05-20076. Airworthiness Directives; Boeing Model 777 Series Airplanes Equipped With Pratt & Whitney Engines and Used in Extended Range Twin-Engine Operations (ETOPS)

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), applicable to certain Boeing Model 777 series airplanes equipped with Pratt & Whitney engines. That action would have required replacement of the integrated drive generator (IDG) and the backup generator with a new IDG and a new backup generator. Since the issuance of the NPRM, the Federal Aviation Administration (FAA) has received new data that indicate that all affected airplanes worldwide have the proper parts installed and all spares are accounted for, and that the identified unsafe condition (loss of electrical power) cannot occur for the reasons specified by the NPRM. Accordingly, the proposed rule is withdrawn.

FOR FURTHER INFORMATION CONTACT:

Tony Castillos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office; 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add a new airworthiness directive (AD), applicable to certain Boeing Model 777 series airplanes equipped with Pratt & Whitney engines, was published in the Federal Register as a Notice of Proposed Rulemaking (NPRM) on January 5, 1998 (63 FR 169). The proposed rule would have required replacement of the integrated drive generator (IDG) and the backup generator with a new IDG and a new backup generator. That action was prompted by reports of IDG shaft failure resulting from design problems in the hydraulic and mechanical systems of the generator, and by reports of backup generator failure resulting from the failure of the oil pressure switch. The proposed actions were intended to prevent continued degradation of the power system, and consequent loss of electrical power.

Actions That Occurred Since the NPRM Was Issued

Since the issuance of that NPRM, the FAA has received and confirmed reports indicating that all affected airplanes worldwide have the proper parts installed and that all spares are accounted for.

FAA's Conclusions

Upon further consideration, the FAA has determined that the unsafe condition identified in the NPRM (loss of electrical power) can no longer occur because of the reasons given in the NPRM. Accordingly, the proposed rule is hereby withdrawn.

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

Regulatory Impact

Since this action only withdraws a notice of proposed rulemaking, 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 notice of proposed rulemaking, Docket 97-NM-78-AD, published in the Federal Register on January 5, 1998 (63 FR 169), is withdrawn.

Issued in Renton, Washington, on September 29, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.