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

Events Leading to the Issuance of This AD

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 Models PC-12 and PC- 12/45 airplanes. The FOCA of Switzerland reports three occurrences where the cables behind the second generator were incorrectly connected. In the above-referenced incidents, the over-voltage protection did not automatically disconnect the second generator from the electrical system when excessive voltage was experienced. This condition, if not corrected in a timely manner, could result in electrical component damage and loss of electrical power during any phase of flight.

Relevant Service Information

Pilatus has issued Service Bulletin No. 24-009, dated September 23, 1998, which specifies procedures for installing a support bracket and a cut-out relay for the second generator control unit, and making all the wiring additions and adjustments necessary for the above-referenced installations. Modification Kit No. 500.50.12.171 includes the parts necessary to accomplish this installation and modification. The FOCA of Switzerland classified this service bulletin as mandatory and issued Swiss AD HB 98-537, dated December 29, 1998, 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 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 This AD

Since an unsafe condition has been identified that is likely to exist or develop in other Pilatus PC-12 and PC-12/45 airplanes of the same type design registered in the United States, the FAA is issuing an AD. This AD requires installing a support bracket and a cut-out relay for the second generator control unit. This AD also requires making all the wiring additions and adjustments necessary for the above-referenced installations. Accomplishment of the actions of this AD would be required in accordance with the previously referenced service bulletin.

Cost Impact

The FAA estimates that 50 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 8 workhours per airplane to accomplish the required action, and that the average labor rate is approximately $60 per work hour. The manufacture will provide parts to owners/operators of the affected airplanes at no cost. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $24,000, or $480 per airplane.

The Direct Final Rule Procedure

The FAA anticipates that this regulation will not result in adverse or negative comment and therefore is issuing it as a direct final rule. The requirements of this direct final rule address an unsafe condition identified by a foreign civil airworthiness authority and do not impose a significant burden on affected operators. In accordance with Section 11.17 of the Federal Aviation Regulations (14 CFR 11.17) unless a written adverse or negative comment, or a written notice of intent to submit an adverse or negative comment, is received within the comment period, the regulation will become effective on the date specified above. After the close of the comment period, the FAA will publish a document in the Federal Register indicating that no adverse or negative comments were received and confirming the date on which the final rule will become effective. If the FAA does receive, within the comment period, a written adverse or negative comment, or written notice of intent to submit such a comment, a document withdrawing the direct final rule will be published in the Federal Register, and

a notice of proposed rulemaking may be published with a new comment period.

Comments Invited

Although this action is in the form of a final rule and was not preceded by notice and an opportunity for public 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 shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. 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. 99-CE-03-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 noncontroversial and unlikely to result in adverse or negative comments. For reasons discussed in the preamble, I certify that this regulation (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. A final evaluation has been prepared for this action and is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

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 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:

99-06-17 Pilatus Aircraft LTD.: Amendment 39-11081; 99-06-18 Docket No. 99-CE-03-AD.

Applicability: Models PC-12 and PC-12/45 airplanes, manufacturer serial numbers (MSN) 101 through MSN 180, certificated in any category.

Note 1: The installations and modifications required by this AD will be incorporated at the factory on Models PC-12 and PC-12/45 airplanes beginning with MSN 181.

Note 2: 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 50 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

Note 3: The compliance time of this AD differs from that specified in Pilatus Service Bulletin No. 24-009, dated September 23, 1998, and in Swiss AD HB 98-537, dated December 29, 1998. This AD takes precedence over any other information on airplanes registered for operation in the United States.

To prevent damage to electrical components because incorrectly connected cables or broken or damaged wires cause excessive voltages to the second generator, which could result in loss of electrical power during any phase of flight, accomplish the following: (a) Install a support bracket and a cut-out relay for the second generator control unit, and make all the wiring additions and adjustments necessary for the above-referenced installations. Modification Kit No. 500.50.12.171 includes the parts necessary to accomplish this installation and modification. Perform these actions in accordance with the Accomplishment Instructions section of Pilatus Service Bulletin No. 24-009, dated September 23, 1998. (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 used if approved by the Manager, Small Airplane Directorate, 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 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small Airplane Directorate.

(d) The installation and modification required by this AD shall be done in accordance with Pilatus Service Bulletin No. 24-009, dated September 23, 1998. 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., Customer Liaison Manager, CH-6371 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 5: The subject of this AD is addressed in Swiss AD HB 98- 537, dated December 29, 1998.

(e) This amendment becomes effective on June 16, 1999.

Issued in Kansas City, Missouri, on March 11, 1999. Marvin R. Nuss, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-6715 Filed 3-22-99; 8:45 am] BILLING CODE 4910-13-U