Document ID: FAA-2009-0622-0006
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Pilatus Aircraft Ltd. Models PC 6, PC 6 H1, PC 6 H2, PC 6/350, PC 6/350 H1, PC 6/350 H2, et al., Airplanes
Posted Date: 2010-10-07T04:00Z

[Federal Register: October 7, 2010 (Volume 75, Number 194)]
[Proposed Rules]               
[Page 62005-62008]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07oc10-16]                         

[[Page 62005]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0622; Directorate Identifier 2009-CE-034-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pilatus Aircraft Ltd. 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

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above that would revise an existing AD. This proposed 
AD results from mandatory continuing airworthiness information (MCAI) 
originated 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:

    Findings of corrosion, wear and cracks in the upper wing strut 
fittings on some PC-6 aircraft have been reported in the past. 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, wear and/or corrosion in this area could cause failure of 
the upper attachment fitting, leading to failure of the wing 
structure and subsequent loss of control of the aircraft.
    To address this problem, FOCA published AD TM-L Nr. 80.627-6/
Index 72-2 and HB-2006-400 and EASA published AD 2007-0114 to 
require specific inspections and to obtain a fleet status. Since the 
issuance of AD 2007-0114, the reported data proved that it was 
necessary to establish and require repetitive inspections.
    EASA published Emergency AD 2007-0241-E to extend the 
applicability and to require repetitive eddy current and visual 
inspections of the upper wing strut fitting for evidence of cracks, 
wear and/or corrosion and examination of the spherical bearing and 
replacement of cracked fittings. Collected data received in response 
to Emergency AD 2007-0241-E resulted in the issuance of EASA AD 
2007-0241R1 that permitted extending the intervals for the 
repetitive eddy current and visual inspections from 100 Flight Hours 
(FH) to 300 FH and from 150 Flight Cycles (FC) to 450 FC, 
respectively. In addition, oversize bolts were introduced by Pilatus 
PC-6 Service Bulletin (SB) 57-005 R1 and the fitting replacement 
procedure was adjusted accordingly.
    Based on fatigue test results, EASA AD 2007-0241R2 was issued to 
extend the repetitive inspection interval to 1100 FH or 12 calendar 
months, whichever occurs first, and to delete the related flight 
cycle intervals and the requirement for the ``Mild Corrosion 
Severity Zone''. In addition, some editorial changes have been made 
for reasons of standardization and readability.
    Revision 3 of this AD referred to the latest revision of the PC-
6 Aircraft Maintenance Manual (AMM) Chapter 5 limitations which have 
included the same repetitive inspection intervals and procedures 
already mandated in the revision 2 of AD 2007-0241. Besides the 
inspections, in the latest revision of the PC-6 AMM, the replacement 
procedures for the fittings were included.
    Additionally, EASA AD 2007-0241R3 introduced the possibility to 
replace the wing strut fitting with a new designed wing strut 
fitting. With this optional part replacement, in the repetitive 
inspection procedure the 1100 FH interval is deleted so that only 
calendar defined intervals of inspections remained applicable.

DATES: We must receive comments on this proposed AD by November 22, 
2010.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.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 this proposed AD, 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.

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:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2009-0622; 
Directorate Identifier 2009-CE-034-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://
regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    On August 18, 2009, we issued AD 2009-18-03, Amendment 39-15999 (74 
FR 43636; August 27, 2009). That AD required actions intended to 
address an unsafe condition on the products listed above.
    Since we issued AD 2009-18-03, Pilatus has updated their 
maintenance programs with new requirements and limitations. Another 
proposed AD action, Docket No. FAA-2010-1011, will require the 
incorporation of the updated maintenance requirements into the 
airworthiness limitations section of the instructions for continued 
airworthiness. Those updated maintenance requirements will include the 
repetitive inspections for the wing strut fittings and the spherical 
bearings currently included in AD 2009-18-03.
    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued EASA 
AD No.: 2007-0241R4, dated August 31, 2010 (referred to after this as 
``the MCAI''), to correct an unsafe condition for the specified 
products. The MCAI states:

    Findings of corrosion, wear and cracks in the upper wing strut 
fittings on some PC-6 aircraft have been reported in the past. 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, wear and/or corrosion in this area could cause failure of 
the upper attachment fitting, leading to failure of the wing 
structure and subsequent loss of control of the aircraft.
    To address this problem, FOCA published AD TM-L Nr. 80.627-6/
Index 72-2 and HB-2006-400 and EASA published AD 2007-0114 to 
require specific inspections and to

[[Page 62006]]

obtain a fleet status. Since the issuance of AD 2007-0114, the 
reported data proved that it was necessary to establish and require 
repetitive inspections.
    EASA published Emergency AD 2007-0241-E to extend the 
applicability and to require repetitive eddy current and visual 
inspections of the upper wing strut fitting for evidence of cracks, 
wear and/or corrosion and examination of the spherical bearing and 
replacement of cracked fittings. Collected data received in response 
to Emergency AD 2007-0241-E resulted in the issuance of EASA AD 
2007-0241R1 that permitted extending the intervals for the 
repetitive eddy current and visual inspections from 100 Flight Hours 
(FH) to 300 FH and from 150 Flight Cycles (FC) to 450 FC, 
respectively. In addition, oversize bolts were introduced by Pilatus 
PC-6 Service Bulletin (SB) 57-005 R1 and the fitting replacement 
procedure was adjusted accordingly.
    Based on fatigue test results, EASA AD 2007-0241R2 was issued to 
extend the repetitive inspection interval to 1100 FH or 12 calendar 
months, whichever occurs first, and to delete the related flight 
cycle intervals and the requirement for the ``Mild Corrosion 
Severity Zone''. In addition, some editorial changes have been made 
for reasons of standardization and readability.
    Revision 3 of this AD referred to the latest revision of the PC-
6 Aircraft Maintenance Manual (AMM) Chapter 5 limitations which have 
included the same repetitive inspection intervals and procedures 
already mandated in the revision 2 of AD 2007-0241. Besides the 
inspections, in the latest revision of the PC-6 AMM, the replacement 
procedures for the fittings were included.
    Additionally, EASA AD 2007-0241R3 introduced the possibility to 
replace the wing strut fitting with a new designed wing strut 
fitting. With this optional part replacement, in the repetitive 
inspection procedure the 1100 FH interval is deleted so that only 
calendar defined intervals of inspections remained applicable.
    The aim of this new revision is to only mandate the initial 
inspection requirement and consequently to limit its applicability 
to aeroplanes which are not already in compliance with EASA AD 2007-
0241R3. All aeroplanes which are in compliance with EASA AD 2007-
0241R3 have to follow the repetitive inspection requirements as 
described in Pilatus PC-6 AMM Chapter 04-00-00, Document Number 
01975, Revision 12 and the Airworthiness Limitations (ALS) Document 
Number 02334 Revision 1 mandated by EASA AD 2010-0176. Therefore the 
repetitive inspection requirements corresponding paragraphs have 
been deleted in this new EASA AD revision. The paragraph numbers of 
EASA AD 2007-0241R numbering has been maintained for referencing 
needs.

The proposed AD would require actions that are intended to address the 
unsafe condition described in the MCAI. You may obtain further 
information by examining the MCAI in the AD docket.

FAA's Determination and Requirements of the Proposed AD

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with this State of Design Authority, they 
have notified us of the unsafe condition described in the MCAI and 
service information referenced above. We are proposing this AD because 
we evaluated all information and determined the unsafe condition exists 
and is likely to exist or develop on other products of the same type 
design.

Differences Between This Proposed 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.
    We might also have proposed 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 proposed AD.

Costs of Compliance

    We estimate that this proposed AD will affect 50 products of U.S. 
registry. We also estimate that it would take about 7 work-hours per 
product to comply with the basic requirements of this proposed AD. The 
average labor rate is $85 per work-hour.
    Based on these figures, we estimate the cost of the proposed AD on 
U.S. operators to be $29,750, or $595 per product.
    In addition, we estimate that any necessary follow-on actions would 
take about 30 work-hours and require parts costing $5,000, for a cost 
of $7,550 per product. 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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify this proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by removing Amendment 39-15999 (74 FR 
43636; August 27, 2009), and adding the following new AD:

Pilatus Aircraft Ltd.: Docket No. FAA-2009-0622; Directorate 
Identifier 2009-CE-034-AD.

[[Page 62007]]

Comments Due Date

    (a) We must receive comments by November 22, 2010.

Affected ADs

    (b) This AD revises AD 2009-18-03, Amendment 39-15999.

Applicability

    (c) This AD applies to Pilatus Aircraft Ltd. 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, all manufacturer serial number (MSN), and 
MSN 2001 through 2092, 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:
    Findings of corrosion, wear and cracks in the upper wing strut 
fittings on some PC-6 aircraft have been reported in the past. 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, wear and/or corrosion in this area could cause failure of 
the upper attachment fitting, leading to failure of the wing 
structure and subsequent loss of control of the aircraft.
    To address this problem, FOCA published AD TM-L Nr. 80.627-6/
Index 72-2 and HB-2006-400 and EASA published AD 2007-0114 to 
require specific inspections and to obtain a fleet status. Since the 
issuance of AD 2007-0114, the reported data proved that it was 
necessary to establish and require repetitive inspections.
    EASA published Emergency AD 2007-0241-E to extend the 
applicability and to require repetitive eddy current and visual 
inspections of the upper wing strut fitting for evidence of cracks, 
wear and/or corrosion and examination of the spherical bearing and 
replacement of cracked fittings. Collected data received in response 
to Emergency AD 2007-0241-E resulted in the issuance of EASA AD 
2007-0241R1 that permitted extending the intervals for the 
repetitive eddy current and visual inspections from 100 Flight Hours 
(FH) to 300 FH and from 150 Flight Cycles (FC) to 450 FC, 
respectively. In addition, oversize bolts were introduced by Pilatus 
PC-6 Service Bulletin (SB) 57-005 R1 and the fitting replacement 
procedure was adjusted accordingly.
    Based on fatigue test results, EASA AD 2007-0241R2 was issued to 
extend the repetitive inspection interval to 1100 FH or 12 calendar 
months, whichever occurs first, and to delete the related flight 
cycle intervals and the requirement for the ``Mild Corrosion 
Severity Zone''. In addition, some editorial changes have been made 
for reasons of standardization and readability.
    Revision 3 of this AD referred to the latest revision of the PC-
6 Aircraft Maintenance Manual (AMM) Chapter 5 limitations which have 
included the same repetitive inspection intervals and procedures 
already mandated in the revision 2 of AD 2007-0241. Besides the 
inspections, in the latest revision of the PC-6 AMM, the replacement 
procedures for the fittings were included.
    Additionally, EASA AD 2007-0241R3 introduced the possibility to 
replace the wing strut fitting with a new designed wing strut 
fitting. With this optional part replacement, in the repetitive 
inspection procedure the 1100 FH interval is deleted so that only 
calendar defined intervals of inspections remained applicable.
    The aim of this new revision is to only mandate the initial 
inspection requirement and consequently to limit its applicability 
to aeroplanes which are not already in compliance with EASA AD 2007-
0241R3. All aeroplanes which are in compliance with EASA AD 2007-
0241R3 have to follow the repetitive inspection requirements as 
described in Pilatus PC-6 AMM Chapter 04-00-00, Document Number 
01975, Revision 12 and the Airworthiness Limitations (ALS) Document 
Number 02334 Revision 1 mandated by EASA AD 2010-0176. Therefore the 
repetitive inspection requirements corresponding paragraphs have 
been deleted in this new EASA AD revision. The paragraph numbers of 
EASA AD 2007-0241R numbering has been maintained for referencing 
needs.
The proposed AD would require actions that are intended to address 
the unsafe condition described in the MCAI.

Actions and Compliance

    (f) Unless already done, do the following actions:
    (1) For airplanes that have not had both wing strut fittings 
replaced within the last 100 hours time-in-service (TIS) before 
September 26, 2007 (the effective date of AD 2007-19-14), or have 
not been inspected using an eddy current inspection method following 
Pilatus Aircraft Ltd. Pilatus PC-6 Service Bulletin No. 57-004, 
dated April 16, 2007, within the last 100 hours TIS before September 
26, 2007 (the effective date of AD 2007-19-14): Before further 
flight after either September 26, 2007 (the effective date of AD 
2007-19-14), or October 1, 2009 (the effective date of AD 2009-18-
03), visually inspect the upper wing strut fittings and examine the 
spherical bearings following the Pilatus Aircraft Ltd. Pilatus PC-6 
Service Bulletin No. 57-005, REV No. 2, dated May 19, 2008.
    (2) For all airplanes: Within 25 hours TIS after September 26, 
2007 (the effective date of AD 2007-19-14), or within 30 days after 
September 26, 2007 (the effective date of AD 2007-19-14), whichever 
occurs first, visually and using eddy current methods, inspect the 
upper wing strut fittings and examine the spherical bearings 
following Pilatus Aircraft Ltd. Pilatus PC-6 Service Bulletin No. 
57-005, REV No. 2, dated May 19, 2008.
    (3) You may also take ``unless already done'' credit for any 
inspection specified in paragraphs (f)(1) or (f)(2) of this AD if 
done before October 1, 2009 (the effective date retained from AD 
2009-18-03) following Pilatus Aircraft Ltd. Pilatus PC-6 Service 
Bulletin No. 57-005, dated August 30, 2007; or Pilatus Aircraft Ltd. 
Pilatus PC-6 Service Bulletin No. 57-005, REV No. 1, dated November 
19, 2007.
    (4) For all airplanes: If during any inspection required by 
paragraphs (f)(1) or (f)(2) of this AD you find cracks in the upper 
wing strut fitting or the spherical bearing is not in conformity, 
before further flight, replace the cracked upper wing strut fitting 
and/or the nonconforming spherical bearing following Chapter 57-00-
02 of Pilatus Aircraft Ltd. Pilatus PC-6 Aircraft Maintenance 
Manual, dated November 30, 2008.

    Note 1:  Another proposed AD action, Docket No. FAA-2010-1011, 
proposes to require the incorporation of the updated maintenance 
requirements into the airworthiness limitations section of the 
instructions for continued airworthiness. Those updated maintenance 
requirements include the repetitive inspections for the wing strut 
fittings and the spherical bearings currently included in AD 2009-
18-03.

FAA AD Differences

    Note 2: This AD differs from the MCAI and/or service information 
as follows: No differences.

Other FAA AD Provisions

    (g) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
Standards Office, 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 EASA AD No.: 2007-0241R4, dated August 31, 
2010; Pilatus Aircraft Ltd. Pilatus PC-6 Service Bulletin No. 57-
005, REV No. 2, dated May 19, 2008;

[[Page 62008]]

Pilatus Aircraft Ltd. Pilatus PC-6 Service Bulletin No. 57-005, REV 
No. 1, dated November 19, 2007; Pilatus Aircraft Ltd. Pilatus PC-6 
Service Bulletin No. 57-005, dated August 30, 2007; Pilatus Aircraft 
Ltd. Pilatus PC-6 Service Bulletin No. 57-004, dated April 16, 2007; 
and Chapter 57-00-02 of Pilatus Aircraft Ltd. Pilatus PC-6 Aircraft 
Maintenance Manual, dated November 30, 2008, for related 
information.

    Issued in Kansas City, Missouri, on September 30, 2010.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-25289 Filed 10-6-10; 8:45 am]
BILLING CODE 4910-13-P