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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-SW-42-AD; Amendment 39-12034; AD 2000-22-51] 
          - 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) 2000-22-51, which was sent previously by individual letters to all known U.S. owners and operators of Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 helicopters manufactured by Bell Helicopter Textron Inc. (BHTI) for the Armed Forces of the United States. This AD requires establishing a retirement life for certain main rotor masts, creating a component history card or equivalent record, and identifying certain masts as unairworthy. This AD also requires removing the hub spring, if installed, and determining whether a main rotor mast (mast) has ever been installed on a helicopter while operated with a hub spring. Conducting certain inspections based on the retirement index number (RIN) and on whether the helicopter was ever operated with a hub spring is also required. Replacing any mast that has inadequate radius or a burr in the damper clamp splined area is also required. Finally, this AD requires sending information concerning the mast to the FAA. This amendment is prompted by the discovery of a crack in a mast with a lower RIN value than the established life limit. This action is necessary to preclude the occurrence of a fatigue crack in the damper clamp splined area of a mast. This condition, if not corrected, could result in failure of a mast or main rotor trunnion (trunnion), separation of the main rotor system, and subsequent loss of control of the helicopter.                     

# DATES:

Effective December 26, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-22-51, issued on November 2, 2000, which contained the requirements of this amendment. 

Comments for inclusion in the Rules Docket must be received on or before February 9, 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-42-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:

Michael Kohner, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone (817) 222-5447, fax (817) 222-5783. 

# SUPPLEMENTARY INFORMATION:

The FAA issued Emergency AD 2000-08-53 (Docket No. 2000-SW-08-AD) on April 26, 2000, which superseded AD 89-17-03, Amendment 39-6251, Docket No. 88-ASW-33 (54 FR 31935, August 3, 1989), which established RIN counting procedures for the mast assemblies installed on H-1 series surplus military helicopters. AD 2000-08-53 also incorporated life-hour adjustments for mast hub spring and helicopter usage. Since issuing AD 2000-08-53, the FAA has issued AD 2000-15-21, Amendment 39-11854, Docket 2000-SW-01-AD (65 FR 48605, August 9, 2000) to require removing masts, part number (P/N) 204-011-450-001 and -005, from service. The FAA also issued Emergency AD 2000-15-52, Docket No. 2000-SW-28-AD, on July 25, 2000, for the BHTI Model 204B, 205A, 205A-1, 205B, and 212 helicopters, which was prompted by a report of another cracked mast, similar to the masts installed on H-1 series helicopters. Metallurgical inspection revealed that the mast cracked as a result of fatigue in snap ring groove radii that were smaller than the 0.020-inch minimum allowable dimension. Detailed takeoff and lift event data for the entire life of the mast confirm that the accumulated RIN count at the time the fatigue crack was detected was approximately 68,000 when calculated in accordance with the RIN counting procedures in effect at the time of the failure. 

                    U.S. Army Safety of Flight Message UH-1-10, dated July 19, 2000, required inspecting masts for a minimum radius of 0.020 inch or for a burr around the                           ( print page 77264)                        circumference of the snap ring groove and removing defective masts from service. Based on that message and a review of fatigue data and previously issued AD's, the FAA has concluded that several corrections to the RIN counting procedures are required as follows:                 
    - Recalculating the accumulated RIN and revised hours TIS to date for certain masts to correct the inadequate factors provided in AD 2000-08-53. New RIN and frequency of event per hour factors are required to calculate the accumulated RIN and revised hours TIS to properly reflect the actual level of torque (horsepower rating of helicopter) applied to the mast when it is installed on the different helicopter models affected by this AD.
    - Using the new RIN factors for each takeoff and external load lift to continue the calculations for the accumulated RIN as installed on the different helicopter models affected by this AD and changing the definition for external load lift.
    - Expanding the serial number (S/N) applicability for a one-time special inspection to detect inadequate radii and burrs in the snap ring grooves to include masts with S/N 00000 through 52720, 61433 through 61444, or 61457 through 61465, regardless of prefix. This action was required based on inadequate radius and burrs detected outside the S/N applicability of the previous AD.
    - Reducing the compliance time to 100,000 accumulated RIN for any affected mast for a one-time special inspection to detect burrs in the snap ring grooves.
    - Adding a one-time special inspection to detect inadequate radii and burrs in the snap ring grooves for any mast that has been previously installed with a hub spring.

Since the unsafe condition described is likely to exist or develop on other Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 helicopters manufactured by BHTI for the Armed Forces of the United States, the FAA issued Emergency AD 2000-22-51 to prevent failure of a mast or trunnion, separation of the main rotor system, and subsequent loss of control of the helicopter. The AD requires the following: 
    - Within 10 hours TIS, create a component history card or equivalent record.
    - Within 10 hours TIS, determine and record the accumulated RIN and revised hours TIS.
    - Establish a retirement life for any mast, P/N 204-011-450-007, -105, or -109, and replace any mast that has accumulated 265,000 RIN or 15,000 or more revised hours TIS and identify the removed mast as unairworthy.
    - Within 25 hours TIS, remove any hub spring.
    - Determine if the mast has ever been operated with a hub spring.
    - Before reaching 100,000 RIN for a mast that has never been on a helicopter operated with a hub spring:
    - Inspect the upper and lower snap ring groove in the damper clamp splined area for an inadequate radius and for a burr.
    - Remove the mast before exceeding 100,000 RIN if any radius is inadequate or before exceeding 170,000 RIN if a burr is found, and identify such masts as unairworthy.
    - Before reaching 100,000 RIN or 400 unfactored flight hours, whichever occurs first, on a mast that was installed on a helicopter with a hub spring or if the history of a hub spring installation is unknown:
    - Inspect each snap ring groove for an inadequate radius or for a burr.
    - Remove any mast before further flight if any groove radius is inadequate or if a burr is found, and identify such masts as unairworthy.
    - After completing the inspections, send the requested information to the FAA. The requirements for retirement life hours for the trunnion remain the same as required in superseded AD 2000-08-53, Docket 2000-SW-08-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, the actions listed previously 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 November 2, 2000, to all known U.S. owners and operators of Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 helicopters manufactured by BHTI for the Armed Forces of the United States. 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 75 helicopters of U.S. registry will be affected by this AD. It will take approximately 10 work hours per helicopter to remove and replace the mast, if necessary; 6 work hours to remove any hub spring; and 10 work hours to inspect the mast for proper radius or a burr. The approximate time necessary for calculating the accumulated RIN and for providing the requested information to the FAA is 15 work hours per helicopter. The average labor rate is $60 per work hour. Required parts will cost approximately $9,538 to replace a mast, if necessary. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $899,850 ($11,998 per helicopter, assuming inspecting 1 mast, removing 1 hub spring, replacing 1 mast, determining the RIN calculations, and providing the requested information to the FAA). 

## 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:                           ( print page 77265)                        “Comments to Docket No. 2000-SW-42-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 39-6251 ( 54 FR 31935, August 3, 1989) and by adding a new airworthiness directive to read as follows:

**2000-22-51 Firefly Aviation Helicopter Services (Previously Erickson Air-Crane Co.); Garlick Helicopters, Inc.; Hawkins and Powers Aviation, Inc.; International Helicopters, Inc.; Tamarack Helicopters, Inc. (Previously Ranger Helicopter Services, Inc.); Robinson Air Crane, Inc.; Williams Helicopter Corporation (Previously Scott Paper Co.); Smith Helicopters; Southern Helicopter, Inc.; Southwest Florida Aviation; Arrow Falcon Exporters, Inc. (Previously Utah State University); U.S. Helicopter, Inc.; and Western International Aviation, Inc.:**                             Amendment 39-12034. Docket No. 2000-SW-42-AD. Supersedes Emergency AD 2000-08-53, Docket No. 2000-SW-08-AD and AD 89-17-03, Amendment 39-6251, Docket No. 88-ASW-33.                         

*Applicability:*                             Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 helicopters, manufactured by Bell Helicopter Textron Inc. (BHTI) for the Armed Forces of the United States, with main rotor mast (mast), part number (P/N) 204-011-450-007, -105, or     -109, or main rotor trunnion (trunnion), P/N 204-011-105-001, 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.                         

# Note 2:

This AD requires using new factors to recalculate the FACTORED flight hours and the accumulated Retirement Index Number (RIN) for masts installed on certain helicopter models. This AD also expands the serial number (S/N) applicability for the one-time special inspection of the mast.

To prevent failure of a mast or trunnion, separation of the main rotor system, and subsequent loss of control of the helicopter, accomplish the following: 

(a) For the mast, P/N 204-011-450-007, -105, or -109: 

# Note 3:

The next higher assembly level for the affected P/N's are the 204-040-366 mast assemblies. Check the aircraft records for the appropriate P/N and assembly level.

(1) Within 10 hours time-in-service (TIS), create a component history card or equivalent record for the mast. 

(2) Within 10 hours TIS, determine and record the accumulated RIN and revised hours TIS for the mast as follows: 

(i) Review the aircraft maintenance records for the mast. If the helicopter model installation history or hours TIS of the mast is unknown, remove the mast from service, identify the mast as unairworthy, and replace it with an airworthy mast before further flight. 

(ii) Determine the accumulated RIN and the revised hours TIS in accordance with the Instructions in Appendix 1. For those hours TIS the mast has been installed on a BHTI Model 204B, 205A, 205A-1, 205B, or 212 helicopter, determine the accumulated RIN in accordance with the AD's issued for those helicopters. 

(iii) Record the accumulated RIN and revised hours TIS for the mast on the component history card or equivalent record. Use the revised hours TIS as the new hours TIS for the mast. 

(3) Before further flight after accomplishing the requirements of paragraph (a)(2) of this AD, remove from service any mast that has accumulated 265,000 or more RIN or 15,000 or more revised hours TIS and identify the mast as unairworthy. Replace the mast with an airworthy mast. 

(4) Within 25 hours TIS, remove any hub spring installed on any affected helicopter. 

# Note 4:

U.S. Army Modification Work Order (MWO) 55-1520-242-50-1 pertains to the removal of the hub spring and replacement of any required parts. U.S. Army Safety of Flight Message UH-1-00-10 dated July 19, 2000, also pertains to the subject of this AD.

(5) Determine whether a mast with S/N 00000 through 52720, 61433 through 61444, or 61457 through 61465 (regardless of prefix), has ever been installed on a helicopter while operated with a hub spring. 

(i) If a mast has never been installed on a helicopter while operated with a hub spring, before reaching 100,000 RIN, inspect the upper and lower snap ring grooves in the damper clamp splined area for: 

(A) A minimum radius of 0.020 inch around the entire circumference (see Figures 1 and 2), using a 100 × or higher magnification. If any snap ring groove radius is less than 0.020 inch, identify the mast as unairworthy and replace it with an airworthy mast before exceeding 100,000 RIN. 

(B) A burr (see Figures 1 through 3), using a 200 × or higher magnification. If a burr is found in any snap ring groove/spline intersection, identify the mast as unairworthy and replace it with an airworthy mast before exceeding 170,000 RIN. 

(ii) If a mast has ever been installed on a helicopter while operated with a hub spring or if the history of a hub spring installation is unknown, before reaching 100,000 RIN or 400 unfactored flight hours, whichever occurs first, inspect the upper and lower snap ring grooves in the damper clamp splined area for: 

(A) A minimum radius of 0.020 inch around the entire circumference (see Figures 1 and 2), using a 100 × or higher magnification. If any snap ring groove radius is less than 0.020 inch, identify the mast as unairworthy and replace it with an airworthy mast before further flight. 

(B) A burr (see Figures 1 through 3), using a 200 × or higher magnification. If a burr is found in any snap ring groove/spline intersection, identify the mast as unairworthy and replace it with an airworthy mast before further flight. 

                            (6) After accomplishing the requirements of paragraph (a)(2) of this AD, continue to calculate the accumulated RIN for the mast by multiplying all takeoff and external load lifts by the RIN factors defined in columns (D) and (G) of Table 1 of Appendix 1 of this AD.                                   ( print page 77266)    

(7) After accomplishing the requirements of paragraph (a)(2) of this AD, continue to count the hours TIS for the mast. Any hours TIS for the mast while installed on a helicopter operated with a hub spring or if the history of a hub spring installation is unknown must be factored in accordance with the instructions in Appendix 1 of this AD. 

(8) This AD establishes a retirement life of 265,000 accumulated RIN or 15,000 hours TIS, whichever occurs first, for mast, P/N 204-011-450-007, -105, and -109. 

(9) Within 10 days after completing the inspections required by paragraph (a)(5) of this AD, send the information contained on the AD compliance inspection report sample format contained in Appendix 2 to the Manager, Rotorcraft Certification Office, Federal Aviation Administration, Fort Worth, Texas 76193-0170, USA. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.
      ( print page 77267)          ( print page 77268)          ( print page 77269)          ( print page 77270)    
(b) For the trunnion, P/N 204-011-105-001:

(1) Within 10 days, create a component history card or equivalent record for the trunnion and record the hours TIS accumulated on the trunnion. If the TIS cannot be determined, enter 900 hours for each year from the date the trunnion was installed.

(2) Remove any trunnion with 14,900 or more hours TIS from service within the next 100 hours TIS.

(3) Remove any trunnion with less than 14,900 hours TIS from service at or before 15,000 hours TIS.

# Note 5:

Paragraph (b) of this AD continues the requirements of the superseded AD for the trunnion.

(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 request through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Certification Office.

# Note 6:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, 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 December 26, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-22-51, issued November 2, 2000, which contained the requirements of this amendment.

      ( print page 77271)    

# APPENDIX 1 

      ( print page 77272)          ( print page 77273)          ( print page 77274)          ( print page 77275)          ( print page 77276)          ( print page 77277)          ( print page 77278)          ( print page 77279)          ( print page 77280)          ( print page 77281)    

      ( print page 77282)    

# Appendix 2 

## Appendix 2 to AD 2000-22-51 

## AD Compliance Inspection Report (Sample Format) P/N 204-011-450-007/-105/-109 Main Rotor Mast 

Provide the following information and mail or fax it to: Manager, Rotorcraft Certification Office, Federal Aviation Administration, Fort Worth, Texas 76193-0170, USA, Fax: 817-222-5783. 

*Aircraft Registration No:*

*Helicopter Model:*

*Helicopter S/N:*

*Mast P/N:*

*Mast S/N:*

*Mast RIN:*

*Mast Total TIS:*

### Inspection Results 

Were any radii during inspection of this mast determined to be less than 0.020 inch? 

If yes, what was the dimension measured? 

Was a burr found in the inspected snap ring grooves? 

Were cracks noted during the inspection? 

Who performed this inspection? 

Provide any other comments? 

Issued in Fort Worth, Texas, on November 30, 2000. 

Larry M. Kelly, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

BILLING CODE 4910-13-P

BILLING CODE 4910-13-C

[FR Doc. 00-31012 Filed 12-8-00; 8:45 am] 

BILLING CODE 4910-13-P