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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 all Pilatus Aircraft Ltd. (Pilatus) Models PC–12 and PC–12/45 airplanes. The proposed AD would require you to inspect the cargo doors to identify front and rear end frames with plain lightening holes and install reinforcing plates on any frame with plain lightening holes. 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 cracking at the edges of the unflanged lightening holes, which could result in major structural damage to the airplane. Such damage could result in possible loss of control of the airplane.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before September 21, 2001.

ADDRESSES:

Submit comments in triplicate to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001–CE–24–AD, 901 Locust, Room 506, 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 41 619 6224; or from Pilatus Business Aircraft Ltd., Product Support Department, 11755 Airport Way, Broomfield, Colorado 80021; telephone: (303) 465–9099; facsimile: (303) 465–6040. This information also may be examined at the Rules Docket at the address above.

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FOR FURTHER INFORMATION CONTACT:

Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329–4059; facsimile: (816) 329–4090.

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SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on the proposed AD? The FAA invites comments on this proposed rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments in triplicate to the address specified under the caption ADDRESSES . The FAA will consider all comments received on or before the closing date. We may amend the proposed rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the proposed AD action and determining whether we need to take additional rulemaking action.

Are there any specific portions of the proposed AD I should pay attention to? The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of the proposed rule that might suggest a need to modify the rule. You may examine all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns the substantive parts of the proposed AD.

We are re-examining the writing style we currently use in regulatory documents, in response to the Presidential memorandum of June 1, 1998. That memorandum requires federal agencies to communicate more clearly with the public. We are interested in your comments on whether the style of this document is clear, and any other suggestions you might have to improve the clarity of FAA communications that affect you. You can get more information about the Presidential memorandum and the plain language initiative at http://www.plainlanguage.gov.

How can I be sure FAA receives my comment? If you want us to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket Start Printed Page 44094 No. 2001–CE–24–AD.” We will date stamp and mail the postcard back to you.

Discussion

What events have caused this proposed AD? The Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, recently notified FAA that an unsafe condition may exist on all Pilatus Models PC–12 and PC–12/45 airplanes. The FOCA reports that, during production, some PC–12 and PC–12/45 airplanes were equipped with cargo doors that do not have reinforcing flanges on the lightening holes in the front and rear end of the cargo door frames.

What are the consequences if the condition is not corrected? If not detected and corrected, cracking at the edges of the unflanged lightening holes could result in major structural damage to the airplane. Such damage could result in possible loss of control of the airplane.

Is there service information that applies to this subject? Pilatus has issued Service Bulletin No. 52–004, dated April 20, 2001.

What are the provisions of this service bulletin? The service bulletin includes procedures for:

—Inspecting the cargo doors to identify front and rear end frames with plain lightening holes; and

—Installing reinforcing plates on any frame with plain lightening holes.

What action did FOCA take? The FOCA classified this service bulletin as mandatory and issued Swiss AD Number HB 2001–389, dated June 25, 2001, in order to assure the continued airworthiness of these airplanes in Switzerland.

Was this in accordance with the bilateral airworthiness agreement? These airplane models are manufactured in Switzerland and are 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 has kept FAA informed of the situation described above.

The FAA's Determination and an Explanation of the Provisions of the Proposed AD

What has FAA decided? The FAA has examined the findings of the FOCA; reviewed all available information, including the service information referenced above; and determined that:

—The unsafe condition referenced in this document exists or could develop on other Pilatus PC–12 and PC–12/45 airplanes of the same type design;

—The actions specified in the previously-referenced service information should be accomplished on the affected airplanes; and

—AD action should be taken in order to correct this unsafe condition.

What would the proposed AD require? This proposed AD would require you to incorporate the actions in the previously-referenced service bulletin.

The Swiss AD and the manufacturer's service information applies to manufacturer serial numbers (MSN) 301 through 370 and all part-number (P/N) 552.30.12.051 and P/N 552.30.12.052, held as spares. We are expanding the applicability of this proposed AD to all serial numbered airplanes. We are expanding the inspection and installation actions to cover MSN 101 through MSN 370, instead of MSN 301 through MSN 370, because these cargo doors may have been installed on MSN 101 through MSN 370 through field approval or other methods. Since cargo doors, part-number P/N 552.30.12.051 and P/N 552.30.12.052, held as spares, may be installed on airplanes not covered by the applicability of the service information, the cargo doors on all serial numbered airplanes would have to be inspected and modified if necessary, prior to installation.

Cost Impact

How many airplanes would the proposed AD impact? We estimate that the proposed AD affects 230 airplanes in the U.S. registry.

What would be the cost impact of the proposed AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the proposed inspection:

We estimate the following costs to accomplish any necessary modifications that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that may need such modification:

Regulatory Impact

Would this proposed AD impact various entities? The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposed rule would not have federalism implications under Executive Order 13132.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed 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 .

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List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

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The Proposed Amendment

Accordingly, under 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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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