AD 96-09-29

This amendment adopts a new airworthiness directive (AD), applicable to Robinson Helicopter Company (Robinson) Model R22 helicopters, that requires replacement of the upper V-belt sheave (sheave). This amendment is prompted by three reports of cracks in the flange of the sheave. The actions specified by this AD are intended to prevent failure of the sheave, which could result in damage to other drive system components, and subsequent loss of control of the helicopter.

Final rule

96-09-29 ROBINSON HELICOPTER COMPANY: Amendment 39-9605. Docket No. 95-SW-23-AD.

Applicability: Model R22 helicopters with upper V-belt sheave (sheave) part number (P/N) A170-1I or J, or P/N A170-2J, installed, 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 any modification, alteration, or repair remove any helicopter from the applicability of this AD.

NOTE 2: Determination of whether the affected sheave has been installed can be accomplished by measuring the depth from the edge of the forward retainer plate to the flange of the sheave in an area located between the webs as shown in Figure 2 of Robinson Helicopter Company R22 Service Bulletin SB-77, dated April 25, 1995. If the depth is greater than 0.30 inch, then either sheave, P/N A170-1I or J, or sheave, P/N A170-2J, is installed.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the sheave, which could result in damage to other drive system components, and subsequent loss of control of the helicopter, accomplish the following:

(a) Within the next 100 hours time-in-service (TIS) or 60 calendar days, whichever occurs first after the effective date of this AD, replace the sheave, P/N A170-1I or J, or P/N A170-2J, with an airworthy sheave, P/N A170-1, or P/N A170-2, having a dimension equal to or less than 0.30 inch measured from the edge of the forward retainer plate to the flange of the sheave in an area located between the webs, in accordance with paragraphs 2 through 15 of the Compliance Procedures of Robinson Helicopter Company R22 Service Bulletin SB-77, dated April 25, 1995.

(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, Los Angeles Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.

(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) Replacement of the sheave shall be done in accordance with paragraphs 2 through 15 of the Compliance Procedures of Robinson Helicopter Company R22 Service Bulletin SB-77, dated April 25, 1995. 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 Robinson Helicopter Company, 2901 Airport Drive, Torrance, California 90505. Copies may be inspected at the FAA, Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663, Fort Worth, Texas, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on June 7, 1996.

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 Robinson Model R22 helicopters was published in the Federal Register on November 28, 1995 (60 FR 58579). That action proposed to require, within the next 100 hours time-in-service (TIS) or 60 calendar days, whichever comes first, replacement of the upper sheave, part number (P/N) A170-1I or J or P/N A170-2J, with a sheave having a dimension equal to or less than 0.30 inch measured from the edge of the forward retainer plate to the flange of the sheave.

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. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 650 helicopters of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,216 per helicopter for the sheave, part number (P/N) A170-1, and $2,298 per helicopter for the sheave, P/N A170-2. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $1,298,050, assuming replacement of the sheave in all 650 helicopters, and assuming that one-half of the helicopters have the sheave, P/N A170-1, installed, and one-half of the helicopters have the sheave, P/N A170-2, installed.

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 thatthis 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 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 AviationAdministration 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 USC 106(g), 40113, 44701.

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