[Federal Register Volume 63, Number 2 (Monday, January 5, 1998)]
[Proposed Rules]
[Pages 167-169]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-69]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 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.
 
 ========================================================================
 

  Federal Register / Vol. 63, No. 2 / Monday, January 5, 1998 / 
Proposed Rules  

[[Page 167]]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-69]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

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

-----------------------------------------------------------------------

SUMMARY: This notice revises an earlier proposed airworthiness 
directive (AD), applicable to Pratt & Whitney JT9D series turbofan 
engines, that would have required initial and repetitive eddy current 
inspections (ECI) of 14th and 15th stage high pressure compressor (HPC) 
disks for cracks, and removal of cracked disks and replacement with 
serviceable parts. That proposal was prompted by reports of disk bore 
cracks found during shop inspections on both the 14th and 15th stage 
HPC disks. This action revises the proposed rule by extending the 
repetitive inspection interval and changing the definition of a shop 
visit. The actions specified by this proposed AD are intended to 
prevent 14th and 15th stage HPC disk rupture, which could result in an 
uncontained engine failure and damage to the aircraft.

DATES: Comments must be received by March 6, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-ANE-69, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[email protected]''. Comments sent via the Internet must contain 
the docket number in the subject line. 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, Publications Department, Supervisor 
Technical Publications Distribution, M/S 132-30, 400 Main St., East 
Hartford, CT 06108; telephone (860) 565-7700. This information may be 
examined at the FAA, New England Region, Office of the Assistant Chief 
Counsel, 12 New England Executive Park, Burlington, MA.

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:

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 95-ANE-69.'' 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. 95-ANE-69, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, -7Q3, and JT9D-7R4 
series turbofan engines, was published as a notice of proposed 
rulemaking (NPRM) in the Federal Register on May 6, 1996 (61 FR 20192). 
That NPRM would have required initial and repetitive eddy current 
inspections (ECI) of 14th and 15th high pressure compressor (HPC) disks 
for cracks in accordance with Non-Destructive Inspection Procedure No. 
858 (NDIP-858), dated November 7, 1995, attached to PW Alert Service 
Bulletin (ASB) No. JT9D-7R4-A72-524, dated December 13, 1995, and ASB 
No. A6232, Revision 1, dated January 11, 1996. That action also 
proposed to require the removal of cracked disks and replacement with 
serviceable parts. That NPRM was prompted by reports of disk bore 
cracks found during shop inspections on both the 14th and 15th stage 
HPC disks. That condition, if not corrected, could result in 14th and 
15th stage HPC disk rupture, which could result in an uncontained 
engine failure and damage to the aircraft.
    Since the issuance of that NPRM, the FAA received several comments 
that required changing the compliance section.
    Several commenters state that the proposed rule's definition for 
shop visit (separation of ``N'' flange) would cause hardship, since 
operators have no records for tracking ``N'' flange separation. The 
commenters propose to change the definition of shop visit to occur when 
the low pressure turbine (LPT) is inspected as a module. One of the 
commenters further states that this inspection is done whenever the LPT 
module is separated from the engine at the ``N'' flange. The FAA 
concurs with this change, since the proposed definition facilitates the 
FAA's intent. Therefore, the ``Shop Visit'' definition

[[Page 168]]

in this final rule has been changed accordingly.
    Another commenter disagrees with the FAA's statement that the 
required action would take place during regularly scheduled 
maintenance. The FAA agrees with the commenter that this inspection may 
not always coincide with scheduled maintenance activity, since the shop 
visit rates can vary between operators. However, the FAA's intent is to 
facilitate this required inspection during a shop visit to the extent 
possible, while maintaining the required level of safety.
    The same commenter proposes that the inspections be required at 
next shop visit, instead of using cycles since last shop visit. The FAA 
disagrees. Shop visit intervals vary among different operators and may 
exceed the inspection intervals established to maintain an acceptable 
level of safety.
    Another commenter states that the cyclic drawdown should be 
extended from 1,000 cycles to 1,500 cycles in order to prevent possible 
premature engine removals. The commenter does not provide any 
additional data/actions that would assure an equivalent level of 
safety. The FAA disagrees, since the proposed additional cycles of 
operation without inspections would result in a reduced level of 
safety. Therefore, the 1,000 cycle in service (CIS) inspection interval 
remains as proposed.
    The FAA conducted an additional review of the proposed inspection 
intervals and concluded that the inspection requirements of paragraph 
(c)(1)(iv) as published are unnecessarily restrictive. Therefore, the 
inspection interval of 3,000 cycles since new is extended to 5,000 
cycles since new, in order to make it consistent with the inspection 
requirement of the preceding paragraph.
    Since this change expands the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.
    There are approximately 1,100 engines of the affected design in the 
worldwide fleet. The FAA estimates that 170 engines would be affected 
by this proposed AD. The FAA anticipates that the majority of the 
required initial and repetitive eddy current inspections would take 
place during regularly scheduled maintenance visits, but it would take 
3 work hours per engine per inspection, and the average labor rate is 
$60 per work hour. Based on these figures, the total cost impact of the 
proposed AD per engine is estimated to be $30,600. Based on these 
estimates, the total cost of the proposed AD would be $5,202,000.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

Pratt & Whitney: Docket No. 95-ANE-69.

    Applicability: Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, -
7Q3, and JT9D-7R4 series turbofan engines, with the following 14th 
and 15th stage high pressure compressor (HPC) disks installed: Part 
Numbers (P/N's) 5000814-01, 790014, 789914, 790114, 5000815-01, 
5000815-021, 704315, 704315-001, 786215, 786215-001, 704314, 789814, 
and 790214. These engines are installed on but not limited to Airbus 
A300 and A310 series aircraft, Boeing 747 and 767 series aircraft, 
and McDonnell Douglas DC-10 series aircraft.

    Note 1: This airworthiness directive (AD) applies to each engine 
identified in the preceding applicability provision, regardless of 
whether it has been modified, altered, or repaired in the area 
subject to the requirements of this AD. For engines that have been 
modified, altered, or repaired so that the performance of the 
requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (f) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent 14th and 15th stage HPC disk rupture, which could 
result in an uncontained engine failure and damage to the aircraft, 
accomplish the following:
    (a) Inspect 14th stage HPC disks, P/N 5000814-01, in accordance 
with Non-Destructive Inspection Procedure No. 858 (NDIP-858), dated 
November 7, 1995, attached to PW Alert Service Bulletin (ASB) No. 
JT9D-7R4-A72-524, dated December 13, 1995, as follows:
    (1) Perform an initial eddy current inspection (ECI) for cracks 
as follows:
    (i) For disks with 7,000 or more cycles since new (CSN), and 
3,000 or more cycles in service (CIS) since last shop visit, on the 
effective date of this AD, inspect within the next 1,000 CIS after 
the effective date of this AD, or at the next shop visit, whichever 
occurs first.
    (ii) For disks with 7,000 or more CSN, and less than 3,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 4,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with less than 7,000 CSN on the effective date 
of this AD, inspect at the next shop visit after the effective date 
of this AD, but before exceeding 4,000 CIS since last shop visit, or 
8,000 CSN, whichever occurs later.
    (iv) For uninstalled disks on or after the effective date of 
this AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 4,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (b) Inspect 14th stage HPC disks, P/N's 790014, 789914, 790114, 
and 15th stage HPC disks, P/N's 5000815-01, 5000815-021, 704315, 
704315-001, 786215, and 786215-001, in accordance with NDIP-858, 
dated November 7, 1995, attached to PW ASB No. JT9D-7R4-A72-524, 
dated December 13, 1995, or PW ASB No. A6232, Revision 1, dated 
January 11, 1996, as applicable, as follows:
    (1) Perform an initial ECI for cracks as follows:
    (i) For disks with 6,500 or more CSN, and 3,000 or more CIS 
since last shop visit, on the effective date of this AD, inspect 
within the next 1,000 CIS after the effective date of this AD, or at 
the next shop visit, whichever occurs first.

[[Page 169]]

    (ii) For disks with 6,500 or more CSN, and less than 3,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 4,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with less than 6,500 CSN on the effective date 
of this AD, inspect at the next shop visit after the effective date 
of this AD, but before exceeding 4,000 CIS since last shop visit, or 
7,500 CSN, whichever occurs later.
    (iv) For uninstalled disks on or after the effective date of 
this AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 4,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (c) Inspect 14th stage HPC disks, P/N's 704314, 789814, and 
790214, in accordance with NDIP-858, dated November 7, 1995, 
attached to PW ASB No. A6232, Revision 1, dated January 11, 1996, as 
follows:
    (1) Perform an initial ECI for cracks as follows:
    (i) For disks with 2,000 or more CSN, and 2,000 or more CIS 
since last shop visit, on the effective date of this AD, inspect 
within the next 1,000 CIS after the effective date of this AD, or at 
the next shop visit, whichever occurs first.
    (ii) For disks with 2,000 or more CSN, and less than 2,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 3,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with 2,000 or more CSN, and no previous shop 
visits, inspect within 3,000 CIS after the effective date of this 
AD, or at the next shop visit, whichever occurs first.
    (iv) For disks with less than 2,000 CSN on the effective date of 
this AD, inspect at the next shop visit after the effective date of 
this AD, but before exceeding 5,000 CSN.
    (iv) For uninstalled disks on or after the effective date of 
this AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 3,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (d) Within 30 days of inspection, report inspection results on 
the form labeled ``14th and 15th Stage HPC Disk Inspection Report,'' 
to Pratt & Whitney Customer Technical Support. The fax number is 
listed on that form which is attached to PW ASB No. JT9D-7R4-A72-
524, dated December 13, 1995. Reporting requirements have been 
approved by the Office of Management and Budget and assigned OMB 
control number 2120-0056.
    (e) For the purpose of this AD, a shop visit is defined as a low 
pressure turbine module removal from an uninstalled engine.
    (f) 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. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (g) Special flight permits may be issued in accordance with 
sections 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 23, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 98-69 Filed 1-2-98; 8:45 am]
BILLING CODE 4910-13-U