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Airworthiness Directives; Bell Helicopter Textron Inc.-Manufactured 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

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Start Preamble


Federal Aviation Administration, DOT.


Final rule.


This amendment adopts a new airworthiness directive (AD) that applies to Bell Helicopter Textron Inc. (BHTI)-manufactured 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. This AD requires removing and replacing certain main rotor mast (mast) assemblies. This AD is prompted by a BHTI-manufactured Model UH-1B accident due to fatigue failure of a thin-wall mast installed on the helicopter. The actions specified by this AD are intended to prevent fatigue failure of the mast and subsequent loss of control of the helicopter.


August 24, 2000.

Start Further Info


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

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A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD for BHTI-manufactured 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 was published in the Federal Register on March 24, 2000 (65 FR 15882). That action proposed to require removing any mast assembly, part number (P/N) 204-011-450-001 or -005, and replacing it with an airworthy mast assembly.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter states that the FAA's reference to the affected aircraft as “BHTI-manufactured” implies BHTI responsibility. The commenter states that BHTI never obtained an FAA type certificate for the affected helicopters. Although BHTI originally manufactured the affected helicopters for the U.S. military, they have not produced any helicopters of these types for 20 years. The commenter requests that we refer to the affected aircraft as “FAA type certificated U.S. military surplus UH-1 helicopters.” The FAA agrees that BHTI is neither the type certificate holder nor the production certificate holder. However, the FAA does not concur that the terminology “Bell Helicopter Textron Inc.-manufactured” implies BHTI responsibility. The type certificate holder is responsible for defining corrective actions for the aircraft on their type certificate (see 14 CFR 21.99). The FAA uses the terminology “Bell Helicopter Textron Inc.-manufactured Model * * *” only to identify the original manufacturer of the helicopter. The use of this terminology in no way intends to assign or imply responsibility to BHTI.

The commenter also requests that the FAA type certificate holders or the applicable entities be specifically identified in the applicability section of the AD. The FAA does not agree to this request because the type certificate holders are already specifically identified by name in the paragraph immediately preceding the “applicability” paragraph of the AD.

The commenter also states that the mast pole referred to in the NPRM was retired by the Army years ago. Since the commenter understands that the Army manuals are used by the FAA in certifying the affected helicopters, the commenter questions why the helicopters are not already out of configuration. The configuration change Start Printed Page 48606to remove these masts from installation eligibility may or may not have been incorporated in the Army manuals. In order to ensure correction of this unsafe condition, the FAA is requiring the design change by issuance of this AD.

The commenter further states that BHTI does not refer to the mast pole as a “thin-walled mast,” but as the “standard wall mast,” and requests that the nomenclature be changed to identify a specific dash numbered mast. The FAA uses the terminology “thin-wall masts” because that wording was used by the U.S. Army in Safety of Flight Message UH-1-84-08 dated July 1984. The terminology is being retained in the summary of this AD for consistency. Specific dash numbers in this AD are used for identifying the affected mast assemblies to be removed. For replacement parts, it is unnecessary to specify the specific dash number; it is only necessary that they be airworthy.

The commenter also states that the term “airworthy mast” is ambiguous. The FAA does not agree. The term “airworthy” is standard aviation terminology and means a part that meets type design and is in a condition for safe operation.

Finally, the commenter states that no mention of the Retirement Index Number (RIN) procedure of counting torque events is mentioned in the NPRM. The commenter states that repeated heavy lifting, such as is involved in logging, greatly reduces the life of the mast as well as other components. The FAA has imposed RIN counting requirements for any replacement masts in Emergency AD 2000-08-53, issued April 26, 2000. RIN counting procedures for the masts, P/N 204-011-450-001 and -005, were mandated by that Emergency AD.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 75 helicopters of U.S. registry will be affected by this AD, that it will take approximately 10 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Replacing a mast assembly will cost approximately $8,862. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $709,650 to replace all the masts in the fleet.

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.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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Adoption of the Amendment

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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:

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

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

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

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2000-15-21 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 (Previously Utah State University); Western International Aviation, Inc.; and U.S. Helicopter, Inc.: Amendment 39-11854. Docket No. 2000-SW-01-AD.

Applicability: Bell Helicopter Textron Inc.-manufactured 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 with a main rotor mast (mast) assembly, part number (P/N) 205-011-450-001 or -005, 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 within 25 hours time-in-service, unless accomplished previously.

To prevent fatigue failure of the mast and subsequent loss of control of the helicopter, accomplish the following:

(a) Remove any mast assembly, part number (P/N) 204-011-450-001 or -005, from service. Replace with an airworthy mast assembly. Neither mast, P/N 204-011-450-001 nor 204-011-450-005, are eligible for installation on any affected helicopter.

(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, Rotorcraft Certification Office, Rotorcraft Directorate, 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.

(c) 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.

(d) This amendment becomes effective on August 24, 2000.

Start Signature

Issued in Fort Worth, Texas, on August 1, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-20186 Filed 8-8-00; 8:45 am]