Skip to Content

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.

Start Preamble Start Printed Page 37394

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that applies to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6 airplanes. This AD requires you to inspect the integral fuel tank wing ribs for cracks and the top and bottom wing skins for distortion, repair any cracks or distortion before further flight, and accomplish a fuel tank ventilating system installation. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. 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.

DATES:

This AD becomes effective on August 15, 2003.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of August 15, 2003.

ADDRESSES:

You may get the service information 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 this information at the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-12-AD, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Start Further Info

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.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Discussion

What Events Have Caused This 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 Is the Potential Impact If FAA Took No Action?

These fatigue cracks on the ribs within the wing could lead to wing failure during flight.

Has FAA Taken Any Action to This Point?

We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all Pilatus Model PC-6 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on April 4, 2003 (68 FR 16458). The NPRM proposed to require you to inspect the integral fuel tank wing ribs for cracks and the top and bottom wing skins for distortion, repair any cracks or distortion before further flight, and accomplish a fuel tank ventilating system installation.

Was the Public Invited To Comment?

The FAA encouraged interested persons to participate in the making of this amendment. We did not receive any comments on the proposed rule or on our determination of the cost to the public.

FAA's Determination

What Is FAA's Final Determination on This Issue?

After careful review of all available information related to the subject presented above, we have determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. We have determined that these minor corrections:

—Provide the intent that was proposed in the NPRM for correcting the unsafe condition; and

—Do not add any additional burden upon the public than was already proposed in the NPRM.

How Does the Revision to 14 CFR Part 39 Affect This 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 Does This AD Impact?

We estimate that this AD affects 35 airplanes in the U.S. registry.

What Is the Cost Impact of This AD on Owners/operators of the Affected Airplanes?

We estimate the following costs to accomplish the 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 will be required based on the results of this inspection. We have no way of determining the number of airplanes that may need such repair. Start Printed Page 37395

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 will be required based on the results of this 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

Regulatory Impact

Does This AD Impact Various Entities?

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

Does This AD Involve a Significant Rule or Regulatory Action?

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) 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 final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

Adoption of the Amendment

Start Amendment Part

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

End Amendment Part Start Part

PART 39—AIRWORTHINESS DIRECTIVES

End Part Start Amendment Part

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

End Amendment Part Start Authority

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

End Authority
[Amended]
Start Amendment Part

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

End Amendment Part

2003-13-04 Pilatus Aircraft LTD.: Amendment 39-13204; 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; (ii) the upper and lower wing skins for damage; and (iii) to determine if the inboard fuel tank vent system is installed.Within the next 100 hours time-in-service (TIS) after August 15, 2003 (the effective date of this AD), unless already accomplished.In accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and the applicable maintenance manual.
(2) If crack damage is found: (i) Correct the crack damage designated as repairable in the service bulletin (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.Prior to further flight after the inspections required in paragraph (d)(1) of this AD.In accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and the applicable maintenance manual.
(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 paragarph (d)(1) of this AD.In 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 AD.In accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 118, dated December 1972, and the applicable maintenance manual.
Start Printed Page 37396

(e) Can I comply with this AD in any other way? To use an alternative method of compliance or adjust the compliance time, use 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) Are any service bulletins incorporated into this AD by reference? Actions required by this AD must be done in accordance with Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 57-002, dated November 27, 2002, and Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 118, dated December 1972. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You may get copies 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 copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note:

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

(g) When does this amendment become effective? This amendment becomes effective on August 15, 2003.

Start Signature

Issued in Kansas City, Missouri, on June 16, 2003.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. 03-15723 Filed 6-23-03; 8:45 am]

BILLING CODE 4910-13-P