01-9075. Airworthiness Directives; Bell Helicopter Textron Canada Model 407 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM); rescission.

SUMMARY:

This amendment proposes rescinding an existing Airworthiness Directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 407 helicopters. That AD currently requires, before further flight, imposing never exceed velocity (Vne) restrictions on the helicopter. The requirements of that AD were intended to prevent tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter. That AD was prompted by an accident suspected of being the result of a tail rotor strike caused by high airspeed. Since the issuance of that AD, accident investigation findings have not substantiated that a tail rotor strike caused by high airspeed was the cause of the accident. This action would require rescinding that AD. This proposal is prompted by the FAA's determination that the Vne restrictions and accompanying actions imposed by that AD do not correct an unsafe condition.

DATES:

Comments must be received on or before May 14, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA) Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2001-SW-02-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. You may also send comments electronically to the Rules Docket at the following address: [e-mail].

FOR FURTHER INFORMATION CONTACT:

Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations Group, Fort Worth, Texas 76193-0111, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this document may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their mailed comments submitted in response to this proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2001-SW-02-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Office of the Regional Counsel, Attention: Rules Docket No. 2001-SW-02-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

On January 30, 2001, the FAA issued AD 2001-01-52, Amendment 39-12100 (66 FR 9031, February 6, 2001), for BHTC Model 407 helicopters. That AD requires, before further flight, reducing the maximum approved Vne to 100 KIAS if an airspeed-actuated pedal stop is not installed or to 110 KIAS if an airspeed-actuated pedal stop is installed; inserting a copy of the AD into the RFM; installing a temporary placard on the flight instrument panel to indicate the reduced Vne limit; and installing a new redline Vne limit at either 100 or 110 KIAS, as specified in the AD, on all airspeed indicators. That action was prompted by an accident in which a helicopter was destroyed on water impact following an in-flight occurrence at approximately 140 KIAS. One of the possible contributing factors was an in-flight tail rotor strike to the tailboom. As a precautionary measure, pending further investigation into the accident, and after reviewing the AD issued by the certifying authority for the helicopter (Transport Canada), the FAA issued AD 2001-01-52 to reduce the Vne.

Actions Since Issuing Previous AD

Since issuing AD 2001-01-52, preliminary accident investigation findings do not substantiate that the accident resulted from a tail rotor strike caused by high airspeed. Information provided by BHTC and reviewed by the FAA supports these findings. Transport Canada has issued a superseding AD, CF-2001-01R1, dated April 3, 2001, stating that the Vne restriction is no longer necessary. Transport Canada advises that no data has emerged from the investigation to confirm that the accident was initiated by a tail rotor strike. While the possibility of a tail rotor strike has not been completely discounted as the cause of the accident, a tail rotor strike occurrence while operating within the approved flight envelope has been discounted. The ongoing accident investigation is currently considering other factors.

FAA's Conclusions

After reviewing the available data, the FAA has determined that it is appropriate to rescind AD 2001-01-52 to prevent operators from performing an unnecessary action. The Vne restrictions and accompanying actions imposed by that AD do not correct an unsafe condition. The ongoing investigation found no information to indicate that the accident was caused by a tail rotor strike during flight at high airspeed. The cause of the accident precipitating AD 2001-01-52 remains under investigation.

This proposed action would rescind AD 2001-01-52. Rescission of AD 2001-01-52 would constitute only such action and if followed by a final action would not preclude the agency from issuing another action in the future nor would it commit the agency to any course of action in the future.

Cost Impact

The FAA estimates that 200 helicopters of U.S. registry are affected by AD 2001-01-52. The actions that are currently required by that AD take approximately 3 work hours per helicopter to manufacture and install each airspeed limitation placard. The average labor rate is $60 per work hour. Required parts cost approximately $10 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $38,000 to install an airspeed limitation placard on all helicopters in the U.S. fleet. However, adopting this proposed rescission would eliminate those costs.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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

[Amended]

2. Section 39.13 is amended by adding an AD removing Amendment 39-12100 to read as follows:

Bell Helicopter Textron Canada: Docket No. 2001-SW-02-AD. Rescinds AD 2001-01-52, Amendment 39-12100.

Applicability: Model 407 helicopters, certificated in any category.

Issued in Fort Worth, Texas, on March 5, 2001.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.