[Federal Register Volume 63, Number 106 (Wednesday, June 3, 1998)]
[Rules and Regulations]
[Pages 30122-30124]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14339]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-60-AD; Amendment 39-10557, AD 98-11-32]
RIN 2120-AA64


Airworthiness Directives; Allison Engine Company AE 3007A and AE 
3007C Series 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 Allison Engine Company AE 3007A and AE 3007C series 
turbofan engines. This action supersedes priority letter AD 98-02-09, 
that currently requires certain checks of the center sump magnetic chip 
collector plug for paste. Engines found with paste are required to be 
removed from service. This action references revisions of the 
applicable Alert Service Bulletins (ASB) providing clarifications of 
check procedures. This amendment is prompted by a change in the part 
number applicability, a change in the check interval, and the 
publication of these revised ASBs. The actions specified by this AD are 
intended to prevent No. 4 bearing failure due to excessive bearing 
wear, which can result in an inflight engine shutdown.

DATES: Effective June 18, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 18, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before August 3, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 97-ANE-60-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``<a href="/cdn-cgi/l/email-protection#a1988cc0c58cabc4cfc6c8cfc4d1d3ced1e1c7c0c08fc5ced58fc6ced7">9-ad-
<span class="__cf_email__" data-cfemail="096c676e60676c797b6679496f6868276d667d276e667f">[email protected]</span></a>''. Comments sent via the Internet must contain 
the docket number in the subject line.
    The service information referenced in this AD may be obtained from 
Allison Engine Company, P.O. Box 420, Speed Code U-15, Indianapolis, IN 
46206-0420; telephone (317) 230-6674. This information may be examined 
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.

FOR FURTHER INFORMATION CONTACT: Kyri Zaroyiannis, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 East Devon Avenue, Des Plaines, IL 60018; telephone (847) 294-
7836, fax (847) 294-7834.

SUPPLEMENTARY INFORMATION: On January 16, 1998, the Federal Aviation 
Administration (FAA) issued priority letter airworthiness directive 
(AD) 98-02-09, applicable to Allison Engine Company AE 3007A and AE 
3007C series turbofan engines, which requires each calendar day, for 
Allison Engine Company AE 3007A series engines, and every three 
calendar days, or prior to the next flight, whichever occurs later, for 
Allison Engine Company AE 3007C series engines, alternating between the 
left hand and right hand engines, checks of the center sump magnetic 
chip collector plug. After checking the center sump magnetic chip 
collector plug , that AD requires, if paste is found, collecting paste, 
examining the O-ring for damage, cleaning the plug once during the 
first check only and not subsequently, performing an engine ground run-
up and again examining the plug for paste. If paste is found on this 
second examination or subsequent examinations, the engine must be 
removed from service. There have been five inflight engine shutdowns 
associated with these bearing failures since December 1, 1997, on 
Allison Engine Company AE 3007A and AE 3007C series turbofan engines, 
which occurred with total time in service since new (TSN) ranging from 
36 to 1,284 hours. The investigation revealed that the No. 4 bearings 
deteriorate due to manufacturing anomalies, which lead to excessive 
bearing wear. Analysis of failed bearings and service history has 
narrowed the unsafe condition to one particular bearing part number. 
That condition, if not corrected, could result in No. 4 bearing failure 
due to excessive bearing wear, which can result in an inflight engine 
shutdown.
    Since the issuance of that priority letter AD, Allison Engine 
Company has issued Alert Service Bulletin (ASB) No. AE 3007A-A-79-014, 
Revision 4, dated April 14, 1998, and ASB No. AE 3007C-A-79-018, 
Revision 3, dated April 21, 1998, which provide clarifications of check 
procedures. In addition, this final rule has added oil leak checks 
after each magnetic chip detector inspection, in order to minimize the 
possibility of

[[Page 30123]]

maintenance-induced errors. Also, this final rule adds a terminating 
action which eliminates the requirement for repetitive magnetic chip 
detector inspections by installing an improved No. 4 main engine 
bearing.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, this AD 
supersedes priority letter AD 98-02-09 to reference revisions of the 
applicable Allison Engine Company ASBs providing clarifications of 
check procedures, change the part number applicability, and change the 
check interval. The 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, 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 97-ANE-60-AD.'' 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 U.S.C. 106(g), 40113, 44701.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

98-11-32 Allison Engine Company: Amendment 39-10557. Docket No. 97-
ANE-60-AD. Supersedes AD 98-02-09.

    Applicability: Allison Engine Company AE 3007A and AE 3007C 
series turbofan engines with No. 4 bearing, Part Number (P/N) 
23062504, installed on but not limited to EMBRAER EMB-145 and Cessna 
750 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 (e) 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 No. 4 bearing failure due to excessive bearing wear, 
which can result in an inflight engine shutdown, accomplish the 
following:
    (a) For Allison Engine Company AE 3007A series engines, within 8 
flight hours after the effective date of this AD, accomplish the 
following in accordance with Allison Engine Company Alert Service 
Bulletin (ASB) No. AE 3007A-A-79-014, Revision 4, dated April 14, 
1998.
    (1) Remove the center sump magnetic chip collector plug (non-
indicating) on each engine and examine it for paste.

    Note 2: Paste is a mixture of very fine metallic particles and 
oil or soft carbon.

    (2) If no paste is found, reinstall the center sump magnetic 
chip collector, perform an oil leak check, and thereafter inspect 
both engines at intervals not to exceed 8 flight hours.
    (3) If paste is found, accomplish the following prior to further 
flight:
    (i) Remove the engine from service if paste was previously found 
on the same engine during any previous checks performed in 
accordance with this AD, otherwise continue with the following 
procedure:
    (ii) Collect the paste on a clean white paper. Cover the sample 
with clear tape and retain it for analysis.
    (iii) Examine the O-ring for damage and replace as necessary.
    (iv) Clean the center sump magnetic chip collector plug.
    (v) Reinstall the center sump magnetic chip collector plug.
    (vi) Perform a ground run-up of the engine as follows:
    (A) Ground Idle for 5 minutes.
    (B) Maximum Takeoff for 2 minutes.
    (C) 50% N1 (Fan speed) for 5 minutes.
    (D) Ground Idle for 3 minutes.
    (E) Stop the engine.
    (vii) Re-examine the center sump magnetic chip collector plug 
for paste. If paste is found, remove the engine from service. If no 
paste is found, thereafter inspect in accordance with paragraph 
(a)(2) of this AD.
    (viii) Send any removed paste to a laboratory or facility 
capable of analysis with a scanning electron microscope and an 
energy dispersive x-ray microanalyzer for analysis.

    Note 3: Two laboratories capable of performing this analysis 
are:


[[Page 30124]]


Aviation Laboratories, 910 Maria Street, Kenner, LA 70062, 504-469-
6751

      or

Spectro Oil Analysis, Palace Gate, High Street, Oldham, Hook, 
Hampshire, RG 291 NP, United Kingdom.

    Send documentation referencing this AD or ASB along with the 
sample.
    (ix) Send the results of the analysis to Allison as follows: 
Manager, AE Customer Support, Large Commercial Engines, fax (317) 
230-4010.
    (x) An engine found with paste either after the engine ground 
run-up or during subsequent checks performed in accordance with this 
AD may not be operated again without the approval of the Manager, 
Chicago Aircraft Certification Office.
    (b) For Allison AE 3007C series engines, within 8 flight hours 
after the effective date of this AD, accomplish the following in 
accordance with Allison Engine ASB No. AE 3007C-A-79-018, Revision 
3, dated April 21, 1998:
    (1) Remove the center sump magnetic chip collector plug (non-
indicating) on each engine and examine it for paste. (See Note 2)
    (2) If no paste is found, reinstall the center sump magnetic 
chip collector, perform an oil leak check, and thereafter inspect 
both engines at intervals not to exceed 8 flight hours.
    (3) If paste is found, accomplish the following prior to further 
flight:
    (i) Remove the engine from service if paste was previously found 
on the same engine during any previous checks performed in 
accordance with this AD.
    (ii) Collect the paste on a clean white paper. Cover the sample 
with clear tape and retain it for analysis.
    (iii) Examine the O-ring for damage and replace as necessary.
    (iv) Clean the center sump magnetic chip collector plug.
    (v) Reinstall the center sump magnetic chip collector plug.
    (vi) Perform a ground run-up of the engine as follows:
    (A) Ground Idle for 5 minutes.
    (B) Maximum Takeoff for 2 minutes.
    (C) 50% N1 (Fan speed) for 5 minutes.
    (D) Ground Idle for 3 minutes.
    (E) Stop the engine.
    (vii) Re-examine the center sump magnetic chip collector plug 
for paste. If paste is found, remove the engine from service. If no 
paste is found, thereafter inspect in accordance with paragraph 
(b)(2) of this AD.
    (viii) Send any removed paste to a laboratory or facility 
capable of analysis with a scanning electron microscope and an 
energy dispersive x-ray microanalyzer for analysis. Send 
documentation referencing this AD or ASB along with the sample. (See 
Note 3)
    (ix) Send the results of the analysis to Allison as follows: 
Manager, AE Customer Support, Large Commercial Engines, fax (317) 
230-4010.
    (x) An engine found with paste either after the engine ground 
run-up or during subsequent checks performed in accordance with this 
AD may not be operated again without the approval of the Manager, 
Chicago Aircraft Certification Office.
    (c) For Allison Engine Company AE 3007A series and AE 3007C 
series engines, remove from service No. 4 main engine bearings, P/N 
23062504, at the next engine shop visit, and replace with 
serviceable parts. Installation of an improved No. 4 main engine 
bearing constitutes terminating action to the repetitive magnetic 
chip detector checks required by paragraphs (a) and (b) of this AD.
    (d) For the purpose of this AD, the following definitions apply:
    (1) A serviceable part is defined as any No. 4 main engine 
bearing P/N other than 23062504.
    (2) A shop visit is defined as any maintenance action resulting 
in the separation of any major engine flange.
    (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, Chicago Aircraft Certification 
Office. Operators shall submit their requests through an appropriate 
FAA Principal Maintenance Inspector, who may add comments and then 
send it to the Manager, Chicago Aircraft Certification Office.

    Note 4: 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.

    (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 check requirements of this AD can be accomplished.
    (g) The actions required by this AD shall be accomplished in 
accordance with the following Allison Engine Company ASBs:

------------------------------------------------------------------------
         Document No.            Page    Revision           Date        
------------------------------------------------------------------------
AE 3007A-A-79-014.............     1-7          4  April 14, 1998.      
Total Pages: 7.                                                         
AE 3007C-A-79-018.............     1-6          3  April 21, 1998.      
Total Pages: 6.                                                         
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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 Allison Engine Company, P.O. Box 
420, Speed Code U-15, Indianapolis, IN 46206-0420; telephone (317) 
230-6674. 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 supersedes priority letter AD 98-02-09, 
issued January 16, 1998.
    (i) This amendment becomes effective on June 18, 1998.

    Issued in Burlington, Massachusetts, on May 22, 1998.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 98-14339 Filed 6-2-98; 8:45 am]
BILLING CODE 4910-13-U


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