Airworthiness Directives; Robinson Helicopter Company Model R22 Helicopters

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) 2000-20-51, which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (RHC) Model R22 helicopters by individual letters. This AD requires checking the yoke half assembly (yoke) for any crack and replacing a cracked yoke assembly before further flight. This AD also requires replacing certain yokes with airworthy yokes before further flight after January 1, 2001. This AD is prompted by the discovery of cracks in the yoke. The actions specified by this AD are intended to detect crack formation and growth, which could result in separation of the yokes from the main rotor drive shaft and subsequent loss of control of the helicopter.

DATES:

Effective November 22, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-20-51, issued on October 4, 2000, which contained the requirements of this amendment.

Comments for inclusion in the Rules Docket must be received on or before January 8, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-51-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.

FOR FURTHER INFORMATION CONTACT:

Fredrick A. Guerin, Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5232, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

On October 4, 2000, the FAA issued Emergency AD 2000-20-51, for RHC Model R22 helicopters, which requires checking the yoke for any crack and replacing a cracked yoke assembly before further flight. The Emergency AD also requires replacing certain yokes with airworthy yokes before further flight after January 1, 2001. That action was prompted by the discovery of cracks in the yokes. The cracked yokes were still in service and functioned for an unknown duration. Several lots of the yokes were machined from 2024-T3 aluminum billet, which has poor stress corrosion properties in the transverse grain directions. Clamping the yokes in place causes a preload tension in areas that have exposed transverse grain. When these areas are exposed to a corrosive environment, such as salty air, stress corrosion causes crack formation and growth. This condition, if not corrected, could result in separation of the yokes from the main rotor drive shaft and subsequent loss of control of the helicopter.

The FAA has reviewed RHC R22 Service Bulletin SB-88A, dated September 13, 2000, which describes procedures for determining the lot number for yokes, P/N A203-5, and replacing any affected yoke with yoke, P/N A203-7.

Since the unsafe condition described is likely to exist or develop on other RHC Model R22 helicopters of the same type design, the FAA issued Emergency AD 2000-20-51 to detect crack formation and growth, which could result in separation of the yokes from the main rotor drive shaft and subsequent loss of control of the helicopter. The AD requires the following:

• Before further flight and thereafter before the first flight of each day, check the identified area of each yoke for a crack. The visual check required by the AD may be performed by an owner/operator (pilot) but must be entered into the aircraft records showing compliance with paragraph (a) of the AD in accordance with 14 CFR 43.11 and 91.417(a)(2)(v). The AD allows a pilot to perform this check because it involves only a visual check for a crack in the yoke and can be performed equally well by a pilot or a mechanic.
• If a yoke has a crack, before further flight, replace the yokes with airworthy yokes, P/N A203-7. Both yokes must be replaced with yoke, P/N A203-7.
• Before further flight after January 1, 2001, determine the lot identifier for each yoke, P/N A203-5, and replace any affected yokes, P/N A203-5, with yokes, P/N A203-7.

Determining that the installed yokes are not in the lots affected by this AD or replacing both yokes, P/N A203-5, with yokes, P/N A203-7, 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 and controllability of the helicopter. Therefore, checking the yoke for any crack and replacing any cracked yoke 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 October 4, 2000 to all known U.S. owners and operators of RHC Model R22 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. However, one minor editorial correction is made in this AD. The note concerning existing alternative methods of compliance was incorrectly numbered in the emergency AD. This AD corrects that Note number as NOTE 3. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 1305 helicopters of U.S. registry will be affected by this AD, that it will take approximately 0.3 work hour per helicopter to check both yokes and 0.5 work hour to replace both yokes. The average labor rate is $60 per work hour. Required parts will cost approximately $150 per helicopter (two yokes). Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $258,390, assuming each helicopter is inspected once and both yokes are replaced on all helicopters.

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-51-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 FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• 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.

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

2000-20-51 Robinson Helicopter Company: Amendment 39-11960. Docket No. 2000-SW-51-AD.

Applicability: Model R22 helicopters, with a yoke half assembly (yoke), Part number ­(P/N) A203-5, 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 (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 failure of a yoke, separation of a yoke from the main rotor drive shaft, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight and thereafter before the first flight of each day, check each yoke for a crack. See Figure A.

(b) If a yoke is cracked, before further flight, replace the yokes with airworthy yokes, P/N A203-7. Both yokes must be replaced with yokes, P/N A203-7.

(c) Before further flight after January 1, 2001,

(1) Determine the Lot identifier of each yoke.

(2) If the Lot identifier is from 24 through 43, if it is a letter code, or if it is illegible, replace yokes, P/N A203-5, with airworthy yokes, P/N A203-7. Yoke, P/N A203-7, cannot be installed with yoke, P/N A203-5.

Note 2:

Robinson Helicopter Company R22 Service Bulletin SB-88A, dated September 13, 2000, pertains to the subject of this AD.

(d) The visual check required by paragraph (a) may be performed by an owner/operator (pilot) holding at least a private pilot certificate and must be entered into the aircraft records showing compliance with paragraph (a) in accordance with 14 CFR 43.11 and 91.417(a)(2)(v).

(e) Determining that the installed yokes, P/N A203-5, are not in the lots affected by this AD, or replacing yokes, P/N A203-5, with yokes, P/N A203-7, is terminating action for the requirements of this AD.

(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, Los Angeles 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, Los Angeles 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 Los Angeles Aircraft Certification Office.

(g) Special flight permits will not be issued.

(h) This amendment becomes effective on November 22, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-20-51, issued October 4, 2000, which contained the requirements of this amendment.