AD 95-21-02 ACTIVE

This amendment supersedes an existing airworthiness directive (AD), applicable to Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, and TH-55A helicopters with certain main rotor (M/R) drive shafts installed, that currently requires a one-time radiographic inspection or other non-destructive inspection of certain M/R drive shafts for cracks, distortion, corrosion, or other surface damage, at specified time intervals or upon the occurrence of specified conditions. This amendment requires the same inspections as the previous AD, but expands the applicability of certain inspections to additional models of the affected helicopters, and excludes certain M/R drive shafts from certain inspections. This amendment is prompted by a reevaluation as a result of a comment to the previous AD suggesting the need to expand the applicability of certain inspections to additional models of the affected helicopters and to exclude certain M/R drive shafts from certain inspections. The actions specified by this AD are intended to prevent structural failure of the M/R drive shaft, separation of the M/R from the helicopter, and subsequent loss of control of the helicopter.

Final rule

95-21-02 SCHWEIZER AIRCRAFT CORPORATION and HUGHES HELICOPTERS, INC: Amendment 39-9387. Docket No. 94-SW-02-AD. Supersedes AD 93-14-06, Amendment 39-8630.

Applicability: Model 269A, 269A-1, 269B, 269C, and TH-55A helicopters, with main rotor (M/R) drive shaft part number (P/N) 269A5305-3 or 269A5305-11 installed, except those M/R drive shafts having a serial number with a prefix of "SZ" or "ZS", 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 (d) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent structural failure of the M/R drive shaft, separation of the M/R from the helicopter, and subsequent loss of control of the helicopter, accomplish the following:

(a) Inspect the M/R drive shaft for cracks, distortion, corrosion, or other surface damage, using either the radiographic inspection procedure or the other non-destructive inspection procedure in accordance with Part I of Schweizer Service Bulletin B-255.1 (SB), dated February 1, 1993. Conduct this inspection at the time intervals and under the conditions stated in the following:

(1) Inspect M/R drive shafts with serial numbers (S/N) S0001 through S1111, and any drive shaft without an "S" prefix on the S/N, having less than 1,100 hours time-in-service (TIS) on the effective date of this AD--
(i) At the next removal of the drive shaft;
(ii) Within the next 600 hours TIS;
(iii) Prior to attaining 1,200 hours total TIS; or
(iv) Within 1 year after the effective date of this AD, whichever occurs first.

(2) Inspect M/R drive shafts with S/N S0001 through S1111, and any drive shaft without an "S" prefix on the S/N with 1,100 hours or more TIS on the effective date of this AD--
(i) Within the next 100 hours TIS; or
(ii) At the next removal of the drive shaft; or
(iii) Within 1 year after the effective date of this AD, whichever occurs first.

(3) Inspect M/R drive shafts with S/N S1112 and higher, regardless of the number of the total hours TIS on the effective date of this AD--
(i) Within the next 25 hours TIS;
(ii) At the next removal of the drive shaft; or
(iii) Within 1 year after the effective date of this AD, whichever occurs first.

(4) Inspect the M/R drive shaft before further flight if M/R vibrations occur that cannot be corrected with track and balance procedures, or if M/R track and balance procedures are required more than once within a 25-hour TIS interval.

(b) Inspect any replacement M/R drive shaft, except those that have a serial number with a prefix of "SZ" or "ZS", prior to installation in accordance with the procedures in Part I of the SB, dated February 1, 1993.

(c) Replace any unairworthy M/R drive shaft with an airworthy M/R drive shaft before further flight.

(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, New York Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, whomay concur or comment and then send it to the Manager, New York Aircraft Certification Office.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York Aircraft 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) only for those helicopters that do not exhibit M/R vibrations due to uncorrected out-of-track or out-of-balance conditions specified in paragraph (a)(4) of this AD. The special flight permit allows flight of the helicopter to a location where the requirements of this AD can be accomplished.

(f) The inspections and replacement, if necessary, shall be done in accordance with Schweizer Service Bulletin B-255.1 (SB), dated February 1, 1993. This incorporation by reference was previously approved by the Director of the Federal Register in accordance with 5U.S.C. 552(a) and 1 CFR part 51 as of October 29, 1993 (58FR53120, October 14, 1993). Copies may be obtained from Schweizer Aircraft Corporation, P.O. Box 147, Elmira, New York 14902. Copies may be inspected at the FAA, Office of the Assistant Chief Counsel, 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.

(g) This amendment becomes effective on November 17, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 93-14-06, Amendment 39-8630 (58 FR 53120, October 14, 1993), which is applicable to Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, and TH-55A helicopters, was published in the Federal Register on November 30, 1994 (59 FR 61298). That action proposed to require a one-time radiographic inspection or other non-destructive inspection of the applicable M/R drive shafts of all affected Model 269 series helicopters. That action also proposed to change paragraph (b) of AD 93-14-06 to exclude those replacement drive shafts having an "SZ" or "ZS" prefix from mandatory inspections prior to their installation.

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 hasdetermined that air safety and the public interest require the adoption of the rule as proposed, except for editorial changes and adding explanatory Note 1, relating to the scope of the applicability statement when modifications, alterations, or repairs have been made in the area subject to the requirements of the AD. 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 1,364 helicopters of U.S. registry will be affected by this AD, that it will take approximately 10 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $818,400.

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.

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 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 USC 106(g), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by removing Amendment 39-8630 (58 FR 53120, October 14, 1993), and by adding a new airworthiness directive (AD), Amendment 39-9387, to read as follows:

The service information referenced in this AD may be obtained from Schweizer Aircraft Corporation, P.O. Box 147, Elmira, New York 14902. This information may be examined 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.

Mr. Raymond J. O'Neill, Aerospace Engineer, FAA, New York Aircraft Certification Office, New England Region, 10 5th Street, Valley Stream, New York 11581, telephone (516) 256-7505, fax (516) 568-2716.