Airworthiness Directives; Dornier Model 328-100 Series Airplanes

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 Dornier Model 328-100 series airplanes. That action would have required installation of two reinforcing brackets on the keel beam in the lower shell of the main landing gear bay. Since the issuance of the NPRM, the Federal Aviation Administration (FAA) has received new data indicating that the unsafe condition addressed in the NPRM does not exist. Accordingly, the proposed rule is withdrawn.

FOR FURTHER INFORMATION CONTACT:

Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

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 Dornier Model 328-100 series airplanes, was published in the Federal Register as a Notice of Proposed Rulemaking (NPRM) on April 6, 1998 (63 FR 16715). The proposed rule would have required installation of two reinforcing brackets on the keel beam in the lower shell of the main landing gear bay. That action was prompted by a report of cracking of the keel beam that was discovered during full-scale fatigue testing. The proposed actions were intended to prevent fatigue cracking of the keel beam, which could result in reduced structural integrity of the airplane.

Actions That Occurred Since the NPRM Was Issued

Since the issuance of that NPRM, the manufacturer has provided the FAA with additional information regarding the unsafe condition identified in the proposed AD. The manufacturer states that an analysis has been accomplished that shows that if the cracking addressed by the proposed AD propagated to its maximum limit, the airplane could still withstand ultimate structural loads.

FAA's Conclusions

Upon further consideration, the FAA has determined that fatigue cracking of the keel beam, which was intended to be addressed by the corrective actions required in the proposed AD, does not constitute an unsafe condition. Accordingly, the proposed rule is hereby withdrawn.

Withdrawal of this notice of proposed rulemaking 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.

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-203-AD, published in the Federal Register on April 6, 1998 (63 FR 16715), is withdrawn.