[Federal Register Volume 64, Number 222 (Thursday, November 18, 1999)]
[Rules and Regulations]
[Pages 62975-62976]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-29824]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-06-AD; Amendment 39-11334; AD 99-20-04]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction

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SUMMARY: This document makes a correction to Airworthiness Directive 
(AD) 99-20-04 applicable to certain Pratt & Whitney (PW) JT9D series 
turbofan engines that was published in the Federal Register on 
September 24, 1999 (64 FR 51683). The final rule inadvertently 
references HPC disk fracture instead of HPT disk fracture and one 
service bulletin (SB) reference in the compliance section is incorrect. 
This document corrects those references. The Compliance section in the 
final rule was inadvertently changed to incorporate the compliance 
requirements used in a similar PW2000 Airworthiness Directive. The 
Compliance requirements were correctly published in the NPRM, but were 
published incorrectly in the Final Rule. This correction will reinstate 
the compliance requirements originally published in the NPRM, and as 
intended for the JT9D. In all other respects, the original document 
remains the same.


[[Page 62976]]


EFFECTIVE DATE: November 18, 1999.

FOR FURTHER INFORMATION CONTACT: Peter White, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7128, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A final rule airworthiness directive 
applicable to Pratt & Whitney (PW) JT9D-7R4 series turbofan engines, 
was published in the Federal Register on September 24, 1999 (64 FR 
51683). The Rule should reference HPT disk fracture instead of HPC disk 
fracture. In addition, a typographical error occurred and, as a result, 
one Service Bulletin reference regarding the performance of the 
inspections is incorrect and has been corrected to refer to the SB that 
contains the actual inspection procedure. The following corrections are 
needed:


Sec. 39.13  [Corrected]

    1. On page 51684, in the first column, in the Compliance Section, 
in the first paragraph, in the second line, ``To prevent a high 
pressure compressor (HPC) disk fracture'' is corrected to read ``To 
prevent a high pressure turbine (HPT) disk fracture.''
    2. On page 51684, in the second column, in the Compliance Section, 
in paragraph (a), in the sixth, seventh, eighth and ninth lines, ``''PW 
SB JT9D-7R4-72-552, Revision 1, dated February 17, 1999 at each 
separation of the HPT disk from the HPT module after the effective date 
of the AD.'' is corrected to read ``PW SB JT9D-7R4-72-553, Revision 1, 
dated February 17, 1999 at each HPT disk piece part accessibility after 
the effective date of this AD.''
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-29824 Filed 11-17-99; 8:45 am]
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