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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-SW-35-AD; Amendment 39-11983; AD 2000-18-51] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule; request for comments. 

# SUMMARY:

                        This document publishes in the                         **Federal Register**                         an amendment adopting superseding Airworthiness Directive (AD) 2000-18-51 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron, Inc. (BHTI) Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters by individual letters. This AD requires recurring liquid penetrant or eddy current inspections of the main rotor blade grip (grip) threads for a crack. If a crack is detected, this AD requires, before further flight, replacing the cracked grip with an airworthy grip. This AD also establishes a retirement life of 1,200 hours time-in-service (TIS) for each grip. This amendment is prompted by the results of an investigation of an August 1998 accident in which a grip failed on a BHTI Model 47G-2 helicopter due to a fatigue crack. An analysis of the field service data revealed fatigue cracks in 70 percent of the grips inspected. The actions specified by this AD are intended to prevent failure of a grip, loss of a main rotor blade, and subsequent loss of control of the helicopter.                     

# DATES:

Effective November 30, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-18-51, issued on August 31, 2000, which contained the requirements of this amendment. 

Comments for inclusion in the Rules Docket must be received on or before January 16, 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-35-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:

Marc Belhumeur, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone (817) 222-5177, fax (817) 222-5783. 

# SUPPLEMENTARY INFORMATION:

The FAA issued AD 86-06-08R1 on May 12, 1987 (52 FR 24135, June 29, 1987), which amended AD 86-06-08 (51 FR 11300, April 2, 1986). Those AD's required an initial and repetitive fluorescent dye penetrant inspection of each grip. On August 31, 2000, the FAA issued Emergency AD 2000-18-51, for BHTI Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters. That emergency AD supersedes AD 86-06-08 and AD 86-06-08R1 and requires recurring liquid penetrant or eddy current inspections of the grip threads for a crack. If a crack is detected, the AD requires, before further flight, replacing the cracked grip with an airworthy grip. The AD also establishes a retirement life of 1,200 hours TIS for each grip. That action was prompted by the results of an investigation of an August 1998 accident in which a grip failed on a BHTI Model 47G-2 helicopter due to a fatigue crack. An analysis of Australian field service data revealed fatigue cracks in the majority of the grips inspected. Since issuance of Emergency AD 2000-18-51, other cracked grips with less than 1200 hours TIS have been discovered. This condition, if not corrected, could result in failure of a grip, loss of a main rotor blade, and subsequent loss of control of the helicopter. 

Since the unsafe condition described is likely to exist or develop on other BHTI Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters of the same type designs, the FAA issued Emergency AD 2000-18-51 to prevent failure of a grip, loss of a main rotor blade, and subsequent loss of control of the helicopter. The AD requires the following for grips, part number (P/N) 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, and 47-120-252-11, and for grips manufactured under Parts Manufacturer Approval, P/N 74-120-252-11 and 74-120-135-5: 
    - Within 100 hours TIS since initial installation on any helicopter or within 10 hours TIS for grips with 100 or more hours TIS, conduct a liquid penetrant or eddy current inspection of the grip threads for a crack.
    - Thereafter, conduct the liquid penetrant or eddy current inspection of the grip threads at intervals not to exceed 200 hours TIS.
    - If a crack is detected, before further flight, replace the cracked grip with an airworthy grip.
    - Establish a retirement life of 1200 hours time-in-service (TIS) for each grip.

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, the above actions are required at the specified time intervals, 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 2000-18-51 to all known U.S. owners and operators of BHTI Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K 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 1000 helicopters of U.S. registry will be                           ( print page 68885)                        affected by this AD, that it will take approximately 10 work hours per helicopter to accomplish either inspection, and that the average labor rate is $60 per work hour. Required parts, if a grip needs to be replaced, will cost approximately $4,000 per grip (there are two grips on each helicopter). Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $8,600,000, assuming one inspection per helicopter and replacement of both grips on each helicopter.                 

## 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-35-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**                    .                 

# 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. 

§ 39.13 

2. Section 39.13 is amended by removing Amendment 39-5260 ( 51 FR 11300, April 2, 1986) and Amendment 39-5626 (52 FR 24135, June 29, 1987) and by adding a new airworthiness directive to read as follows: 

**2000-18-51 Bell Helicopter Textron, Inc.:**                             Amendment 39-11983. Docket No. 2000-SW-35-AD. Supersedes AD 86-06-08, Amendment 39-5260, and AD 86-06-08 R1, Amendment 39-5626, Docket No. 86-ASW-10.                         

*Applicability:*                            Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters, with main rotor blade grips, part number (P/N) 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11 and 74-120-135-5, 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 (c) 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 main rotor blade grip (grip), separation of a main rotor blade, and subsequent loss of control of the helicopter, accomplish the following: 

(a) Within 100 hours time-in-service (TIS) since initial installation on any helicopter or within 10 hours TIS for grips with 100 or more hours TIS, conduct a liquid penetrant or eddy current inspection of the grip threads for a crack. Thereafter, conduct the liquid penetrant or eddy current inspection at intervals not to exceed 200 hours TIS. If a crack is detected, before further flight, replace the cracked grip with an airworthy grip. 

(b) On or before 1200 hours TIS, replace each grip with an airworthy grip. This AD establishes a retirement life of 1200 hours TIS for grips, P/N 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11, and 74-120-135-5. 

(c) 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, Rotorcraft 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, Rotorcraft Certification Office. 

# Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office.

(d) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished. 

(e) This amendment becomes effective on November 30, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-18-51, issued August 31, 2000, which contained the requirements of this amendment. 

Issued in Fort Worth, Texas, on November 2, 2000. 

Mark R. Schilling, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

[FR Doc. 00-29049 Filed 11-14-00; 8:45 am] 

BILLING CODE 4910-13-U