Document ID: FAA-2009-0938-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 Airplanes
Posted Date: 2009-10-09T04:00Z

[Federal Register: October 9, 2009 (Volume 74, Number 195)]
[Proposed Rules]               
[Page 52156-52158]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09oc09-20]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0938; Directorate Identifier 2009-CE-052-AD]
RIN 2120-AA64

 
Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 
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. 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:

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks caused by stress corrosion in the main-gear 
support struts. All the main-gear support struts that had cracks 
were made from material AA2024-T351 which has a lower resistance to 
stress corrosion cracking.
    Such cracks, if undetected, could lead to the failure of the 
strut during landing which could then cause the Main Landing Gear 
(MLG) to collapse.

The proposed AD would require actions that are intended to address the 
unsafe condition described in the MCAI.

DATES: We must receive comments on this proposed AD by November 23, 
2009.

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; e-mail: 
doug.rudolph@faa.gov.

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-2009-0938; 
Directorate Identifier 2009-CE-052-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://
www.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

    The Federal Office of Civil Aviation (FOCA), which is the aviation 
authority for Switzerland, has issued FOCA AD HB-2009-011, dated 
September 10, 2009 (referred to after this as ``the MCAI''), to correct 
an unsafe condition for the specified products. The MCAI states:

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks caused by stress corrosion in the main-gear 
support struts. All the main-gear support struts that had cracks 
were made from material AA2024-T351 which has a lower resistance to 
stress corrosion cracking.
    Such cracks, if undetected, could lead to the failure of the 
strut during landing which could then cause the Main Landing Gear 
(MLG) to collapse.
    In order to correct and control the situation, this AD mandates 
the identification of the main-gear support struts to check if they 
have rounded clevis lugs and a Non-Destructive Inspection (NDI) 
procedure on the main-gear support struts if they have chamfered 
clevis lugs.

For main-gear support struts with chamfered clevis lugs that show 
cracks during the NDI, the MCAI also requires replacing any cracked 
main-gear support struts with parts of improved design. You may obtain 
further information by examining the MCAI in the AD docket.

Relevant Service Information

    PILATUS Aircraft Ltd. has issued PILATUS PC-7 Service Bulletin No. 
32-024, Rev. No. 1, dated November 17, 2008; and PILATUS PC-7 Service 
Bulletin No. 32-025, Rev. No. 1, dated November 17, 2008. The actions 
described in this service information are intended to correct the 
unsafe condition identified in the MCAI.

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

[[Page 52157]]

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 10 products of U.S. 
registry. We also estimate that it would take about 4 work-hours per 
product to comply with the basic requirements of this proposed AD. The 
average labor rate is $80 per work-hour.
    Based on these figures, we estimate the cost of the proposed AD on 
U.S. operators to be $3,200, or $320 per product.
    In addition, we estimate that any necessary follow-on actions would 
take about 20 work-hours and require parts costing $20,000, for a cost 
of $21,600 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 adding the following new AD:

PILATUS Aircraft Ltd: Docket No. FAA-2009-0938; Directorate 
Identifier 2009-CE-052-AD.

Comments Due Date

    (a) We must receive comments by November 23, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Model PC-7 airplanes, manufacturer serial 
numbers 101 through 618 that are:
    (1) Equipped with main-gear support struts part number (P/N) 
532.10.09.039 or P/N 114.48.07.172; and
    (2) Certificated in any category.

Subject

    (d) Air Transport Association of America (ATA) Code 32: Landing 
Gear.

Reason

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

    This Airworthiness Directive (AD) is prompted due to the 
discovery of cracks caused by stress corrosion in the main-gear 
support struts. All the main-gear support struts that had cracks 
were made from material AA2024-T351 which has a lower resistance to 
stress corrosion cracking.
    Such cracks, if undetected, could lead to the failure of the 
strut during landing which could then cause the Main Landing Gear 
(MLG) to collapse.
    In order to correct and control the situation, this AD mandates 
the identification of the main-gear support struts to check if they 
have rounded clevis lugs and a Non-Destructive Inspection (NDI) 
procedure on the main-gear support struts if they have chamfered 
clevis lugs.

For main-gear support struts with chamfered clevis lugs that show 
cracks during the NDI, the MCAI also requires replacing any cracked 
main-gear support struts with parts of improved design. You may 
obtain further information by examining the MCAI in the AD docket.

Actions and Compliance

    (f) Unless already done, do the following actions:
    (1) Within the next 30 hours time-in-service (TIS) after the 
effective date of this AD or within the next 30 days after the 
effective date of this AD, whichever occurs first, visually inspect 
the left and right main-gear support struts to determine if they 
have rounded or chamfered clevis lugs. Do the inspection following 
paragraph 3.A. of PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 
1, dated November 17, 2008.
    (2) Based on the results of the inspection required in paragraph 
(f)(1) of this AD, if the main-gear support strut has rounded clevis 
lugs, no further action is required except the requirement specified 
in paragraph (f)(4) of this AD still applies. Make an entry in the 
airplane logbook to show compliance with this AD.
    (3) Based on the results of the inspection required in paragraph 
(f)(1) of this AD, if the main-gear support strut has chamfered 
clevis lugs, before further flight do a Non-Destructive Inspection 
(NDI). Do the NDI following paragraphs 3.B. through 3.E. of PILATUS 
PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 
2008.
    (i) If cracks are found during the inspection required in 
paragraph (f)(3) of this AD:
    (A) Before further flight after the inspection, replace any 
cracked main-gear support struts with new main-gear support struts, 
P/N 532.10.09.128. Do the replacement following PILATUS PC-7 Service 
Bulletin No. 32-025, Rev. No. 1, dated November 17, 2008.

[[Page 52158]]

    (B) Within the next 10 days after the inspection, report the 
cracks to PILATUS AIRCRAFT LTD., Customer Liaison Manager, CH-6371 
STANS, Switzerland, using the Crack Report Form (Figure 4) in 
PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 
17, 2008. The Office of Management and Budget (OMB) approved the 
information collection requirements contained in this regulation 
under the provisions of the Paperwork Reduction Act and assigned OMB 
Control Number 2120-0056.
    (ii) If no cracks are found during the inspection required in 
paragraph (f)(3) of this AD, no further action is required. Make an 
entry in the airplane logbook to show compliance with this AD.
    (4) As of 30 days after the effective date of this AD, do not 
install any main-gear support struts, P/N 532.10.09.039 or P/N 
114.48.07.172, with chamfered clevis lugs.

    Note 1: If you have any main-gear support struts, P/N 
532.10.09.039 or P/N 114.48.07.172, with chamfered clevis lugs held 
as spares, you may return them to PILATUS AIRCRAFT LTD., Customer 
Liaison Manager, CH-6371 STANS, Switzerland, for replacement with a 
new main-gear support strut, P/N 532.10.09.128.

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; e-mail: 
doug.rudolph@faa.gov. 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 FOCA AD HB-2009-011, dated September 10, 2009; 
and PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated 
November 17, 2008; and PILATUS PC-7 Service Bulletin No. 32-025, 
Rev. No. 1, dated November 17, 2008, for related information.

    Issued in Kansas City, Missouri, on October 5, 2009.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-24450 Filed 10-8-09; 8:45 am]

BILLING CODE 4910-13-P