[Federal Register Volume 59, Number 242 (Monday, December 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31061]


[[Page Unknown]]

[Federal Register: December 19, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 81-ANE-03]

 

Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This notice revises an earlier proposed airworthiness 
directive (AD), applicable to Pratt & Whitney JT8D series turbofan 
engines, that would have amended an existing AD by eliminating an 
optional on-wing ultrasonic inspection of the 10th stage high pressure 
compressor (HPC) disk, and by including an engine model inadvertently 
omitted. That proposal was prompted by a report of an uncontained 
failure of a 10th stage HPC disk that was previously inspected using 
the on-wing ultrasonic inspection method. This action revises the 
proposed rule by removing the reference to the inadvertently omitted 
engine model, as the FAA has remedied this discrepancy in an earlier 
correction to the AD, and changing the proposed action from amending AD 
81-08-02 R2 to superseding that AD. The actions specified by this 
proposed AD are intended to prevent uncontained fractures of 9th 
through 12th stage HPC disks and engine failure.

DATES: Comments must be received by February 17, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration, New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 81-ANE-03, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Pratt & Whitney, Technical Publications Department, M/S 
132-30, 400 Main Street, East Hartford, Connecticut, 06108. This 
information may be examined at the FAA, New England Region, Office of 
Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Mark A. Rumizen, Aerospace Engineer 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7137; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 81-ANE-03.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 81-ANE-03, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On February 7, 1984, the Federal Aviation Administration (FAA) 
issued airworthiness directive (AD) 81-08-02 R2, Amendment No. 39-4817 
(49 FR 7361; February 29, 1984), to require initial and repetitive 
inspections of 9th through 12th stage high pressure compressor (HPC) 
disks at the tierod holes in Pratt & Whitney (PW) JT8D series turbofan 
engines. That action was prompted by cracks in the tierod holes in HPC 
disks that resulted in engine failures. That condition, if not 
corrected, can result in uncontained fractures of 9th through 12th 
stage HPC disks and engine failure.
    On August 30, 1984, the FAA issued a correction to AD 81-08-02 R2, 
Amendment 39-4817 (49 FR 35618; September 11, 1984), to include an 
engine model that had been inadvertently omitted from the AD.
    Since issuance of AD 81-08-02 R2, the FAA received a report of an 
uncontained fracture of a 10th stage HPC disk. This disk had been 
subjected to three previous on-wing ultrasonic inspections prior to 
fracture. This method has since been determined as inadequate for 
detecting tierod hole cracking.
    On May 8, 1989, the FAA issued an NPRM that was published in the 
Federal Register (54 FR 22306; May 23, 1989), that would have amended 
the existing AD by eliminating the optional on-wing ultrasonic 
inspection of the 10th stage HPC disk, and by including an engine model 
inadvertently omitted.
    Since the issuance of that NPRM, the FAA has determined that the 
reference to the inadvertently omitted engine model was unnecessary, as 
the FAA had remedied this discrepancy in the August 30, 1984, 
correction. Also, the FAA now utilizes a revised format that supersedes 
existing AD's by publishing a complete document rather than only 
amending applicable paragraphs of the compliance section. This 
document, therefore, reprints the corrected AD compliance section text 
in its entirety for clarity.
    Since the FAA has changed the format of the proposed rule, the FAA 
has determined that it is desirable to reopen the comment period to 
provide additional opportunity for public comment.
    There are approximately 200 engines which would be affected by this 
AD, and the FAA has determined that eliminating the optional on-wing 
ultrasonic inspection would have negligible economic impact, since most 
operators use uninstalled tenth stage disk inspections.
    The regulations proposed herein would not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13   [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. 81-ANE-03.

    Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -7, -7A, -7B, -
9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines 
installed on but not limited to Boeing 727 series and 737 series, 
and McDonnell Douglas DC-9 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously in accordance with PW Alert Service Bulletin (ASB) No. 
4723, Revision 9, dated July 13, 1983; Revision 10, dated September 
15, 1986; or Revision 11, dated October 30, 1987. All inspections 
subsequent to the effective date of this airworthiness directive 
(AD) must be accomplished in accordance with the methods and 
intervals identified in PW ASB No. 4723, Revision 12, dated March 8, 
1990, except as is specified in paragraph (d) of this AD.
    To prevent uncontained fractures of 9th through 12th stage high 
pressure compressor (HPC) disks and engine failure, accomplish the 
following:
    (a) Initially inspect 9th through 12th stage HPC disks at the 
tierod holes in accordance with PW ASB No. 4273, Revision 12, dated 
March 8, 1990.
    (b) Thereafter, inspect 9th through 12th stage HPC disks at the 
tierod holes in accordance with Tables I through V and Table VIII of 
PW ASB No. 4723, Revision 12, dated March 8, 1990. Disks initially 
inspected prior to the first inspection limit must be reinspected 
before reaching the specified reinspection interval, or before 
reaching the first inspection limit, whichever is later. In no case 
shall the established life limits of the disks be exceeded.
    (c) Remove cracked disks from service prior to further flight, 
and replace with a serviceable part. Disks may be returned to 
service if repaired in accordance with Paragraph 7 of PW ASB No. 
4723, Revision 12, dated March 8, 1990.
    (d) For 10th stage HPC disks that were last inspected in 
accordance with the on-wing ultrasonic inspection procedure 
specified in AD 81-08-02 R2 prior to the effective date of this AD, 
inspect as follows:
    (1) Perform a magnetic particle inspection or eddy current 
inspection in accordance with the procedure defined in Paragraph 6 
and Appendix B of PW ASB No. 4723, Revision 12, dated March 8, 1990, 
no later than 750 cycles in service (CIS) since the last on-wing 
inspection.
    (2) Accomplish all subsequent inspections in accordance with the 
methods and intervals specified in PW ASB No. 4723, Revision 12, 
dated March 8, 1990.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (f) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on December 9, 1994.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 94-31061 Filed 12-16-94; 8:45 am]
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