Airworthiness Directives; Allison Engine Company, Inc AE 2100A and AE 2100C Series Turboprop Engines

[Federal Register Volume 64, Number 161 (Friday, August 20, 1999)]
[Rules and Regulations]
[Pages 45421-45423]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-21330]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-14-AD; Amendment 39-11257; AD 99-17-09]
RIN 2120-AA64


Airworthiness Directives; Allison Engine Company, Inc AE 2100A 
and AE 2100C Series Turboprop 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, Inc AE 2100A and AE 2100C 
series turboprop engines. This action requires initial and repetitive 
visual inspections of the propeller gearbox (PGB) and power section (P/
S) strut fittings for notches and cracks, and, if necessary, 
replacement with serviceable parts. In addition, this action requires 
removing and replacing strut fittings as well as reworking them to the 
latest configuration identified by a new part number (P/N). This 
amendment is prompted by reports of P/S strut fitting notches and 
cracks. The actions specified in this AD are intended to prevent PGB 
and P/S strut fitting cracks, which could result in PGB misalignment, 
in-flight engine shutdown, and possible loss of the propeller.

DATES: Effective September 7, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 7, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before October 19, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 99-NE-14AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ane-
[email protected]''. 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 
Rolls-Royce Allison, P.O. Box 420, Speed Code R-01B, Indianapolis, IN 
46202-0420; telephone (317) 230-2720, fax (317) 230-3381. 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: Chung-Der Young, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 East Devon Avenue, Des Plaines, IL 60018; telephone (847) 294-
7309, fax (847) 294-7834.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received reports of propeller gearbox (PGB) and power section (P/S) 
strut fitting failures on Allison Engine Company AE 2100A and AE 2100C 
series turboprop engine. The investigation revealed small radius 
notched strut fittings on 90% of the engines inspected. Four of the P/S 
strut fittings were cracked, and one of the PGB strut fittings was 
cracked. The notched fittings cause a concentrated stress region that 
can lead to cracks in the notched strut fitting areas. This condition, 
if not corrected, could result in PGB and P/S strut fitting cracks, 
which could result in propeller gearbox misalignment, inflight engine 
shutdown, and possible loss of the propeller.
    The FAA has reviewed and approved the technical contents of Rolls-
Royce Alert Service Bulletin (ASB) AE 2100A-A-72-193, also designated 
AE 2100C-A-72-143, Revision 1, dated October 20, 1998, that describes 
procedures for visual inspections of PGB and P/S strut fittings for 
notches and cracks; and ASB AE 2100A-A-72-197, also designated AE 
2100C-A-72-149, dated May 19, 1999, describes the procedures to remove 
and replace strut fittings as well as rework them to the latest 
configuration identified by a new part number (P/N). Rolls-Royce has 
acquired the Allison Engine Company and now publishes the service 
documents (including manuals and bulletins) for Allison engines.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this AD is 
being issued to prevent PGB and P/S strut fitting failures. This AD 
requires visual inspections of PGB and P/S strut fittings for notches 
and cracks. If the affected parts are found cracked, this AD requires, 
prior to further flight, replacement with serviceable parts. If notched 
fittings are found on both struts, this AD requires repetitive 
inspections at intervals not to exceed 100 hours time-in-service (TIS). 
If notched fittings are found on only one strut, the repetitive 
inspection intervals is 400 hours TIS. In addition, this AD requires 
removing and replacing strut fittings as well as reworking them to the 
latest configuration identified by a new P/N. 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 commenters' 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.

[[Page 45422]]

    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 99-NE-14-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:

99-17-09  Allison Engine Company, Inc: Amendment 39-11257. Docket 
99-NE-14-AD.

    Applicability: Allison Engine Company, Inc. AE 2100A and AE 
2100C series turboprop engines, installed on but not limited to SAAB 
2000 series and Industri Pesawat Terbang Nusantara (IPTN) N-250 
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 (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 propeller gearbox (PGB) and power section (P/S) strut 
fitting cracks, which could result in PGB misalignment, in-flight 
engine shutdown, and possible loss of the propeller, accomplish the 
following:
    (a) Perform initial and repetitive visual inspections of the PGB 
and P/S strut fittings for notches and cracks, and, if necessary, 
replace with serviceable parts, in accordance with Rolls-Royce Alert 
Service Bulletin (ASB) AE 2100A-A-72-193, also designated AE 2100C-
A-72-143, Revision 1, dated October 20, 1998, as follows:
    (1) Perform the initial inspection within 100 hours time-in-
service (TIS) after the effective date of this AD. Record findings 
in Table 1 at the end of the ASB to determine the inspection 
interval.
    (2) If parts are found cracked, prior to further flight, remove 
from service cracked propeller gearboxes or power section strut 
fittings and replace with serviceable parts.
    (3) If both strut fittings are found notched, thereafter inspect 
at intervals not to exceed 100 hours timein-service (TIS) since last 
inspection.
    (4) If one strut fitting is found notched, thereafter inspect at 
intervals not to exceed 400 hours TIS since last inspection.
    (5) If no parts are found cracked and neither strut fitting is 
found notched, no repetitive inspections are required, and rework 
the strut fittings in accordance with paragraph(b) of this AD.
    (b) Perform one of the following in accordance with Rolls-Royce 
ASB AE 2100A-A-72-197, also designated AE 2100CA-72-149, dated May 
19, 1999:
    (1) Remove the old PGB and P/S strut fittings and install the 
new serviceable strut fittings in accordance with the strut fittings 
part number charts in paragraph (4) of the ASB.
    (2) Rework the existing parts within the schedule determined by 
the inspection results of paragraph (a) of this AD in accordance 
with the Rolls-Royce ASB AE 2100A-A-72-193, or AE 2100C-A-72-143, 
Revision 1, dated October 20, 1998, page 12, Table 1, entries in the 
``Answer'' column, as follows:
    (i) If two ``Yes'' entries are contained in the ``Answer 
Column'', rework within the next 100 hour TIS after the inspection 
performed in accordance with paragraph (a) of this AD.
    (ii) If one ``Yes'' entry is contained in the ``Answer Column'', 
or there are no ``Yes'' entries in the ``Answer Column'' refer to 
Section 2 in Rolls-Royce ASB AE 2100A-A-72197, also designated AE 
2100C-A-72-149, dated May 19, 1999, for the affected PGB and P/S 
strut fittings rework or replace instructions.
    (iii) Following completion of the rework, mark affected parts in 
accordance with the following configuration chart:

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                 New P/N                               Name                       Old P/N              QTY/ENG
----------------------------------------------------------------------------------------------------------------
23071762.................................  Fitting, Strut (RH),         23055218...................            1
                                            Propeller Gearbox.
23071763.................................  Fitting, Strut (LH),         23055217...................            1
                                            Propeller Gearbox.
23071764.................................  Fitting, Strut (RH), Power   23055228, 23057098.........            1
                                            Section.
23071765.................................  Fitting, Strut (LH), Power   23055229, 23057099.........            1
                                            Section.
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    (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. 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 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 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a

[[Page 45423]]

location where the inspection requirements of this AD can be 
accomplished.
    (e) The actions required by this AD shall be done in accordance 
with the following Rolls-Royce ASBs:

----------------------------------------------------------------------------------------------------------------
            Document No.              Pages               Revision                            Date
----------------------------------------------------------------------------------------------------------------
AE 2100A-A-72-193/AE 2100C-A-72-143     1-12  1...............................  October 20, 1998.
    Total pages: 12.
ASB AE 2100A-A-72-197/AE 2100C-A-72-    1-25  Original........................  May 19, 1999.
 149.
    Total pages: 25
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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 Rolls-Royce Allison, P.O. Box 
420, Speed Code R-01B, Indianapolis, IN 46202-0420; telephone (317) 
230-2720, fax (317) 230-3381. 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.
    (f) This amendment becomes effective on September 7, 1999.

    Issued in Burlington, Massachusetts, on August 11, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-21330 Filed 8-19-99; 8:45 am]
BILLING CODE 4910-13-U

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