E6-18734. Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-7 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA adopts a new airworthiness directive (AD) for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-7 airplanes. This AD requires you to do repetitive eddy-current, non-destructive inspections of the nose skin and adjacent structure above the left and right main landing gear bay and repetitive visual inspections of the forward support structure of the floor panel for crack damage. If you find any crack damage, this AD requires you to contact Pilatus to obtain a repair solution and incorporate the repair. This AD results from mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. We are issuing this AD to detect and correct cracks in the nose skin and adjacent structure above the left and right main landing gear bay and in the forward support structure of the floor panel. Crack propagation in certain areas could lead to failure of the main wing torsion box, which could result in loss of control.

DATES:

This AD becomes effective on December 13, 2006.

As of December 13, 2006, the Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulation.

ADDRESSES:

To get the service information identified in this AD, contact Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: [phone]; fax: [phone].

To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2006-25582; Directorate Identifier 2006-CE-42-AD.

FOR FURTHER INFORMATION CONTACT:

Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Discussion

On September 11, 2006, 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 certain Pilatus Model PC-7 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on September 15, 2006 (71 FR 54441). The NPRM proposed to require you to do repetitive eddy-current, non-destructive inspections of the nose skin and adjacent structure above the left and right main landing gear bay and repetitive visual inspections of the forward support structure of the floor panel for crack damage. If crack damage is found, the NPRM proposed to require you to contact Pilatus to obtain a repair solution and incorporate the repair.

Comments

We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:

We received one comment from Pilatus Aircraft in favor of the proposed AD.

Comment Issue No. 1: Publish the Manufacturer Service Information

Jack Buster with the Modification and Replacement Parts Association (MARPA) provides comments on the MCAI AD process pertaining to how the FAA addresses publishing manufacturer service information as part of a proposed AD action. The commenter states that the proposed rule attempts to require compliance with a public law by reference to a private writing (as referenced in paragraph (e) of the proposed AD). The commenter would like the FAA to incorporate by reference (IBR) the Pilatus service bulletin.

We agree with Mr. Buster. However, we do not IBR any document in a proposed AD action, instead we IBR the document in the final rule. Since we are issuing the proposal as a final rule AD action, Pilatus PC-7 Service Bulletin No. 57-009, dated January 29, 2004, is incorporated by reference.

Comment Issue No. 2: Availability of IBR Documents in the Docket Management System (DMS)

Mr. Buster requests IBR documents be made available to the public by publication in the Federal Register or in the DMS.

We are currently reviewing issues surrounding the posting of service bulletins in the Department of Transportation's DMS as part of the AD docket. Once we have thoroughly examined all aspects of this issue and have made a final determination, we will consider whether our current practice needs to be revised.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections:

• Are consistent with 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.

Differences Between the FOCA AD, the Service Information, and This AD

The FOCA AD HB-2006-374, effective date August 2, 2006, allows continued flight if cracks are found in the nose skin that do not exceed certain limits. The applicable service bulletin specifies repair of the nose skin only if cracks are found exceeding limits illustrated in Pilatus PC-7 Service Bulletin No. 57-009, dated January 29, 2004, as does FOCA AD HB-2006-374, effective date August 2, 2006. This AD does not allow continued flight if any crack is found. The FAA policy is to disallow airplane operation when known cracks exist in primary structure, unless the ability to sustain ultimate load with these cracks is proven. The nose skin is considered primary structure, and the FAA has not received any analysis to prove that ultimate load can be sustained with cracks in this area.

The requirements of this AD take precedence over the provisions in the service information.

Costs of Compliance

We estimate that this AD affects 10 airplanes in the U.S. registry.

We estimate the following costs to accomplish the inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
3 work-hours × $80 per hour = $240	No parts required	$240	$2,400

Any required “upon-condition” repairs will vary depending upon the damage found. Based on this, we have no way of determining the potential repair costs for each airplane or the number of airplanes that will need the repairs based on the result of the inspections.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that this AD:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the 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.

We prepared a summary of the costs to comply with this AD (and other information as included in the Regulatory Evaluation) and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “Docket No. FAA-2006-25582; Directorate Identifier 2006-CE-42-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

§ 39.13

[Amended]

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

2006-23-01 Pilatus Aircraft Ltd.: Amendment 39-14813; Docket No. FAA-2006-25582; Directorate Identifier 2006-CE-42-AD.

Effective Date

(a) This AD becomes effective on December 13, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model PC-7 airplanes, manufacturer serial numbers 101 through 618 inclusive, that are certificated in any category.

Unsafe Condition

(d) This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified in this AD are intended to detect and correct cracks in the nose skin and adjacent structure above the left and right main landing gear bay and in the forward support structure of the floor panel. Crack propagation in certain areas could lead to failure of the main wing torsion box. This failure could result in loss of control.

Compliance

(e) To address this problem, you must do the following:

Actions	Compliance	Procedures
(1) Inspect:
(i) The forward area of the floor panel and the related structure for cracks using magnified, visual methods. (ii) The nose skin and adjacent structure above the left and right main landing gear bay for cracks using eddy-current, non-destructive methods	Initially inspect within the next 150 hours time-in-service or 6 calendar months, whichever occurs first, after December 13, 2006 (the effective date of this AD), unless already done. Repetitively inspect thereafter at intervals specified in paragraph 2.B. of Pilatus PC-7 Aircraft Maintenance Manual (AMM) 05-10-00, dated March 4, 2005	Do the initial inspection following Pilatus PC-7 Service Bulletin No. 57-009, dated January 29, 2004. Do the repetitive inspections following the procedures in AMM 57-10-03, dated March 4, 2005, and AMM 05-30-05, dated February 28, 2006.
(2) If crack damage is found during any inspection required by paragraph (e)(1) of this AD, obtain an FAA-approved repair solution from the manufacturer through the FAA at the address specified in paragraph (f) of this AD and incorporate the repair	Before further flight after any inspection in which crack damage is found. Further flight with crack damage is not permitted. After incorporating the repair, repetitively inspect as specified in paragraph (e)(1) of this AD	Obtain an FAA-approved repair solution from the manufacturer through the FAA at the address specified in paragraph (f) of this AD and incorporate the repair.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Standards Staff, FAA, Small Airplane Directorate, Attn: Doug Rudolph, Aerospace Engineer, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone], has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(g) The Federal Office for Civil Aviation Swiss AD HB-2006-374, effective date August 2, 2006, also addresses the subject of this AD.

Material Incorporated by Reference

(h) You must use Pilatus PC-7 Service Bulletin No. 57-009, dated January 29, 2004, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: [phone]; fax: [phone].

(3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Kansas City, Missouri, on October 26, 2006.

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.