[Federal Register Volume 62, Number 36 (Monday, February 24, 1997)]
[Proposed Rules]
[Pages 8198-8201]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4370]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 97-ANE-08]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT8D-200 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to Pratt & Whitney JT8D-200 
series turbofan engines, that currently 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, the current AD requires reporting 
the findings of cracked fan hubs. This action will not change the 
current AD's inspection procedures, or the effectivity date that starts 
the cycle count for the initial inspection schedules. This AD will, 
however, add an additional inspection schedule that requires the 
initial inspection of certain fan hubs with standard drilled holes and 
coolant channel drilled (CCD) holes to occur earlier than the existing 
AD requires. This proposal is prompted by additional investigation 
since publication of the current AD that reveals that certain fan hubs 
with standard drilled holes and CCD holes may be more susceptible to 
cracking. This proposal also requires reporting the results of the 
initial fan hub inspections. The actions specified by the proposed 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: Comments must be received by April 25, 1997.

ADDRESSES: Submit comments in triplicate to the Federal
    Aviation Administration (FAA), New England Region, Office of the 
Assistant Chief Counsel, Attention: Rules Docket No. 97-ANE-08, 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, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-6600, fax (860) 565-4503. 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: Diane Cook, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-

[[Page 8199]]

 5299; telephone (617) 238-7134, fax (617) 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 97-ANE-08.'' 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. 97-ANE-08, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On January 13, 1997, the Federal Aviation Administration (FAA) 
issued airworthiness directive AD 97-02-11, Amendment 39-9896 (62 FR 
4902, February 3, 1997), applicable to Pratt & Whitney (PW) JT8D-200 
series turbofan engines, to require cleaning, initial and repetitive 
eddy current inspections (ECI) and fluorescent penetrant inspections 
(FPI) for cracks of tierod and counterweight holes; removal of 
bushings; the cleaning and 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 front compressor front hub (fan hub) Serial Numbers (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 AD requires reporting 
findings of cracked fan hubs. That action was prompted by a report of 
an uncontained failure of a fan hub. That condition, if not corrected, 
could result in fan hub failure due to tierod, counterweight, or bushed 
hole cracking, which could result in an uncontained engine failure and 
damage to the aircraft.
    Since the issuance of that AD, the FAA has conducted additional 
investigation of fan hub cracking and has determined it necessary to 
include an additional inspection schedule for certain fan hubs with 
standard drilled holes and coolant channel drilled (CCD) holes. The FAA 
reviewed the manufacturing records of all fan hubs, a total of 253 
which had notations related to the tierod or counterweight holes. 
Notations are made in the manufacturing records if an event occurred 
during manufacture of the hole such as a tool break, which can result 
in work hardened material, which is more susceptible to cracking. Of 
the 253 fan hubs with such notations, 113 were manufactured with a CCD 
and the remaining 140 were manufactured with a standard drill. Although 
CCD fan hubs are more prone to a work hardened layer, a standard drill, 
under certain circumstances, may also cause a work hardened layer and 
subsequent cracking.
    The FAA has reviewed and approved the technical contents of PW ASB 
No. A6272, dated September 24, 1996, that describes procedures for 
cleaning and ECI and FPI of tierod and counterweight holes for cracks; 
removal of bushings; and the cleaning, FPI, and ECI of bushed holes for 
cracks. Even though the ASB contains three of the S/Ns of the fan hubs 
that were removed from service in accordance with AD 96-15-06, the 
manufacturer has informed the FAA that these fan hubs have been 
destroyed during the investigation to confirm the failure mode.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 97-02-11 to include an additional 
inspection schedule for certain fan hubs with standard drilled holes 
and CCD holes without changing inspection procedures, the existing 
inspection schedules, or the current effectivity date of March 5, 1997.
    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 would be affected by this proposed AD, that 
it would take 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 proposed AD on U.S. operators is estimated to be 
$862,560.
    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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9896 (62 FR 
4902, February 3, 1997) and by adding

[[Page 8200]]

a new airworthiness directive to read as follows:

Pratt & Whitney: Docket No. 97-ANE-08. Supersedes AD 97-02-11, 
Amendment 39-9896.

    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.

    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 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) Inspect fan hubs 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, as follows:
    (1) For fan hubs identified by Serial Numbers (S/Ns) in Table 2 
of this AD, after the fan hub has accumulated more than 4,000 cycles 
since new (CSN), as follows:
    (i) Initially inspect within 790 cycles in service after March 
5, 1997 (the effective date of AD 97-02-11), or 4,790 CSN, whichever 
occurs later.
    (ii) Thereafter, reinspect after accumulating 2,500 CIS since 
last inspection, but not to exceed 10,000 CIS since last inspection.
    (2) For fan hubs identified by S/Ns in Appendix A of PW ASB No. 
A6272, dated September 24, 1996, after the fan hub has accumulated 
more than 4,000 CSN, as follows:
    (i) Select an initial inspection interval from Table 1 of this 
AD, and inspect accordingly.

                                 Table 1                                
------------------------------------------------------------------------
           Initial inspection                        Reinspection       
------------------------------------------------------------------------
1. Within 1,050 cycles in service (CIS)       After accumulating 2,500  
 after the effective date of AD 97-02-         CIS since last           
 11, March 5, 1997, or prior to                inspection, but not to   
 accumulating 5,050 CSN, whichever             exceed 6,000 CIS since   
 occurs later;                                 last inspection.         
                                          or                            
2. Within 990 CIS after the effective         After accumulating 2,500  
 date of AD 97-02-11, March 5, 1997, or        CIS since last           
 prior to accumulating 4,990 CSN,              inspection, but not to   
 whichever occurs later;                       exceed 8,000 CIS since   
                                               last inspection.         
                                          or                            
3. Within 965 CIS after the effective         After accumulating 2,500  
 date of AD 97-02-11, March 5, 1997, or        CIS since last           
 prior to accumulating 4,965 CSN,              inspection, but not to   
 whichever occurs later.                       exceed 10,000 CIS since  
                                               last inspection.         
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                                 Table 2                                
                     [Hubs with traveler notations]                     
------------------------------------------------------------------------
     Non CCD            Non CCD            Non CCD           Non CCD    
------------------------------------------------------------------------
M67663             M67802             P66880            S25545          
M67671             M67812             P66885            S25558          
M67675             M67826             R32732            S25564          
M67681             M67829             R32733            S25598          
M67685             M67830             R32735            S25618          
M67686             M67831             R32740            S25621          
M67687             M67832             R32741            S25637          
M67697             M67834             R32810            S25640          
M67700             M67843             R32849            T50693          
M67706             M67849             R32850            T50752          
M67710             M67858             S25222            T50785          
M67712             M67866             S25464            T50791          
M67713             M67868             S25481            T50792          
M67714             M67869             S25483            T50819          
M67715             M67872             S25484            T50823          
M67716             M67888             S25486            T50827          
M67717             N71771             S25488            T50874          
M67722             N71804             S25489            T50875          
M67723             N71806             S25490            T51058          
M67725             N71810             S25491            T51104          
M67726             N71811             S25492            R33186          
M67730             N71875             S25494            S25528          
M67731             N71876             S25495                            
M67746             N71921             S25497                            
M67751             N71965             S25498                            
M67753             N72062             S25499                            
M67764             N72126             S25500                            
M67765             N72152             S25501                            
M67784             N72162             S25502                            
M67791             N72207             S25505                            
M67792             N72216             S25506                            
M67793             N72219             S25507                            
M67794             N72242             S25508                            
M67795             P66693             S25509                            
M67796             P66695             S25514                            
M67797             P66696             S25529                            
M67798             P66698             S25532                            
M67799             P66699             S25541                            
M67800             P66737             S25543                            
M67801             P66753             S25544                            
------------------------------------------------------------------------
     CCD Hub            CCD Hub            CCD Hub                      
------------------------------------------------------------------------
P66747             R33099             S25292                            
P66756             R33107             S25299                            
P66800             R33113             S25301                            
P66814             R33124             S25302                            
P66819             R33131             S25308                            
P66831             R33132             S25312                            
R32767             R33133             S25316                            
R32787             R33136             S25323                            
R32792             R33152             S25334                            
R32795             R33157             S25335                            
R32796             R33163             S25337                            
R32800             R33165             S25344                            
R32807             R33168             S25369                            
R32856             R33171             S25377                            
R32860             R33173             S25378                            
R32870             R33180             S25381                            
R32883             R33181             S25394                            
R32905             R33189             S25399                            
R32926             R33194             S25402                            
R32930             R33198             S25406                            
R32952             R33201             S25411                            
R32964             R33202             S25413                            
R32966             R33207             S25414                            
R32971             S25193             S25415                            
R32976             S25195             S25418                            
R32981             S25207             S25419                            
R32990             S25208             S25421                            
R32994             S25221             S25422                            
R33000             S25229             S25430                            
R33004             S25238             S25437                            
R33040             S25246             S25439                            
R33055             S25248             S25449                            
R33059             S25250                                               
R33077             S25256                                               
R33080             S25262                                               
R33082             S25268                                               
R33086             S25278                                               
R33087             S25287                                               
R33089             S25288                                               
R33090                                                                  
------------------------------------------------------------------------

    (ii) Thereafter, reinspect at intervals that correspond to the 
selected inspection interval.
    (3) If a fan hub is identified in both Table 2 of this AD and 
Appendix A of PW ASB No. A6272, dated September 24, 1996, inspect in 
accordance with paragraph (a)(1) of this AD.
    (4) For fan hubs with S/Ns not listed in Table 2 of this AD or 
in Appendix A of PW ASB No. A6272, dated September 24, 1996, after 
the fan hub has accumulated more than 4,000 CSN, inspect the next 
time the fan hub is in the shop at piece-part level, but not to 
exceed 10,000 CIS after March 5, 1997.
    (5) Prior to further flight, remove from service fan hubs found 
cracked or that exceed the bushed hole acceptance criteria described

[[Page 8201]]

in PW ASB No. A6272, dated September 24, 1996.
    (b) Report the number of completed inspections on a monthly 
basis and 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.
    (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 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.

    (d) 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 inspection requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on February 14, 1997.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-4370 Filed 2-21-97; 8:45 am]
BILLING CODE 4910-13-P