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Proposed Rule

Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-6 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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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) Model PC-6 airplanes. This proposed AD would require you to inspect the integral fuel tank wing ribs for cracks and the top and bottom wing skins for distortion and repair before further flight, and accomplish a fuel tank ventilating system installation. This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this proposed AD are intended to detect and correct cracks in the ribs of the inboard integral fuel tanks in the left and right wings, which could lead to wing failure during flight.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before May 12, 2003.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-12-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. You may view any comments at this location between 8 a.m. and 4 p.m., Monday through Friday, except Federal holidays. You may also send comments electronically to the following address: 9-ACE-7-Docket@faa.gov. Comments sent electronically must contain “Docket No. 2003-CE-12-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII text.

You may get service information that applies to this proposed AD 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. You may also view this information 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 this 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 to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date. We may amend this proposed rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of this proposed AD action and determining whether we need to take additional rulemaking action.

Are there any specific portions of this proposed AD I should pay attention to? The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of this proposed rule that might suggest a need to modify the rule. You may view 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 Start Printed Page 16459contact we have with the public that concerns the substantive parts of this proposed AD.

How can I be sure FAA receives my comment? If you want FAA to acknowledge the receipt of your mailed comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 2003-CE-12-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 Model PC-6 airplanes. The FOCA reports an incident where cracks have been found in the ribs of the inboard integral fuel tanks in the left and right wings of a Model PC-6 airplane. Investigation revealed that the cracks can occur when there are excessive pressure differentials between the ambient air pressure and that of the fuel tanks. The effect of this differential can be to compress the wing in the area of the fuel tank and cause distortion of the related structure. This distortion may result in fatigue cracks on ribs within the wing.

What are the consequences if the condition is not corrected? These fatigue cracks on the ribs within the wing could lead to wing failure during flight.

Is there service information that applies to this subject? Pilatus has issued the following:

—Service Bulletin (SB) No. 57-002, dated November 27, 2002; and

—SB No. 118, dated December 1972.

What are the provisions of this service information? The service bulletins include procedures for:

—Inspecting the ribs in the left and right inboard fuel tanks;

—Repairing a rib;

—Inspecting to determine if the inboard fuel tank vent system is installed; and

—Installing the inboard fuel tank vent system.

What action did the FOCA take? The FOCA classified this service bulletin as mandatory and issued Swiss AD Number HB 2003-092, dated February 17, 2003, in order to ensure the continued airworthiness of these airplanes in Switzerland.

Was this in accordance with the bilateral airworthiness agreement? This airplane model is manufactured in Switzerland and is type certificated for operation in the United States under the provisions of § 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 This 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 Model PC-6 airplanes of the same type design that are on the U.S. registry;

—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 this proposed AD require? This proposed AD would require you to incorporate the actions in the previously-referenced service bulletins.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Cost Impact

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 35 airplanes in the U.S. registry.

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

Labor costParts costTotal cost per airplaneTotal cost on U.S. operators
5 workhours × $60 per hour = $300Not applicable$300$300 × 35 = $10,500.

We estimate the following costs for each rib to accomplish any necessary rib repair that would be required based on the results of this proposed inspection. We have no way of determining the number of airplanes that may need such repair.

Labor costParts costTotal cost per rib per airplane
3 workhours × $60 per hour = $180 per rib$50 per rib$230 per rib.

We estimate the following costs to install any inboard fuel tank vent system that would be required based on the results of this proposed inspection. We have no way of determining the number of airplanes that may need such installation.

Labor costParts costTotal cost per airplane
12 workhours × $60 per hour = $720$200$920
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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

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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.

End Authority
[Amended]

2. FAA amends § 39.13 by adding a new airworthiness directive (AD) to read as follows:

Pilatus Aircraft Ltd.: Docket No. 2003-CE-12-AD

(a) What airplanes are affected by this AD? This AD affects Model PC-6 airplanes, all manufacturer serial numbers (MSN) up to and including 939, that are certificated in any category.

(b) Who must comply with this AD? Anyone who wishes to operate any of the airplanes identified in paragraph (a) of this AD must comply with this AD.

(c) What problem does this AD address? The actions specified by this AD are intended to detect and correct cracks in the ribs of the inboard integral fuel tanks in the left and right wings, which could lead to wing failure during flight.

(d) What actions must I accomplish to address this problem? To address this problem, you must accomplish the following:

ActionsComplianceProcedures
(1) Inspect:
(i) The ribs in the inboard integral fuel tanks and related structure in the left and right wings for crack damage;Within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless already accomplishedIn accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and the applicable manual.
(ii) The upper and lower wing skins for damage; and
(iii) To determine if the inboard fuel tank vent system is installed
(2) If crack damage is found:
(i) Correct the crack damage designated as repairable in the service bulletinPrior to further flight after the inspections required in paragraph (d)(1) of this ADIn accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and the applicable maintenance manual.
(ii) For other crack damage, obtain a repair scheme from the manufacturer through FAA at the address specified in paragraph (e) of this AD and incorporate this repair scheme
(3) If wing distortion is found, obtain a repair scheme from the manufacturer through FAA at the address specified in paragraph (e) of this AD and incorporate this repair schemePrior to further flight after the inspections required in paragraph (d)(1) of this ADIn accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and the applicable maintenance manual.
(4) If the inboard fuel tank vent system is not installed, install the inboard fuel tank vent systemPrior to further flight after the inspections required in paragraph (d)(1) of this ADIn accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 118, dated December 1972, and the applicable maintenance manual.

(e) Can I comply with this AD in any other way? To use an alternative method of compliance or adjust the compliance time, follow the procedures in 14 CFR 39.19. Send these requests to the Manager, Standards Office, Small Airplane Directorate. For information on any already approved alternative methods of compliance, 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.

(f) How do I get copies of the documents referenced in this AD? You may get copies of the documents referenced in this AD 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. You may view these documents at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

Note:

The subject of this AD is addressed in Swiss AD Number HB 2003-092, dated February 17, 2003.

Start Signature

Issued in Kansas City, Missouri, on March 28, 2003.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 03-8199 Filed 4-3-03; 8:45 am]

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