AD 99-06-17

This action confirms the effective date of Airworthiness Directive (AD) 99-06-17, which applies to certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. AD 99-06-17 requires installing a support bracket and a cut-out relay for the second generator control unit. AD 99-06-17 also requires making all the wiring additions and adjustments necessary for the above-referenced installations. This AD was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified in this AD are intended 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.

Direct final rule; confirmation of effective date.

99-06-17 PILATUS AIRCRAFT LTD.: Amendment 39-11081; 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 thisAD; 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.

The FAA published this direct final rule with request for comments in the Federal Register on March 23, 1999 (64 FR 13882). The FAA uses the direct final rulemaking procedure for a non-controversial rule where the FAA anticipates that there will be no adverse public comment. This direct final rule advised the public that no adverse comments were anticipated, and that unless a written adverse comment, or a written notice of intent to submit such an adverse comment, was received within the comment period, the regulation would become effective on June 16, 1999. No adverse comments were received, and thus this notice confirms that this final rule will become effective on that date.