2021-21050. Airworthiness Directives; Arrow Falcon Exporters, Inc. (Previously Utah State University); California Department of Forestry; Firefly Aviation Helicopter Services (Previously Erickson Air-Crane Co.); Garlick Helicopters, Inc.; Global ...

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Proposed rule; withdrawal.

SUMMARY:

The FAA is withdrawing a notice of proposed rulemaking (NPRM) that proposed to supersede Airworthiness Directive (AD) AD 2002-20-01, which applies to certain Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters; and Southwest Florida Aviation Model SW204, SW204HP, SW205, and SW205A-1 helicopters, manufactured by Bell Helicopter Textron, Inc. (BHTI) for the Armed Forces of the United States. The NPRM would have required removing certain serial-numbered tension-torsion (TT) straps from service, reducing the retirement life for other TT straps, and establishing a retirement life in terms of calendar time in addition to hours time-in-service (TIS) for certain other affected TT straps. The NPRM also would have added two model helicopters to the applicability of the AD. The NPRM was prompted by fatigue cracking in certain TT straps that have stainless steel filament windings and a determination that corrosion damage, which is related to calendar time, necessitated a calendar time retirement life for certain TT straps in addition to the retirement life based on hours TIS. The NPRM was also prompted by fatigue cracking in other TT straps with encased thin stainless steel plates. Since issuance of the NPRM, the FAA has re-reviewed the available information and determined that the totality of the available information does not support issuance of a final rule. Accordingly, the NPRM is withdrawn.

DATES:

As of September 30, 2021 the proposed rule, which was published in the Federal Register on April 22, 2010 (75 FR 20933), is withdrawn.

ADDRESSES:

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2010-0427; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD action, any comments received, and other information. The street address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Jurgen Priester, Aviation Safety Engineer, Delegation Oversight Section, DSCO Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone [phone]; email [e-mail].

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued an NPRM that proposed to amend 14 CFR part 39 by removing AD 2002-20-01, Amendment 39-12895 (67 FR 61771, October 2, 2002), which applies to restricted category Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters; and Southwest Florida Aviation Model SW204, SW204HP, SW205, and SW205A-1 helicopters, manufactured by BHTI for the Armed Forces of the United States. The NPRM published in the Federal Register on April 22, 2010 (75 FR 20933). The NPRM would have applied to Model AH-1G, AH-1S, HH-1K, TH-1F, TH-1L, UH -A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters with BHTI main rotor TT strap, part number (P/N) 204-011-113-1, 204-012-112-1, 204-012-112-5, 204-012-112-7, 204-012-122-1, 204-012-122-5, 204 310-101-101, or Bendix Energy Controls Co. P/N 2601139, 2601399, 2601400, or 2606650, installed; and Southwest Florida Aviation Model UH-1B (SW204 and SW204HP) and UH-1H (SW205) helicopters. The NPRM was prompted by fatigue cracking in certain TT straps that have stainless steel filament windings and a determination that corrosion damage, which is related to calendar time, necessitates a calendar time retirement life for certain TT straps in addition to the retirement life based on hours TIS. The NPRM was also prompted by fatigue cracking in other TT straps with encased thin stainless steel plates.

The NPRM proposed to require removing certain serial-numbered TT straps from service, reducing the retirement life for other TT straps, and establishing a retirement life in terms of calendar time in addition to hours TIS for certain other affected TT straps. The NPRM also proposed to add two model helicopters to the applicability. The proposed actions were intended to prevent failure of a TT strap, loss of a main rotor blade, and subsequent loss of control of the helicopter.

Actions Since the NPRM Was Issued

Since issuance of the NPRM, the FAA has re-reviewed the available information and failure data used to justify issuance of the NPRM, and reviewed the service difficulty data produced since the NPRM was issued. Through that review, the FAA determined that there have not been any further reported problems with the affected part number TT straps since the NPRM was issued. Based on that review, the FAA concluded that the totality of the available information and the lack of additional reports does not support issuance of a final rule. The potential unsafe condition identified as the justification for issuance of the NPRM has not materialized. Therefore, the FAA has determined that AD action is not appropriate.

Withdrawal of the NPRM constitutes only such action and does not preclude the FAA from further rulemaking on this issue, nor does it commit the FAA to any course of action in the future.

Comments

The FAA gave the public the opportunity to comment on the NPRM and received 38 comments. The FAA received comments from individual commenters as well as from organizations on a variety of topics, including the costs estimates, compliance times, and requests to withdraw the NPRM. You may examine the comments received in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2010-0427.

The FAA acknowledges these comments to the NPRM. However, because the FAA is withdrawing the NPRM, the commenter's requests are no longer necessary.

FAA's Conclusions

Upon further consideration of the available information, the FAA has determined that the NPRM is unnecessary. Accordingly, the NPRM is withdrawn.

Regulatory Findings

Since this action only withdraws an NPRM, it is neither a proposed nor a final rule. This action therefore is not covered under Executive Order 12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Withdrawal

Accordingly, the notice of proposed rulemaking, Docket No. FAA-2010-0427, which was published in the Federal Register on April 22, 2010 (75 FR 20933), is withdrawn.

Issued on September 23, 2021.

Gaetano A. Sciortino,

Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.