division or the 
Small Airplane Directorate.

    (e) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to Pilatus Britten-
Norman Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR; 
telephone 44-1983 872511; facsimile 44-1983 873246; or may examine 
this document 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 28, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-5840 Filed 3-7-97; 8:45 am]
BILLING CODE 4910-13-U