05-16167. Airworthiness Directives: Rolls-Royce plc RB211-535 Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Proposed rule; withdrawal.

SUMMARY:

The FAA is withdrawing a notice of proposed rulemaking (NPRM). That NPRM proposed a new airworthiness directive (AD) that applies to certain Rolls-Royce plc (RR) models RB211-535C-37, RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 turbofan engines. The NPRM had applied to those engines with radial drive steady bearing part number (P/N) LK76084 installed, with fewer than 3,000 engine operating hours on the bearing. That proposed action would have required initial and repetitive visual inspections of the engine oil scavenge filter for evidence of radial drive steady bearing failure. If after finding evidence, the proposed action would have required a visual inspection of the radial drive steady bearing for damage and evidence of bearing debris. Since we issued that NPRM, RR notified us that all at-risk radial drive steady bearings are removed from service. RR also notified us that remaining bearings in service are now well over the 3,000-engine-operating-hour threshold and are no longer at risk. Accordingly, we withdraw the proposed rule.

FOR FURTHER INFORMATION CONTACT:

Ian Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA proposed to amend 14 CFR part 39 with a proposed airworthiness directive (AD). The proposed AD applies to Rolls-Royce plc (RR) models RB211-535C-37, RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 turbofan engines. The proposed AD would have applied to those engines with radial drive steady bearing, P/N LK76084 installed, with fewer than 3,000 engine-operating-hours on the bearing. We published the proposed AD in the Federal Register on October 9, 2003, (68 FR 58291). That proposed action would have required initial and repetitive visual inspections of the engine oil scavenge filter for evidence of radial drive steady bearing failure. If evidence was found, that proposed action would have required a visual inspection of the radial drive steady bearing for damage and evidence of bearing debris. That proposed action was prompted by notification from the Civil Aviation Authority (CAA), which is the airworthiness authority for the U.K. The CAA notified us that an unsafe condition may exist on RR models RB211-535C-37, RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 turbofan engines. The unsafe condition had applied to those engines with radial drive steady bearing P/N LK76084 installed with fewer than 3,000 engine operating hours on the bearing. The CAA received reports of seven low time failures of radial drive steady bearings within a four-month period. These failures were not detected through routine magnetic chip detector monitoring because the failed bronze bearing cages are nonmagnetic, and the cage failure mode is rapid. The proposed actions intended to prevent a possible dual-engine in-flight shutdown caused by radial drive steady bearing failure.

Since the issuance of that NPRM, RR notified us that all at-risk radial drive steady bearings are removed from service. RR also notified us that the remaining bearings in service are now well over the 3,000-engine-operating-hour threshold and are no longer at risk.

Upon further consideration, we hereby withdraw the proposed rule for the following reasons:

• After RR notifying us of the removal from service and bearing threshold information, stated previously.
• AD 2000-09-14 (65 FR 30527, May 12, 2000) and AD 2001-19-05 (66 FR 49099, September 26, 2001) currently address the same radial drive steady bearing, P/N LK76084.
• AD 2000-09-14 and AD 2001-19-05 mandate replacing low-time bearings that are at risk.

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.

Since this action only withdraws a notice of proposed rulemaking, it is neither a proposed nor a final rule. Therefore, Executive Order 12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979) do not cover this withdrawal.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Withdrawal

Accordingly, the notice of proposed rulemaking, Docket 2003-NE-31-AD, published in the Federal Register on October 9, 2003, (68 FR 58291), is withdrawn.

Issued in Burlington, Massachusetts, on August 9, 2005.

Francis A. Favara,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.