AD 98-24-23

This amendment adopts a new airworthiness directive (AD) that is applicable to Eurocopter France Model SE.3160, SA.316B, SA.316C, and SA.319B helicopters. This action requires inspecting certain horizontal stabilizer spar tubes and replacing them if cracks are found or repairing them if crazing, corrosion, fretting marks, or scratches are found and are repairable. This amendment is prompted by several service reports of spar tube corrosion and fatigue cracks discovered during normal maintenance inspections, which could cause loss of the horizontal stabilizer and subsequent loss of control of the helicopter.

Final rule; request for comments

98-24-23 EUROCOPTER FRANCE: Amendment 39-10909. Docket No. 98-SW-17-AD.
Applicability: Model SE.3160, SA.316B, SA.316C, and SA.319B helicopters, certificated in any category.

NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (b) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of anymodification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously

To prevent failure of the horizontal stabilizer due to a fatigue crack in a spar tube, Part Number (P/N) 3160.35.30.031.1 or .2, which could cause loss of control of the helicopter, accomplish the following:

(a) Within 50 hours time-in-service (TIS) and thereafter at intervals not to exceed 200 hours TIS or 12 calendar months, whichever comes first, using a 10-power or higher magnifying glass, visually inspect the horizontal stabilizer spar tubes, particularly the embedded areas adjacent to the left and right attach fittings in accordance with paragraph 1.C.1) through 5) of the Planning Information of Eurocopter France Service Bulletin 05.84, Revision 2, dated December 19, 1997 (SB).

(1) If the inspection reveals a crack, before further flight, replace the spar tube with an airworthy spar tube in accordancewith paragraph 1.C.7) of the SB.

(2) If the inspection reveals any crazing (fine cracking in the paint), before further flight, remove the paint by rubbing with 200 grit abrasive paper down to bare metal and inspect the spar tube in accordance with paragraphs 1.C.5) and 1.C.6) a) of the SB.

(3) If corrosion pitting, fretting marks, or scratches are found, before further flight, inspect in accordance with paragraphs 1.C.4), 1.C,5), and 1.C.6)a) and c).

(4) If any corrosion pit equals or exceeds 0.5 mm in diameter or if a crack is found as a result of the dye penetrant inspection specified in paragraph 1.C.6)(a) of the SB, before further flight, replace the spar tube with an airworthy spar tube in accordance with paragraph 1.C.7) of the SB.

(5) If pits are less than 0.5mm in diameter or corrosion, fretting, or scratches are repairable, before further flight, repair the spar tube in accordance with paragraph 1.C.6) and reinstall the spar tube in accordance with paragraph 1.C.7) of the SB.

(6) If no corrosion pitting, fretting marks, scratches or crazing are found, reinstall the spar tube in accordance with paragraph 1.C.7) of the SB.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished.(d) The inspection, replacement and repair shall be done in accordance with Eurocopter France Service Bulletin 05.84, Revision 2, dated December 19, 1997. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Direction Generale De L'Aviation Civile (France) AD 91-020-049(A)R2 dated March 11, 1998.

(e) This amendment becomes effective on December 10, 1998.

The Direction Generale De L'Aviation Civile (DGAC), which is the airworthiness authority for France, recently notified the FAA that an unsafe condition may exist on Eurocopter France Model SE.3160, SA.316B, SA.316C, and SA.319B helicopters. The DGAC advises that fatigue cracks in certain horizontal spar tubes have been reported originating at or near the airframe attaching fitting.

Eurocopter France has issued Eurocopter France Service Bulletin 05.84, Revision 2, dated December 19, 1997 (SB). The SB specifies inspections of horizontal stabilizer spar tubes, part numbers (P/N) 3160.35.30.031.1 or .2, for fatigue cracks caused by corrosion or fretting and specifies a procedure to repair them if no cracks are present. The DGAC classified this SB as mandatory and issued AD 91-020-049(A)R2, dated March 11, 1998, to assure the continued airworthiness of these helicopters in France.

These helicopter models are manufactured in France and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Since an unsafe condition has been identified that is likely to exist or develop on other Model SE.3160, SA.316B, SA.316C, and SA.319B helicopters of the same type design registered in the United States, this AD is being issued to prevent failure of the horizontal stabilizer due to fatigue cracks in the horizontal stabilizer spar tubes, P/N's 3160.35.30.031.1 and .2, which could cause loss of the horizontal stabilizer and subsequent loss of control of the helicopter. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, inspections of the horizontal stabilizer spar tubes for cracks are required within 50 hours time-in-service (TIS), and this AD must be issued immediately.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

The FAA estimates that 66 helicopters of U.S. registry will be affected by this AD, that it will take 6 work hours per helicopter to accomplish the actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1987 per helicopter. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $154,902.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, 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 should 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-SW-17-AD." The postcard will be date stamped and returned to the commenter.

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 an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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.

39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: