Discussion
On October 29, 1997, the FAA issued AD 97-23-04, amendment 39-10192 (62 FR 5993, November 6, 1997), which applies to certain Pilatus Models PC-12 and PC-12/45 airplanes. AD 97-23-04 was the result of a report from the Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, of an instance of abnormal automatic engagement of the fuel booster pumps during normal operation of a Pilatus Model PC-12 airplane. The FOCA's investigation revealed that the fuel tank inward vent valves may fail in the closed position under certain conditions. Moisture ingestion, followed by cold soak, can lead to the fuel tank inward vent valve freezing.
AD 97-23-04 required replacing the fuel tank vent valves with modified fuel tank vent valves before the FAA superseded it with AD 98-11-01, Amendment 39-10528 (63 FR 27195, May 18, 1998). AD 98-11-01 currently requires the fuel tank vent valves replacement required by AD 97-23-04, and requires drilling a 4.8 millimeter (0.1875 inch) hole in each fuel filler cap.
This AD also requires inserting the following temporary revision to the POH that specifies checking to assure that the fuel filler cap hole is clear of ice and foreign objects:
"PC-12 Pilot's Operating Handbook, Pilatus Report No. 01973-001, Temporary Revision, Fuel Filler Cap, dated March 27, 1998."
Accomplishment of the replacement is required in accordance with Pilatus Service Bulletin No. 28-003, Revision 1, dated September 30, 1997. Accomplishment of the drilling and POH insertion is required in accordance with Pilatus Service Bulletin No. 28-004, dated March 27, 1998.
AD 98-11-01 was the result of a report of an incident where the inward vent valve of the fuel tank froze closed on one of the affected airplanes that was in compliance with the fuel tank vent valves replacement requirement of AD 97-23-04. This resulted in permanent structural damage to the wing skins and ribs.
This condition, if not corrected, could result in wing airfoil distortion and structural damage with consequent degradation of the airplane's handling qualities.
Relevant Service Information
Pilatus has issued Service Bulletin No. 28-005, dated May 4, 1998, which specifies procedures for modifying the fuel tank vent valves. This modification, when incorporated, would eliminate the need for the drilling and POH requirements of AD 98-11-01.
The FOCA of Switzerland classified this service bulletin as mandatory and issued Swiss AD HB 98-126, dated May 15, 1998, in order to assure the continued airworthiness of these airplanes in Switzerland.
The FAA's Determination
This airplane model is manufactured in Switzerland and is type certificated for operation in the United States under the provisions of Sec. 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 of Switzerland has kept the FAA informed of the situation described above.
The FAA has examined the findings of the FOCA of Switzerland; reviewed all available information, including the referenced service information; and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Explanation of the Provisions of This AD
Since an unsafe condition has been identified that is likely to exist or develop in other Models PC-12 and PC-12/45 airplanes of the same type design registered in the United States, the FAA is issuing an AD to revise AD 98-11-01. This AD:
--Maintains the requirements in AD 98-11-01 of replacing the fuel tank vent valves, drilling a 4.8 millimeter (0.1875 inch) hole in each fuel filler cap, and inserting a temporary revision in the POH that specifies checking to assure that the fuel filler cap hole is clear of ice and foreign objects; and
--Adds the option of modifying the fuel tank vent valves instead of the drilling and POH requirements carried over from AD 98-11-01.
Accomplishment of the actions specified in this AD would be required in accordance with the following:
--Replacement: Pilatus Service Bulletin No. 28-003, Revision 1, dated September 30, 1997;
--Drilling: Pilatus Service Bulletin No. 28-004, dated March 27, 1998; and
--Modification: Pilatus Service Bulletin No. 28-005, dated May 4, 1998.
Cost Impact
The FAA estimates that 100 airplanes in the U.S. registry will be affected by this AD. The only difference between this AD and AD 98-11-01 is the provision of accomplishing the modification instead of the drilling and POH insertion requirements carried over from AD 98-11-01. This replacement takes approximately 8 workhours per airplane to accomplish at an average labor rate of approximately $60 per work hour. Parts will be provided at no cost to the owner/operator of the affected airplanes. Based on thesefigures, the cost impact of this AD on U.S. operators that choose to incorporate the modification option instead of the drilling and POH requirements carried over from AD 98-11-01 is estimated to be $48,000, or $480 per airplane.
The Direct Final Rule Procedure
The FAA anticipates that this regulation will not result in adverse or negative comment and therefore is issuing it as a direct final rule. The requirements of this direct final rule address an unsafe condition identified by a foreign civil airworthiness authority and do not impose a significant burden on affected operators. In accordance with Sec. 11.17 of the Federal Aviation Regulations (14 CFR 11.17) unless a written adverse or negative comment, or a written notice of intent to submit an adverse or negative comment, is received within the comment period, the regulation will become effective on the date specified above. After the close of the comment period, the FAA will publish a document in the Federal Register indicating that no adverse or negative comments were received and confirming the date on which the final rule will become effective. If the FAA does receive, within the comment period, a written adverse or negative comment, or written notice of intent to submit such a comment, a document withdrawing the direct final rule will be published in the Federal Register, and a notice of proposed rulemaking may be published with a new comment period.
Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 98-CE-40-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
The FAA has determined that this regulation is noncontroversial and unlikely to result in adverse or negative comments. For reasons discussed in the preamble, I certify that this regulation (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 theRegulatory Flexibility Act. A final evaluation has been prepared for this action and is contained in the Rules Docket. A copy of it may be obtained from 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, pursuant to 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. Section 39.13 is amended by removing Airworthiness Directive (AD) 98-11-01, Amendment 39-10528 (63 FR 27195, May 18, 1998), and by adding a new AD to read as follows: