[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]
BILLING CODE 4910-13-P