Airworthiness directives: Pilatus Aircraft Ltd.,

[Federal Register: August 13, 1999 (Volume 64, Number 156)]

[Proposed Rules]

[Page 44137-44139]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr13au99-20]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-CE-54-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).

SUMMARY: This document proposes to adopt a new airworthiness directive

[[Page 44138]]

(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 flap inboard attachment fittings through the installation of a reinforcement angle bracket on the inside of the center web of both flap inner attachment fittings. 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 the potential of the inboard flap attachment fittings buckling while operating at full flaps with full power into a head-on wind gust, which could result in loss of control of the airplane.

DATES: Comments must be received on or before September 13, 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-54-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 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-54-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-54-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 that static testing shows that insufficient safety margins could occur in certain situations. Operating the airplane at full flaps (at the maximum allowable aircraft speed) with full power into a head-on wind gust could result in the inboard flap attachment fittings buckling.

This condition, if not corrected, could result in loss of control of the airplane.

Relevant Service Information

Pilatus has issued Service Bulletin No. 57-004, dated June 11, 1999, which specifies procedures for modifying the flap inboard attachment fittings through the installation of a reinforcement angle bracket on the inside of the center web of both flap inner attachment fittings.

The FOCA of Switzerland classified this service bulletin as mandatory and issued Swiss AD HB 99-353, dated July 12, 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 flap inboard attachment fittings through the installation of a reinforcement angle bracket on the inside of the center web of both flap inner attachment fittings. Accomplishment of the proposed action would be required in accordance with Pilatus Service Bulletin No. 57-004, dated June 11, 1999.

Cost Impact

The FAA estimates that 77 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 by the manufacturer at no cost to the owners/operators of the affected airplanes. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $23,100, 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

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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.

   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-54-AD.

   Applicability: Models PC-12 and PC-12/45 airplanes, manufacturer serial number (MSN) 101 through MSN 300, 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 the potential for the inboard flap attachment fittings buckling while operating at full flaps with full power into a head-on wind gust, which could result in loss of control of the airplane, accomplish the following:

   (a) Within the next 100 hours time-in-service (TIS) after the effective date of this AD, modify the flap inboard attachment fittings by installing a reinforcement angle bracket on the inside of the center web of both flap inner attachment fittings (Modification Kit Number 500.50.12.199). Accomplish this modification in accordance with the Accomplishment Instructions section of Pilatus Service Bulletin No. 57-004, dated June 11, 1999.

   (b) As of the effective date of this AD, no person may install on any of the affected airplanes, flap inboard attachment fittings that do not have Modification Kit Number 500.50.12.199 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 2: 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: 57-004, dated June 11, 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 3: The subject of this AD is addressed in Swiss AD HB 99- 353, dated July 12, 1999.

   Issued in Kansas City, Missouri, on August 6, 1999. Michael Gallagher, Manager, Small Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-21017Filed8-12-99; 8:45 am]

   BILLING CODE 4910-13-P