00-6036. Airworthiness Directives; Sikorsky Model S-61 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) applicable to Sikorsky Model S-61 helicopters. This action requires inspecting certain pylon upper and lower hinge web fittings (web fittings) for corrosion or a crack and either repairing certain web fittings or replacing any unairworthy web fittings with airworthy web fittings. The AD also requires creating a log card or equivalent record and implementing a recurring inspection of the web fittings. This amendment is prompted by the discovery of extensive cracking in the area of the web fittings. The actions specified in this AD are intended to prevent structural failure of the tail boom due to a crack or corrosion of certain web fittings and subsequent loss of control of the helicopter.

DATES:

Effective March 30, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 30, 2000.

Comments for inclusion in the Rules Docket must be received on or before May 15, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-61-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: Manager, Commercial Tech Support, 6900 Main Street, P. O. Box 9729, Stratford, Connecticut 06497-9129, phone [phone], fax [phone]. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 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.

FOR FURTHER INFORMATION CONTACT:

Brian K. Murphy, Aerospace Engineer, ANE-150, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

This amendment adopts a new AD applicable to Sikorsky Model S-61 helicopters with pylon, part number, (P/N) S6120-76265-001 or S6120-76266-507, installed. The AD requires inspecting and repairing or, if necessary, replacing certain web fittings and the fitting faying surfaces. The AD also requires making an entry on the log card or equivalent record.

This amendment is prompted by the discovery of extensive cracking in the area of the web fitting. The actions specified in this AD are intended to prevent structural failure of certain web fittings due to stress corrosion and subsequent structural failure of the tailboom. This condition, if not corrected, could result in loss of control of the helicopter.

The FAA has reviewed Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B20-33, dated September 3, 1999 (ASB), which describes procedures for inspecting and repairing or, if necessary, replacing certain web fittings having a crack or corrosion.

Since an unsafe condition has been identified that is likely to exist or develop on other Sikorsky Model S61 helicopters of the same type design, this AD is being issued to prevent structural failure of certain web fittings due to a crack or corrosion. This AD requires inspecting and repairing or replacing the web fittings as necessary. The actions are required to be accomplished in accordance with the ASB described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, inspecting for a crack or corrosion in the web fittings and repairing or replacing, if necessary, an unairworthy web fitting with an airworthy web fitting is required prior to further flight and this AD must be issued immediately.

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.

The FAA estimates that 125 helicopters will be affected by this AD, that it will take approximately 115 work hours to accomplish the inspection and replacement of parts, and that the average labor rate is $60 per work hour. Required parts will cost approximately $75,000 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $10,237,500 if the parts have to be replaced on the entire 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 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. 99-SW-61-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, 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.

List of Subjects 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 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

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

AD 2000-05-16 Sikorsky Aircraft Corporation: Amendment 39-11626. Docket No. 99-SW-61-AD.

Applicability: Model S-61 helicopters with pylon, part number (P/N) S6120-76265-001 or S6120-76266-507, 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 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 of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) 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 structural failure due to a crack or corrosion of pylon upper and lower hinge web fittings (web fittings), P/N S6120-76261-012, -013 (upper) or S6120-76262-012, -013 (lower), and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 25 hours time-in-service (TIS),

(1) Determine the alloy-temper of the web fittings in accordance with Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B20-33, dated September 3, 1999 (ASB), Accomplishment Instructions, paragraph 3.A.

(2) Prepare the web fittings for inspection in accordance with the ASB Accomplishment Instructions, paragraph 3.B.

(3) Inspect the web fitting in accordance with the ASB Inspection Plan, Chart A, and the Accomplishment Instructions, paragraphs 3.C., 3.D, and 3.E. Nicks, scratches, corrosion pitting or prior rework beyond the limits specified in paragraph 3.C.(5) require approval by the FAA.

(4) Repair or replace web fittings, as necessary, in accordance with the ASB Accomplishment Instructions, paragraph 3.C.(3) through (6). Nicks, scratches, corrosion pitting, or prior rework beyond the limits specified in paragraph 3.C.(5) require approval by the FAA.

(5) If replacing an unairworthy web fitting with an airworthy web fitting, replace it in accordance with the ASB Accomplishment Instructions, paragraph 3.F., prior to further flight.

(6) Create a log card for the pylon, if none exists. Make an entry on the log card or equivalent record implementing recurring inspection intervals in accordance with Chart A of the ASB.

(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, 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 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) Special flight permits may be issued in accordance with §§ 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) The inspection, repair, and replacement shall be done in accordance with the Inspection Plan, Chart A, and the Accomplishment Instructions of Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B20-33, dated September 3, 1999. 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 [phone], fax [phone]. 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.

(e) This amendment becomes effective on March 30, 2000.

Issued in Fort Worth, Texas, on March 6, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.