[Federal Register Volume 71, Number 52 (Friday, March 17, 2006)]
[Proposed Rules]
[Page 13787]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-3907]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19930; Directorate Identifier 2004-NE-33-AD]


Airworthiness Directives: Rolls-Royce plc RB211 Trent 800 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: This action withdraws a notice of proposed rulemaking (NPRM). 
That NPRM proposed a new airworthiness directive (AD) that applies to 
Rolls-Royce plc (RR) RB211 Trent 800 series turbofan engines. That 
proposed action would have required initial and repetitive borescope 
inspections of the high pressure-and-intermediate pressure (HP-IP) 
turbine internal and external oil vent tubes for coking and carbon 
buildup, and cleaning or replacing the vent tubes if necessary. Since 
we issued that NPRM, RR notified us that the RB211 Trent 800 series 
turbofan engines are significantly less susceptible to vent tube carbon 
build-up than the RB211 Trent 700 series turbofan engines. Repeat on-
wing inspections therefore, are not required to maintain fleet safety. 
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 (781) 238-
7178; fax (781) 238-7199.

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 RB211 Trent 800 series turbofan engines. We 
published the proposed AD in the Federal Register on December 27, 2004 
(69 FR 77144). That proposed action would have required initial and 
repetitive borescope inspections of the HP-IP turbine internal and 
external oil vent tubes for coking and carbon buildup, and cleaning or 
replacing the vent tubes if necessary. That proposed action resulted 
from a report of an RB211 Trent 700 series engine experiencing a disk 
shaft separation, overspeed of the intermediate pressure (IP) turbine 
rotor, and multiple blade release of IP turbine blades.
    Since we issued that NPRM, RR notified us that data collected from 
a onetime inspection of 200 RB211 Trent 800 series turbofan engines 
shows that these engines are significantly less susceptible to vent 
tube carbon build-up than the RB211 Trent 700 series turbofan engines. 
The RB211 Trent 800 series engines had no evidence of significant 
accumulation. RR's analysis concluded that repeat on-wing inspections 
are not required to maintain fleet safety. The vent tube inspection and 
cleaning can be done at each shop visit. This will ensure that the 
probability of carbon blockage and spontaneous ignition will be 
negligible. Based on this analysis, RR has stated they will cancel 
Alert Service Bulletin RB.211-72-AE362, dated May 7, 2004.
    Upon further consideration, we hereby withdraw the proposed rule 
based on RR's analysis and conclusion stated above.
    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. 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, we withdraw the notice of proposed rulemaking, FAA-
2004-19930; Directorate Identifier 2004-NE-33-AD, published in the 
Federal Register on December 27, 2004 (69 FR 77144).

    Issued in Burlington, Massachusetts, on March 13, 2006.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E6-3907 Filed 3-16-06; 8:45 am]
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