[Federal Register: November 15, 2002 (Volume 67, Number 221)]
[Proposed Rules]
[Page 69152-69154]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15no02-14]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NE-27-AD]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-1, -1A, -1B, -7, -
7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a
new airworthiness directive (AD) that is applicable to Pratt & Whitney
JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -
17R, and -17AR turbofan engines. This proposal would require removal
from service of certain part number (P/N) 3rd-4th and 4th-5th stage
compressor rotor spacer assemblies and incorporation of a new tierod
retention configuration. This proposal is prompted by two reports of
uncontained failure of JT8D turbofan engines, caused by turbine rotor
overspeed resulting from first and second stage fan section separation
from the low pressure compressor (LPC). The actions specified by the
proposed AD are intended to prevent first and second stage fan section
separation from the LPC, resulting in turbine rotor overspeed,
uncontained engine failure, and damage to the airplane.
DATES: Comments must be received by January 14, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Regional
Counsel, Attention: Rules Docket No. 2002-NE-27-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday
through Friday, except Federal holidays. Comments may also be sent via
the Internet using the following address: ``9-ane-adcomment@faa.gov''.
Comments sent via the Internet must contain the docket number in the
subject line.
The service information referenced in the proposed rule may be
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108;
telephone (860) 565-8770; fax (860) 565-4503. This information may be
examined, by appointment, at the FAA, New England Region, Office of the
Regional Counsel, 12 New England Executive Park, Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Christopher Spinney, Aerospace
[[Page 69153]]
Engineer, Engine Certification Office, FAA, Engine and Propeller
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299;
telephone (781) 238-7175, 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 action 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 action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2002-NE-27-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRM's
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, New England Region, Office of the Regional Counsel,
Attention: Rules Docket No. 2002-NE-27-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
The FAA has received two reports of turbine rotor overspeed
resulting in uncontained engine failure on JT8D turbofan engines. The
overspeeds resulted from separation of the first and second stage fan
section from the rear stages of the LPC. The separations resulted from
LPC tierod fractures, which were caused by fretting due to spacer-to-
disk snap diameter looseness. The manufacturer has determined that
incorporating a tighter snap diameter fit by installing new design or
modified parts and incorporating increased sleeve-to-tierod clearances
will reduce the number of tierod fractures due to fatigue initiated by
fretting. Installation of the new tierod retention configuration will
reduce the likelihood of a single tierod fracture damaging the
remaining tierods. This condition, if not corrected, could result in a
first and second stage fan section separation from the LPC, uncontained
engine failure, and damage to the airplane.
Manufacturer's Service Information
The FAA has reviewed and approved the technical contents of Pratt &
Whitney Service Bulletin (SB) No. JT8D 6429, dated August 23, 2002,
that describes procedures for incorporating a new tierod retention
configuration. Pratt & Whitney SB's No. 5409, No. SB 5716, and No. SB
No. 5734 are referenced in this proposal because they provide
information on modification of the parts requiring removal to make them
serviceable.
FAA's Determination of an Unsafe Condition and Proposed Actions
Since an unsafe condition has been identified that is likely to
exist or develop on other JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11,
-15, -15A, -17, -17A, -17R, and -17AR turbofan engines of the same type
design that are used on airplanes registered in the United States, the
proposed AD would require at the next accessibility:
[sbull] Removing from service of 3rd-4th stage compressor rotor
spacer assemblies part numbers (P/N's) 479927, 522194, 583385, 656814,
656815, 660649, 660655, 716851, 716853, 716854, 762140, 762145, 762271,
762468, 789554, and 789752 and replacement with a serviceable part.
[sbull] Removing from service of 4th-5th stage compressor rotor
spacer assemblies P/N's 479929, 522196, 656816, 656817, 660650, 660656,
716855, 762138, and 762142 and replacement with a serviceable part.
[sbull] Removing from service 4th-5th stage compressor rotor spacer
assemblies P/N 628778 that do not incorporate SB 5409 and replacement
with a serviceable part.
[sbull] Incorporating a new tierod retention configuration in
accordance with the service bulletin described previously.
Economic Analysis
There are approximately 4,180 engines of the affected design in the
worldwide fleet. The FAA estimates that 1,800 engines installed on
aircraft of U.S. registry would be affected by this proposed AD. The
FAA also estimates that it would take approximately 41 work hours per
engine to accomplish the proposed actions, and that the average labor
rate is $60 per work hour. Required parts would cost approximately
$3,600 per engine. Based on these figures, the total cost of the
proposed AD to U.S. operators is estimated to be $10,908,000.
Regulatory Analysis
This proposed rule does not have federalism implications, as
defined in Executive Order 13132, because it would not have a
substantial direct effect 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.
Accordingly, the FAA has not consulted with state authorities prior to
publication of this proposed rule.
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. 2002-NE-27-AD.
Applicability: This airworthiness directive (AD) is applicable
to Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -
15, -15A, -17, -17A, -17R, and -17AR turbofan engines. These engines
are installed on, but
[[Page 69154]]
not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9
series airplanes.
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 (d) 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: Compliance with this AD is required as indicated,
unless already done.
To prevent first and second stage fan section separation from
the low pressure compressor (LPC), resulting in turbine rotor
overspeed, uncontained engine failure, and damage to the airplane,
do the following:
(a) At the next accessibility, do the following:
(1) Remove from service 3rd-4th stage compressor rotor spacer
assemblies part numbers (P/N's) 479927, 522194, 583385, 656814,
656815, 660649, 660655, 716851, 716853, 716854, 762140, 762145,
762271, 762468, 789554, and 789752 and replace with a serviceable
part.
(2) Remove from service 4th-5th stage compressor rotor spacer
assemblies P/N's 479929, 522196, 656816, 656817, 660650, 660656,
716855, 762138, and 762142 and replace with a serviceable part.
(3) Remove from service 4th-5th stage compressor rotor spacer
assemblies P/N's 628778 that do not incorporate SB 5409, and replace
with a serviceable part.
Note 2: Information on modifying parts listed in paragraphs
(a)(1), (a)(2), and (a)(3) of this AD into servicable parts is
contained in Pratt & Whitney (PW) SB's No. 5409, No. SB 5716, and
No. SB No. 5734.
(4) Incorporate new tierods, retaining rings, 2nd stage
compressor air seal or spacer assembly, flat washers and tierod nuts
in the LPC in accordance with the Accomplishment Instructions of PW
SB JT8D 6429, dated August 23, 2002.
(b) After the effective date of this AD, do not install 3rd-4th
or 4th-5th stage compressor rotor spacer assemblies listed in
paragraphs (a)(1), (a)(2), and (a)(3) of this AD into any engine.
Definition
(c) For the purpose of this AD, accessibility means removal of
the LPC from the engine and disassembly that provides piece-part
exposure to the parts listed in paragraph (a) of this AD.
Alternative Methods of Compliance
(d) 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 (ECO).
Operators must submit their request through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, ECO.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the ECO.
Special Flight Permits
(e) Special flight permits may be issued in accordance with
Sec. Sec. 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be done.
Issued in Burlington, Massachusetts, on November 8, 2002.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 02-29002 Filed 11-14-02; 8:45 am]
BILLING CODE 4910-13-P