[Federal Register Volume 62, Number 41 (Monday, March 3, 1997)]
[Proposed Rules]
[Pages 9390-9392]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5157]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-CE-24-AD]
RIN 2120-AA64
Airworthiness Directives; Pilatus Britten-Norman Ltd. BN-2A 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 supersede Airworthiness Directive
(AD) 75-24-07 R1, which currently requires repetitively inspecting the
left-hand (LH) rudder bar assembly for cracks and loose fasteners on
certain Pilatus Britten-Norman Ltd. BN-2A and BN-2A Mk 111 series
airplanes, and replacing any cracked part. The Federal Aviation
Administration's policy on aging commuter-class aircraft is to
eliminate certain repetitive short-interval inspections when improved
parts or modifications are available. The proposed action would require
inspecting the LH rudder bar assembly, determining the wall thickness
of the slider tube unit, modifying the rudder bar assembly by replacing
the LH slider tube with a new strengthened slider tube unit as
terminating action for the repetitive inspections that are currently
required by AD 75-24-07 R1. The actions specified in the proposed AD
are intended to prevent failure of the pilot's rudder bar assembly,
which, if not detected and corrected, could result in loss of control
of the airplane.
DATES: Comments must be received on or before May 5, 1997.
ADDRESSES: Submit comments on the proposal in triplicate to the Federal
Aviation Administration (FAA), Central Region, Office of the Assistant
Chief Counsel, Attention: Rules Docket No. 96-CE-24-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: 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
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-24-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-24-AD, Room 1558, 601 E. 12th Street,
Kansas City, Missouri 64106.
[[Page 9391]]
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
the change could replace a critical repetitive inspection. With this
policy in mind, the FAA recently conducted a review of existing ADs
that apply to certain Pilatus Britten-Norman Ltd. (PBN) BN-2A and BN-2A
Mk 111 series airplanes. Assisting the FAA in this review were (1)
Pilatus Britten-Norman Ltd.; (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 Airworthiness Directive
75-24-07 R1, Amendment 39-4571, as one that should be superseded with a
new AD that would require a modification eliminating the need for
short-interval and critical repetitive inspections. AD 75-24-07 R1
currently requires repetitively inspecting the LH rudder bar assembly
for cracks and loose fasteners on certain PBN BN-2A and BN-2A Mk 111
series airplanes, and replacing any cracked part.
Related Service Information
Pilatus Britten-Norman, Ltd. has issued Service Bulletin (SB) No.
BN- 2/SB. 111, Issue: 1, dated October 25, 1977 and SB BN-2/SB.56,
Issue 2, dated February 13, 1978 which specifies procedures for
installing Modification NB/M/948 which is a new, strengthened LH slider
tube unit that does not require the repetitive inspection of AD 75-24-
07 R1.
FAA's Determination
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 eliminate the repetitive short-interval
inspections required by AD 75-24-07 R1, Amendment 39-4571, and to
prevent failure of the LH rudder bar assembly, which, if not detected
and corrected, could result in loss of control of the airplane.
Explanation of the Provisions of the Proposed AD
Since an unsafe condition has been identified that is likely to
exist or develop in other PBN BN-2A and BN-2A Mk 111 series airplanes
of the same type design, the proposed AD would supersede AD 75-24-07 R1
with a new AD that would require:
(1) Inspecting for cracks in the LH rudder bar assembly using a dye
penetrant method, and measuring the thickness of the slider tube to
determine the applicability of the proposed action, either .056-inch
(17 gauge) or .036-inch (20 gauge),
(2) Repetitively inspecting for cracks until the accumulation of a
determined number of landings, then accomplishing Modification NB/M/948
by installing a new, strengthened central piller/slider tube assembly,
part number (P/N) NB-45-A1-2975, and
(3) If cracks are found during any inspection, prior to further
flight, accomplish Modification NB/M/948 by installing P/N NB-45-A1-
2975.
The proposed actions would be accomplished in accordance with
Pilatus SB No. BN-2/SB. 111, Issue: 1, dated October 25, 1977, and
Pilatus SB No. BN-2/SB.56, Issue 2, dated February 13, 1978.
Proposed Compliance Time
For airplanes equipped with the thinner (20 gauge) slider tubes,
the proposed AD would require accomplishing the modification upon the
total accumulation of 2,500 landings, or within the next 500 landings
after the effective date of the proposed action, whichever occurs
later; and for airplanes equipped with the thicker (17 gauge) slider
tubes, the proposed AD would require accomplishing the modification
within the next 500 landings after the effective date of the proposed
action or upon the total accumulation of 5,000 landings, whichever
occurs later.
Note: If the operator has not recorded the number of landings,
they can be figured by calculating 3 landings per 1 hour time-in-
service.
Cost Impact
The FAA estimates that 109 airplanes in the U.S. registry would be
affected by the proposed AD, that it would take approximately 15
workhours per airplane to accomplish the proposed action, and that the
average labor rate is approximately $60 an hour. Parts cost
approximately $560 per airplane. Based on these figures, the total cost
impact of the proposed AD on U.S. operators is estimated to be $159,140
or $1,460 per airplane. The FAA has no way to determine the number of
affected owners/operators who may have accomplished the proposed action
and therefore must assume that none of the affected owners/operators of
the affected airplanes have 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 109 airplanes in the U.S. registry that would be
affected by the proposed AD, the FAA has determined that approximately
30 percent are operated in scheduled passenger service by 11 different
operators. A significant number of the remaining 70 percent are
operating in other forms of air transportation such as air cargo and
air taxi.
The average utilization of the fleet for those airplanes in
commercial commuter service is approximately 20 to 40 landings per week
with approximately 3 landings per 1 hour TIS per week. Based on these
figures, operators of commuter-class airplanes involved in commercial
operation would have to accomplish the proposed modification within
approximately 3 to 5 calendar months after the proposed AD would become
effective. For private owners, who typically operate their airplanes
between 100 to 200 landings per year, this would allow 12 to 25 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
[[Page 9392]]
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 14
CFR part 39 of the Federal Aviation Regulations as follows:
1. The authority citation for part 39 continues to read as follows:
PART 39--AIRWORTHINESS DIRECTIVES
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Airworthiness Directive
(AD), 75-24-07 R1, Amendment 39-4571, and by adding a new AD to read as
follows:
Pilatus Britten-Norman: Docket No. 96-CE-24-AD; Supersedes AD 75-24-
07 R1, Amendment 39-4571.
Applicability: BN-2A and BN-2A Mk 111 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.
Compliance: Required as indicated after the effective date of
this AD, unless already accomplished. For operators who have not
kept records of the landings of the airplane, use 3 landings per 1
hour time-in-service (TIS).
To prevent failure of the left-hand (LH) rudder bar assembly,
which, if not detected and corrected, could result in loss of
control of the airplane, accomplish the following:
(a) Within the next 500 landings after the effective date of
this AD, inspect the LH rudder bar unit for cracks (using a dye
penetrant method), and measure the thickness/gauge of the LH slider
tube in accordance with paragraph 1. of the ACTION Inspection
section of Pilatus Britten-Norman (PBN) Service Bulletin (SB) No.
BN-2/SB.111, Issue 1, dated October 25, 1977 or paragraphs 1 through
3 in the ACTION section of PBN BN-2/SB.56, Issue 2, dated February
13, 1978.
(1) If no cracks are visible, accomplish the following in
accordance with paragraph 3a. and 3b. of the ACTION Inspection
section of PBN SB No. BN-2/SB.111, dated October 25, 1977:
(i) For airplanes that have slider tubes with 17 gauge metal
(.056-inch thick), continue to inspect the LH rudder bar assembly
for cracks every 500 landings and,
(ii) Upon the total accumulation of 5,000 landings or within the
next 500 landings after the effective date of this AD, whichever
occurs later, accomplish Modification NB/M/948 by installing a new,
strengthened slider tube unit, part number (P/N) NB-45-A1-2975, in
accordance with the ACTION Rectification section of PBN SB BN-2/
SB.111, dated October 25, 1977.
(iii) For airplanes that have slider tubes with 20 gauge metal
(.036-inch) continue to inspect the LH rudder bar assembly for
cracks every 250 landings and,
(iv) Upon the total accumulation of 2,500 landings or within the
next 500 landings after the effective date of this AD, whichever
occurs later, accomplish Modification NB/M/948 by installing a new,
strengthened slider tube unit, part number (P/N) NB-45-A1-2975, in
accordance with the ACTION Rectification section of PBN SB BN-2/
SB.111, dated October 25, 1977.
(2) If cracks are visible during any inspection required by this
AD, prior to further flight, accomplish Modification NB/M/948 in
accordance with the ACTION Rectification section of PBN SB BN-2/
SB.111, dated October 25, 1977.
(b) Accomplishing Modification NB/M/948 using P/N NB-45-A1-2975
at any time prior to the required number of accumulated landings in
paragraphs (a)(1)(ii) and (iv) of this AD is terminating action for
the repetitive inspections.
(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; or 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, Brussels
Aircraft Certification Division or the Manager, 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.
(e) 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;
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.
(f) This amendment supersedes AD 75-24-07 R1, Amendment 39-4571.
Issued in Kansas City, Missouri, on February 24, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-5157 Filed 2-28-97; 8:45 am]
BILLING CODE 4910-13-U