[Federal Register Volume 71, Number 65 (Wednesday, April 5, 2006)]
[Proposed Rules]
[Page 17033]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-4923]


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 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
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  Federal Register / Vol. 71, No. 65 / Wednesday, April 5, 2006 / 
Proposed Rules  

[[Page 17033]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19157; Directorate Identifier 2004-NE-30-AD]


Airworthiness Directives: Rolls-Royce Deutschland (RRD) (Formerly 
Rolls-Royce plc) Tay 650-15 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 
certain RRD Tay 650-15 series turbofan engines. That proposed action 
would have required initial and repetitive inspections of the high 
pressure compressor (HPC) shaft and high pressure turbine (HPT) shaft 
for spline flank wear. Since we issued that NPRM, the Luftfahrt-
Bundesamt (LBA), which is the airworthiness authority for Germany, 
notified us that the spline flank wear inspections are now downgraded 
by RRD from ``mandatory'' to ``recommended''. 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 RRD Tay 650-15 series turbofan engines. We published the proposed AD 
in the Federal Register on October 4, 2004 (69 FR 59148). That proposed 
action would have required initial and repetitive inspections of the 
HPC shaft and HPT shaft for spline flank wear. That proposed action 
resulted from a number of occurrences of excessive HPC shaft and HPT 
shaft spline flank wear discovered during on-wing and in-shop 
inspections.
    Since we issued that NPRM, the LBA notified us that RRD downgraded 
the spline flank wear inspections from ``mandatory'' to 
``recommended''. RRD based the downgrade on performance calculation, 
rig test, and statistical analysis derived using the variation of HP 
spline wear rate, measured during engine teardowns and from data 
submitted by operators when accomplishing RRD Service Bulletin No. TAY-
72-1485. We reviewed the RRD risk assessment and agree that we no 
longer need to require the inspections.
    On further consideration, we withdraw the proposed rule based on 
RRD's analysis and our conclusion stated above.
    Withdrawing this NPRM constitutes only that action, and does not 
prevent us from issuing another NPRM in the future, nor does it commit 
us to any course of action in the future.
    Since this action only withdraws an NPRM, 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-
2004-19157; Directorate Identifier 2004-NE-30-AD, published in the 
Federal Register on October 4, 2004 (69 FR 59148).

    Issued in Burlington, Massachusetts, on March 30, 2006.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E6-4923 Filed 4-4-06; 8:45 am]
BILLING CODE 4910-13-P