[Federal Register Volume 62, Number 3 (Monday, January 6, 1997)]
[Rules and Regulations]
[Pages 600-602]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-31]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-ANE-39; Amendment 39-9875; AD 97-01-05]
RIN 2120-AA64
Airworthiness Directives; Williams International, L.L.C. Model
FJ44-1A Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to Williams International, L.L.C. Model FJ44-1A turbofan
engines. This action requires initial and repetitive eddy current
inspections (ECI) for possible cracks in high pressure turbine (HPT)
disk blade retention posts. In addition, this AD requires the
installation of advanced design HPT disks as terminating action to the
inspection requirements of this AD. This amendment is prompted by two
incidents of HPT disk blade retention post separations. The actions
specified in this AD are intended to locate possible cracks in HPT disk
blade retention posts, thereby preventing the separation of these posts
and the liberation of the turbine blades that they retain, and a
subsequent loss of engine power. In addition, the actions specified in
this AD are intended to prevent the possible high disk speed
uncontained liberation of disk posts and turbine blades, which could
cause aircraft damage.
DATES: Effective January 21, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 21, 1997.
Comments for inclusion in the Rules Docket must be received on or
before March 7, 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. 96-ANE-39, 12 New England
Executive Park, Burlington, MA 01803-5299.
The service information referenced in this AD may be obtained from
Mr. John Teeter, Manager, Customer Support, Williams International,
2280 West Maple Road, P.O. Box 200, Walled Lake, MI 48390-0200;
telephone (810) 624-5200, fax (810) 669-9515. This information may be
examined 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.
FOR FURTHER INFORMATION CONTACT: Eugene H. Messal, Aerospace Engineer,
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate,
2300 East Devon Avenue, Des Plaines, Illinois 60018; telephone (847)
294-7011, fax (847) 294-7834.
SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA)
has verified two reports of inflight HPT disk post separations on
Williams International model FJ44-1A turbofan engines. One of these
inflight post separations was uncontained. The investigation revealed
that in both cases, high pressure turbine (HPT) disk blade retention
posts separated due to cracking caused by material creep/fatigue. This
condition, if not corrected, could result in other engines experiencing
HPT disk blade retention post separations and turbine blade
liberations, and subsequent losses of engine power. In addition, this
condition could, if not corrected, result in other engines experiencing
high disk speed uncontained liberation of disk posts and turbine
blades, which could cause aircraft damage.
The FAA has reviewed and approved the technical contents of
Williams-Rolls Alert Service Bulletin (ASB) No. FJ44-A72-30, dated
November 6, 1996, that describes procedures for eddy current
inspections (ECI) for possible cracks in HPT disk blade retention
posts; and ASB No. FJ44-A72-31, dated November 4, 1996, that describes
procedures for replacement of existing HPT disks with advanced design
HPT disks.
Since an unsafe condition has been identified that is likely to
exist or develop on other engines of the same design, this AD is being
issued to locate possible cracks in HPT disk blade retention posts,
which could lead to the liberation of the turbine blades that they
retain, and subsequent loss of engine power. In addition, this AD is
being issued to prevent the separation of HPT disk posts that could
lead to a high disk speed uncontained liberation of disk posts and
turbine blades, which could result in aircraft damage. This AD requires
initial and repetitive ECI for possible cracks in HPT disk blade
retention posts. The inspection population is divided into two groups,
with the higher risk group listed by engine serial number (S/N). This
group of HPT disks is at a higher risk due to a lower stress rupture
strength characteristic. In addition, this AD requires replacement of
the existing HPT disks, Part Number (P/N) 48629, with advanced design
HPT disks, P/N 55291, by July 1, 1997, as terminating action to the
inspection requirements of this AD. The calendar end-dates for this AD
were determined based upon each suspect disk group's time to crack
initiation, subsequent crack propagation rate, and its failure
probability. In addition, the total in-service cycles and hours of each
of the suspect disks of both groups, and the ASB replacement parts
availability were contributing factors for determining the end-dates.
These actions are required to be accomplished in accordance with the
ASBs described previously.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the rule. All comments submitted will be
available, both before and after the closing date for comments,
[[Page 601]]
in the Rules Docket for examination by interested persons. A report
that summarizes each FAA-public contact concerned with the substance of
this AD 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-39.'' The postcard will be date stamped and
returned to the commenter.
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and is not a ``significant regulatory action''
under Executive Order 12866. It has been determined further that this
action involves an emergency regulation under DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979). If it is determined
that this emergency regulation otherwise would be significant under DOT
Regulatory Policies and Procedures, a final regulatory evaluation will
be prepared and placed in the Rules Docket. A copy of it, if filed, 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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
97-01-05 Williams International, L.L.C.: Amendment 39-9875. Docket
96-ANE-39.
Applicability: Williams International L.L.C. Model FJ44-1A
turbofan engines, with serial numbers 1001-1179, 1196, and 1197,
installed on, but not limited to, Cessna Citation Model 525
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 possible high pressure turbine (HPT) disk blade
retention post separations and the release of their retained turbine
blades, subsequent loss of engine power, and possible high disk
speed uncontained liberation of disk posts and the turbine blades,
which could cause aircraft damage, accomplish the following:
(a) Perform initial and repetitive eddy current inspections
(ECI) for cracks in HPT disks, Part Number (P/N) 48629, blade
retention posts in accordance with the following schedule and
requirements:
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Repetitive
Engine serial Nos. Initial compliance inspection
required required
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1001, 1004-1010, 1016, 1017, Within 50 cycles Thereafter, at
1020, 1023-1026, 1031, 1033, after the intervals not to
1036, 1039, 1041, 1042, 1043, effective date of exceed 125 cycles
1046-1048, 1051-1056, 1063, this AD or by in service (CIS)
1069, 1071, 1072, 1076, 1080, February 1, 1997, since last
1082, 1091, 1092, 1095-1098, whichever occurs inspection.
1107, 1108, 1111, 1125, 1127- first.
1129, 1133, 1134, 1165, 1172,
1178
Remaining serial number engines No later than May Thereafter, at
with 575 CIS or more as of 1, 1997. intervals not to
April 1, 1997 exceed 125 CIS
since last
inspection.
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(1) Perform the initial and repetitive eddy current inspections
for cracks in HPT disk blade retention posts in accordance with
Williams-Rolls Alert Service Bulletin (ASB) No. FJ44-A72-30, dated
November 6, 1996.
(2) Remove from service HPT disks that do not meet the ``return
to service'' criteria stated in Williams-Rolls ASB No. FJ44-A72-30,
dated November 6, 1996, and replace them with serviceable HPT disks,
P/N 48629, that meet the required ASB ``return to service''
criteria, or replace them with advanced design HPT disks, P/N 55291,
in accordance with paragraph (b) of this AD.
(b) No later than July 1, 1997, replace all existing HPT disks,
P/N 48629, with advanced design HPT disks, P/N 55291, in accordance
with Williams-Rolls ASB No. FJ44-A72-31, dated November 4, 1996.
Installation of this advanced design HPT disk constitutes
terminating action to the repetitive inspection requirements of this
AD.
(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, Chicago Aircraft 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, Chicago Aircraft 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 Chicago Aircraft 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 requirements of this AD can be accomplished.
(e) The actions required by this AD shall be done in accordance
with the following Williams-Rolls ASBs:
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Document No. Pages Date
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FJ44-A72-30........................... 1-7 November 6, 1996.
Total pages: 7
FJ44-A72-31........................... 1-7 November 4, 1996.
Total pages: 7
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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 Mr. John Teeter, Manager,
Customer Support, Williams International, 2280 West Maple Road, P.O.
Box 200, Walled Lake, MI 48390-0200; telephone (810) 624-5200, fax
(810) 669-9515. 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
[[Page 602]]
Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on January 21, 1997.
Issued in Burlington, Massachusetts, on December 27, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 97-31 Filed 1-3-97; 8:45 am]
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