[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:

------------------------------------------------------------------------
                                                          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:

------------------------------------------------------------------------
             Document No.                Pages             Date         
------------------------------------------------------------------------
FJ44-A72-30...........................      1-7  November 6, 1996.      
Total pages: 7                                                          
FJ44-A72-31...........................      1-7  November 4, 1996.      
Total pages: 7                                                          
------------------------------------------------------------------------

    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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