[Federal Register Volume 62, Number 244 (Friday, December 19, 1997)]
[Proposed Rules]
[Pages 66561-66563]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-33143]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-46-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Pilatus Aircraft Ltd. (Pilatus) Models 
PC-12 and PC-12/45 airplanes. The proposed action would require 
installing aluminum bonding bushings over certain screws in certain 
fuel tank underwing access panels. Several reports from the field 
revealing fuel tank access panels insufficiently electrically bonded to 
the airframe prompted this proposed AD. The actions specified by

[[Page 66562]]

the proposed AD are intended to prevent electrical arcing in the fuel 
tanks and detonation of the fuel-air mixture, which can be created by 
poor electrical bonding of fuel tank underwing access panels, and if 
not corrected, could result in a fire on the airplane.

DATES: Comments must be received on or before February 20, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 97-CE-46-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland; telephone +41-
41-6196-233; facsimile +41-41-6103-351. This information also may be 
examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Roman Gabrys, Project Officer, 
FAA, Small Airplane Directorate, Aircraft Certification Service, 1201 
Walnut, suite 900, Kansas City, Missouri 64106; telephone (816) 426-
6934; facsimile (816) 426-2169.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 97-CE-46-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 97-CE-46-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

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 certain Pilatus Model PC-12 and PC-12/
45 airplanes. FOCA reports that during routine inspections of some of 
these airplanes, the inspectors found that the underwing access panels 
to the fuel tank were not sufficiently electrically bonded to the 
airframe. These conditions, if not corrected, could result in 
detonation of the airplane's fuel tanks by electrical arcing through 
the fuel-air mixture.

Relevant Service Information

    Pilatus Aircraft Ltd. has issued service bulletin (SB) No. 57-001, 
dated February 28, 1997 which specifies procedures for installing 
aluminum bonded bushings over the screws to the underwing fuel tank 
access panels to assure a positive electrical bonding to the airframe 
structure.

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 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, FOCA has kept the FAA informed of 
the situation described above. The FAA has examined the findings of 
FOCA, reviewed all available information including the service 
information referenced above, 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 the Proposed 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 in the United States, the proposed 
AD would require installing aluminum bonding bushes over the screws in 
the fuel tank underwing access panels. Accomplishment of the proposed 
action would be in accordance with Pilatus Service Bulletin No. 57-001, 
dated February 28, 1997.

Cost Impact

    The FAA estimates that 40 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 6 work 
hours per airplane to accomplish the proposed action, and that the 
average labor rate is approximately $60 an hour. Parts would be 
provided at no cost by the manufacturer. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be $14,400, or $360 per airplane.

Regulatory Impact

    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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) if promulgated, 
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 draft regulatory evaluation 
prepared for this action has been placed 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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

[[Page 66563]]

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

    Pilatus Aircraft Ltd.: Docket No. 97-CE-46-AD.

    Applicability: Model PC-12 and PC-12/45 airplanes (serial 
numbers MSN 001 through MSN 168), 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 100 hours time-in-service 
(TIS) after the effective date of this AD, unless already 
accomplished.
    To prevent electrical arcing in the fuel tanks and detonation of 
the fuel-air mixture, which can be created by poor electrical 
bonding of fuel tank underwing access panels, and if not corrected, 
could result in a fire on the airplane, accomplish the following:
    (a) Install aluminum bonding bushings onto the screws for 
certain fuel tank underwing access panels in accordance with Part A 
and Part B of the Accomplishment Instructions in Pilatus Aircraft 
LTD PC12 Service Bulletin No. 57-001, dated February 28, 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, Aircraft 
Certification Service, 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 compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.
    (d) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to Pilatus Aircraft 
Ltd., CH-6370 Stans, Switzerland; or may examine this document at 
the FAA, Central Region, Office of the Regional Counsel, Room 1558, 
601 E. 12th Street, Kansas City, Missouri 64106.

    Issued in Kansas City, Missouri, on December 11, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-33143 Filed 12-18-97; 8:45 am]
BILLING CODE 4910-13-U