[Federal Register Volume 62, Number 46 (Monday, March 10, 1997)]
[Proposed Rules]
[Pages 10754-10756]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5846]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 /
Proposed Rules
[[Page 10754]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-CE-17-AD]
RIN 2120-AA64
Airworthiness Directives; Pilatus Britten-Norman Ltd. BN-2, 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
(AD) that would apply to Pilatus Britten-Norman Ltd. (Pilatus) BN-2,
BN-2A, BN-2B, and BN-2T series airplanes. The proposed action would
require modifying the upper engine mounting brackets on the wing front
spar as terminating action for the repetitive inspections that were
required in AD 84-23-06, which is the subject of a proposal to
eliminate the Pilatus BN-2, BN-2A, BN-2B, and BN-2T series airplanes
from its applicability in a separate action. The proposed action is
prompted by several reports of cracks in the upper engine mounting
brackets and a new terminating action to eliminate the repetitive
inspections for Pilatus BN-2, BN-2A, BN-2B, and BN-2T series airplanes.
The actions specified by the proposed AD are intended to prevent the
failure of the engine mounting brackets on the 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. 96-CE-17-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 Ltd., 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: Tom Rodriguez, Project Engineer, FAA,
Brussels Aircraft Certification Division, Europe, Africa, and Middle
East Office, c/o American Embassy, B-1000 Brussels, Belgium; telephone
(322) 513.3830, ext. 2716; 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 64105; 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-17-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-17-AD, Room 1558, 601 E. 12th Street,
Kansas City, Missouri 64106.
Events Leading to the Proposed Action
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 Pilatus BN-2, BN-2A, BN-2B, and BN-2T series
airplanes. The UK CAA reports cracking in the upper engine mounting
brackets on the wing mounted engines attached to the wing front spar.
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.
The Pilatus BN-2, BN-2A, BN-2B, and BN-2T series airplanes are
included in the applicability section of AD 84-23-06. A proposal to
remove these airplanes from the applicability of AD 84-23-06 is being
issued in a separate revised Notice of Proposed Rulemaking. The
repetitive inspections that have been required by AD 84-23-06 would be
terminated with a modifying action that is only applicable to the BN-2,
BN-2A, BN-2B, and BN-2T series airplanes in this proposed action.
The FAA's Aging Aircraft Policy
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
[[Page 10755]]
aircraft policy that requires incorporating a known design change when
it could replace a critical repetitive inspection.
Based on its aging commuter-class aircraft policy and after
reviewing all available information, the FAA has determined that AD
action should be taken to modify the upper engine wing mounting
brackets of the affected airplanes to eliminate the repetitive short-
interval inspections, and to prevent failure of the upper engine wing
mounting brackets on wing mounted engines which could possibly cause
structural failure of the airplane.
Related Service Information
Pilatus issued Service Bulletin No. BN-2/SB.61, Issue 5, dated
December 9, 1981, which specifies procedures for modifying the engine
mounting brackets on the wing mounted engines and terminating the
repetitive inspection after accomplishing the modification.
The UK CAA classified these service bulletins as mandatory and has
issued AD No. 0619 in order to assure the continued airworthiness of
these airplanes in the United Kingdom.
FAA's Determination
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 including
the service information referenced above, 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-2, BN-2A, BN-2B, and BN-2T series
airplanes of the same type design registered in the United States, the
proposed AD would require initially inspecting the upper engine
mounting brackets on the wing mounted engines for:
(1) Cracks at the bolt-holes,
(2) Elongation of the bolt holes,
(3) Fretting within the holes,
(4) Cracks at the rivet holes,
(5) Distortion or delamination of the lugs, and that
(6) The bearings are the correct length and the bolts are not
threadbound.
If there is no evidence of damage or defects similar to any of the
above-mentioned items, continue to repetitively inspect at regular
intervals until the accumulation of 2,000 hours time-in-service after
the effective date of the proposed AD, at which time the proposed AD
would require accomplishing Pilatus Modification NB/M/1147.
If any damage or defects are found similar to any of the six items
previously mentioned, prior to further flight, the proposed action
would require accomplishing Pilatus Modification NB/M/1147. This
modification consists of replacing damaged brackets, bolts, and bushes
with parts of an improved design. Accomplishing this modification is
considered a terminating action to the proposed repetitive inspections.
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 37
workhours per airplane to accomplish the initial inspection and
modification, and that the average labor rate is approximately $60 an
hour. Parts cost approximately $800 per airplane to accomplish the
modification. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $338,240 or $3,020 per
airplane. This figure is based on the initial inspection and
modification only. It does not take into account the cost for the
repetitive inspections that may be incurred over the life of the
airplane until the modification is accomplished. The FAA has no way to
determine the number of owners/operators that may have already
accomplished the proposed action.
The Proposed Action's Impact Utilizing the FAA's Aging Commuter Class
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
18 percent are operated in scheduled passenger service by 11 different
operators. A significant number of the remaining 82 percent are
operated in other forms of air transportation such as air cargo and air
taxi.
The proposed AD allows 2,000 hours time-in-service (TIS) after the
effective date of the proposed AD before mandatory accomplishment of
the design modification. 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-class
airplanes involved in commercial operation would have to accomplish the
proposed modification within 5 to 10 calendar months 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
before the proposed modification would be mandatory.
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.
[[Page 10756]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
Pilatus Britten-Norman Ltd.: Docket No. 96-CE-17-AD.
Applicability: Models BN-2 (serial numbers 1 through 2033), BN-
2T (serial numbers 419, and 2030 through 2033), and Models BN-2A and
BN-2B (serial numbers 1 through 2116), 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 (g) 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 within the next 500 hours time-in-service
(TIS) after the last compliance with AD 84-23-06, or within the next
100 hours TIS after the effective date of this AD, whichever occurs
later, unless already accomplished.
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) Inspect the upper mounting brackets, bolts, and bushings on
both wing mounted engines for:
(1) Cracks at the bolt holes,
(2) Elongation of the bolt holes,
(3) Fretting within the bolt holes,
(4) Cracks at the rivet holes,
(5) Distortion or delamination of the lugs, and
(6) Correct bearing length and inspect for bolts that are
threadbound, in accordance with the ``ACTION--Inspection'' section
in Pilatus Britten-Norman (Pilatus) Service Bulletin (SB) No. BN-2/
SB.61, Issue 5, dated December 9, 1981.
(b) If the inspection reveals any evidence of damage or defects
similar to the items in paragraphs (a)(1) through (a)(6), prior to
further flight, accomplish Pilatus Modification NB/M/1147 by
replacing the brackets, bushes, and bolts with brackets (part number
(P/N) NB-20-D-7165), bushes (P/N NB-20-A4-7171), and bolts of
improved design in accordance with paragraphs 1, 2, 3, and 5 of the
``ACTION--Rectification/Modification'' section in Pilatus SB No. BN-
2/SB.61, Issue 5, dated December 9, 1981.
(c) If damage or defects are found on just one of the two
brackets on each engine, then both brackets must be replaced, prior
to further flight, in accordance with paragraph 1 of the ``ACTION--
Rectification/Modification'' section in Pilatus SB No. BN-2/.SB.61,
Issue 5, dated December 9, 1981.
(d) If no damage or defects are found similar to the items in
paragraphs (a)(1) through (a)(6) of this AD, continue to inspect at
intervals not to exceed 500 hours TIS until the accumulation of
2,000 hours TIS after the effective date of this AD, at which time
Modification NB/M/1147 must be accomplished on both upper mounting
brackets on both engines in accordance with paragraphs 1, 2, 3, and
5 of the ``ACTION--Rectification/Modification'' section of Pilatus
SB No. BN-2/SB.61, Issue 5, dated December 9, 1981.
(e) Accomplishing Modification NB/M/1147 in the ``ACTION--
Rectification/Modification'' section of Pilatus SB No. BN-2/SB.61,
Issue 5, dated December 9, 1981, is considered terminating action to
the repetitive inspections required in paragraph (d) of this AD.
(f) 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.
(g) 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, and Middle East Office, c/o
American Embassy, B-1000 Brussels, Belgium or the Manager, Small
Airplane Directorate, 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 Division or the Small
Airplane Directorate.
Note 2: 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.
(h) All persons affected by this directive may obtain copies of
the document referred to herein upon request to Pilatus Britten-
Norman Ltd., Bembridge, Isle of Wight, United Kingdom PO35 5PR; 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. 97-5846 Filed 3-7-97; 8:45 am]
BILLING CODE 4910-13-U
