Airworthiness Directives; Pilatus Aircraft Limited Model PC-6 Series Airplanes

[Federal Register Volume 72, Number 145 (Monday, July 30, 2007)]
[Rules and Regulations]
[Pages 41436-41438]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-14428]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28157 Directorate Identifier 2007-CE-046-AD; 
Amendment 39-15138; AD 2007-15-09]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Limited Model PC-6 
Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final Rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. This AD results from mandatory continuing 
airworthiness information (MCAI) issued by an aviation authority of 
another country to identify and correct an unsafe condition on an 
aviation product. The MCAI describes the unsafe condition as:

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks in the upper wing strut fittings of some PC-6 
aircraft.
    It is possible that the spherical bearing of the wing strut 
fittings installed in the underwing can be loose in the fitting or 
cannot rotate because of corrosion. In this condition, the joint 
cannot function as designed and fatigue cracks may then develop. 
Undetected cracks in this area could lead to failure of the upper 
attachment fitting. This could result in the failure of the wing 
structure with subsequent loss of control of the airplane.

We are issuing this AD to require actions to correct the unsafe 
condition on these products.

DATES: This AD becomes effective September 4, 2007.
    On September 4, 2007, the Director of the Federal Register approved 
the incorporation by reference of certain publications listed in this 
AD.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at Document Management Facility, U.S. 
Department of Transportation, Docket Operations, M-30, West Building 
Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 
20590.

FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aerospace Engineer, FAA, 
Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 
64106; telephone: (816) 329-4059; fax: (816) 329-4090.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on May 30, 2007 (72 FR 
29895). That NPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states:

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks in the upper wing strut fittings of some PC-6 
aircraft.
    It is possible that the spherical bearing of the wing strut 
fittings installed in the underwing can be loose in the fitting or 
cannot rotate because of corrosion. In this condition, the joint 
cannot function as designed and fatigue cracks may then develop. 
Undetected cracks in this area could lead to failure of upper the 
attachment fitting. This could result in the failure of the wing 
structure with subsequent loss of control of the airplane.
    In order to correct and monitor this situation, the present AD 
mandates a one time inspection of the wing strut fittings and 
replacement of damaged wing strut fittings with new ones. This AD 
also requires examination of the spherical bearings installed in the 
wing strut fittings and their replacement for bearings that do not 
pass the examination criteria.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We have considered the comment received.

Comment Issue: Allow a Dye-Penetrant Inspection

    One commenter requested that we allow a dye-penetrant inspection as 
an option to the eddy current inspection.
    Without specific procedures and proposed intervals, the FAA is not 
able to approve dye-penetrant inspection as an approved method for this 
AD. The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community and Pilatus (the 
design organization approval holder) only approved using an eddy 
current procedure for this inspection. Pilatus has only established 
procedures to detect cracks in the affected areas using the eddy 
current method. The FAA will not change the AD to allow for dye-
penetrant inspections in place of eddy current as called out for in the 
NPRM per the Pilatus service bulletin (SB) without having specific 
procedures and intervals that we can coordinate with EASA and Pilatus. 
An operator may propose these procedures and intervals to the FAA using 
the alternative method of compliance (AMOC) process specified in 14 CFR 
39.19 and the AD. The AMOC proposal must provide the complete method of 
inspection that the operator believes will provide an acceptable level 
of safety as that proposed in the AD. The FAA will then coordinate the 
proposed AMOC with Pilatus and EASA to determine if the method provides 
an acceptable level of safety. If so, an AMOC can be granted for the 
FAA issued AD.
    We are making no changes to the final rule AD action based on this 
comment.

Conclusion

    We reviewed the available data, including the comment received, and 
determined that air safety and the public interest require adopting the 
AD as proposed.

Differences Between this AD and the MCAI or Service Information

    We have reviewed the MCAI and related service information and, in 
general, agree with their substance. But we might have found it 
necessary to use different words from those in the MCAI to ensure the 
AD is clear for U.S. operators and is enforceable. In making these 
changes, we do not intend to differ substantively from the information 
provided in the MCAI and related service information.

[[Page 41437]]

    We might also have required different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a NOTE within the AD.

Costs of Compliance

    We estimate that this AD will affect 50 products of U.S. registry. 
We also estimate that it will take about 7 work-hours per product to 
comply with basic requirements of this AD. The average labor rate is 
$80 per work-hour. Based on these figures, we estimate the cost of this 
AD to the U.S. operators to be $28,000 or $560 per product.
    In addition, we estimate that any necessary follow-on actions would 
take about 15 work-hours and require parts costing $2,500, for a cost 
of $3,700 per fitting or $7,400 per product if both fittings are 
replaced. We have no way of determining the number of products that may 
need these actions.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. ``Subtitle VII: Aviation 
Programs,'' describes in more detail the scope of the Agency's 
authority.
    We are issuing this rulemaking under the authority described in 
``Subtitle VII, Part A, Subpart III, Section 44701: General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We determined that this AD will not have federalism implications 
under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify this AD:
    (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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD Docket.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov; or in person at the Docket Management Facility between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains the NPRM, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (telephone (800) 647-5527) is in the ADDRESSES section. Comments 
will be available in the AD docket shortly after receipt.

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 FAA amends 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. The FAA amends Sec.  39.13 by adding the following new AD:

2007-15-09 Pilatus Aircraft Limited: Amendment 39-15138; Docket No. 
FAA-2007-28157; Directorate Identifier 2007-CE-046-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective 
September 4, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, 
PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, 
PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 
airplanes; manufacturer serial numbers (MSN) 101 through 951, and 
MSN 2001 through 2092; that are certificated in any category. These 
airplanes are also identified as Fairchild Republic Company PC-6 
airplanes, Fairchild Industries PC-6 airplanes, Fairchild Heli 
Porter PC-6 airplanes, or Fairchild-Hiller Corporation PC-6 
airplanes.

Subject

    (d) Air Transport Association of America (ATA) Code 57: Wings.

Reason

    (e) The mandatory continuing airworthiness information (MCAI) 
states:

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks in the upper wing strut fittings of some PC-6 
aircraft.
    It is possible that the spherical bearing of the wing strut 
fittings installed in the underwing can be loose in the fitting or 
cannot rotate because of corrosion. In this condition, the joint 
cannot function as designed and fatigue cracks may then develop. 
Undetected cracks in this area could lead to failure of the upper 
attachment fitting. This could result in the failure of the wing 
structure with subsequent loss of control of the airplane.
    In order to correct and monitor this situation, the present AD 
mandates a one time inspection of the wing strut fittings and 
replacement of damaged wing strut fittings with new ones. This AD 
also requires examination of the spherical bearings installed in the 
wing strut fittings and their replacement for bearings that do not 
pass the examination criteria.

Actions and Compliance

    (f) Unless already done, do the following actions:
    (1) For MSN 2001 through MSN 2092: Within the next 100 hours 
time-in-service (TIS) on the upper wing strut fitting after 
September 4, 2007 (the effective date of this AD) or within 3 months 
after September 4, 2007 (the effective date of this AD), whichever 
occurs first, and repetitively thereafter at intervals not to exceed 
12 months, do the actions specified in paragraph (f)(3) of this AD.
    (2) For MSN 101 through MSN 951 do the following actions, as 
applicable:
    (i) If the upper wing strut fitting has less than 3,500 hours 
TIS or has been installed for less than 84 months (7 years): Within 
the next 1,000 hours TIS on the upper wing strut fitting after 
September 4, 2007 (the effective date of this AD) or within 24 
months after September 4, 2007 (the effective date of this AD) 
without exceeding 3,600 hours TIS or 87 months (7 years, 3 months), 
whichever occurs first, and repetitively thereafter at intervals not 
to exceed 12 months, do the actions specified in paragraph (f)(3) of 
this AD, or;
    (ii) If the upper wing strut fitting has 3,500 or more hours TIS 
or has been installed for 84 months (7 years) or longer: Within the 
next 100 hours TIS on the upper wing strut fitting after September 
4, 2007 (the effective date of this AD) or within 3 months after 
September 4, 2007 (the effective date of this AD), whichever occurs 
first, and repetitively thereafter at intervals not to exceed 12 
months, do the actions specified in paragraph (f)(3) of this AD.

    Note 1: If the TIS of the upper wing strut fittings cannot be 
positively determined by a review in the airplane maintenance 
records, then by default the upper wing strut fittings

[[Page 41438]]

were installed from the date of original Certificate of 
Airworthiness.

    (3) Do the following at the times specified in paragraph (f)(1) 
or (f)(2) of this AD:
    (i) Perform a visual and non-destructive inspection of the upper 
wing strut fittings for cracks following the Accomplishment 
Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-004, 
dated April 16, 2007.
    (ii) Examine for conformity the spherical bearings following the 
Accomplishment Instructions in Pilatus Aircraft Ltd. Service 
Bulletin No. 57-004, dated April 16, 2007.
    (4) If during any inspection required by paragraph (f)(3)(i) of 
this AD cracks are found in the upper wing strut fitting, before 
further flight replace the wing strut fitting with a new part number 
(P/N) 111.35.06.185 (left side) or P/N 111.35.06.186 (right side) 
following the Accomplishment Instructions in Pilatus Aircraft Ltd. 
Service Bulletin No. 57-004, dated April 16, 2007. Replacement of 
the upper wing strut fitting does not terminate the repetitive 
inspection specified in paragraph (f)(3) of this AD.
    (5) If during any inspection required by paragraph (f)(3)(ii) of 
this AD the spherical bearing is found not in conformity, before 
further flight replace the bearing with a new P/N 944.61.00.109 
following the Accomplishment Instructions in Pilatus Aircraft Ltd. 
Service Bulletin No. 57-004, dated April 16, 2007. Replacement of 
the spherical bearing does not terminate the repetitive inspection 
specified in paragraph (f)(3) of this AD.
    (6) Report to Pilatus Aircraft Ltd. Customer Liason Manager 
results of the inspection/examination using Table 1 of Pilatus 
Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007.

FAA AD Differences

    Note 2: This AD differs from the MCAI and/or service information 
as follows:

    (1) The FAA AD is requiring repetitive inspections and reporting 
results to the manufacturer, not just a one-time inspection and 
report as required in the MCAI.
    (2) The Service Bulletin specifies ``subsequent inspections for 
cracks will be included in Chapter 5 of the Aircraft Maintenance 
Manual (AMM).'' The only way we (FAA) can mandate these repetitive 
inspections is through an AD.

Other FAA AD Provisions

    (g) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
Standards Staff, FAA, has the authority to approve AMOCs for this 
AD, if requested using the procedures found in 14 CFR 39.19. Send 
information to ATTN: Doug Rudolph, Aerospace Engineer, FAA, Small 
Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 
64106; telephone: (816) 329-4059; fax: (816) 329-4090. Before using 
any approved AMOC on any airplane to which the AMOC applies, notify 
your appropriate principal inspector (PI) in the FAA Flight 
Standards District Office (FSDO), or lacking a PI, your local FSDO.
    (2) Airworthy Product: For any requirement in this AD to obtain 
corrective actions from a manufacturer or other source, use these 
actions if they are FAA-approved. Corrective actions are considered 
FAA-approved if they are approved by the State of Design Authority 
(or their delegated agent). You are required to assure the product 
is airworthy before it is returned to service.
    (3) Reporting Requirements: For any reporting requirement in 
this AD, under the provisions of the Paperwork Reduction Act (44 
U.S.C. 3501 et. seq.), the Office of Management and Budget (OMB) has 
approved the information collection requirements and has assigned 
OMB Control Number 2120 0056.

Related Information

    (h) Refer to MCAI European Aviation Safety Agency (EASA) AD No: 
2007-0114, dated May 02, 2007; and Pilatus Aircraft Ltd. Service 
Bulletin No. 57-004, dated April 16, 2007, for related information.

Material Incorporated by Reference

    (i) You must use Pilatus Aircraft Ltd. Service Bulletin No. 57-
004, dated April 16, 2007, to do the actions required by this AD, 
unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact 
Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 STANS, 
Switzerland; telephone: +41 (0)41 619 6580; fax: +41 (0)41 619 6576; 
e-mail: aircaft.com">fodermatt@pilatus-aircaft.com.
    (3) You may review copies at the FAA, Central Region, Office of 
the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 
64106; or at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Kansas City, Missouri, on July 19, 2007.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
 [FR Doc. E7-14428 Filed 7-27-07; 8:45 am]
BILLING CODE 4910-13-P

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