[Federal Register Volume 66, Number 98 (Monday, May 21, 2001)]
[Proposed Rules]
[Pages 27914-27915]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-12674]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-59-AD]


Airworthiness Directives; Pratt & Whitney JT8D 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 proposed a new airworthiness directive (AD), applicable to Pratt & 
Whitney (PW) JT8D series turbofan engines. That action would have 
superseded an existing AD to require initial and repetitive borescope 
inspections for loss of fuel nozzle nut torque and nozzle support wear, 
and replacement or modification of the fuel nozzles at the next 
accessibility of the diffuser build group as terminating action to the 
inspections. That proposal was prompted by reports of loss of fuel 
nozzle nut torque and nozzle support wear. Since the issuance of that 
NPRM, the FAA has reevaluated the likelihood that the unsafe condition 
will exist or develop on other products of the same type design. 
Accordingly, the proposed rule is withdrawn.

FOR FURTHER INFORMATION CONTACT: Tara Goodman, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; telephone (781) 238-
7130; fax (781) 238-7199.

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 PW JT8D series turbofan engines, was 
published in the Federal Register on May 1, 1998 (63 FR 24138). The 
proposed rule would have required initial and repetitive borescope 
inspections for loss of fuel nozzle nut torque and nozzle support wear, 
and replacement or modification of the fuel nozzles at the next 
accessibility of the diffuser build group as terminating action to the 
inspections. That action was prompted by reports of loss of fuel nozzle 
nut torque and nozzle support wear. The proposed actions were intended 
to prevent loss of fuel nozzle nut torque and nozzle support wear, 
which could result in a fuel leak and possible engine fire.
    Since issuing that NPRM, the FAA has reevaluated the safety 
concerns that the proposed actions would have

[[Page 27915]]

addressed using the most recent fleet data. Field experience shows that 
leaking fuel nozzles, which can lead to burn-through of the diffuser 
case, was a significant flight safety concern primarily at the number 7 
location because of the proximity of oil lines. This is addressed by AD 
95-02-16.
    To date, there have not been any incidents of diffuser case burn-
through due to fuel leakage across the fuel nozzle secondary seal where 
the fuel nozzle configuration is as prescribed by AD 95-02-16. There 
has been one incident where the fuel nozzle at the number 7 position 
has leaked due to loss of nut torque, ignited, and burned through the 
diffuser case. However, because the oil line fittings had been replaced 
in accordance with AD 95-02-16, there was no burn-through of the oil 
fittings and no oil fire. The following requirements of AD 95-02-16, 
are sufficient to mitigate the safety concern:
    <bullet> Initial and repetitive inspections of the number 7 fuel 
nozzle and support assembly, AND
    <bullet> Replacement of the number 7 fuel nozzle and support 
assembly with a more leak resistant configuration, AND
    <bullet> Replacement of aluminum oil pressure and scavenge tube 
fittings with steel fittings, AND
    <bullet> Replacement of an aluminum oil scavenge line bolt with a 
steel bolt.
    Upon further consideration, the FAA has determined that there is no 
longer a likelihood that the unsafe condition will exist or develop on 
other products of the same type design, and as a result, superseding 
the existing AD is no longer required. 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.
    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-ANE-59-
AD, published in the Federal Register on May 1, 1998, (63 FR 24138), is 
withdrawn.

    Issued in Burlington, Massachusetts, on May 10, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-12674 Filed 5-18-01; 8:45 am]
BILLING CODE 4910-13-U