[Federal Register Volume 64, Number 109 (Tuesday, June 8, 1999)]
[Rules and Regulations]
[Pages 30382-30384]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-14447]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket 98-ANE-43-AD; Amendment 39-11188; Ad 99-12-04]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT8D-200 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-200 series turbofan engines, that 
requires revisions to the engine manufacturer's Time Limits Section 
(TLS) of the JT8D-200 Turbofan Engine 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 part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to Pratt & Whitney (PW) JT8D-200 
series turbofan engines was published in the Federal Register on July 
28, 1998 (63 FR 40216). 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 PW JT8D-200 Turbofan Engine Manual, and, 
for air carriers, the approved continuous airworthiness maintenance 
program. The manufacturer of JT8D-200 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.
    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 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.
    One commenter suggests 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 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, FAA 
established the 100 cycle threshold. No consideration for crack growth 
time was given in the choice of this number nor was time-since-new 
(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

[[Page 30383]]

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 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 suggested that the parts requiring focused inspection 
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 states that a ``spot focused'' fluorescent-penetrant 
inspection (FPI) should be performed in the rivet area of the fan hub 
instead of removing rivets, the air seal, and the compressor duct to 
inspect the fan hub. The commenter believes that rivet removal and 
replacement may induce stresses and cause cracks. The FAA does not 
concur. Inspection of the entire fan hub (i.e., bore, all holes, fillet 
radii, rim slot bottom, upper lug surface, pressure face of dovetail 
slots) is needed to detect all possible crack indications. Although few 
cracks have been detected thus far, there is concern that other high 
stress areas (e.g. dovetail slots) may be affected. Furthermore, 
removal of the assembled parts (air seal and compressor duct) will 
provide assurance that liquids for inspection and cleaning will not 
become entrapped in the titanium hub.
    One commenter states that the phrase ``by or related to the cause 
of its removal from the engine'' should be added for clarification to 
paragraph (2)(b) of Inspection Requirements, paragraph A, in the 
Compliance Section. The FAA concurs and the phrase has been added.
    One commenter states that the affected assembly part number (P/N) 
in the Compliance Section, paragraph B, Parts Requiring Inspection 
Table, is in error and should be 5000421-01. The FAA concurs and the P/
N has been revised.
    One commenter states that AD 97-17-04 compliance requirements 
relative to the JT8D Engine Manual, P/N 773128, 72-33-31 Insp-02, 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. The inspection 
requirements of AD 97-17-04 remain intact and are not affected by this 
AD. While the inspection techniques are similar, this AD will require 
inspections at every piece-part opportunity without having to remove 
bushings. AD 97-17-04 requires inspections with bushings removed at 
fixed inspection intervals depending on part serial number.
    One commenter states that an existing alternative method of 
compliance (AMOC) for removal of C1 hub bushings prior to eddy current 
inspection should be allowed for this AD. The FAA does not concur. 
Because this AD does not require the removal of bushings at every 
piece-part opportunity, no AMOC for an alternate bushing removal 
procedure is required.
    One commenter states that the PW JT8D-200 Turbofan Engine Manual 
section reference in the Parts Requiring Inspection table is in error 
and should read 72-33-31. The FAA concurs and the table has been 
revised.
    No comments were received on the economic analysis contained in the 
proposed rule. Based on the analysis, the FAA has determined that the 
annual per engine cost of $240 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 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:

99-12-04  Pratt & Whitney: Amendment 39-11188. Docket 98-ANE-43-AD.

    Applicability Pratt & Whitney (PW) JT8D-209, -217, -217A, -217C, 
and -219 series turbofan engines, installed on but not limited to 
McDonnell Douglas MD80 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

[[Page 30384]]

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, alternation, 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 Limit Section (TLS) of the PW JT8D-200 Engine Manual 
(EM), Part Number 773128, and for air carrier operations revise the 
approved continuous airworthiness maintenance program, by adding the 
following:

``3. 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 is not damaged or 
related to the cause of its removal from the engine.
    (3) The inspections specified in this section do not replace or 
make unnecessary 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.

------------------------------------------------------------------------
             Description                 Section         Inspection
------------------------------------------------------------------------
Hub (Disk), 1st Stage Compressor:
    5000501-01 (Hub detail)..........    72-33-31  -02,-03
    5000421-01 (Hub assembly)........    72-33-31  -02,-03''
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    (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 TLS of the PW JT8D-
200 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 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 airplane to a location where the 
requirements 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. Alternately, 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 alternate 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 
alternate 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 to reflect the 
requirements in the engine manuals.

    (b) 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. 99-14447 Filed 6-7-99; 8:45 am]
BILLING CODE 4910-13-M