AD 97-19-06 ACTIVE

This amendment supersedes an existing priority letter airworthiness directive (AD), applicable to Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM, R, and V helicopters, that currently requires inspecting certain main rotor blade assemblies (blades) to determine if a blade has a blade trailing edge pocket assembly (pocket assembly) that was anodized by Poly-Metal Company during a specified time period, and if so, replacing it with an airworthy blade. This amendment requires the same actions as the existing AD, but corrects two serial numbers in the list of the applicable blades. This amendment is prompted by the manufacturer's issuance of a service bulletin with a revised list of blade serial numbers. The actions specified by this AD are intended to prevent disbonding and separation of portions of the blade, subsequent excessive vibrations, and loss of control of the helicopter.

Final rule; request for comments

97-19-06 SIKORSKY AIRCRAFT CORPORATION: Amendment 39-10126. Docket No. 97-SW-18-AD. Supersedes priority letter AD 97-10-04, issued April 30, 1997.
Applicability: Model S-61A, D, E, L, N, NM, R, and V helicopters, certificated in any category, with a main rotor blade assembly (blade), part number (P/N) S6115-20501 or P/N 61170-20201, installed, having one of the following four-digit or eight-digit serial numbers:

1282-1554
2721
3016-2850
3305-3106
3517-3311
4787-4793
2183
2751
3019
3317-3115
3525-3310
4800-4794
2380-2498
2781-2644
3138
3343-3147
3637-3459
4835-4790
2495
2800-2671
3168-3585
3343-3648
3694-3481
5484-5363
2500
2817
3192-2999
3364-3180
3748-3543
5974-5816
2520
2819
3215-3012
3451-3239
3752-3527
5981-5813
2521
2839
3216-3023
3491-3278
3753-3528
7069-6583
2644
2883
3242-3044
3499-3936
3840-3620
7779-7033
2673
2919-2771
3249-3052
3511-3293
3966-3737
8099-8054
2716-2683
3008
3250-3043
3512-3292
4216-4392

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.

Compliance: Required before further flight, unless accomplished previously.To prevent disbonding and separation of portions of the blade, subsequent excessive vibrations, and loss of control of the helicopter, accomplish the following:

(a) Inspect each blade having one of the affected serial numbers in accordance with Section 2A of the Accomplishment Instructions of Sikorsky Alert Service Bulletin (ASB) No. 61B15-29A, Revision A, dated May 9, 1997, to determine the anodizing date for all blade trailing edge pocket assemblies (pocket assemblies) installed on the blade in locations as specified in the Planning Information Section, paragraph 1D(3) of the ASB, that were anodized by Poly-Metal Company. Remove any blade having a pocket assembly anodized by Poly-Metal Company during the period from October 1, 1996 through December 31, 1996, and replace the blade with an airworthy blade.

(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, BostonAircraft 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, Boston 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 Boston Aircraft Certification Office.

(c) A one-time only special flight permit may be issued to operate the helicopter to a location where the requirements of this AD can be accomplished, after inspecting all pocket assemblies for disbonding.

(d) The inspection shall be done in accordance with Sikorsky ASB No. 61B15-29A, Revision A, dated May 9, 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 Sikorsky Aircraft Corporation, Attn: Mr. Paul Dionne, CAR Office, 6900 Main Street, P.O. Box 9729, Stratford, Connecticut 06497-9129, telephone (203) 386-7860, fax (203) 386-4703. 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 October 6, 1997.

On April 30, 1997, the FAA issued priority letter AD 97-10-04 to require, before further flight, inspecting certain blades to determine the anodizing date for certain pocket assemblies installed on the blade, and if a blade has a pocket assembly that was anodized by Poly-Metal Company from October 1, 1996 through December 31, 1996, replacing it with an airworthy blade. That action was prompted by the discovery of a manufacturing defect that may cause disbonding and separation of portions of a blade. This defect is the result of an anodizing process, used during the manufacture of the pocket assembly, that did not meet the Type Design specifications. That condition, if not corrected, could result in disbonding and separation of portions of the blade, subsequent excessive vibrations, and loss of control of the helicopter.

Since the issuance of that AD, Sikorsky Aircraft Corporation has issued Sikorsky Alert Service Bulletin (ASB) No. 61B15-29A, Revision A, dated May 9, 1997, which corrects two of the blade serial numbers listed in the ASB that were referenced in the priority letter AD.

Since an unsafe condition has been identified that is likely to exist or develop on other Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM, R, and V helicopters of the same type design, this AD supersedes AD 97-10-04 to require, before further flight, inspecting certain blades to determine the anodizing date for certain pocket assemblies installed on the blade, and if a blade has a pocket assembly that was anodized by Poly-Metal Company during the period of October 1, 1996, through December 31, 1996, replacing it with an airworthy blade. The actions are required to be accomplished in accordance with the service bulletin described previously.

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 overallregulatory, 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. 97-SW-18-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 USC 106(g), 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive (AD), Amendment 39-10126, to read as follows:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-SW-18-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

The service information referenced in this AD may be obtained from Sikorsky Aircraft Corporation, Attn: Mr. Paul Dionne, CAR Office, 6900 Main Street, P.O. Box 9729, Stratford, Connecticut 06497-9129, telephone (203) 386-7860, fax (203) 386-4703. This information may be examined 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.

Mr. Bob Mann, Aerospace Engineer, Boston Aircraft Certification Office, ANE-150, 12 New England Executive Park, Burlington, MA 01803, telephone (617) 238-7190, fax (617) 238-7199.