[Federal Register Volume 64, Number 109 (Tuesday, June 8, 1999)]
[Rules and Regulations]
[Pages 30379-30382]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-14446]
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Rules and Regulations
Federal Register
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This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
to and codified in the Code of Federal Regulations, which is published
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Federal Register / Vol. 64, No. 109 / Tuesday, June 8, 1999 / Rules
and Regulations
[[Page 30379]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-48-AD; Amendment 39-11187; AD 99-12-03]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-1, -1A, -1B, -7, -
7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Series
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A,
-11, -15, -15A, -17, -17A, -17R, and -17AR series turbofan engines,
that requires revisions to the engine manufacturer's Time Limits
Section (TLS) of the JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15,
-15A, -17, -17A, -17R, and -17AR Turbofan Engines Manual to include
enhanced inspection of selected critical life-limited parts at each
piece-part exposure. This amendment will also require an air carrier's
approved continuous airworthiness maintenance program to incorporate
these inspection procedures. This amendment is prompted by a Federal
Aviation Administration (FAA) study of in-service events involving
uncontained failures of critical rotating engine parts that indicated
the need for improved inspections. The improved inspections are needed
to identify those critical rotating parts with conditions that if
allowed to continue in service, could result in uncontained failures.
The actions specified by this AD are intended to prevent critical life-
limited rotating engine part failure, which could result in an
uncontained engine failure and damage to the airplane.
DATES: Effective July 8, 1999.
FOR FURTHER INFORMATION CONTACT: Christopher Spinney, Aerospace
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: A proposal to amend pat 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to Pratt & Whitney (PW) PW JT8D-1, -
1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -
17AR series turbofan engines was published in the Federal Register on
July 28, 1998 (64 FR 40226). That action proposed to require, within
the next 30 days after the effective date of this AD, revisions to the
Time Limits Section (TLS) of the JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -
9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Turbofan Engines Manual,
and, for air carriers, the approved continuous airworthiness
maintenance program. The manufacturer of JT8D series turbofan engines
has provided the Federal Aviation Administration (FAA) with a detailed
proposal that identifies and prioritizes the critical life-limited
rotating engine parts with the highest potential to hazard the airplane
in the event of failure, along with instructions for enhanced, focused
inspection methods. The enhanced inspections resulting from this AD
will be conducted at piece-part opportunity, as defined in this AD,
rather than specific inspection intervals.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the measures outlined in the proposed rule.
Several commenters ask that the FAA clarify the record keeping
aspects of the mandatory inspections resulting from the required
changes to the Original Equipment Manufacturer's manual and operator's
continuous airworthiness maintenance program. Two commenters believe
that paragraph (e) of the proposed rule is unclear and suggests that
certain preamble language be added to it for clarity and that it be
revised by eliminating the word ``or'' from the first sentence and
beginning a second sentence with ``In lieu of the record. * * *'' Two
commenters state that the AD should be revised to clearly specify which
types of maintenance records must be retained (i.e., inspection
results, defect reporting requirements, date of performed maintenance,
signature of the person performing the maintenance). These commenters
believe that these revisions are necessary in order to avoid potential
differences in interpretation between the air carriers and the FAA.
And, one commenter states that the AD should clarify that there is no
need for a special form to comply with the AD record keeping
requirements. The FAA concurs in part. Generally, record keeping
requirements are addressed in other regulations and this AD does not
change those requirements. In order to allow flexibility from operator
to operator, the FAA does not concur that the AD itself specify the
precise nature of the records that will result from the required
changes to the manufacturer's manual and operator's maintenance
program. The FAA has, however, revised Paragraph (e) of this AD to
clarify record keeping aspects of the new mandatory inspections.
Several commenters suggested that the tables used to specify those
parts requiring mandatory inspections be given standardized formats and
that the parts be identified by ``all'' rather than by specific part
number. The FAA does not concur. The FAA intentionally allowed each
manufacturer to choose a format that fits their products manual.
Identification of parts requiring mandatory inspections has been
accomplished by either part number identification or use of the word
``all''. Part number identification was chosen by some manufacturers
since the processes and procedures needed to conduct new inspections
were not yet developed for all parts of a certain type, i.e., fan
disks/hubs. The FAA wants the manufacturers to have flexibility in
managing how their manuals are structured within Air Transport
Association code requirement.
One commenter requests that the FAA link the conduct of mandatory
inspections on whether the subject part was removed from an engine
while the engine was installed on the airplane or while the engine was
removed and in an overhaul shop. The commenter wishes to exempt those
parts that are removed
[[Page 30380]]
from installed engines from the focused inspections. The FAA does not
concur. The mandatory inspections are based on a single trigger. The
trigger is a part being completely disassembled using the engine manual
instructions (piece-part opportunity), and is not dependent on whether
an engine is installed on the airplane. This final rule mandates that
the definition of piece-part opportunity appears in the mandatory
section of each affected engine manual. This final rule further
mandates that an operator's continuous airworthiness maintenance
program be modified to capture those engine manual changes.
Several commenters suggest that the 100 cycle in service inspection
waiver provided in the piece-part opportunity definition was too low
and could not be justified from a crack growth standpoint or that
language be added to the requirements adding a minimum cycles in
service threshold after which mandatory inspections would be
applicable. The FAA does not concur. The 100 cycle waiver is intended
to allow short term alleviation from mandatory inspections for a part
recently inspected in accordance with the engine manual requirements.
It was specifically aimed at disassembled parts removed from an engine
following a test cell reject or some other occurrence that caused the
parts removal shortly after successful completion of mandatory
inspections. Waiver of mandatory inspections in this instance also
requires that the part was not damaged or related to the cause for its
removal from the engine. Mandatory inspections are also required on
fully disassembled parts regardless of time-since-new (TSN). The FAA is
aware that cracks can be missed during part inspections and that each
time a part is processed through an inspection line, the probability of
detecting a crack is increased. Commonly used on-condition maintenance
plans make it likely that a given part could be returned to service for
thousands of cycles without the need for additional focused inspection.
Recognizing two opposing aspects of part removal and inspection, i.e.,
a need for a brief exemption period following conduct of mandatory
inspections and the benefits of increased frequency of inspection, the
FAA established the 100 cycle threshold. No consideration for crack
growth time was given in the choice of this number nor was TSN
considered as a possible reason for exempting parts from focused
inspection. It is based strictly on keeping the frequency of mandatory
inspection as high as practical and therefore increasing the
probability of crack detection while providing a brief window of
exemption from mandatory inspection if certain conditions are met.
Therefore, the 100 cycle limit will remain in the compliance section of
the AD and no exemption will be allowed for low TSN parts.
One commenter states that the mandatory manual chapters were
modified to require new inspection requirements prior to issuance of
the final rule AD and that the FAA should provide written notification
to Flight Standards Offices that the inspections proposed in the
proposed rule are not mandatory until the establishment of an
effectivity date in a published final rule AD. Some confusion between
Operators, Manufacturers and Principal Maintenance Inspectors was
created when the mandatory manual sections were modified prior to the
release of a final rule AD. The FAA concurs in part. The manuals were
modified prior to issuance of the final rule to minimize implementation
delays from lengthy original equipment manufacturer EM revision cycles.
FAA will attempt a higher level of coordination of timing the manual
revisions so that the revisions follow final rule ADs in the future.
Such a notice, however, is beyond the scope of this AD and may well
cause additional confusion rather than clarify the present situation.
One commenter states that the proposed rule should be revised to
allow use of Foerster Defectometer eddy current instrument for Insp-02,
as it is currently approved for use in Insp-03. 72-33-31 Insp-02
currently only requires that a certain probe and sensitivity standard
be used to accomplish the inspection. The eddy current instrument to be
used for 72-33-31 Insp-02 is specified in the PW Standard Practices
manual, 70-37-02. The requirement for the Eddy Current signal
instrument is that it be equivalent in performance to a Foerster
Defectometer Model H 2.835. An eddy current signal instrument needs to
be deemed equivalent to the Defectometer Model H 2.835 in order to be
acceptable for 72-33-31 Insp-02. Therefore no changes are necessary to
the AD.
One commenter states that AD 95-10-10 compliance requirements
relative to the JT8D Engine Manual, P/N 481672, 72-33-31 Insp-03, as
specified in the proposed rule should be clarified. The FAA does not
concur that a change needs to be made to the AD, but offers the
following explanation for clarification purposes. AD 95-10-10 is
applicable to certain serial number fan hubs installed on JT8D engines.
While the inspections required are similar to this AD, 95-10-10 also
contains other overhaul requirements and very specific inspection
intervals. This AD is intended to inspect all JT8D first and second
stage compressor disks at every piece-part opportunity. The
requirements of both ADs must be met regardless of the overlapping
requirements.
One commenter states that ``XX'' in the inspection column of the
Table in the Compliance Section under paragraph B needs clarification.
The FAA concurs. At the time the proposed rule was published Insp-04
was not available. Chapter 5 of the Engine Manual was revised August 1,
1998, to include Insp-04. Inspection -XX has been changed to inspection
number -04 for first stage compressor disks.
One commenter states that stage 2 compressor disks in the Table
should be repositioned for clarity and Insp-02 should be included. The
FAA concurs. Inspection number -XX has been replaced with inspection
number -02 for second stage compressor disks.
One commenter states that the reference to Chapter 05-11-00 in Note
3 of the Compliance Section is incorrect. The FAA concurs. This final
rule has been revised to reference Chapter 05-10-00.
No comments were received on the economic analysis contained in the
proposed rule. Based on that analysis, the FAA has determined that the
annual per engine cost of $420 does not create a significant economic
impact on small entities.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic
[[Page 30381]]
impact, positive or negative, on a substantial number of small entities
under the criteria of the Regulatory Flexibility Act. A final
evaluation has been prepared for this action and it is contained in the
Rules Docket. A copy of it may be obtained from 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.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 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.
99-12-03 Pratt & Whitney: Amendment 39-11187, Docket 98-ANE-48-AD.
Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -
7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series
turbofan engines, installed on but 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 (c) 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 critical life-limited rotating engine part failure,
which could result in an uncontained engine failure and damage to
the airplane, accomplish the following:
(a) Within the next 30 days after the effective date of this AD,
revise the Time Limits Section (TLS) of the Pratt & Whitney (PW)
JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A,
-17R, and -17AR Turbofan Engines Engine Manual (EM), part number
481672, and for air carrier operations revise the approved
continuous airworthiness maintenance program, by adding the
following:
``5. Critical Life Limited Part Inspection
A. Inspection Requirements:
(1) This section has the definitions for individual engine piece
parts and the inspection procedures which are necessary when these
parts are removed from the engine.
(2) It is necessary to do the inspection procedures of the piece
parts in paragraph B when:
(a) The part is removed from the engine and disassembled to the
level specified in paragraph B and
(b) The part has accumulated more than 100 cycles since the last
piece part inspection, provided that the part was not damaged or
related to the cause for its removal from the engine.
(3) The inspections specified in this paragraph do not replace
or make not necessary other recommended inspections for these parts
or other parts.
B. Parts Requiring Inspection
Note: Piece part is defined as any of the listed parts with all
the blades removed.
------------------------------------------------------------------------
Engine manual description Section Inspection
------------------------------------------------------------------------
Hub (Disk), 1st Stage Compressor:
491201......................... 72-33-31 -04,-02,-03
496501......................... 72-33-31 -04,-02,-03
504101......................... 72-33-31 -04,-02,-03
515201......................... 72-33-31 -04,-02,-03
594301......................... 72-33-31 -04,-02,-03
640501......................... 72-33-31 -04,-02,-03
640601......................... 72-33-31 -04,-02,-03
743301......................... 72-33-31 -04,-02,-03
749701......................... 72-33-31 -04,-02,-03
749801......................... 72-33-31 -04,-02,-03
750001......................... 72-33-31 -04,-02,-03
750101......................... 72-33-31 -04,-02,-03
778901......................... 72-33-31 -04,-02,-03
791401......................... 72-33-31 -04,-02,-03
791501......................... 72-33-31 -04,-02,-03
791601......................... 72-33-31 -04,-02,-03
791701......................... 72-33-31 -04,-02,-03
791801......................... 72-33-31 -04,-02,-03
806001......................... 72-33-31 -04,-02,-03
806101......................... 72-33-31 -04,-02,-03
817401......................... 72-33-31 -04,-02,-03
844401......................... 72-33-31 -04,-02,-03
845401......................... 72-33-31 -04,-02,-03
848001......................... 72-33-31 -04,-02,-03
848101......................... 72-33-31 -04,-02,-03
Disk, 2nd Stage Compressor:
482502......................... 72-33-33 -02
502502......................... 72-33-33 -02
520602......................... 72-33-33 -02
570302......................... 72-33-33 -02
570402......................... 72-33-33 -02
678202......................... 72-33-33 -02
730202......................... 72-33-33 -02
730302......................... 72-33-33 -02
730402......................... 72-33-33 -02
740502......................... 72-33-33 -02
745702......................... 72-33-33 -02
745902......................... 72-33-33 -02
746002......................... 72-33-33 -02
746802......................... 72-33-33 -02
760402......................... 72-33-33 -02
760502......................... 72-33-33 -02
807502......................... 72-33-33 -02
5002402-01..................... 72-33-33 -02
790832 (Disk assembly)......... 72-33-33 -02
------------------------------------------------------------------------
(b) Except as provided in paragraph (c) of this AD, and
notwithstanding contrary provisions in section 43.16 of the Federal
Aviation Regulations (14 CFR 43.16), these mandatory inspections
shall be performed only in accordance with the Time Limits section
in the EM.
(c) 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 Engine Certification Office. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector (PMI), who may add comments and then send it
to the 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.
(d) Special flight permits may be used in accordance with
Sec. 21.197 and Sec. 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirement of this AD can be accomplished.
(e) FAA-certificated air carriers that have an approved
continuous airworthiness maintenance program in accordance with the
record keeping requirement of Sec. 121.369(c) of the Federal
Aviation Regulations [14 CFR 121.369(c)] of this chapter must
maintain records of the mandatory inspections that result from
revising the Time Limits section of the Instructions for Continuous
Airworthiness (ICA) and the air carrier's continuous airworthiness
program. Alternatively, certificated air carriers may establish an
approved system of record retention that provides a method for
preservation and retrieval of the maintenance records that include
the inspections resulting from this AD, and include the policy and
procedures for implementing this alternative method in the air
carrier's maintenance manual required by Sec. 121.369(c) of the
Federal Aviation Regulations [14 CFR 121.369(c)]; however, the
alternative system must be accepted by the appropriate PMI and
require the maintenance records be maintained either indefinitely or
until the work is repeated. Records of the piece-part inspections
are not required under Sec. 121.380 (a)(2)(vi) of the Federal
Aviation Regulations [14 CFR 121.380(a)(2)(vi)]. All other Operators
must maintain the records of mandatory inspections required by the
applicable regulations governing their operations.
Note 3: The requirements of this AD have been met when the
engine manual changes are made and air carriers have modified their
continuous airworthiness maintenance plans
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to reflect the requirements in the engine manuals.
(f) This amendment becomes effective on July 8, 1999.
Issued in Burlington, Massachusetts, on June 1, 1999.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-14446 Filed 6-7-99; 8:45 am]
BILLING CODE 4910-13-M