[Federal Register Volume 66, Number 43 (Monday, March 5, 2001)]
[Proposed Rules]
[Pages 13271-13273]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-5169]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-CE-82-AD]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft LTD Models PC-12 and 
PC-12/45 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) 99-17-08, which currently requires modifying the generator 2 
excitation by removing certain diodes and installing a new 5-amp 
circuit breaker and suppression filter found on certain Pilatus 
Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. The 
Federal Aviation Administration has determined that the A250 voltage 
spike suppression filter in the modification kit can cause the circuit 
breaker 235 to trip because of overload. In extreme circumstances, this 
can lead to overheating of wiring. The proposed AD would require 
modifying the generator 2 excitation by removing certain diodes, 
installing a new 5-amp circuit breaker and new suppression filter 
requirement in accordance with revised procedures. The proposed AD is 
the result of mandatory continuing airworthiness information (MCAI) 
issued by the airworthiness authority for Switzerland. The actions 
specified by the proposed AD are intended to prevent damage to 
electrical components if generator 2 is not switched off before engine 
shutdown and it overheats. This could result in loss of electrical 
power to certain critical airplane components.

DATES: The FAA must receive any comments on this proposed rule by April 
12, 2001.

ADDRESSES: Send three copies of comments to FAA, Central Region, Office 
of the Regional Counsel, Attention: Rules Docket No. 99-CE-82-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. Comments may be 
inspected at this location between 8 a.m. and 4 p.m., Monday through 
Friday, except holidays.
    You may get service information that applies to the proposed AD 
from Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 65 09; facsimile: +41 41 610 33 51. 
You may also read this information at the Rules Docket at the address 
above.

FOR FURTHER INFORMATION CONTACT: Roman T. Gabrys, Aerospace Engineer, 
FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, 
Missouri 64106; telephone: (816) 329-4141; facsimile: (816) 329-4090.

SUPPLEMENTARY INFORMATION:

Comments Invited

    How do I comment on this proposed AD? We invite your comments on 
the proposed rule. You may send whatever written data, views, or 
arguments you choose. You need to include the rule's docket number and 
send your comments in triplicate to the address mentioned under the 
caption ADDRESSES. We will consider all comments received by the 
closing date mentioned above, before acting on the proposed rule. We 
may change the proposals contained in this notice because of the 
comments received.
    Are there any specific portions of the proposed AD I should pay 
attention to? The FAA specifically invites comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
rule that might call for a need to change the proposed rule. You may 
read all comments we receive. We will file a report in the Rules Docket 
that summarizes each FAA contact with the public that concerns the 
substantive parts of this proposal.
    The FAA is reexamining the writing style we currently use in 
regulatory documents, in response to the Presidential memorandum of 
June 1, 1998. That memorandum requires federal agencies to communicate 
more clearly with the public. We are interested in your comments on the 
ease of understanding this document, and any other suggestions you 
might have to improve the clarity of FAA communications that affect 
you. You can get more information about the Presidential memorandum and 
the plain language initiative at http://www.faa.gov/language/.
    How can I be sure FAA receives my comment? If you want us to 
acknowledge the receipt of your comments, you must include a self-
addressed, stamped postcard. On the postcard, write ``Comments to 
Docket No. 99-CE-82-AD.'' We will date stamp and mail the postcard back 
to you.

Discussion

    Has FAA taken any action to this point? The FAA issued AD 99-17-08, 
Amendment 39-11256 (64 FR 45149, August 19, 1999), against Pilatus 
models PC-12 and PC-12/45 airplanes, to prevent damage to electrical 
components if generator 2 is not switched off before engine shutdown 
and it overheats. This could result in loss of electrical power to 
certain critical airplane components of Pilatus Models PC-12 and PC-12/
45 airplanes.
    AD 99-17-08 requires that you do the following on the affected 
airplanes:

--modify the generator 2 excitation by removing certain diodes; and
--install a new 5-amp circuit breaker and suppression filter.

    AD 99-17-08 was the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for 
Switzerland.
    What has happened since AD 99-17-08 to begin this action? The 
Federal Office for Civil Aviation (FOCA), which is the airworthiness 
authority for Switzerland, recently notified FAA of the need to change 
AD 99-17-08. The FOCA reports that after installation of Pilatus 
Service Bulletin SB 21-012 and turning on electrical power on one of 
the affected airplanes, the circuit breaker CB 235 tripped.
    Investigation revealed that the suppression filter (A250) (part 
number 524.52.12.358) was shorted. The suppression diode, installed in 
the filter was shorted and the wrong type. The manufacturer's A250 
voltage spike suppression filter is inadequate and must be replaced 
with a new A250 voltage spike suppression filter.
    Is there service information that applies to this subject? Pilatus 
issued:

--Service Bulletin No 24-012, dated February 19, 1999; and
--Service Bulletin No 24-014, dated October 27, 1999.

    What are the provisions of these service bulletins? These service 
bulletins include procedures for:

--modifying the generator 2 excitation by removing certain diodes and 
installing a new 5-amp circuit breaker and suppression filter;
--removing the A250 voltage spike suppression filter; and
--installing the new A250 voltage spike suppression filter.

    What action did the FOCA take? The FOCA classified both service 
bulletins as mandatory and issued Swiss AD HB 99-143, dated February 
19, 1999, and AD HB 99-542, dated October 29, 1999, to assure the 
continued airworthiness of these airplanes in Switzerland.

[[Page 13272]]

    Was this in accordance with the bilateral airworthiness agreement? 
This airplane model is manufactured in Switzerland 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.
    Complying with this bilateral airworthiness agreement, the FOCA has 
kept FAA informed of the situation described above.

The FAA's Determination and an Explanation of the Provisions of the 
Proposed AD

    What has FAA decided? The FAA has examined the findings of the 
FOCA; reviewed all available information, including the service 
information referenced above; and determined that:

--the unsafe condition referenced in this document exists or could 
develop on other Pilatus Models PC-12 and PC-12/45 airplanes of the 
same type design that are equipped with one of the previously 
referenced stabilizer trim actuators;
--the actions specified in the previously-referenced service 
information should be done on the affected airplanes; and
--AD action should be taken to correct this unsafe condition.

    What would the proposed AD require? This proposed AD would 
supersede AD 99-17-08 with a new AD that would require you to 
incorporate the actions in the previously referenced service bulletins.

Cost Impact

    How many airplanes would the proposed AD impact? We estimate that 
the proposed AD affects 69 airplanes in the U.S. registry.
    What would be the cost impact of the proposed AD on owners/
operators of the affected airplanes? We estimate the following costs to 
do the proposed modification of the generator 2 excitation:

----------------------------------------------------------------------------------------------------------------
                                                                                                   Total cost on
                 Labor cost                               Parts cost              Total cost per   U.S. airplane
                                                                                     airplane        operators
----------------------------------------------------------------------------------------------------------------
8 workhours  x  $60 per hour = $480........  Parts will be provided at no cost              $480         $33,120
                                              to the owners/operators of the
                                              affected aircraft.
----------------------------------------------------------------------------------------------------------------

    If the modification of the generator 2 excitation has been done 
with the manufacturer's modification kit, then we estimate the 
following costs to remove the A250 voltage spike suppression filter and 
replace it with the new A250 voltage spike suppression filter:

----------------------------------------------------------------------------------------------------------------
                                                                                                   Total cost on
                 Labor Cost                               Parts cost              Total cost per   U.S. airplane
                                                                                     airplane        operators
----------------------------------------------------------------------------------------------------------------
3 workhours  x  $60. per hour = $180.......  Parts will be provided at no cost              $180         $12,420
                                              to the owners/operators of the
                                              affected aircraft.
----------------------------------------------------------------------------------------------------------------

Regulatory Impact

    Would this proposed AD impact various entities? The regulations 
proposed would not have a substantial direct effect 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. We have determined that this proposed rule would not 
have federalism implications under Executive Order 13132.
    Would this proposed AD involve a significant rule or regulatory 
action? For the reasons discussed above, I certify that this proposed 
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. You may request copy 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, under 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.


Sec. 39.13  [Amended]

    2. FAA amends Sec. 39.13 by removing airworthiness directive (AD) 
99-17-08, Amendment 39-11256 (64 FR 45149, August 19, 1999), and by 
adding a new AD to read as follows:

Pilatus Aircraft Ltd.: Docket No. 99-CE-82-AD; Supersedes AD 99-17-
08, Amendment 39-11256.

    (a) What airplanes are affected by this AD? This AD affects 
Models PC-12 and PC-12/45 airplanes, serial numbers 101 through 289, 
that are certificated in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes must comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to prevent damage to electrical components if 
generator 2 is not switched off before engine shutdown and it 
overheats. This could result in loss of electrical power to certain 
critical airplane components.
    (d) What actions must I accomplish to address this problem? To 
address this problem, unless already done, you must do the 
following:

[[Page 13273]]



------------------------------------------------------------------------
           Action                Compliance time         Procedures
------------------------------------------------------------------------
(1) Modify the generator 2    Within the next 100   Do this action
 excitation with the           hours time-in-        following the
 modification kit, part        service (TIS) after   ACCOMPLISHMENT
 number 500.50.12.192,         the effective date    INSTRUCTIONS
 replacing the A250 voltage    of this AD.           section of Pilatus
 spike suppression filter,                           Service Bulletin
 part number 524.52.12.358,                          No. 24-012, dated
 with a new A250 voltage                             February 19, 1999,
 spike suppression filter,                           and Service
 part number 524.52.12.502.                          Bulletin No. 24-
                                                     014, dated October
                                                     27, 1999.
(2) If the modification kit,  Within the next 100   Do this action
 part number 500.50.12.192,    hours TIS after the   following the
 is already installed using    effective date of     ACCOMPLISHMENT
 the A250 voltage spike        this AD.              INSTRUCTIONS
 suppression filter, part                            section of Pilatus
 number 524.52.12.358, only                          Service Bulletin
 replace this voltage spike                          No. 24-014, dated
 suppression filter with a                           October 27, 1999.
 new A250 voltage spike
 suppression filter, part
 number 524.52.12.502.
(3) Do not install any A250   As of the effective   Not Applicable.
 voltage spike suppression     date of this AD.
 filter, part number
 524.52.12.358, or FAA-
 approved equivalent part
 number.
------------------------------------------------------------------------

    (e) Can I comply with this AD in any other way? You may use an 
alternative method of compliance or adjust the compliance time if:
    (1) Your alternative method of compliance provides an equivalent 
level of safety; and
    (2) The Manager, Small Airplane Directorate, approves your 
alternative. Send your request through an FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Small Airplane Directorate.

    Note 1: This AD applies to each airplane identified in paragraph 
(a) of this AD, 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 (e) 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 you have not eliminated the unsafe condition, specific 
actions you propose to address it.

    (f) Where can I get information about any already-approved 
alternative methods of compliance? Contact Roman T. Gabrys, 
Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, 
Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4141; 
facsimile: (816) 329-4090.
    (g) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your airplane to a location where 
you can accomplish the requirements of this AD.
    (h) How do I get copies of the documents referenced in this AD? 
You may get copies of the documents referenced in this AD from 
Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 65 09; facsimile: +41 41 610 33 
51. You may read these documents at FAA, Central Region, Office of 
the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 
64106.

    Note 2: The subject of this AD is addressed in these Swiss AD's:
    --HB 99-143, dated February 19, 1999; and
    --HB 99-542, dated October 29, 1999.


    Issued in Kansas City, Missouri, on February 26, 2001.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certfication Service.
[FR Doc. 01-5169 Filed 3-2-01; 8:45 am]
BILLING CODE 4910-13-U