Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-6 Airplanes

[Federal Register Volume 68, Number 121 (Tuesday, June 24, 2003)]
[Rules and Regulations]
[Pages 37394-37396]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-15723]



[[Page 37394]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-CE-12-AD; Amendment 39-13204; AD 2003-13-04]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-6 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6 airplanes. 
This AD requires you to inspect the integral fuel tank wing ribs for 
cracks and the top and bottom wing skins for distortion, repair any 
cracks or distortion before further flight, and accomplish a fuel tank 
ventilating system installation. This AD is the result of mandatory 
continuing airworthiness information (MCAI) issued by the airworthiness 
authority for Switzerland. The actions specified by this AD are 
intended to detect and correct cracks in the ribs of the inboard 
integral fuel tanks in the left and right wings, which could lead to 
wing failure during flight.

DATES: This AD becomes effective on August 15, 2003.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulations as of 
August 15, 2003.

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. 2003-CE-12-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?

    The Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, recently notified FAA that an 
unsafe condition may exist on all Pilatus Model PC-6 airplanes. The 
FOCA reports an incident where cracks have been found in the ribs of 
the inboard integral fuel tanks in the left and right wings of a Model 
PC-6 airplane. Investigation revealed that the cracks can occur when 
there are excessive pressure differentials between the ambient air 
pressure and that of the fuel tanks. The effect of this differential 
can be to compress the wing in the area of the fuel tank and cause 
distortion of the related structure. This distortion may result in 
fatigue cracks on ribs within the wing.

What Is the Potential Impact If FAA Took No Action?

    These fatigue cracks on the ribs within the wing could lead to wing 
failure during flight.

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 Model PC-6 airplanes. This proposal was published in the 
Federal Register as a notice of proposed rulemaking (NPRM) on April 4, 
2003 (68 FR 16458). The NPRM proposed to require you to inspect the 
integral fuel tank wing ribs for cracks and the top and bottom wing 
skins for distortion, repair any cracks or distortion before further 
flight, and accomplish a fuel tank ventilating system installation.

Was the Public Invited To Comment?

    The FAA encouraged interested persons to participate in the making 
of this amendment. We did not receive any comments on the proposed rule 
or on our determination of the cost to the public.

FAA's Determination

What Is FAA's Final Determination on This Issue?

    After careful review of all available information related to the 
subject presented above, we have determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. We have determined that these 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.

How Does the Revision to 14 CFR Part 39 Affect This AD?

    On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 
FR 47997, July 22, 2002), which governs FAA's AD system. This 
regulation now includes material that relates to special flight 
permits, alternative methods of compliance, and altered products. This 
material previously was included in each individual AD. Since this 
material is included in 14 CFR part 39, we will not include it in 
future AD actions.

Cost Impact

How Many Airplanes Does This AD Impact?

    We estimate that this AD affects 35 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 inspection:

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                                                               Total cost per
             Labor cost                     Parts cost            airplane        Total cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
5 workhours x $60 per hour = $300...  Not applicable........            $300   $300 x 35 = $10,500
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    We estimate the following costs for each rib to accomplish any 
necessary rib repair that will be required based on the results of this 
inspection. We have no way of determining the number of airplanes that 
may need such repair.

[[Page 37395]]



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              Labor cost                             Parts cost               Total cost  per rib per  airplane
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3 workhours x $60 per hour = $180 per   $50 per rib........................  $230 per rib.
 rib.
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    We estimate the following costs to install any inboard fuel tank 
vent system that will be required based on the results of this 
inspection. We have no way of determining the number of airplanes that 
may need such installation.

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                                                        Total cost per
          Labor cost                 Parts cost            airplane
------------------------------------------------------------------------
12 workhours x $60 per hour =                 $200                 $920
 $720.........................
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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

0
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

0
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]

0
2. FAA amends Sec.  39.13 by adding a new AD to read as follows:

2003-13-04 Pilatus Aircraft LTD.: Amendment 39-13204; Docket No. 
2003-CE-12-AD.

    (a) What airplanes are affected by this AD? This AD affects 
Model PC-6 airplanes, all manufacturer serial numbers (MSN) up to 
and including 939, that are certificated in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the airplanes identified in paragraph (a) of this AD must 
comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to detect and correct cracks in the ribs of the 
inboard integral fuel tanks in the left and right wings, which could 
lead to wing failure during flight.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Inspect:                  Within the next 100   In accordance with
(i) the ribs in the inboard    hours time-in-        Pilatus Aircraft
 integral fuel tanks and       service (TIS) after   Ltd. PC-6 Service
 related structure in the      August 15, 2003       Bulletin No. 57-
 left and right wings for      (the effective date   002, dated November
 crack damage;.                of this AD), unless   27, 2002, and the
(ii) the upper and lower       already               applicable
 wing skins for damage; and.   accomplished.         maintenance manual.
(iii) to determine if the
 inboard fuel tank vent
 system is installed..
(2) If crack damage is        Prior to further      In accordance with
 found:.                       flight after the      Pilatus Aircraft
(i) Correct the crack damage   inspections           Ltd. PC-6 Service
 designated as repairable in   required in           Bulletin No. 57-
 the service bulletin.         paragraph (d)(1) of   002, dated November
(ii) For other crack damage,   this AD.              27, 2002, and the
 obtain a repair scheme from                         applicable
 the manufacturer through                            maintenance manual.
 FAA at the address
 specified in paragraph (e)
 of this AD and incorporate
 this repair scheme..
(3) If wing distortion is     Prior to further      In accordance with
 found, obtain a repair        flight after the      Pilatus Aircraft
 scheme from the               inspections           Ltd. PC-6 Service
 manufacturer through FAA at   required in           Bulletin No. 57-
 the address specified in      paragarph (d)(1) of   002, dated November
 paragraph (e) of this AD      this AD.              27, 2002, and the
 and incorporate this repair                         applicable
 scheme.                                             maintenance manual.
(4) If the inboard fuel tank  Prior to further      In accordance with
 vent system is not            flight after the      Pilatus Aircraft
 installed, install the        inspections           Ltd. PC-6 Service
 inboard fuel tank vent        required in           Bulletin No. 118,
 system.                       paragraph (d)(1) of   dated December
                               this AD.              1972, and the
                                                     applicable
                                                     maintenance manual.
------------------------------------------------------------------------


[[Page 37396]]

    (e) Can I comply with this AD in any other way? To use an 
alternative method of compliance or adjust the compliance time, use 
the procedures in 14 CFR 39.19. Send these requests to the Manager, 
Standards Office, Small Airplane Directorate. For information on 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.
    (f) Are any service bulletins incorporated into this AD by 
reference? Actions required by this AD must be done in accordance 
with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated 
November 27, 2002, and Pilatus Aircraft Ltd. PC-6 Service Bulletin 
No. 118, dated December 1972. The Director of the Federal Register 
approved this incorporation by reference under 5 U.S.C. 552(a) and 1 
CFR part 51. You may 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 may view 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.

    Note: The subject of this AD is addressed in Swiss AD Number HB 
2003-092, dated February 17, 2003.

    (g) When does this amendment become effective? This amendment 
becomes effective on August 15, 2003.

    Issued in Kansas City, Missouri, on June 16, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-15723 Filed 6-23-03; 8:45 am]
BILLING CODE 4910-13-P

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