Skip to Content

Rule

Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76 Series Helicopters

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2000-11-52, which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Corporation (Sikorsky) Model S-76 series helicopters by individual letters. This AD requires determining the serial number (S/N) of each main rotor blade and removing certain serial numbered main rotor blades. This AD also requires visually inspecting and replacing, if necessary, other certain serial numbered main rotor blades. This AD is prompted by a report of a crack in a main rotor blade and three reports of root end pocket separation from main rotor blades during flight. The crack and the main rotor blade root end pocket separation were due to improper manufacture of certain main rotor blade skins. The actions specified by this AD are intended to prevent main rotor blade root end pocket separation, impact with main rotor or tail rotor blades, and subsequent loss of control of the helicopter.

DATES:

Effective August 31, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-11-52, issued on May 26, 2000, which contained the requirements of this amendment.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of August 31, 2000.

Comments for inclusion in the Rules Docket must be received on or before October 16, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-26-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: 9-asw-adcomments@faa.gov.

The applicable service information may be obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Tech Support, 6900 Main Street, P. O. Box 9729, Stratford, Connecticut 06497-9129, phone (203) 386-7860, fax (203) 386-4703. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Wayne Gaulzetti, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7156, fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

On May 26, 2000, the FAA issued Emergency AD 2000-11-52, for Sikorsky Model S-76 series helicopters, which requires determining the S/N of each main rotor blade and removing certain serial numbered main rotor blades. The AD also requires visually inspecting and replacing, if necessary, other certain serial numbered main rotor blades. That action was prompted by a report of a 20-inch crack in the root end pocket of a main rotor blade and three reports of root end pocket separation of 4 to 6 foot sections of main rotor blades during flight. The crack and the main rotor blade root end pocket separation were due to improper manufacture of certain main rotor blade skins. This condition, if not corrected, could result in a root end pocket separating and impacting a main rotor or tail rotor blade and Start Printed Page 49904subsequent loss of control of the helicopter.

The FAA has reviewed Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-50, dated May 25, 2000 (ASB), which identifies certain serial-numbered main rotor blades that need to be removed from service. The ASB also describes performing a visual inspection, implementing a recurring visual inspection of certain serial-numbered main rotor blades for span-wise skin cracks, and removing any main rotor blade with a span-wise crack from service before further flight.

Since the unsafe condition described is likely to exist or develop on other Sikorsky Model S-76 series helicopters of the same type design, the FAA issued Emergency AD 2000-11-52 to prevent main rotor blade root end pocket separation, impact with main rotor or tail rotor blades, and subsequent loss of control of the helicopter. The AD requires, before further flight, determining the S/N of each main rotor blade and accomplishing the following actions in accordance with the ASB described previously:

  • Remove any main rotor blade identified by S/N in Group 1 of the ASB Planning Information before further flight.
  • Before each flight and at intervals not to exceed 3 hours time-in-service, visually inspect any main rotor blade identified by S/N in Group 2 of the ASB Planning Information for a span-wise crack in the upper and lower root end area. Remove any main rotor blade with a span-wise crack and replace it with an airworthy blade before further flight.

Any blade repaired in accordance with Sikorsky Aircraft Corporation Overhaul and Repair Instructions (ORI) No. 76150-023, Revision A, dated May 26, 2000, is not affected by the requirements of this AD. Accomplishing ORI 76150-023, Revision A, dated May 26, 2000, on each affected blade is terminating action for the requirements of this AD. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, the actions listed previously are required before further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on May 26, 2000, to all known U.S. owners and operators of Sikorsky Model S-76 series helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

The FAA estimates that 167 helicopters of U.S. registry will be affected by this AD. It will take approximately 10 work hours to replace each main rotor blade, if necessary, and 4 work hours per helicopter to inspect the main rotor blades. The average labor rate is $60 per work hour. Required parts will cost approximately $99,651 per helicopter (assuming replacement of all 4 blades). Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $4,248,480 ($40,080 to inspect the fleet and $4,208,400 to replace all main rotor blades on 25 percent of the U.S. fleet).

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 mailed 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. 2000-SW-26-AD.” The postcard will be date stamped and returned to the commenter.

The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

Adoption of the Amendment

Start Amendment Part

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

End Amendment Part Start Part

PART 39—AIRWORTHINESS DIRECTIVES

End Part Start Amendment Part

1. The authority citation for part 39 continues to read as follows:

End Amendment Part Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]
Start Amendment Part

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

End Amendment Part

2000-11-52 Sikorsky Aircraft Corporation: Amendment 39-11861. Docket No. 2000-SW-26-AD.

Applicability: Model S-76 series helicopters, certificated in any category.

Note 1:

This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise 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 Start Printed Page 49905of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent main rotor blade root end pocket separation, impact with main rotor or tail rotor blades, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, determine the serial number of each main rotor blade.

(b) Any main rotor blade identified in paragraphs (c) or (d) of this AD that has been repaired in accordance with Sikorsky Aircraft Corporation Overhaul and Repair Instructions (ORI) No. 76150-023, Revision A, dated May 26, 2000, and marked as RS-023-1 is not affected by the requirements of this AD.

(c) Before further flight, remove any main rotor blade identified by serial number (S/N) in the Group 1, paragraph 1.A. Planning Information of Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-50, dated May 25, 2000 (ASB).

(d) Before each flight and at intervals not to exceed 3 hours time-in-service, visually inspect any main rotor blade, identified by S/N in Group 2, paragraph 1.A. of the ASB Planning Information, for a span-wise crack in the upper and lower root end area, in accordance with paragraph 3.B. of the ASB Accomplishment Instructions. Remove any main rotor blade with a span-wise crack and replace with an airworthy blade before further flight.

(e) Accomplishing ORI 76150-023, Revision A, dated May 26, 2000, on each affected blade is terminating action for the requirements of this AD.

Note 2:

A crack, other than a span-wise crack, in the root end cap of the main rotor blade should be dispositioned in accordance with the applicable Maintenance Manual.

(f) 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, Boston 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, Boston 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 Boston Aircraft Certification Office.

(g) 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.

(h) The removal of certain serial numbered main rotor blades shall be done in accordance with Group 1, paragraph 1.A. Planning Information of Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-50, dated May 25, 2000. The visual inspection shall be done in accordance with paragraph 3.B. of the Accomplishment Instructions of Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-50, dated May 25, 2000. 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: Manager, Commercial Tech Support, 6900 Main Street, P.O. Box 9729, Stratford, Connecticut 06497-9129, phone (203) 386-7860, fax (203) 386-4703. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 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.

(i) This amendment becomes effective on August 31, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-11-52, issued May 26, 2000, which contained the requirements of this amendment.

Start Signature

Issued in Fort Worth, Texas, on August 7, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. 00-20502 Filed 8-15-00; 8:45 am]

BILLING CODE 4910-13-P