[Federal Register Volume 65, Number 146 (Friday, July 28, 2000)]
[Proposed Rules]
[Page 46378]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-19074]


 ========================================================================
 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. 65, No. 146 / Friday, July 28, 2000 / 
Proposed Rules  

[[Page 46378]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-38]


Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: This action withdraws a supplemental notice of proposed 
rulemaking (SNPRM) that proposed a new airworthiness directive (AD) 
applicable to Pratt & Whitney (PW) JT9D-7R4 series turbofan engines. 
That action would have required the addition of initial and repetitive 
on-wing eddy current inspections (ECI) of affected diffuser case 
assembly bosses for cracks, and replacement of cracked bosses with 
serviceable parts. In addition, that action would have revised the 
initial accomplishment time for the previously proposed actions. 
Finally, that action would have added further etches, fluorescent 
penetrant inspections (FPIs), x-ray inspections, and shotpeening to the 
shop requirements, and would have provided an optional terminating 
action in the form of a redesigned diffuser case. The actions specified 
by the SNPRM were intended to prevent diffuser case assembly rupture, 
which could result in an uncontained engine failure, engine fire, and 
damage to the airplane. Since the issuance of the SNPRM, the FAA has 
reevaluated the safety risk to the fleet using the most recent fleet 
data , including the status of how much of the fleet has already 
undergone the modifications and inspections included in the proposed 
actions.. The drawdown period of the fleet management program that was 
originally proposed has been completed. All case assemblies continue to 
be inspected on-wing as part of normal maintenance actions. Therefore, 
the safety risk has been considerably reduced. As a result, the FAA has 
determined that an AD is no longer required, and 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 01803-5299; 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 AD, applicable to PW 
JT9D-7R4 series turbofan engines, was published in the Federal Register 
on August 23, 1995 (60 FR 43730). That proposal would have required the 
removal of material from certain bosses on the diffuser case assembly, 
inspection of the reworked area using Flourscent Penetrant and x-ray 
methods, and shotpeening of the reworked area. That action was prompted 
by reports of cracks at the aft corners of bosses on the diffuser case 
assemblies.
    The FAA received comment on the proposed rule, and in response to 
those comments and further analysis of the unsafe condition published a 
Supplemental Notice of Proposed Rulemaking (SNPRM) on December 8, 1997 
(62 FR 64523). As supplemented the proposed rule would have required 
the addition of initial and repetitive on-wing eddy current inspection 
(ECI) of affected diffuser case assembly bosses for cracks, and 
replacement, if necessary, with serviceable parts. The proposed rule as 
supplemented also would have revised the initial accomplishment time 
for the previously proposed actions. Finally, the supplemented proposed 
rule would have added further etches, FPIs, x-ray inspections, and 
shotpeening to the shop requirements and would have provided an 
optional terminating action in the form of a redesigned diffuser case. 
The proposed actions were intended to prevent diffuser case assembly 
rupture, which could result in an uncontained engine failure, engine 
fire, and damage to the airplane.
    Since the issuance of that SNPRM, the FAA has reevaluated the 
safety risk to the fleet using the most recent fleet data, including 
the status of how much of the fleet has already undergone the 
modifications and inspections included in the proposed actions. The 
drawdown period of the fleet management program that was originally 
proposed, which corresponds to the actions in the service bulletins, 
has been completed. All case assemblies continue to be inspected on-
wing as part of normal maintenance actions. Therefore, the safety risk 
has been considerably reduced.
    Upon further consideration, the FAA has determined that the unsafe 
condition no longer exists. Accordingly, the proposed rule is hereby 
withdrawn.
    Withdrawal of this supplemental 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 supplemental 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 supplemental notice of proposed rulemaking, Docket 
95-ANE-38, published in the Federal Register on December 8, 1997 (62 FR 
64523), is withdrawn.

    Issued in Burlington, Massachusetts, on July 21, 2000.
Robert Guyotte,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-19074 Filed 7-27-00; 8:45 am]
BILLING CODE 4910-13-U