[Federal Register Volume 64, Number 92 (Thursday, May 13, 1999)]
[Rules and Regulations]
[Pages 25802-25804]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-11635]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-ANE-02; Amendment 39-11164; AD 99-10-11]
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 supersedes an existing airworthiness directive 
(AD), applicable to Pratt & Whitney JT8D-200 series turbofan engines, 
that currently requires periodic inspection of fan blades for locked 
rotors and foreign object damage (FOD), unlocking of shrouds if 
necessary, lubrication of fan blade shrouds, and dimensional 
restoration of the fan blade leading edge. In addition, that AD 
requires installation of improved design fan blades as terminating 
action for the inspections. This AD will reduce the lubrication 
interval, and require removal of rotors that experience repeat lockups 
within 225 cycles in service. This supersedure is prompted by reports 
of twenty-five fan blade failures to date. The actions specified by the 
AD are intended to prevent fan blade failure, which can result in 
damage to the aircraft.

DATES: Effective June 14, 1999. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of June 14, 1999.

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 Regional Counsel, 12 New England Executive Park, 
Burlington, MA 01803-5299; or at the Office of the Federal Register, 
800 North Capitol Street, NW, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Peter White, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7128, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding airworthiness 
directive (AD) 96-23-15, Amendment 39-9821 (61 FR 63706, December 2, 
1996), applicable to certain Pratt & Whitney (PW) JT8D-200 series 
turbofan engines, was published in the Federal Register on December 2, 
1998 (63 FR 66500). That action proposed to require periodic inspection 
of fan blades for locked rotors and foreign object damage (FOD), 
unlocking of shrouds if necessary, lubrication of fan blade shrouds, 
removal from service of fan rotors which experience repeat lockup 
events within 225 cycles in service, and dimensional restoration of the 
fan blade leading edge. In addition, that AD requires installation of 
improved design fan blades as terminating action for the inspections.
    Since the issuance of that AD, the FAA has received reports of 7 
additional fan blade failures on engines that had been inspected in 
accordance with the current AD, bringing the total of reported failures 
to 25. The fan blades are failing as a result of high cycle fatigue. 
Contributing factors are foreign object damage (FOD), leading edge 
erosion, manufacturing discrepancies, and locked fan shrouds. These fan 
blade failures indicate that the currently mandated fleet management 
plan is insufficient.
    The FAA has reviewed and approved the technical contents of PW 
Alert Service Bulletin (ASB) No. A6241, Revision 2, dated June 29, 
1998, that reduces the lubrication interval, and requires removal of 
rotors that experience repeat lockups within 225 cycles in service 
(CIS).
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Three commenters concur with the rule as proposed. Two of these are 
already in compliance with the rule as proposed.
    One commenter suggests that alternate method of compliance (AMOC) 
approvals for ADs 95-12-19 and 96-23-15 should be applicable to this 
AD, without requiring additional approval. The proposal only references 
AMOC approvals to 95-12-19. The FAA does not agree. This AD represents 
the third AD in a line of ADs addressing the fan blade shroud locking 
problem on PW JT8D-200 engines. Normally when an AD supersedes a 
previously issued AD, all AMOC approvals to the superseded AD cease on 
the effective date of the superseding AD, and operators must either 
comply with the requirements of the new AD or reapply for a new AMOC 
approval. On further review of the issue

[[Page 25803]]

of whether previous AMOC approvals should be allowed to continue in 
force, the FAA has determined that AMOC approvals for neither of the 
previous ADs should be allowed to continue in force after the effective 
date of this AD. The inspection requirements for ASB 6241, Rev. 2, 
dated June 29, 1998, incorporated in this AD, differ significantly from 
those of the current AD in that blades that experience repeat lockups 
within 225 cycles must be removed. Therefore, the FAA has determined to 
remove proposed paragraph (e) from the final rule. All AMOC approvals 
issued for either AD 95-12-19 or AD 96-23-15 will cease on the 
effective date of this AD.
    One commenter believes that it is unnecessary to track repeat 
lockups and remove from service rotors that experience repeat lockups 
within 225 cycles, because the foreign object damage (FOD) checks and 
lubrication of the shrouds address the root cause of the problem. The 
FAA does not concur. Analysis of fan blade fracture events revealed a 
strong correlation between repeat lockup histories and subsequent 
fractures. The requirement to track lockup events and remove rotors 
which experience repeat lockups within 225 cycles is a key part of the 
fleet management proposal, and is required to provide the full safety 
benefit of this proposal. A statement clarifying the requirement to 
remove rotors from service per Part 3 of ASB6241 rev. 2 was added to 
paragraph (a) of this AD. Previously this was stated directly only in 
the Summary and Supplementary Information sections of the AD. Since 
comments indicate that operators implied that to be the case, this 
addition to paragraph (a) does not expand the scope of the AD or add 
any additional burden to operators.
    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 as proposed.
    There are approximately 2,650 engines of the affected design in the 
worldwide fleet. The FAA estimates that 960 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take no additional work hours to perform these inspections 
except at a shorter lubrication interval. Rework costs for the fan 
blades are $275 per blade, of which approximately $140 per blade is 
attributable to this AD action. With the manufacturer's rebate of $50 
per blade, the total cost to industry of reworking these blades is 
$2,750 per engine.
    The manufacturer estimates that it will take 19 work hours per 
engine to remove and reinstall the blades. Using labor costs of $60 per 
work hour, the labor costs to remove and reinstall the blades are 
$1,140 per engine. Hence, the increased costs generated by this 
proposed AD on U.S. operators is estimated to be $3,890 per engine, or 
$3,734,400 to retrofit the remaining 960 engines.
    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 removing Amendment 39-9821 (61 FR 
63706, December 2, 1996) and by adding a new airworthiness directive, 
Amendment 39-11164, to read as follows:

99-10-11
Pratt & Whitney: Amendment 39-11164. Docket 96-ANE-02. Supersedes AD 
96-23-15, Amendment 39-9821.

    Applicability: Pratt & Whitney (PW) Models JT8D-209, -217, -
217A, -217C, and -219 turbofan engines that have not incorporated PW 
Service Bulletin (SB) No. 6193, dated October 31, 1994, or with fan 
blades, Part Numbers (P/N's) 798821, 798821-001, 808121, 808121-001, 
809221, 811821, 851121, 851121-001, 5000021-02, 5000021-022, and 
5000021-032 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 (f) 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 blade failure, which can result in damage to the 
aircraft, accomplish the following:
    (a) Inspect fan blades and shrouds, unlock fan blade shrouds, 
lubricate fan blade shrouds, restore leading edge dimensions, remove 
from service those fan rotors which experience repeat lockup events 
within 225 cycles, and modify or install improved design fan blades 
in accordance with the schedule and procedures described in Parts 1, 
2, and 3 of the Accomplishment Instructions of PW Alert Service 
Bulletin (ASB) No. A6241, Revision 2, dated June 29, 1998.
    (b) Modification of fan blades to the improved design 
configuration or installation of improved design fan blades in 
accordance with Part 3 of the Accomplishment Instructions of PW ASB 
No. A6241, Revision 2, dated June 29, 1998, constitutes terminating 
action to the inspections and maintenance actions described in 
paragraph (a) of this AD.
    (c) For the purpose of this AD, the accomplishment effective 
date to be used for determination of compliance intervals, as 
required by Section 2 of PW ASB No. A6241, Revision 2, dated June 
29, 1998, is defined as the effective date of this AD.
    (d) For the purpose of this AD, ``repair'' as specified in Part 
3, Paragraph A. (1)(b) of the Accomplishment Instructions of PW ASB 
No. A6241, Revision 2, dated June 29, 1998 is defined as the 
modification of fan blades to incorporate the revised shroud angle, 
cutback the leading edge, and restore leading edge dimensions in 
accordance with Part 3, Paragraph C of the Accomplishment

[[Page 25804]]

Instructions of PW ASB No. A6241, Revision 2, dated June 29, 1998.
    (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 method of compliance with this AD, 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 accomplished in 
accordance with the following Pratt & Whitney ASB:

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            Document No.                Pages                  Revision                          Date
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A6241..............................         1-14  Rev. 2...........................  June 29, 1998.
    Total pages: 14.
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    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, Publication 
Department, Supervisor Technical Publications Distribution, M/S 132-
30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700, 
fax (860) 565-4503. Copies may be inspected at the FAA, New England 
Region, Office of the Regional 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 June 14, 1999.

    Issued in Burlington, Massachusetts, on May 4, 1999.
Diane S. Romanosky,
Acting Manager, Engine and Propeller Directorate,
Aircraft Certification Service.
[FR Doc. 99-11635 Filed 5-12-99; 8:45 am]
BILLING CODE 4910-13-P