01-8147. Airworthiness Directives; Bell Helicopter Textron Model 412 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Proposed rule; withdrawal.

SUMMARY:

This action withdraws a notice of proposed rulemaking (NPRM) that proposed a new airworthiness directive (AD) for the Bell Helicopter Textron, Inc. (BHTI) Model 412 high landing gear aft crosstube assembly (crosstube assembly) that would have required determining the number of landings, inspecting for damage, vibro-etching a part number (P/N) and a serial number (S/N), creating a component history card or equivalent record, establishing a retirement life, and replacing each unairworthy crosstube assembly. Since the issuance of the NPRM, the FAA has determined that the NPRM contained incorrect part numbers. Also, the FAA is conducting a more thorough review of the service history to determine whether a yearly inspection of the crosstube assembly is a better corrective action. Accordingly, the proposed rule is withdrawn.

FOR FURTHER INFORMATION CONTACT:

Michael Kohner, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

A proposal to amend 14 CFR part 39 to adopt a new AD for BHTI Model 412 helicopters was published in the Federal Register on November 15, 2000 (65 FR 68953). The proposed rule would have contained the following requirements for certain crosstube assemblies:

• Reviewing the aircraft maintenance records to determine the number of landings;
• Inspecting for damage and replacing any unairworthy crosstube assembly;
• Vibro-etching a P/N on the crosstube assembly;
• Vibro-etching a S/N on the crosstube assembly;
• Creating a component history card or equivalent record; and
• Establishing a retirement life of 10,000 landings for crosstube assemblies, P/N 412-050-010-101 and 412-050-011-107 FM, and a retirement life of 20,000 landings for crosstube assemblies, P/N 412-050-045-107.

That action was prompted by reports of failures indicating that a retirement life should be assigned to the crosstube assembly. The proposed actions were intended to detect damage that could lead to a fatigue crack and failure of the crosstube assembly and subsequent loss of control of the helicopter during landing.

Since the issuance of that NPRM, the FAA has received new data from the manufacturer indicating that the NPRM contained incorrect part numbers. The FAA has also gathered more failure data and service history of certain crosstube assemblies.

Upon further consideration and review of this new data, the FAA has determined that the NPRM contained incorrect part numbers. Also, after reviewing the service history, the FAA has determined that assigning a retirement life to the crosstube assembly might not adequately address the unsafe condition. However, the FAA is still reviewing the failure data and service history to determine whether to require yearly inspections of certain crosstube assemblies to more adequately address the unsafe condition. Accordingly, we have decided to withdraw the proposed rule.

Withdrawal of this NPRM constitutes only such action and does not preclude the agency from issuing another notice in the future, nor does it commit the agency to any course of action in the future.

Since this action only withdraws an NPRM, it is neither a proposed nor a final rule and, 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
• Safety

The Withdrawal

Accordingly, the NPRM, Docket No. 2000-SW-60-AD, published in the Federal Register on November 15, 2000 (65 FR 68953), is withdrawn.

Issued in Fort Worth, Texas, on March 22, 2001.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.