Federal Register: June 14, 1999 (Volume 64, Number 113)Proposed RulesPage 31758-31760From the Federal Register Online via GPO Access [wais.access.gpo.gov]

DOCID:fr14jn99-17

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

Docket No. 99-CE-10-ADRIN 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).

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 AD would require modifying the generator 2 excitation by removing certain diodes and installing a new 5-amp circuit breaker and suppression filter. The proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by the proposed AD are intended to prevent damage to electrical components if the generator 2 is not switched off prior to engine shutdown and it overheats, which could result in loss of electrical power to certain critical airplane components.

DATES: Comments must be received on or before July 14, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-CE-10-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., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 610 33 51. This information also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Roman T. Gabrys, Aerospace Engineer, FAA, Small Airplane Directorate, 1201 Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-6932; 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

[Page 31759]proposal will be filedin 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. 99-CE-10-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. 99-CE-10-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 Models PC-12 and PC- 12/45 airplanes. The FOCA of Switzerland reports two instances of the generator 2 not coming on-line during a normal start-up procedure. When re-attempting to start-up the generator 2, smoke was noticed in the area of the flight compartment floor.

The generator 2 control unit is not designed to prevent electrical feedback from the generator 2 field excitation on engine shut-down. If the pilot does not switch off the generator 2 prior to engine shutdown, voltage spikes are created at relay K234. Consequent overheating and damage to electrical components of the generator control circuit could then occur.

This condition could exist on airplanes with one of the following generators installed:

--a BOSCH Generator 2, part number (P/N) 524.32.12.158. This generator is installed at the factory on Pilatus Models PC-12 and PC-12/45 airplanes beginning with manufacturer serial number 231 and could be installed on airplanes with a manufacturer serial number in the range of 101 through 230 by incorporating Pilatus Service Bulletin No. 24- 010, dated September 28, 1998; or --an ELECTRO SYSTEMS Generator 2, P/N 978.87.24.121, with Pilatus Service Bulletin No. 24-009 (installation of support bracket and cut- out relay) incorporated. This generator is installed at the factory on Pilatus Models PC-12 and PC-12/45 airplanes with a manufacturer serial number in the range of 101 through 230. AD 99-06-17, Amendment 39-11081 (64 FR 13882, March 23, 1999), requires installing the support bracket and cut-out relay specified in Pilatus Service Bulletin No. 24-009, dated September 23, 1998, on Pilatus Models PC-12 and PC-12/45 airplanes with a manufacturer serial number in the range of 101 through 180. This service bulletin is incorporated at the factory on airplanes with a manufacturer serial number in the range of 181 through 230.

This condition, if not corrected, could result in the generator 2 not going on-line with consequent loss of electrical power to certain critical airplane components.

Relevant Service Information

Pilatus has issued Service Bulletin No. 24-012, dated February 19, 1999, which specifies procedures for modifying the generator 2 excitation by removing certain diodes and installing a new 5-amp circuit breaker and suppression filter.

The FOCA of Switzerland classified this service bulletin as mandatory and issued Swiss AD HB 99-143, dated February 19, 1999, 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 Sec. 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 the Proposed 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 proposing AD action. The proposed AD would require modifying the generator 2 excitation by removing certain diodes and installing a new 5-amp circuit breaker and suppression filter.

Accomplishment of the proposed action would be required in accordance with Pilatus Service Bulletin No. 24-012, dated February 19, 1999.

Cost Impact

The FAA estimates that 69 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 5 workhours per airplane to accomplish the proposed action, and that the average labor rate is approximately $60 an hour. Parts will be provided at no cost to the owners/operators of the affected aircraft. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $20,700, or $300 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:

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.

[Page 31760]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. 99-CE-10-AD. Applicability: Models PC-12 and PC-12/45 airplanes, manufacturer serial numbers 101 through MSN 260, 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 (d) 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 as indicated in the body of this AD, unless already accomplished.

To prevent damage to electrical components if the generator 2 is not switched off prior to engine shutdown and it overheats, which could result in loss of electrical power to certain critical airplane components, accomplish the following:

  (a) Within the next 100 hours time-in-service (TIS) after the effective date of this AD, modify the generator 2 excitation by removing certain diodes and installing a new 5-amp circuit breaker and suppression filter. Perform these actions in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Pilatus Service Bulletin No. 24-012, dated February 19, 1999.

Note 2: The affected airplanes incorporate one of the following generators:

--a BOSCH Generator 2, part number (P/N) 524.32.12.158. This generator is installed at the factory on Pilatus Models PC-12 and PC-12/45 airplanes beginning with manufacturer serial number 231 and could be installed on airplanes with a manufacturer serial number in the range of 101 through 230 by incorporating Pilatus Service Bulletin No. 24-010, dated September 28, 1998; or --an ELECTRO SYSTEMS Generator 2, P/N 978.87.24.121, with Pilatus Service Bulletin No. 24-009 (installation of support bracket and cut-out relay) incorporated. This generator is installed at the factory on Pilatus Models PC-12 and PC-12/45 airplanes with a manufacturer serial number in the range of 101 through 230. AD 99- 06-17, Amendment 39-11081 (64 FR 13882, March 23, 1999), requires installing the support bracket and cut-out relay specified in Pilatus Service Bulletin No. 24-009, dated September 23, 1998, on Pilatus Models PC-12 and PC-12/45 airplanes with a manufacturer serial number in the range of 101 through 180. This service bulletin is incorporated at the factory on airplanes with a manufacturer serial number in the range of 181 through 230.

  (b) As of the effective date of this AD, no person may install, on any affected airplane, a generator 2 that does not have the modification referenced in paragraph (a) of this AD incorporated.

  (c) Special flight permits may be issued in accordance with Secs. 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.

  (d) An alternative method of compliance or adjustment of the compliance times that provides an equivalent level of safety may be 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small Airplane Directorate.

  (e) Questions or technical information related to Pilatus Service Bulletin No. 24-012, dated February 19, 1999, should be directed to Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 610 33 51. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Note 4: The subject of this AD is addressed in Swiss AD HB 99- 143, dated February 19, 1999.

Issued in Kansas City, Missouri, on June 4, 1999. Marvin R. Nuss, Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

FR Doc. 99-14936Filed6-11-99; 8:45 amBILLING CODE 4910-13-U