AD 94-18-09

This amendment adopts a new airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. Model 205A, 205A-1, 205B, 212, and 412 series helicopters, that requires removal and replacement of a certain design main transmission lower planetary spider (spider), and establishes a 2,500 hours time-in-service retirement life for the spider. This amendment is prompted by five failures of the spider that occurred during the manufacturer's fatigue tests. The actions specified by this AD are intended to prevent fatigue failure of the spider, failure of the main transmission, and subsequent loss of control of the helicopter.

Final rule

94-18-09 BELL HELICOPTER TEXTRON, INC. : Amendment 39-9022. Docket No. 93-SW-17-AD.

Applicability: Model 205A, 205A-1, 205B, 212, and 412 series helicopters, with main transmission lower planetary spider (spider) part number (P/N) 412-040-785-101, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue failure of the spider, that could result in failure of the main transmission, and subsequent loss of control of the helicopter, accomplish the following:

(a) For spiders with 2,400 hours or more time-in-service (TIS) on the effective date of this airworthiness directive (AD), within the next 100 hours TIS, remove and replace the spider with an airworthy spider in accordance with the Accomplishment Instructions of Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-93-54, dated June 18, 1993, for the Models 205A and 205A-1; ASB 205B-93-16, dated June18, 1993, for the Model 205B; ASB 212-93-83, dated June 18, 1993, for the Model 212; and ASB 412-93-72, Revision A, dated June 18, 1993, for the Model 412 helicopters.

(b) For spiders with less than 2,400 hours TIS on the effective date of this AD, prior to or upon attaining 2,500 hours TIS, remove and replace the spider with an airworthy spider in accordance with the accomplishment instructions of the appropriate ASB referred to in paragraph (a).

(c) This AD revises the Airworthiness Limitations sections of the applicable helicopter maintenance manuals by establishing a retirement life of 2,500 hours TIS for the spider. However, spiders with 2,400 or more hours TIS on the effective date of this AD need not be retired until on or before the accumulation of an additional 100 hours TIS.

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

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

(e) 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.

(f) The removal and replacement of the spider shall be done in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-93-54, dated June 18, 1993, for the Models 205A and 205A-1; ASB 205B-93-16, dated June 18, 1993, for the Model 205B; ASB 212-93-83,dated June 18, 1993, for the Model 212; and ASB 412-93-72, Revision A, dated June 18, 1993, for the Model 412 helicopters. 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 Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101. Copies may be inspected at the FAA, Office of the Assistant Chief Counsel, 2601 Meacham Boulevard, Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on October 14, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. Model 205A, 205A-1, 205B, 212, and 412 series helicopters was published in the Federal Register on January 5, 1994 (59 FR 555). That action proposed to require removal and replacement of a certain design main transmission lower planetary spider (spider), and proposed to establish a 2,500 hours time-in-service retirement life for the spider.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. However, the FAA has added a sentence to paragraph (c) of this AD to make it clear that the retirement life established is 2,500 hours time-in-service; but, since this AD establishes a new retirement life, those spiders with 2,400 or more hours TIS on the effective date of this AD need not be retired until on or before the accumulation of an additional 100 hours TIS. Additionally, the FAA aerospace engineer to contact regarding this rule has changed since the issuance of the notice and the AD has been changed accordingly. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed, with the noted changes. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 40 helicopters of U.S. registry will be affected by this AD, that it will take approximately 26 work hours per helicopter to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will cost approximately $8,929 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $414,360.

The regulations adoptedherein 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.

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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at thelocation 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

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