[Federal Register Volume 63, Number 89 (Friday, May 8, 1998)]
[Rules and Regulations]
[Pages 25389-25391]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12063]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-40-AD; Amendment 39-10514; AD 98-10-03]
RIN 2120-AA64
Airworthiness Directives; Allison Engine Company Model 250-C47B
Turboshaft Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD) 97-21-09, applicable to Allison Engine Company Model 250-C47B
turboshaft engines, that currently requires replacing the engine main
electrical harness assembly with an improved assembly, installing a new
hydromechanical unit (HMU) and electronic control unit (ECU), removing
the placard notifying the pilot that the overspeed protection system is
disabled, and revising the Bell Helicopter Textron, A Division of
Textron Canada Ltd. (BHTC), Model 407 Rotorcraft Flight Manual (RFM).
This amendment continues the requirements of the current AD, but adds
the requirement to install ECUs with improved resistance to corrosion.
This amendment is prompted by reports of ECUs with annunciated hard
faults due to corrosion on internal connectors. The actions specified
by this AD are intended to prevent uncommanded inflight engine
shutdowns, which can result in autorotation, forced landing, and
possible loss of the helicopter.
DATES: Effective May 26, 1998.
The incorporation by reference of Allison Engine Company Alert
Commercial Engine Bulletin (CEB) CEB-A-73-6010, dated October 15, 1996,
CEB A-73-6015, Revision 1, dated July 30, 1997, and Revision 2, dated
October 31, 1997, and BHTC Flight Manual BHT-407-FM-1, Revision 5,
dated June 24, 1997, as listed in the regulations, was approved
previously by the Director of the Federal Register as of December 3,
1997 (62 FR 61438, November 18, 1997).
The incorporation by reference of Allison Engine Company Alert CEB-
A-73-6017, Revision 1, dated February 18, 1998, and Revision 2, dated
April 9, 1998, is approved by the Director of the Federal Register as
of May 26, 1998.
Comments for inclusion in the Rules Docket must be received on or
before July 7, 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-40-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``9-ad-
[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
Allison Engine Company, P.O. Box 420, Speed Code P-40A, Indianapolis,
IN 46206-0420; telephone (317) 230-2720, fax (317) 230-3381. This
information may be examined at the FAA, New England Region, Office of
the Regional Counsel, Burlington, MA; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Patricia Bonnen, Aerospace Engineer,
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate,
2300 East Devon Ave., Des Plaines, IL 60018; telephone (847) 294-7134,
fax (847) 294-7834.
SUPPLEMENTARY INFORMATION: On November 10, 1997, the Federal Aviation
Administration (FAA) issued airworthiness directive (AD) 97-21-09,
Amendment 39-10162 (62 FR 61438, November 18, 1997), to require
replacing the engine main electrical harness assembly with an improved
assembly, installing a new hydromechanical unit (HMU) and electronic
control unit (ECU), removing the placard notifying the pilot that the
overspeed protection system is disabled, and revising the Bell
Helicopter Textron, A Division of Textron Canada Ltd. (BHTC) Model 407
Rotorcraft Flight Manual (RFM). That action was prompted by development
of overspeed protection system modifications to reactivate the
overspeed solenoid (which had been disabled in accordance with AD 96-
24-09 to prevent engine shutdown due to zero fuel flow when tripped) in
conjunction with raising the power turbine overspeed trip point and
revising the overspeed system to default to a minimum fuel flow in the
event of its activation. That condition, if not corrected, could result
in uncommanded inflight engine shutdowns, which can result in
autorotation, forced landing, and possible loss of the helicopter.
Since the issuance of that AD, the FAA received reports of two BHTC
407 rotorcraft involved in incidents where there was an annunicated
hard fault with the ECU. In each case, the result was a failed fixed
event in which the pilot transitioned to manual mode without incident.
The hard faults have been attributed to corrosion on internal
connectors. Subsequent to the incidents, the manufacturer conducted an
initial investigation on returned ECUs and found two additional units
with corrosion on internal connectors.
The FAA has reviewed and approved the technical contents of Allison
Engine Company Alert CEB-A-73-6017, Revision 1, dated February 18,
1998, and Revision 2, dated April 9, 1998, that describes procedures
for installing ECUs with improved resistance to corrosion.
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 AD 97-21-09 and continues to require replacement of the
engine main electrical harness assembly with an improved assembly, and,
after replacing the ECU and HMU, removing the ``OVRSPD SYSTEM INOP''
placard required by paragraph (d) of AD 96-24-09, revising the BHTC
Model 407 RFM. These actions are now required prior to further flight,
if not already accomplished. In addition, this AD adds a requirement to
install an ECU with improved resistance to corrosion within 45 days
after the effective date of this AD, based upon the need to protect the
affected engines against effects of corrosion. Installation of the
improved, corrosion resistant ECU will meet the requirement to install
a new ECU. The requirements of paragraph (c) of this AD have been
coordinated with the Rotorcraft Directorate. The actions are required
to be accomplished in
[[Page 25390]]
accordance with the service documents 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-40-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 removing Amendment 39-10162, (62 FR
61438, November 18, 1997), and by adding a new airworthiness directive,
Amendment 39-10514, to read as follows:
98-10-03 Allison Engine Company: Amendment 39-10514. Docket 97-ANE-
40-AD. Supersedes AD 97-21-09, Amendment 39-10162.
Applicability: Allison Engine Company Model 250-C47B turboshaft
engines, installed on but not limited to Bell Helicopter Textron, A
Division of Textron Canada Ltd. (BHTC) Model 407 helicopters.
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 uncommanded inflight engine shutdowns, which
can result in autorotation, forced landing, and possible loss of the
helicopter, accomplish the following:
(a) Prior to further flight, replace the engine main electrical
harness assembly, part number (P/N) 23062796, with an improved
assembly, P/N 23065805, in accordance with Allison Engine Company
Alert Commercial Engine Bulletin (CEB) CEB-A-73-6010, dated October
15, 1996.
(b) Prior to May 20, 1998, install a new hydromechanical control
unit (HMU) and electronic control unit (ECU) in accordance with
Allison Engine Company Alert CEB-A-73-6015, Revision 1, dated July
30, 1997, or Revision 2, dated October 31, 1997.
(c) After completing the requirements of paragraph (b) of this
AD, and prior to further flight:
(1) Remove the ``OVRSPD SYSTEM INOP'' placard required by
paragraph (d) of AD 96-24-09, and
(2) Revise the FAA-approved Rotorcraft Flight Manual (RFM) by
removing the pages added by paragraph (f) of AD 96-24-09, and
incorporate BHTC RFM BHT-407-FM-1, Revision 5, dated June 24, 1997.
(d) Within 45 days after the effective date of this AD, install
a corrosion resistant electronic control unit (ECU) in accordance
with Allison Engine Company Alert CEB-A-73-6017, Revision 1, dated
February 18, 1998, or Revision 2, dated April 9, 1998. Installation
of a corrosion resistant ECU in accordance with this paragraph will
satisfy the requirement in paragraph (b) of this AD to install a new
ECU.
(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 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.
(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 requirements of this AD can be accomplished.
(g) The actions required by this AD shall be done in accordance
with the following service documents:
[[Page 25391]]
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Document No. Pages Revision Date
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Allison Engine Company Alert, 1-7..................... Original................ October 15, 1996.
CEB-A-73-6010.
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Total pages: 7.
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BHTC Rotorcraft Flight Manual Cover................... 5....................... June 24, 1997.
BHT-407-FM-1.
NP...................... 3....................... July 30, 1996.
A,B..................... 5....................... June 24, 1997.
C/D..................... 5....................... June 24, 1997.
1-3..................... 5....................... June 24, 1997.
1-4-1-7................. 4....................... November 4, 1996.
1-8..................... 5....................... June 24, 1997.
1-13.................... 4....................... November 4, 1996.
1-14.................... 5....................... June 24, 1997.
1-14A/14B............... 5....................... June 24, 1997.
1-19/1-20............... 5....................... June 24, 1997.
2-3..................... 5....................... June 24, 1997.
2-4..................... 1....................... March 8, 1996.
2-7-2-10................ 5....................... June 24, 1997.
2-13, 2-14.............. 5....................... June 24, 1997.
3-3-3-5................. 5....................... June 24, 1997.
3-6..................... 2....................... May 9, 1996.
3-7, 3-8................ 5....................... June 24, 1997.
3-15.................... 5....................... June 24, 1997.
3-16.................... 2....................... May 9, 1996.
3-17-3-22............... 5....................... June 24, 1997.
4-5, 4-6................ 5....................... June 24, 1997.
4-9..................... Original................ February 9, 1996.
4-10-4-12............... 5....................... June 24, 1997.
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Total pages: 40.
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Allison Engine Company Alert, 1-4..................... 1....................... July 30, 1997.
CEB-A-73-6015.
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Total pages: 4.
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Allison Engine Company Alert, 1-4..................... 2....................... October 31, 1997.
CEB-A-73-6015.
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Total pages: 4.
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Allison Engine Company Alert, 1-5..................... 1....................... February 18, 1998.
CEB-A-73-6017.
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Total pages: 5
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Allison Engine Company Alert, 1-5..................... 2....................... April 9, 1998.
CEB-A-73-6017.
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Total pages: 5
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(h) The incorporation by reference of Allison Engine Company
Alert CEB-A-73-6010, dated October 15, 1996, CEB A-73-6015, Revision
1, dated July 30, 1997, and Revision 2, dated October 31, 1997, and
BHTC RFM BHT-407-FM-1, Revision 5, dated June 24, 1997, was approved
previously by the Director of the Federal Register as of December 3,
1997 (62 FR 61438, November 18, 1997).
(i) The incorporation by reference of Allison Engine Company
Alert CEB-A-73-6017, Revision 1, dated February 18, 1998, and
Revision 2, dated April 9, 1998, is approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51 as of May 26, 1998.
(j) Copies of these service documents may be obtained from
Allison Engine Company, P.O. Box 420, Speed Code P-40A,
Indianapolis, IN 46206-0420; 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.
(k) This amendment becomes effective on May 26, 1998.
Issued in Burlington, Massachusetts, on April 29, 1998.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 98-12063 Filed 5-7-98; 8:45 am]
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