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 that the lower attachment bracket of the horizontal stabilizer actuator broke, which resulted in an emergency landing outside the airport.
The FOCA also reports two other instances of total failure of the stabilizer trim attachment on in-service airplanes.
What is the potential impact if FAA took no action? If not detected and corrected, defects in the stabilizer-trim attachment and surrounding structural components could cause the stabilizer-trim attachment to fail. This failure could lead to loss of control of the airplane.
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 March 24, 2005 (70 FR 15019). The NPRM proposed to require you to:
--Inspect the stabilizer-trim attachment and structural components (the fitting, the connecting piece, the bearing fork, the bearing support assembly, and the auxiliary frame, as applicable) for cracks and corrosion;
--Inspect the diameters of the boltholes on the fittings, auxiliary frame, and connecting piece (as applicable) for discrepancies;
--Replace any cracked, corroded, or defective part with a new part; and
--Replace all Fairchild connecting pieces with a Pilatus connecting piece.
We received comments on the NPRM requesting the following:
--Incorporate revised service to include a procedure for replacing certain fittings with an improved part and to correct the allowable limits of the actuator attachment hole diameters;
--Change the repetitive inspection intervals; and
--Clarify the applicability of the affected airplanes.
As a result of the above comments, we issued a supplemental NPRM that was published in the Federal Register on June 14, 2005 (34401). The Supplemental NPRM proposed to require you to:
--Inspect the stabilizer-trim attachment and structural components (the fitting, the connecting piece, the bearing fork, the bearing support assembly, and the auxiliary frame, as applicable) for cracks and corrosion;
--Inspect the diameters of the boltholes on the fittings, auxiliary frame, and connecting piece (as applicable) for discrepancies;
--Replace any cracked part with a new part;
--Repair or replace corroded or defective part;
--Replace all Fairchild connecting pieces, P/N 6232.0026.XX with a Pilatus connecting piece. The Fairchild part has a rivet in the middle that is not on the Pilatus part; and
--Replace all fittings, P/N 116.40.06.033 without an index after the P/ N with an improved part, P/N 116.40.06.033 with an index after the P/N or P/N 116.40.06.112.
Comments
Was the public invited to comment? We provided the public the opportunity to participate in developing this AD.
Pilatus Aircraft Ltd. submitted a comment stating that they have no further comments on the Supplemental NPRM.
Comment Issue: Update Reference to the Swiss AD
What is the commenter's concern? FOCA has superseded Swiss AD HB- 2005-080, effective date March 2, 2005, with Swiss AD HB-2005-263, effective date June 16, 2005.
The commenter requests that the reference to the Swiss AD be changed to incorporate the new AD number.
What is FAA's response to the concern? We concur with the commenter and will change the final rule AD action.
What is FAA's final determination on this issue? We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for the changes discussed above and minor editorial corrections. We have determined that these changes and 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.
Docket Information
Where can I go to view the docket information? You may view the AD docket that contains information relating to this subject in person at the DMS Docket Offices between 9 a.m. and 5 p.m. (eastern standard time), Monday through Friday, except Federal holidays. The Docket Office (telephone 1-800-647-5227) is located on the plaza level of the Department of Transportation NASSIF Building at the street address stated in ADDRESSES. You may also view the AD docket on the Internet at http://dms.dot.gov.
Changes to 14 CFR Part 39--Effect on the AD
How does the revision to 14 CFR part 39 affect this AD? On July 10, 2002, the FAA published a new version of 14 CFR part 39 (67 FR47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. 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.
Costs of Compliance
How many airplanes does this AD impact? We estimate that this AD affects 41 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 do the inspections:
Labor cost
Parts cost
Total cost per airplane
Total cost on U.S. operators
11 work hours $65 per hour = $715
Not applicable
$715
$715 41 = $29,315
We estimate the following costs to do any necessary replacements that will be required based on the results of the inspections. We have no way of determining the number of airplanes that may need these replacements:
Labor cost
Parts cost
Total cost per airplane to replace all parts
10 work hours $65 = $650
$2,000 to replace all parts
$650 + $2,000 = $2,650
Authority for This Rulemaking
What authority does FAA have for issuing this rulemaking action? 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 addressesan unsafe condition that is likely to exist or develop on products identified in this AD.
Regulatory Findings
Will this AD impact various entities? 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.
Will this AD involve a significant rule or regulatory action? 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-2005-20515; Directorate Identifier 2005-CE-09-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.
Sec. 39.13 [Amended]
2. FAA amends Sec. 39.13 by adding a new AD to read as follows: