[Federal Register Volume 62, Number 127 (Wednesday, July 2, 1997)]
[Rules and Regulations]
[Pages 35670-35672]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-17098]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-CE-24-AD; Amendment 39-10058; AD 97-14-01]
RIN 2120-AA64
Airworthiness Directives; Pilatus Britten-Norman Ltd. BN-2A and
BN-2A Mk 111 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes 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 superseding action requires
inspecting the LH rudder bar assembly and determining the wall
thickness of the slider tube unit. This action also would require
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 currently required by AD 75-24-07 R1. The
development of a modification to the rudder bar assembly, which
terminates
[[Page 35671]]
the repetitive inspections required by AD 75-24-07 R1, prompted this
AD. The actions specified by this AD are intended to prevent failure of
the pilot's rudder bar assembly, which could result in loss of control
of the airplane during landing operations.
DATES: Effective August 18, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 18, 1997.
ADDRESSES: Service information that applies to this 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 may also be examined at the Federal Aviation
Administration (FAA), Central Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket 96-CE-24-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 Britten-
Norman Ltd. BN-2A and BN-2A Mk 111 series airplanes was published in
the Federal Register on March 3, 1997 (62 FR 9390). The action proposed
to 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, accomplishing
Modification NB/M/948 by installing P/N NB-45-A1-2975.
Accomplishment of the proposed action would be in accordance with
Pilatus Britten-Norman Service Bulletin No. BN-2/SB.111, Issue 1, dated
October 25, 1977 or Pilatus Britten-Norman Service Bulletin No. BN-2/
SB.56, Issue 2, dated February 13, 1978, whichever is applicable.
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.
FAA's Aging Aircraft Commuter Class Policy
The actions required by this AD are consistent with the FAA's aging
commuter aircraft policy, which briefly states that, when a
modification exists that could eliminate or reduce the number of
required critical inspections, the modification should be incorporated.
This policy is based on the FAA's determination that reliance on
critical repetitive inspections on airplanes utilized in commuter
service 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 of the airplane
if the known problem is not detected by the inspection; (2) the
reliability of the inspection such as the probability of not detecting
the known problem; (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.
Compliance Time
The compliance time for this AD is based on number of landings
rather than hours time-in-service. The reason for this type of
compliance is that the area that is showing fatigue is the pilot's
rudder bar assembly and piller/slider tube unit. This area of the
airplane is used during the landing operation; furthermore, the stress
and fatigue is greater in this thinner gauged metal slider tube unit
upon landing. Therefore, it has been determined to use the number of
landings rather than hours time-in-service as the compliance time for
this AD.
For airplanes equipped with the thinner (20 gauge) slider tubes,
the AD requires accomplishing the modification upon the total
accumulation of 2,500 landings, or within the next 500 landings after
the effective date of the action, whichever occurs later; and for
airplanes equipped with the thicker (17 gauge) slider tubes, the AD
requires accomplishing the modification within the next 500 landings
after the effective date of the action or upon the total accumulation
of 5,000 landings, whichever occurs later.
(Note: If the operators have not recorded the number of
landings, the landings can be calculated by multiplying 3 landings
per 1 hour time-in-service.)
Cost Impact
The FAA estimates that 109 airplanes in the U.S. registry will be
affected by this AD, that it will take approximately 15 workhours per
airplane to accomplish this 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 this AD on U.S.
operators is estimated to be $159,140 or $1,460 per airplane. 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.
The AD'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 will be
affected by this 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,
[[Page 35672]]
operators of commuter-class airplanes involved in commercial operation
will have to accomplish the modification within approximately 3 to 5
calendar months after the AD becomes effective. For private owners, who
typically operate their airplanes between 100 to 200 landings per year,
this will allow 12 to 25 years before the modification will be
mandatory.
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 removing airworthiness directive
(AD) 75-24-07 R1, Amendment 39-4571 and by adding a new AD to read as
follows:
97-14-01 Pilatus Britten-Norman, Ltd.: Amendment 39-10058; Docket
No. 96-CE-24-AD.
Applicability: BN-2A and 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 (f) 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.
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 during landing operations, 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, and paragraphs 1 through 3
in the ACTION section of PBN SB No. BN-2/SB.56, Issue 2, dated
February 13, 1978.
Note 2: For operators who have not kept records of the landings
of the airplane, use 3 landings per 1 hour time-in-service (TIS).
(b) 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:
(1) For airplanes that have slider tubes with 17 gauge metal
(.056-inch thick),
(i) 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 No. BN-2/
SB.111, dated October 25, 1977.
(2) For airplanes that have slider tubes with 20 gauge metal
(.036-inch thick),
(i) Continue to inspect the LH rudder bar assembly for cracks
every 250 landings and,
(ii) 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, P/N NB-45-A1-2975 in accordance with
the ACTION Rectification section of PBN SB No. BN-2/SB.111, dated
October 25, 1977.
(c) 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 No. BN-2/
SB.111, dated October 25, 1977.
(d) 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 (b)(1)(ii) and (b)(2)(ii) of this AD is a terminating
action for the repetitive inspections required by this AD.
(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 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, 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.
(g) The inspections and modifications required by this AD shall
be done in accordance with Pilatus Britten-Norman Service Bulletin
No. BN-2/SB.111, Issue 1, dated October 25, 1977, or Pilatus
Britten-Norman Service Bulletin No. BN-2/SB.56, Issue 2, dated
February 13, 1978, whichever is applicable. 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 Pilatus Britten-Norman Ltd., Bembridge, Isle of Wight,
United Kingdom PO35 5PR. Copies may be inspected at the FAA, Central
Region, Office of the Assistant Chief 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 supersedes AD 75-24-07 R1, Amendment 39-4571.
(i) This amendment (39-10058) becomes effective on August 18,
1997.
Issued in Kansas City, Missouri, on August 18, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-17098 Filed 7-1-97; 8:45 am]
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