01-15445. Airworthiness Directives; Bell Helicopter Textron Canada Model 407 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; rescission.

SUMMARY:

This amendment rescinds an existing airworthiness directive (AD) that applies to Bell Helicopter Textron Canada (BHTC) Model 407 helicopters and 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 amendment rescinds that AD. This amendment is prompted by the FAA's determination that the Vne restrictions and accompanying actions imposed by that AD do not correct an unsafe condition.

EFFECTIVE DATE:

July 25, 2001.

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:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by rescinding AD 2001-01-52, Amendment 39-12100 (66 FR 9031, February 6, 2001), which applies to BHTC Model 407 helicopters, was published in the Federal Register on April 12, 2001 (66 FR 18884). AD 2001-01-52 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 AD 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.

Further investigations conducted since the issuance of AD 2001-01-52 did 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.

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.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

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 rescission eliminates those costs.

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 FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

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

[Amended]

2. Section 39.13 is amended by removing Amendment 39-12100 ( 66 FR 9031, February 6, 2001).

AD 2001-01-52 R1 Bell Helicopter Textron Canada: Amendment 39-12272. 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 June 8, 2001.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.