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CFR Citation: 14 CFR Part 39

Docket ID: [Docket No. 99-CE-77-AD; Amendment 39-12088; AD 2001-02-04]

RIN ID: RIN 2120-AA64

NOTICE: RULES

ACTION: Airworthiness directives:

DOCUMENT ACTION: Final rule.

SUBJECT CATEGORY: Airworthiness Directives; Pilatus Aircraft LTD Model PC-6 Airplanes

DATES: This AD becomes effective on March 13, 2001.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of March 13, 2001.

DOCUMENT SUMMARY: This amendment adopts a new airworthiness directive (AD) that applies to all Pilatus Aircraft LTD (Pilatus) Model PC6 airplanes that are equipped with a certain stabilizer trim actuator. This AD requires you to inspect the lower lug of the actuator for cracks, damage, or distortion; verify that the staked bearing is correctly installed in the bore of the lug; and repair any cracked, damaged, or distorted parts and reassemble any incorrectly installed staked bearing, as necessary. 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 damage, distortion, or cracks in the lower lug assembly, which could result in failure of the lower lug. Such failure could lead to loss of the stabilizer trim actuator with consequent loss of control of the airplane.

SUMMARY: Pilatus Aircraft Ltd.,

SUPPLEMENTAL INFORMATION

What events have caused this AD? The Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, recently notified the FAA that an unsafe condition may exist on all Pilatus Model PC6 airplanes that are equipped with a stabilizer trim actuator, part number (P/N) 978.73.18.101, 978.73.18.102, or 978.73.18.103 (Electomech P/N EM 4831, 4832, or 4833). The FOCA reports an incident of a cracked, damaged, and distorted lower lug of the horizontal stabilizer trim actuator. Analysis of this incident reveals that the staked bearing was loose, which caused excessive wear and failure of the actuator lower lug.

What are the consequences if the condition is not corrected? Damage, distortion, or cracks in the lower lug assembly, if not detected and corrected, could result in failure of this part. Such failure could lead to loss of the
[[Page 8080]]
stabilizer trim actuator with consequent 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 PC6 airplanes that are equipped with a certain stabilizer trim actuator. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on November 2, 2000 (65 FR 65789). The NPRM proposed to require you to inspect the lower lug of the actuator for cracks, damage, or distortion; verify that the staked bearing is correctly installed in the bore of the lug; and repair any cracked, damaged, or distorted parts and reassemble any incorrectly installed staked bearing, as necessary.

Was the public invited to comment? Interested persons were afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The 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 determined that these minor corrections:
Will not change the meaning of the AD; and
Will not add any additional burden upon the public than was already proposed.

Cost Impact

How many airplanes does this AD impact? We estimate that this AD affects 7 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 :
Total cost per Total cost on U.S. airplane Labor cost Parts cost airplane operators 1 workhour x $60 per hour = $60.. Not applicable....... $60 per airplane..... $60 x 7=$420.

If any distortion, damage, or cracks are found during the inspection, you will have to repair the actuator assembly in accordance with an FAAapproved repair scheme developed by the manufacturer. The FAA has no way of determining how much incorporating each repair scheme will cost since the damage to each airplane will be unique. 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. 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 39AIRWORTHINESS 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: 20010204 Pilatus Aircraft Ltd.: Amendment 3912088; Docket No. 99CE77AD.
(a) What airplanes are affected by this AD? This AD affects Model PC6 airplanes, all serial numbers, that are:
(1) Certificated in any category; and
(2) Equipped with a stabilizer trim actuator, part number (P/N) 978.73.18.101, 978.73.18.102, or 978.73.18.103 (Electomech P/N EM 4831, 4832, or 4833), or FAAapproved equivalent part number. (b) Who must comply with this AD? Anyone who wishes to operate any of the above airplanes must comply with this AD.
(c) What problem does this AD address? The actions specified by this AD are intended to detect and correct damage, distortion, or cracks in the lower lug assembly, which could result in failure of the lower lug. Such failure could lead to loss of the stabilizer trim actuator with consequent loss of control of the airplane. (d) What actions must I accomplish to address this problem? To address this problem, you must accomplish the following:
Action Compliance time Procedures (1) Inspect the lower lug of Upon accumulating Accomplish the the actuator for cracks, 500 hours timein inspection in damage, or distortion, and service (TIS) on accordance with the assure that the staked the airplane or ACCOMPLISHMENT bearing is correctly within the next 100 INSTRUCTIONS installed in the bore of hours TIS after section of Pilatus the lug. March 13, 2001 (the Service Bulletin effective date of No. 178, dated this AD), whichever September 29, 1999. occurs later,
unless already
accomplished.
(2) Repair any cracked, Prior to further Accomplish any damaged, or distorted flight after the repairs in parts, as necessary, and inspection required accordance with an reassemble any incorrectly by paragraph (d)(1) FAAapproved repair installed staked bearing. of this AD. scheme obtained from the manufacturer. Accomplish the reassembly in accordance with the instructions in the maintenance manual. [[Page 8081]]
(e) Can I comply with this AD in any other way? You may use an alternative method of compliance or adjust the compliance time if: (1) Your alternative method of compliance provides an equivalent level of safety; and
(2) The Manager, Small Airplane Directorate, approves your alternative. Submit your request through an FAA Principal
Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.

Note 1: This AD applies to each airplane identified in paragraph (a) of this AD, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/ operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if you have not eliminated the unsafe condition, specific actions you propose to address it.
(f) Where can I get information about any already approved alternative methods of compliance? Contact Roman T. Gabrys, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 3294141; facsimile: (816) 3294090.
(g) What if I need to fly the airplane to another location to comply with this AD? The FAA can issue a special flight permit under sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate your airplane to a location where you can accomplish the requirements of this AD.
(h) Are any service bulletins incorporated into this AD by reference? Actions required by this AD must be done in accordance with Pilatus Service Bulletin No. 178, dated September 29, 1999. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You can get copies from Pilatus Aircraft Ltd., Customer Liaison Manager, CH6371 Stans, Switzerland. You can look at 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.
(i) When does this amendment become effective? This amendment becomes effective on March 13, 2001.

Note 2: The subject of this AD is addressed in Swiss AD HB 99 507, dated October 1, 1999.

Issued in Kansas City, Missouri, on January 12, 2001. Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 012002 Filed 12601; 8:45 am] BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Roman T. Gabrys, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 3294141; facsimile: (816) 3294090.