[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Rules and Regulations]
[Pages 4902-4904]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1703]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-ANE-33; Amendment 39-9896; AD 97-02-11]
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 (PW) JT8D-200 series turbofan engines, 
that requires, for front compressor front hubs (fan hubs), cleaning; 
initial and repetitive eddy current (ECI) and fluorescent penetrant 
inspections (FPI) of tierod and counterweight holes for cracks; removal 
of bushings; the cleaning and ECI and FPI of bushed holes for cracks; 
and, if necessary, replacement with serviceable parts. In addition, 
this AD requires reporting the findings of cracked fan hubs. This 
amendment is prompted by a report of an uncontained failure of a fan 
hub. The actions specified by this AD are intended to prevent fan hub 
failure due to tierod, counterweight, or bushed hole cracking, which 
could result in an uncontained engine failure and damage to the 
aircraft.

DATES: Effective March 5, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 5, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-6600, fax (860) 565-4503. This information may be 
examined at the Federal Aviation Administration (FAA), New England 
Region, Office of the Assistant Chief Counsel, 12 New England Executive 
Park, Burlington, MA; or at the Office of the Federal Register, 800 
North Capitol Street, NW., Suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-
7134, fax (617) 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 
October 4, 1996 (61 FR 51847). That action proposed to require 
cleaning, initial and repetitive eddy current inspections (ECI) and 
fluorescent penetrant inspections (FPI) for cracks of tierod and 
counterweight holes; removing bushings; initial and repetitive ECI and 
FPI of bushed holes for cracks; and, if necessary, replacing with 
serviceable parts. The compliance requirements allow selection of 
inspection schedules depending on fan hub S/Ns listed in PW Alert 
Service Bulletin (ASB) No. A6272, dated September 24, 1996, and 
includes an inspection schedule for those fan hubs whose S/Ns are not 
listed in the ASB. In addition, the proposed AD requires reporting the 
number of initial inspections and the findings of cracked fan hubs.
    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 states that the Notice of Proposed Rulemaking (NPRM) 
as written was confusing and subject to interpretation, and offered a 
number of editorial suggestions. The FAA reviewed the suggestions and 
concurs in part with the changes.
    The commenter states that the applicability should be expressed to 
the lowest practical level by including the phrase ``front compressor 
front hub (fan hub)'' and its corresponding part number in the 
applicability statement. The FAA concurs. The applicability section in 
this final has been revised to read ``* * * engines with front 
compressor front hub (fan hub) Part Number 5000501-01 installed''.
    The commenter states that a stronger statement regarding the 
initial inspections for fan hubs with less than 4,000 cycles since new 
(CSN) was

[[Page 4903]]

needed. The commenter suggests adding the intent of the first note on 
page 8 of PW ASB No. A6272, dated September 24, 1996, which requires 
inspection after the fan hub has accumulated more than 4,000 cycles in 
service. This change would eliminate the need for paragraph (a) of the 
proposed rule. The FAA concurs. The structure of the compliance section 
in this final rule has been modified to include the initial 4,000 CSN 
inspection requirement in the beginning of each of two compliance 
paragraphs. Paragraph (a) of this final rule will cover coolant channel 
drilled (CCD) fan hubs identified by S/N in the SB, and paragraph (b) 
for inspection of all other affected fan hubs. For each population of 
hubs, the initial inspection must not be completed until the fan hub 
has accumulated more than 4,000 CSN.
    The commenter states that paragraph (c) of the NPRM is vague and 
should specify what is to be reported. The FAA concurs and has added 
the requirement of reporting in accordance with Accomplishment 
Instructions, Paragraph F, of Attachment 1 to PW ASB No. A6272, dated 
September 24, 1996, to this final rule.
    The commenter states that paragraph (a) and Table 1 of the NPRM do 
not clearly indicate that the operator is to choose one of the three 
options in Table 1 and stick with the corresponding reinspection 
interval. The commenter suggests adding ``or'' after options 1 and 2 in 
Table 1 and adding a note to require that the operator follow the 
initial and repetitive requirements of the option chosen. The FAA 
concurs in part. The ``or'' has been added as suggested. The original 
proposal contained such a requirement in proposed paragraph (b)(1)(i), 
which has been carried over into new paragraph (a)(2). Operators must 
follow the repetitive inspection interval corresponding to the selected 
initial inspection time.
    The commenter states that the time limit for reporting in paragraph 
(c) of the NPRM is unreasonable because its administrative personnel do 
not work on weekends and during holiday periods. The commenter 
recommends a 10 day limit for reporting. The FAA does not concur. A 48 
hour period should be adequate and is a standard reporting requirement 
time limit in ADs. The AD does not require that only administrative 
personnel submit the report to the FAA.
    Two commenters, including the National Transportation Safety Board, 
state that they agree with the NPRM's proposed initial and repetitive 
inspection program on the population of hubs that were produced using 
the CCD procedure, based on the investigation that indicates that these 
hubs may have a higher risk of abusive machining damage. However, since 
the commenters do not agree that CCD hubs are the only suspect fan 
hubs, the commenters do not agree with the proposed inspection program 
for the remaining hub population. The NPRM proposed to inspect the 
remaining population (those hubs not CCD) when the hub assembly is 
stripped to the piece part level. The commenters are concerned that 
this proposal may allow hubs to be initially inspected as late as 
10,000 cycles in service (CIS) after the effective date of this AD. The 
commenters believe that these hubs are of nearly equal concern as the 
fan hubs produced by CCD and the proposed interval is too long to 
detect all potential cracks before they may be expected to propagate to 
failure. The commenters propose that inspection/reinspection occur at 
the next shop visit for all of those hubs that have between 10,000 and 
15,000 CIS since new regardless of the type of drill used during 
manufacture.
    The FAA does not concur at this time. The FAA's analysis of this 
problem indicates that hubs manufactured using coolant-channel drills 
are more susceptible to work hardened areas in the tierod and 
counterweight holes that could serve as a crack origin. The FAA 
concludes, therefore, that it is logical to treat these two distinct 
populations of compressor hubs differently in terms of when operators 
must perform the required inspections. Requiring all hubs to be 
inspected according to the CCD schedule is not supported by the 
available data. The investigation, however, continues and should any 
additional data become available, the FAA may initiate further 
rulemaking as required.
    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.
    There are approximately 2,624 engines of the affected design in the 
worldwide fleet. The FAA estimates that 1,279 engines installed on 
aircraft of U.S. registry will be affected by this AD, that it will 
take approximately 20 work hours per engine for 360 engines to 
disassemble, remove, inspect, and reassemble engines, and 4 work hours 
per engine for 919 engines to inspect at piece-part exposure, and that 
the average labor rate is $60 per work hour. Based on these figures, 
the total cost impact of the AD on U.S. operators is estimated to be 
$862,560.
    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, Incorporation by 
reference, 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:

97-02-11  Pratt & Whitney: Amendment 39-9896. Docket 96-ANE-33.

    Applicability: Pratt & Whitney JT8D-209, -217, -217C, and -219 
series turbofan engines with front compressor front hub (fan hub), 
Part Number (P/N) 5000501-01, installed. These engines are installed 
on but not limited to McDonnell Douglas MD-80 series aircraft.


[[Page 4904]]


    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 (e) 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 front compressor front hub (fan hub) failure due to 
tierod, counterweight, or bushed hole cracking, which could result 
in an uncontained engine failure and damage to the aircraft, 
accomplish the following:
    (a) For fan hubs identified by serial numbers (S/Ns) in Appendix 
A of PW Alert Service Bulletin (ASB) No. A6272, dated September 24, 
1996, after the fan hub has accumulated more than 4,000 cycles in 
service since new (CSN), accomplish the following:
    (1) Select an initial inspection interval from Table 1 of this 
AD and inspect for cracks in accordance with the Accomplishment 
Instructions, Paragraph A, Part 1, and, if applicable, Paragraph B, 
of PW ASB No. A6272, dated September 24, 1996.
    (2) Reinspect at the interval in Table 1 of this AD that 
corresponds to the selected initial inspection interval, and in 
accordance with the Accomplishment Instructions, Paragraph A, Part 
1, and, if applicable, Paragraph B, of PW ASB No. A6272, dated 
September 24, 1996.

                                 Table 1                                
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            Initial inspection                      Reinspection        
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1. Within 1,050 cycles in service (CIS)     After accumulating 2,500 CIS
 after the effective date of this AD, or     since last inspection, but 
 prior to accumulating 5,050 CSN,            not to exceed 6,000 CIS    
 whichever occurs later.                     since last inspection.     
                                                                        
                                   OR                                   
                                                                        
2. Within 990 CIS after the effective date  After accumulating 2,500 CIS
 of this AD, or prior to accumulating        since last inspection, but 
 4,990 CSN, whichever occurs later.          not to exceed 8,000 CIS    
                                             since last inspection.     
                                                                        
                                   OR                                   
                                                                        
3. Within 965 CIS after the effective date  After accumulating 2,500 CIS
 of this AD, or prior to accumulating        since last inspection, but 
 4,965 CSN, whichever occurs later.          not to exceed 10,000 CIS   
                                             since last inspection.     
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    (b) For fan hubs with S/Ns not listed in Appendix A of PW ASB 
No. A6272, dated September 24, 1996, after the fan hub has 
accumulated more than 4,000 CSN, inspect at the next time the fan 
hub is in the shop at piece-part level, but not to exceed 10,000 CIS 
after effective date of this AD in accordance with the 
Accomplishment Instructions, Paragraph A, Part 2, and, if 
applicable, Paragraph B, of PW ASB No. A6272, dated September 24, 
1996.
    (c) Remove from service fan hubs found cracked or fan hubs that 
exceed the bushed hole acceptance criteria in accordance with PW ASB 
No. A6272, dated September 24, 1996, and replace with serviceable 
parts.
    (d) Report findings of cracked fan hubs in accordance with 
Accomplishment Instructions, Paragraph F, of Attachment 1 to PW ASB 
No. A6272, dated September 24, 1996, within 48 hours after 
inspection to Robert Guyotte, Manager, Engine Certification Branch, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 
12 New England Executive Park, Burlington, MA 01803-5299; telephone 
(617) 238-7142, fax (617) 238-7199; Internet: 
Robert.G[email protected]. Reporting requirements have been 
approved by the Office of Management and Budget and assigned OMB 
control number 2120-0056.
    (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 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.

    (f) 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.
    (g) The actions required by this AD shall be done in accordance 
with the following PW ASB:

------------------------------------------------------------------------
          Document No.             Pages    Revision          Date      
------------------------------------------------------------------------
A6272..........................      1-21  Original    September 24,    
                                                        1996.           
NDIP-892.......................      1-30  A           September 15,    
                                                        1996.           
Attachment I...................     AI-1-              .................
                                     AI-4  A           September 15,    
                                                        1996.           
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Total pages: 55.

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Pratt & Whitney, 400 Main St., 
East Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-
4503. Copies may be inspected at the FAA, New England Region, Office 
of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street NW., Suite 700, Washington, DC.
    (h) This amendment becomes effective on March 5, 1997.

    Issued in Burlington, Massachusetts, on January 13, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 97-1703 Filed 1-31-97; 8:45 am]
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