AD 97-23-04

[Federal Register Volume 62, Number 215 (Thursday, November 6, 1997)]
[Rules and Regulations]
[Pages 59993-59995]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-29236]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-95-AD; Amendment 39-10192; AD 97-23-04]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 
airplanes. This AD requires replacing the fuel tank vent valves with 
modified fuel tank vent valves. This AD is the result of mandatory 
continued airworthiness information (MCAI) issued by the airworthiness 
authority for Switzerland. The actions specified by this AD are 
intended to prevent the fuel tank inward vent valve from freezing, 
which, if followed by a cold soak at altitude, could result in wing 
airfoil distortion and structural damage with consequent degradation of 
the airplane's handling qualities.

DATES: Effective December 1, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 1, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before December 8, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket 97-CE-95-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland. This information may 
also be examined at the Federal Aviation Administration (FAA), Central 
Region, Office of the Regional Counsel, Attention: Rules Docket 97-CE-
95-AD, Room 1558, 601 E. 12th Street, 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: Mr. Roman T. Gabrys, Aerospace 
Engineer, FAA, Small Airplane Directorate, 1201 Walnut, suite 900, 
Kansas City, Missouri 64106; telephone (816) 426-6934; facsimile (816) 
426-2169.

SUPPLEMENTARY INFORMATION:

Discussion

    The Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, recently notified the FAA that 
an unsafe condition may exist on Pilatus Models PC-12 and PC-12/45 
airplanes. The FOCA reports an instance of abnormal automatic 
engagement of the fuel booster pumps during normal operation of a 
Pilatus Model PC-12 airplane. The FOCA's investigation reveals that the 
fuel tank inward vent valves may fail in the closed position under 
certain conditions. Moisture ingestion, followed by cold soak, can lead 
to the fuel tank inward vent valve freezing. This condition, if not 
corrected, could result in wing airfoil distortion and structural 
damage with consequent degradation of the airplane's handling 
qualities.

Relevant Service Information

    Pilatus issued Service Bulletin No. 28-003, Revision 1, dated 
September 30, 1997, which specifies procedures for replacing the fuel 
tank vent valves with modified fuel tank vent valves.
    The FOCA of Switzerland classified this service bulletin as 
mandatory and

[[Page 59994]]

issued Swiss AD HB 97-432A, dated October 3, 1997, in order to assure 
the continued airworthiness of these airplanes in Switzerland.

The FAA's Determination

    This airplane model is manufactured in Switzerland and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the FOCA of Switzerland has kept the 
FAA informed of the situation described above.
    The FAA has examined the findings of the FOCA of Switzerland; 
reviewed all available information, including the service bulletin 
referenced in this document; and determined that AD action is necessary 
for products of this type design that are certificated for operation in 
the United States.

Explanation of the Provisions of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Pilatus Models PC-12 and PC-12/45 airplanes 
of the same type design registered for operation in the United States, 
the FAA is issuing an AD. This AD requires replacing the fuel tank vent 
valves with modified fuel tank vent valves. Accomplishment of the 
replacement is required in accordance with Pilatus Service Bulletin No. 
28-003, Revision 1, dated September 30, 1997.

Determination of the Effective Date of the AD

    Since a situation exists (possible wing airfoil distortion and 
structural damage with consequent degradation of the airplane's 
handling qualities) that requires the immediate adoption of this 
regulation, it is found that notice and opportunity for public prior 
comment hereon are impracticable, and that good cause exists for making 
this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting immediate flight safety and, thus, was not 
preceded by notice and opportunity to comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified above. All communications 
received on or before the closing date for comments will be considered, 
and this rule may be amended in light of the comments received. Factual 
information that supports the commenter's ideas and suggestions is 
extremely helpful in evaluating the effectiveness of the AD action and 
determining whether additional rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 97-CE-95-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a significant regulatory action under 
Executive Order 12866. It has been determined further that this action 
involves an emergency regulation under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979). If it is determined that 
this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket (otherwise, an evaluation is 
not required). A copy of it, if filed, may be obtained from the Rules 
Docket.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, pursuant to 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

97-23-04  Pilatus Aircraft, LTD.: Amendment 39-10192; Docket No. 97-
CE-95-AD.

    Applicability: Models PC-12 and PC-12/45 airplanes; serial 
numbers 101 through 186, certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, 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 (c) 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 the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required within the next 10 hours time-in-service 
(TIS) after the effective date of this AD, unless already 
accomplished.
    To prevent the fuel tank inward vent valve from freezing, which, 
if followed by a cold soak at altitude, could result in wing airfoil 
distortion and structural damage with consequent degradation of the 
airplane's handling qualities, accomplish the following:
    (a) Replace the fuel tank vent valves with modified fuel tank 
vent valves in accordance with the Accomplishment Instructions 
section of Pilatus Service Bulletin No. 28-003, Revision 1, dated 
September 30, 1997.
    (b) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Small Airplane Directorate, FAA, 1201 
Walnut, suite 900, Kansas City, Missouri 64106. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Small Airplane 
Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of

[[Page 59995]]

compliance with this AD, if any, may be obtained from the Small 
Airplane Directorate.

    (d) The replacement required by this AD shall be done in 
accordance with Pilatus Service Bulletin No. 28-003, Revision 1, 
dated September 30, 1997. This incorporation by reference was 
approved by the Director of the Federal Register in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland. Copies may be 
inspected at the FAA, Central Region, Office of the Regional 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

    Note 3: The subject of this AD is addressed in Swiss AD HB 97-
432A, dated October 3, 1997.

    (e) This amendment (39-10192) becomes effective on December 1, 
1997. Issued in Kansas City, Missouri, on October 29, 1997.
Mary Ellen A. Schutt,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-29236 Filed 11-5-97; 8:45 am]
BILLING CODE 4910-13-U