[Federal Register Volume 61, Number 88 (Monday, May 6, 1996)]
[Proposed Rules]
[Pages 20194-20195]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-11168]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-ANE-02]
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 certain 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.
This action would add a requirement to install improved design fan
blades as terminating action for the inspections. This proposal is
prompted by the introduction into service of improved design fan
blades. The actions specified by the proposed AD are intended to
prevent fan blade failure, which can result in damage to the aircraft.
DATES: Comments must be received by July 5, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 96-ANE-02, 12 New England
Executive Park, Burlington, MA 01803-5299. 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: Mark A. Rumizen, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7137, 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 96-ANE-02.'' 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. 96-ANE-02, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
On June 5, 1995, the Federal Aviation Administration (FAA) issued
airworthiness directive (AD) 95-12-19, Amendment 39-9270 (60 FR 31388,
June 15, 1995), applicable to certain Pratt & Whitney (PW) JT8D-200
series turbofan engines, to require a periodic inspection of fan blades
for locked rotors and foreign object damage (FOD), unlocking of shrouds
if necessary, lubrication of the fan blade shrouds, and dimensional
restoration of the fan blade leading edge. That action was prompted by
the determination that fan blades can fail due to high cycle fatigue
(HCF) cracking. This HCF cracking can be
[[Page 20195]]
caused by FOD, locked shrouds, which can reduce blade vibratory
dampening, and leading edge erosion, which can produce blade flutter.
That condition, if not corrected, could result in fan blade failure,
which can result in damage to the aircraft.
Since the issuance of that AD, the manufacturer has introduced into
service fan blades with an improved design configuration that is more
resistant to HCF-induced failures.
The FAA has reviewed and approved the technical contents of PW
Alert Service Bulletin (ASB) No. A6241, dated January 25, 1996, that
describes procedures for inspection of fan blades for locked rotors and
FOD, unlocking of shrouds if necessary, lubrication of fan blade
shrouds, and dimensional restoration of the fan blade leading edge.
This ASB also provides procedures for modification or replacement of
fan blades with an improved design configuration that is more resistant
to HCF-induced failures.
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 95-12-19 to continue to require the
inspection and maintenance requirements of that AD, and to add a
requirement to modify or install the improved design fan blades as
terminating action for those inspections and maintenance requirements.
The FAA estimates that 1,100 engines installed on aircraft of U.S.
registry would be affected by this proposed AD, that it would take
approximately 19 work hours per engine to accomplish the proposed
actions, and that the average labor rate is $60 per work hour. The FAA
also estimates that the parts modification would cost is $2,720 per
engine, which includes a manufacturer's discount of $1,700 per engine.
Based on these figures, the total cost impact of the proposed AD on
U.S. operators is estimated to be $4,246,000.
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 39-9270 (60 FR
31388, June 15, 1995) and by adding a new airworthiness directive to
read as follows:
Pratt & Whitney: Docket No. 96-ANE-02. Supersedes AD 95-12-19,
Amendment 39-9270.
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
blade, 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 aircraft.
Note: This 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 use the authority provided in paragraphs (d) and
(e) to request approval from the FAA. This approval may address
either no action, if the current configuration eliminates the unsafe
condition, or different actions necessary to address the unsafe
condition described in this AD. Such a request should include an
assessment of the effect of the changed configuration on the unsafe
condition addressed by this AD. In no case does the presence of any
modification, alteration, or repair remove any engine from the
applicability of this AD.
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, 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, dated January 25, 1996.
(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, dated January 25, 1996, constitutes terminating action to
the inspections and maintenance actions described in Parts 1 and 2
of that ASB.
(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, dated January 25, 1996,
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, dated January 25, 1996, is defined as the refurbishment
of fan blades in accordance with Part 3, Paragraph C of the
Accomplishment Instructions of PW ASB No. A6241, dated January 25,
1996.
(e) Alternative methods of compliance that have been approved
for AD 95-12-19 are applicable for this AD and additional approval
is not required.
(f) 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: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(g) 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.
Issued in Burlington, Massachusetts, on April 1, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 96-11168 Filed 5-3-96; 8:45 am]
BILLING CODE 4910-13-U
