[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