AD 95-03-12 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 series helicopters, that currently requires an initial and repetitive visual inspections of the clutch control spring assembly for component wear and replacement of affected unairworthy parts. This amendment requires the same initial and repetitive visual inspections and replacements required by the existing Priority Letter AD, but references a revised service bulletin and provides replacement procedures for the aluminum spring retainer thermofit tube (plastic sleeve). This amendment is prompted by a recent accident involving a Model 269C helicopter that reportedly lost engine drive power at 100 feet above ground level (AGL) with a resulting unsuccessful autorotative landing, and the manufacturer's issuance of revised service information that provides more detailed instructions for replacementof two components of the belt drive clutch control assembly. The actions specified by this AD are intended to prevent failure of the aluminum spring retainer, loss of power to the rotor drive system, and a subsequent forced landing.

Final rule; request for comments

95-03-12 SCHWEIZER AIRCRAFT CORPORATION AND HUGHES HELICOPTERS, INC.: Amendment 39-9148. Docket No. 94-SW-15-AD. Supersedes Priority Letter AD 93-03-01, issued on March 4, 1993.

Applicability: Model 269A, 269A-1, 269B, 269C, and TH-55A series helicopters, with aluminum spring retainer, part number (P/N) 269A5452, P/N 269A5452-3, P/N 269A5452-5, or P/N 269A5483-7, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the aluminum spring retainer, loss of power to the rotor drive system, and a subsequent forced landing, accomplish the following:

(a) Within the next 5 hours time-in-service after the effective date of this AD, and thereafter at intervals not to exceed 100 hours time-in-service from the last inspection, visually inspect the clutch control spring assembly for component wear in accordance with the provisions of Part I, paragraph a(2) of Schweizer Service Bulletin (SB) B-256.2, dated June 11, 1993.

(b) If worn parts are found during the inspections accomplished in accordance with paragraph (a) of this AD, before the next flight, disassemble and inspect the clutch control spring assembly and replace parts found to be unairworthy with airworthy parts in accordance with Part I, paragraph b. of SB B-256.2, dated June 11, 1993.

(c) 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, who may concur or comment and then send it to the Manager, New York Aircraft Certification Office.

NOTE: 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.

(d) Special flight permits may be issued in accordancewith 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 inspection requirements of this AD can be accomplished.

(e) The inspections and replacement, if necessary, shall be done in accordance with SB B-256.2, dated June 11, 1993. This incorporation by reference was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of September 1, 1994 (59 FR 38354, July 28, 1994). 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment becomes effective on March 1, 1995.

On March 4, 1993, the FAA issued Priority Letter AD 93-03-01, to require an initial and repetitive visual inspections of the clutch control spring assembly (assembly) for component wear and security, and replacement of affected unairworthy parts. That action was prompted by an accident involving a Schweizer Aircraft Corporation Model 269C helicopter. Reportedly, the helicopter lost engine drive power and was unsuccessful in performing a forced landing from 100 feet above ground level (AGL). A subsequent investigation revealed that the assembly had failed, and that the aluminum spring retainer, part number (P/N) 269A5483-7, of the failed assembly had excessive wear. That condition, if not corrected, could result in failure of the aluminum spring retainer, loss of power to the rotor drive system, and a subsequent forced landing.

Since the issuance of that AD, the manufacturer has issued a revised service bulletin, Schweizer Service Bulletin (SB)B-256.2, dated June 11, 1993, that describes procedures for an initial and repetitive inspections for component wear of the assembly in greater detail than the previously-issued service bulletin, and describes procedures for further inspections if disassembly is necessary. It also describes procedures for replacement of the aluminum spring retainer, P/N 269A5452, P/N 269A5452-3, P/N 269A5452-5, or P/N 269A5483-7, and the plastic sleeve, P/N 269A5590-101, which was not described in SB B-256.1, dated January 20, 1993, the SB cited in AD 93-03-01.

Since an unsafe condition has been identified that is likely to exist or develop on other Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, and TH-55A helicopters of the same type design, this AD supersedes AD 93-03-01 to require an initial and repetitive visual inspections of the assembly for component wear; and, if any worn or unairworthy parts are found, disassembly, further inspections, and replacement of any unairworthy parts. The actions are required to be accomplished in accordance with SB B-256.2, dated June 11, 1993, described previously. The assembly puts tension on the belt drive between the transmission and the main rotor. If the assembly fails and there is no tension on the belt, the transmission will not turn the main rotor. Due to the criticalness of the clutch control assembly, and a short compliance time, this rule must be issued immediately to correct an unsafe condition in aircraft.

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.

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. 94-SW-15-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 citationfor 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 (AD), Amendment 39-9148, to read as follows:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Assistant Chief Counsel, Attention: Rules Docket No. 94-SW-15-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.
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 Reinhardt, Aerospace Engineer, New York Aircraft Certification Office, FAA, New England Region, 10 Fifth Street, Valley Stream, New York 11581, telephone (516) 256-7532; fax (516) 568-2716.