[Federal Register Volume 66, Number 246 (Friday, December 21, 2001)]
[Rules and Regulations]
[Pages 65829-65832]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-31102]



[[Page 65829]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-77-AD; Amendment 39-12563; AD 2001-25-10]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-12 and 
PC-12/45 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
supersedes Airworthiness Directive (AD) 99-19-32, which applies to 
certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 
airplanes. AD 99-19-32 currently requires you to inspect the flap 
actuator internal gear system for correct end-play and backlash 
measurements and accomplish any corrective adjustments, as necessary. 
Pilatus has identified modifications for the flap system and designed 
and manufactured a new flap control and warning unit (FCWU) that 
permits the flap power drive-unit circuit breaker to close during 
flight. This AD requires you to modify the flap control wiring and 
install a flap power drive-unit field control panel. The actions 
specified by this AD are intended to allow the flap power drive-unit 
circuit breaker to close during flight and prevent current surges in 
the flap control system. If the pilot cannot close the circuit breaker 
during flight, the flight control and warning unit (FCWU) would not 
sense a worn actuator. Current surges in the flap control system could 
decrease the electrical life of the flap power drive-unit motor 
contactor. Both conditions have the potential for flap system failure 
with consequent reduced or loss of control of the airplane.

DATES: This AD becomes effective on January 25, 2002.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulations as of 
January 25, 2002.

ADDRESSES: You may get the service information referenced in this AD 
from Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 619 6224; 
or from Pilatus Business Aircraft Ltd., Product Support Department, 
11755 Airport Way, Broomfield, Colorado 80021; telephone: (303) 465-
9099; facsimile: (303) 465-6040. You may view this information at the 
Federal Aviation Administration (FAA), Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2000-CE-77-AD, 901 
Locust, Room 506, 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: Doug Rudolph, Aerospace Engineer, FAA, 
Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 
64106; telephone: (816) 329-4059; facsimile: (816) 329-4090.

SUPPLEMENTARY INFORMATION:

Discussion

What Events Have Caused This AD?

    Reports of excessive backlash in the flap actuators of the internal 
gear system on certain Pilatus Models PC-12 and PC-12/45 airplanes 
caused FAA to issue AD 99-19-32, Amendment 39-11319 (64 FR 50439, 
September 17, 1999).
    AD 99-19-32 currently requires you to inspect the flap actuator 
internal gear system for correct end-play and backlash measurements and 
accomplish any corrective adjustments, as necessary.
    The Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, recently notified FAA of the 
need to change AD 99-19-32. The FOCA reports that Pilatus has 
identified modifications for the flap system and designed and 
manufactured a new flap control and warning unit (FCWU) that permits 
the flap power drive-unit circuit breaker to close during flight.
    The previous FCWU does not allow the pilot to close the flap power 
drive-unit circuit breaker during flight and the FCWU cannot sense when 
a single actuator becomes worn. This could result in flap panel 
distortion. The incorporation of these modifications to the flap system 
and the installation of the new design FCWU, Pilatus part number FCWU 
99-3, make the current end-play and backlash measurement procedures 
incorrect.
    Pilatus has also identified quality deficiencies with serial 
numbers less than 100,001 of Pilatus part number FCWU 99-3.
    In addition, the FOCA reports that electrical surges in the flap 
system can decrease the electrical life of the flap power drive-unit 
motor contactor. At the 40-degree flaps position, the flaps-down limit 
switch (S035) operates before the flap control warning unit can stop 
the extend command, which causes the flap power drive-unit's Up/Down 
relay (K32) to change from the extend to the retract position. The 
current in the field winding then goes in the opposite direction while 
a current still flows to the motor. Electrical current to the flap 
power drive-unit motor and field windings remains when the circuit 
breaker (CB034) closes and the motor contactor (K31 or K670) stays 
closed.

Has FAA Taken Any Action to This Point?

    We issued a proposal to amend part 39 of the Federal Aviation 
Regulations (14 CFR part 39) to include an AD that would apply to all 
Pilatus PC-12 and PC-12/45 airplanes. This proposal was published in 
the Federal Register as a notice of proposed rulemaking (NPRM) on 
September 20, 2001 (66 FR 48381). The NPRM proposed to supersede AD 99-
19-32 and proposed to require you to accomplish the following:

--Repetitively inspect the flap actuator internal gear system for 
correct end-play and backlash measurements with any necessary 
corrective adjustments;
--Incorporate certain modifications to the flap system and install a 
new design FCWU with a serial number of 100,001 or higher, or FAA-
approved equivalent part number; and
--Modify the flap control wiring and install a flap power drive-unit 
field control panel.

    Accomplishment of these proposed actions as specified in the NPRM 
would be required in accordance with the following:

--Pilatus PC-12 Service Bulletin No. 27-008, which incorporates the 
following pages:

------------------------------------------------------------------------
       Effective pages        Revision level             Date
------------------------------------------------------------------------
1, 2, and 11................               2  September 13, 2000.
3 through 10 and 12 through                1  June 26, 2000
 114.
------------------------------------------------------------------------


[[Page 65830]]

--Pilatus PC-12 Service Bulletin No. 27-012, dated September 13, 2000;
--Pilatus PC-12 Maintenance Manual Temporary Revision No. 27-13, dated 
April 30, 2000; and
--Pilatus PC-12 Service Bulletin No. 27-011, Revision No. 1, dated 
January 26, 2001.

    Note: We added to the final rule Pilatus PC-12 Maintenance 
Manual Temporary Revision No. 27-14 (which superseded Temporary 
Revision No. 27-13), dated December 4, 2000, and Pilatus PC-12 
Aircraft Maintenance Manual 27-50-03, pages 601 through 608, dated 
April 30, 2000.

What Is the Potential Impact if FAA Took No Action?

    These conditions, if not corrected, could cause the flap power 
drive-unit circuit breaker to not close during flight and cause current 
surges in the flap control system. Both conditions have the potential 
for flap system failure with consequent reduced or loss of control of 
the airplane.

Was the Public Invited To Comment?

    The FAA encouraged interested persons to participate in the making 
of this amendment. The following presents the comments received on the 
proposal and FAA's response to each comment:
Comment Issue No. 1: The AD Is not Necessary
    What is the commenter's concern? Several commenters state that the 
AD is not necessary and the actions that are currently required by AD 
99-19-32 are sufficient. The commenters request that FAA withdraw the 
NPRM.
    What is FAA's response to the concern? We do not concur that this 
AD is not necessary. As previously discussed, the unsafe conditions 
specified in this document, if not corrected, could cause the flap 
power drive-unit circuit breaker to not close during flight and cause 
current surges in the flap control system. If the pilot cannot close 
the circuit breaker during flight, the flight control and warning unit 
(FCWU) would not sense a worn actuator. Current surges in the flap 
control system could decrease the electrical life of the flap power 
drive-unit motor contactor. Both conditions have the potential for flap 
system failure with consequent reduced or loss of control of the 
airplane.
    We are not changing the final rule as a result of these comments.
Comment Issue No. 2: Change the Compliance Time
    What is the commenter's concern? One commenter suggests that FAA 
change the repetitive inspection interval for the actuator backlash 
from 100 hours time-in-service (TIS) to 600 hours TIS. This would 
coincide with Pilatus PC-12 Service Bulletin No. 27-008 and Pilatus PC-
12 Maintenance Manual Temporary Revision No. 27-14 (which superseded 
Temporary Revision No. 27-13), dated December 4, 2000, or Pilatus PC-12 
Aircraft Maintenance Manual 27-50-03, pages 601 through 608, dated 
April 30, 2000.
    What is FAA's response to the concern? We concur with this comment. 
Our intent was to make the repeat inspections at 600-hour TIS intervals 
once the improved design actuators were installed.
    We are changing the final rule to reflect:

--The change in repeat inspections from 100-hour TIS to 600-hour TIS 
intervals; and
--Reference to Pilatus PC-12 Maintenance Manual Temporary Revision No. 
27-14 (which superseded Temporary Revision No. 27-13), dated December 
4, 2000, or Pilatus PC-12 Aircraft Maintenance Manual 27-50-03, pages 
601 through 608, dated April 30, 2000.

FAA's Determination

What Is FAA's Final Determination on This Issue?

    We carefully reviewed all available information related to the 
subject presented above and determined that air safety and the public 
interest require the adoption of the rule as proposed except for the 
changes discussed above and minor editorial questions. We have 
determined that these changes and minor corrections:

--Provide the intent that was proposed in the NPRM for correcting the 
unsafe condition; and
--Do not add any additional burden upon the public than was already 
proposed in the NPRM.

Cost Impact

How Many Airplanes Does This AD Impact?

    We estimate that this AD affects 135 airplanes in the U.S. 
registry.

What Is the Cost Impact of This AD on Owners/Operators of the Affected 
Airplanes?

    We estimate the following costs to accomplish the initial 
inspection of the flap actuator internal gear system for end-play and 
backlash measurements. We have no way of determining the number of 
corrective adjustments each owner/operator of the affected airplanes 
would need to accomplish, the nature of such adjustments, or the number 
of repetitive inspections each owner/operator would incur. Therefore, 
the cost estimate only takes into account the cost of the proposed 
initial inspection:

----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
               Labor cost                              Parts cost                   airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
6 workhours  x  $60 per hour = $360....  Not Applicable.......................            $360          $48,600
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to incorporate certain 
modifications to the flap system and install a new design FCWU with a 
serial number of 100,001 or higher:

----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
                Labor cost                              Parts cost                  airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
70 workhours  x  $60 per hour = $4,200....  Pilatus will provide parts at no            $4,200         $567,000
                                             cost to the owner/operator.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to modify the flap control wiring 
and install a flap power drive-unit field control panel:

[[Page 65831]]



----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
                Labor cost                              Parts cost                  airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
5 workhours  x  $60 per hour = $300.......  Pilatus will provide parts at no              $300          $40,500
                                             cost to the owner/operator.
----------------------------------------------------------------------------------------------------------------

Regulatory Impact

Does This AD Impact Various Entities?

    The regulations adopted herein will 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.

Does This AD Involve a Significant Rule or Regulatory Action?

    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, under 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. FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 
99-19-32, Amendment 39-11319 (64 FR 50439, September 17, 1999), and 
adding a new AD to read as follows:

2001-25-10  Pilatus Aircraft Ltd.: Amendment 39-12563; Docket No. 
2000-CE-77-AD. Supersedes AD 99-19-32, Amendment 39-11319.

    (a) What airplanes are affected by this AD? This AD affects 
Models PC-12 and PC-12/45 airplanes, all serial numbers, that are 
certificated in any category. Carefully check paragraphs (d)(1) 
through (d)(6) of this AD for the specific actions that apply to 
each airplane. All airplanes will be affected by multiple actions 
specified in these paragraphs.
    (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 
the AD are intended to allow the flap power drive-unit circuit 
breaker to close during flight and prevent current surges in the 
flap control system. If the pilot cannot close the circuit breaker 
during flight, the flight control and warning unit (FCWU) would not 
sense a worn actuator. Current surges in the flap control system 
could decrease the electrical life of the flap power drive-unit 
motor contactor. Both conditions have the potential for flap system 
failure with consequent reduced or loss of control of the airplane.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) For airplanes that        Within the next 50    In accordance with
 incorporate a manufacturer    hours time-in-        the Accomplishment
 serial number (MSN) in the    service (TIS) after   Instructions
 range of 101 through 320,     January 25, 2002      section of Pilatus
 accomplish the following:.    (the effective date   PC-12 Service
                               of this AD), unless   Bulletin No. 27-
                               already               008, pages 1, 2,
                               accomplished.         and 11 at the
                                                     Revision 2 level,
                                                     dated September 13,
                                                     2000; and pages 3
                                                     through 10 and 12
                                                     through 114 at the
                                                     Revision 1 level,
                                                     dated June 26,
                                                     2000. Pilatus PC-12
                                                     Service Bulletin 27-
                                                     012, dated
                                                     September 13, 2000,
                                                     also relates to
                                                     this subject.
    (i) Do the modifications
     and installations to
     the flap system, as
     specified in the
     service information.
    (ii) Install a new
     design flap control and
     warning unit (FCWU)
     (Pilatus part number
     FCWU 99-3) with a
     serial number of
     100,001 or higher, or
     FAA-approved equivalent
     part number.
------------------------------------------------------------------------
(2) If you accomplished the   Within the next 50    In accordance with
 modifications required by     hours TIS after       the Accomplishment
 paragraph (d)(1) of this AD   January 25, 2002      Instructions
 in accordance with Pilatus    (the effective date   section of Pilatus
 PC-12 Service Bulletin 27-    of this AD), unless   PC-12 Service
 008, all pages at the         already               Bulletin No. 27-
 Revision 1 level, dated       accomplished.         008, pages 1, 2,
 June 26, 2000, you only                             and 11 at the
 have to install a new                               Revision 2 level,
 design FCWU (Pilatus part                           dated September 13,
 number FCWU 99-3) with a                            2000; and pages 3
 serial number of 100,001 or                         through 10 and 12
 higher, or FAA-approved                             through 114 at the
 equivalent part number..                            Revision 1 level,
                                                     dated June 26,
                                                     2000. Pilatus PC-12
                                                     Service Bulletin 27-
                                                     012, dated
                                                     September 13, 2000,
                                                     also relates to
                                                     this subject.
------------------------------------------------------------------------

[[Page 65832]]

 
(3) For airplanes that        Within the next 50    In accordance with
 incorporate an MSN in the     hours TIS after       the Accomplishment
 range of 321 through 331,     January 25, 2002      Instructions
 333, 335, 336, 338 through    (the effective date   section of Pilatus
 341, 343, or 345, install a   of this AD), unless   PC-12 Service
 new design FCWU (Pilatus      already               Bulletin No. 27-
 part number FCWU 99-3) with   accomplished.         008, pages 1, 2,
 a serial number of 100,001                          and 11 at the
 or higher, or FAA-approved                          Revision 2 level,
 equivalent part number..                            dated September 13,
                                                     2000; and pages 3
                                                     through 10 and 12
                                                     through 114 at the
                                                     Revision 1 level,
                                                     dated June 26,
                                                     2000. Pilatus PC-12
                                                     Service Bulletin 27-
                                                     012, dated
                                                     September 13, 2000,
                                                     also relates to
                                                     this subject.
------------------------------------------------------------------------
(4) For airplanes that        Within the next 50    In accordance with
 incorporate an MSN in the     hours TIS after       the Accomplishment
 range of 101 through 400,     January 25, 2002      Instructions
 modify the flap control       (the effective date   section of Pilatus
 wiring and install a flap     of this AD).          PC-12 Service
 power drive-unit field                              Bulletin No. 27-
 control panel..                                     011, Revision No.
                                                     1, dated January
                                                     26, 2001.
------------------------------------------------------------------------
(5) For all MSN airplanes,    Inspect initially     In accordance with
 inspect the flap actuator     within the next 50    the instructions in
 internal gear system for      hours TIS after       Pilatus PC-12
 correct end-play and          January 25, 2002      Maintenance Manual
 backlash measurements and     (the effective date   Temporary Revision
 make any necessary            of this AD) and       No. 27-14 (which
 corrective adjustments..      thereafter at         superseded
                               intervals not to      Temporary Revision
                               exceed 600 hours      No. 27-13), dated
                               TIS. Accomplish       December 4, 2000,
                               corrective            or Pilatus PC-12
                               adjustments prior     Aircraft
                               to further flight     Maintenance Manual
                               after the             27-50-03, pages 601
                               inspection where      through 608, dated
                               deficiencies are      April 30, 2000, as
                               detected.             applicable.
------------------------------------------------------------------------
(6) For all MSN airplanes,    As of January 25,     Not Applicable.
 do not install any Pilatus    2002 (the effective
 part number FCWU 99-3 that    date of this AD).
 has a serial number of
 100,000 or less..
------------------------------------------------------------------------


    Note 1: The FAA recommends that you incorporate the most up-to-
date Pilatus reports and revisions pertaining to this subject into 
the Pilatus PC-12 Pilot's Operating Handbook. The most up-to-date 
documents as of the issue date of this AD are Temporary Revision No. 
15, Report No. 01973-001, Issued: April 3, 2000, Sections 3 and 7; 
and Temporary Revision No. 32, Report No. 01973-001, Issued: January 
8, 2001, Sections 2 and 3.

    (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. Submit your request through an FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Small Airplane Directorate.

    Note 2: 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 Doug Rudolph, Aerospace 
Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, 
Kansas City, Missouri 64106; telephone: (816) 329-4059; 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) Are any service bulletins incorporated into this AD by 
reference? Actions required by this AD must be done in accordance 
with Pilatus PC-12 Service Bulletin No. 27-008, pages 1, 2, and 11 
at the Revision 2 level, dated September 13, 2000, and pages 3 
through 10 and 12 through 114 at the Revision 1 level, dated June 
26, 2000; Pilatus PC-12 Service Bulletin 27-012, dated September 13, 
2000; Pilatus PC-12 Service Bulletin No. 27-011, Revision No. 1, 
dated January 26, 2001; Pilatus PC-12 Maintenance Manual Temporary 
Revision No. 27-14 (which superseded Temporary Revision No. 27-13), 
dated December 4, 2000; and Pilatus PC-12 Aircraft Maintenance 
Manual 27-50-03, pages 601 through 608, dated April 30, 2000. The 
Director of the Federal Register approved this incorporation by 
reference under 5 U.S.C. 552(a) and 1 CFR part 51. You can get 
copies from Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 
Stans, Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 
619 6224; or from Pilatus Business Aircraft Ltd., Product Support 
Department, 11755 Airport Way, Broomfield, Colorado 80021; 
telephone: (303) 465-9099; facsimile: (303) 465-6040. You can look 
at copies at the FAA, Central Region, Office of the Regional 
Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the 
Office of the Federal Register, 800 North Capitol Street, NW, suite 
700, Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on January 25, 2002.

    Issued in Kansas City, Missouri, on December 11, 2001.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 01-31102 Filed 12-20-01; 8:45 am]
BILLING CODE 4910-13-P