[Federal Register: June 21, 2006 (Volume 71, Number 119)]
[Rules and Regulations]
[Page 35505-35507]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21jn06-7]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-22594; Directorate Identifier 2005-NE-28-AD;
Amendment 39-14659; AD 2006-13-06]
RIN 2120-AA64
Airworthiness Directives; Rolls-Royce Corporation (Formerly
Allison Engine Company, Allison Gas Turbine Division, and Detroit
Diesel Allison) 250-B and 250-C Series Turboprop and Turboshaft Engines
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
Rolls-Royce Corporation 250-B and 250-C series turboprop and turboshaft
engines with certain part numbers (P/Ns) of gas producer rotor assembly
tie bolts manufactured by EXTEX Ltd., Pacific Sky Supply Inc., Rolls-
Royce Corporation (RRC), and Superior Air Parts Inc. This AD requires
operators to remove from service affected gas producer rotor assembly
tie bolts, and install serviceable tie bolts. This AD results from
eleven reports of RRC tie bolt failure due to high cycle fatigue. We
are issuing this AD to prevent tie bolt failure that could cause loss
of engine power, resulting in a first stage turbine wheel overspeed and
an uncontained engine failure.
DATES: This AD becomes effective July 26, 2006.
ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov
or in Room PL-401 on the plaza level of the Nassif
Building, 400 Seventh Street, SW., Washington, DC.
FOR FURTHER INFORMATION CONTACT:
Robert Baitoo, Aerospace Engineer, Los Angeles Aircraft
Certification Office, FAA, Transport Airplane Directorate, 3960
Paramount Blvd., Lakewood, CA 90712-4137; telephone: (562) 627-5245,
fax: (562) 627-5210, for questions about, EXTEX Ltd., or Pacific Sky
Supply Inc. gas producer rotor assembly tie bolts.
John Tallarovic, Aerospace Engineer, Chicago Aircraft
Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, IL
60018-4696; telephone (847) 294-8180; fax (847) 294-7834, for questions
about RRC gas producer rotor assembly tie bolts.
Jurgen Priester, Aerospace Engineer, Rotorcraft
Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137-4298,
telephone (817) 222-5159, fax (817) 222-5785, for questions about
Superior Air Parts Inc. gas producer rotor assembly tie bolts.
SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39
with a proposed AD. The proposed AD applies to Rolls-Royce Corporation
250-B and 250-C series turboprop and turboshaft engines with certain P/
Ns of gas producer rotor assembly tie bolts manufactured by EXTEX Ltd.,
Pacific Sky Supply Inc., RRC, and Superior Air Parts Inc. We published
the proposed AD in the Federal Register on November 10, 2005 (70 FR
68381). That action proposed to require operators to remove from
service affected gas producer rotor assembly tie bolts.
Examining the AD Docket
You may examine the docket that contains the AD, any comments
received, and any final disposition in person at the Docket Management
Facility Docket Office between 9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays. The Docket Office (telephone (800)
647-5227) is located on the plaza level of the Department of
Transportation Nassif Building at the street address stated in
ADDRESSES. Comments will be available in the AD docket shortly after
the DMS receives them.
Comments
We provided the public the opportunity to participate in the
development of this AD. We have considered the comments received.
Request To Exclude Parts Manufacturer Approval (PMA) Tie Bolts
One commenter requests that the PMA tie bolts be excluded from the
AD action, because there are no reported failures of the PMA tie bolts.
Also, the commenter states that there are numerous opportunities for
significant design differences between PMA tie bolts approved under
Test and Computation, and the original equipment manufacturer (OEM) tie
bolts.
We do not agree. Although there are no reported failures of PMA
parts, the tie bolts from all four manufacturers are essentially the
same and share many common features. The fact that there are no
reported failures of PMA parts is statistically insignificant since the
PMA parts only account for several hundred of the approximately 5,000
tie bolts in service, and there have been only 11 failures.
Additionally, failures of a specific part number are not a prerequisite
for declaring an unsafe condition. A failure mode's net result on the
product (in this case loss of engine power, first stage turbine wheel
overspeed, and an uncontained engine failure); the assumed or predicted
rate of occurrence, and other factors linking affected or suspect parts
to failed parts, help make that decision. While minor differences may
exist between the OEM tie bolts and the PMA tie bolts, the commenter
gave no justification as to how those unnamed differences should exempt
the PMA parts from this AD action. Finally, we did compare design data
as part of the decision making process.
Request To Withdraw the Proposed AD
The same commenter requests that we withdraw the proposed AD and
not re-issue it until we are prepared to fully disclose what design
features caused the tie bolt failures. The commenter further states
that since the tie bolt requires a sustained preload for safe
operation, one would expect that maintenance or assembly practices are
more likely contributors, as the likelihood of high-cycle-fatigue
failures increases if the preload is not established or maintained
correctly.
We do not agree. While they may have minor differences between
them, the tie bolts from all four manufacturers are essentially the
same and share many common features. The commenter provides no data to
support the assertion that maintenance or assembly practices are more
likely contributors to the high-cycle-fatigue failures. Analysis of the
failures did not find any assembly problems. We did not change the AD.
Request To Provide Instructions on How to Make the Engine Airworthy
The same commenter requests that we provide instructions on how to
make the engine airworthy. The commenter states that the AD action
essentially specifies an action of ``remove, and do not reinstall, tie
bolt part numbers listed in Table 1.'' The commenter assumes there
[[Page 35506]]
will be instructions provided on how to make the engine airworthy.
We partially agree. While there is no way to make the removed tie
bolts airworthy, we reworded the AD to include a statement that the
removed tie bolts be replaced with tie bolts with P/Ns that are not
listed in Table 1 of the AD.
Conclusion
We have carefully reviewed the available data, including the
comments received, and determined that air safety and the public
interest require adopting the AD with the changes described previously.
We have determined that these changes will neither increase the
economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
About 700 RRC 250-B and 250-C series turboprop and turboshaft
engines with affected P/Ns of gas producer rotor assembly tie bolts
manufactured by EXTEX Ltd., Pacific Sky Supply Inc., Rolls-Royce
Corporation (RRC), and Superior Air Parts Inc., installed on aircraft
of U.S. registry, will be affected by this AD. We also estimate that it
will take about 20 workhours per engine to perform the actions, and
that the average labor rate is $65 per workhour. Required parts will
cost about $421 per engine. Based on these figures, we estimate the
total cost of the AD to U.S. operators to be $1,204,700.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
subtitle VII, part A, subpart III, section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will not have a
substantial direct effect 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.
For the reasons discussed above, I certify that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866;
(2) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and
(3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this AD and
placed it in the AD Docket. You may get a copy of this summary at the
address listed under ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the Federal Aviation Administration amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
2006-13-06 Rolls-Royce Corporation (formerly Allison Engine Company,
Allison Gas Turbine Division, and Detroit Diesel Allison): Amendment
39-14659. Docket No. FAA-2005-22594; Directorate Identifier 2005-NE-
28-AD.
Effective Date
(a) This airworthiness directive (AD) becomes effective July 26,
2006.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Rolls-Royce Corporation (formerly Allison
Engine Company, Allison Gas Turbine Division, and Detroit Diesel
Allison) 250-B17, -B17B, -B17C, -B17D, -B17E, -B17F, -B17F/1, -B17F/
2, 250-C18, -C20, -C20B, -C20F, -C20J, -C20R, -C20R/1, -C20R/2, -
C20R/4, -C20S, and ``C20W series turboprop and turboshaft engines
with the gas producer rotor assembly tie bolt part numbers (P/Ns)
listed in the following Table 1, installed:
Table 1.--Affected Gas Producer Rotor Assembly Tie Bolts
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Manufacturer Affected part numbers
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EXTEX Ltd. (EXTEX)............................. A23008020 and E23008020
Rolls-Royce Corporation (RRC).................. 23008020, 6843388 and 6876991
Superior Air Parts Inc. (SAP).................. A23008020
Pacific Sky Supply Inc......................... 23008020P
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These engines are installed on, but not limited to, aircraft in
the following Table 2:
Table 2.--Applicable Aircraft
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Helicopter Models
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Agusta................................... A109, A109A, A109A II, A109C.
Arrow Falcon Exporters................... OH-58A+ and OH-58C.
Bell Textron............................. 206A, 206B, 206L.
Enstrom.................................. TH-28, 480, 480B.
Eurocopter France........................ AS355E, AS355F, AS355F1, AS355F2.
Eurocopter Deutschland................... BO-105A, BO-105C, BO-105S.
[[Page 35507]]
FH-1100 Manufacturing Corp............... FH-1100.
Garlick.................................. OH-58A + OH-58C.
McDonnell Douglas Company................ 369D, 369E, 369F, 369H, 369HM, 369HS, 369HE, 500N.
San Joaquin.............................. OH-58A+ and OH-58C.
Schweizer................................ 269D.
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Aircraft Models
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B-N Group Ltd............................ BN-2T and BN-2T-4R.
SIAI Marchetti s.r.l..................... SF600, SF600A.
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Unsafe Condition
(d) This AD results from eleven reports of RRC tie bolt failure
due to high-cycle-fatigue. We are issuing this AD to prevent tie
bolt failure that could cause loss of engine power, resulting in a
first stage turbine wheel overspeed and an uncontained engine
failure.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified unless the
actions have already been done.
Remove Gas Producer Rotor Assembly Tie Bolts
(f) Remove the P/N gas producer rotor assembly tie bolts listed
in Table 1 of this AD from service the next time they are
disassembled for any reason, or by October 31, 2011, whichever
occurs first, and replace with tie bolts with P/Ns that are not
listed in Table 1 of this AD.
(g) After the effective date of this AD, do not install any gas
producer rotor assembly tie bolt P/Ns listed in Table 1 of this AD
in any RRC 250-B and 250-C Series turboprop and turboshaft engines.
Alternative Methods of Compliance
(h) The Manager, Los Angeles Aircraft Certification Office, has
the authority to approve alternative methods of compliance for
EXTEX, and Pacific Sky Supply Inc. gas producer rotor assembly tie
bolts addressed in this AD, if requested, using the procedures found
in 14 CFR 39.19. The Manager, Chicago Aircraft Certification Office,
has the authority to approve alternative methods of compliance for
RRC gas producer rotor assembly tie bolts addressed in this AD, if
requested, using the procedures found in 14 CFR 39.19. The Manager,
Southwest Special Certification Office, has the authority to approve
alternative methods of compliance for SAP gas producer rotor
assembly tie bolts addressed in this AD, if requested, using the
procedures found in 14 CFR 39.19.
Related Information
(i) RRC Commercial Engine Bulletin (CEB) CEB A-304, CEB A-1371,
CEB A-72-4076, TP CEB A-176, TP CEB A-1319, TP CEB A-72-2027,
Revision N/C, dated May 23, 2005, and EXTEX Service Bulletin T-090,
Revision N/C, dated May 23, 2005, pertain to the subject of this AD.
Issued in Burlington, Massachusetts, on June 14, 2006.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 06-5547 Filed 6-20-06; 8:45 am]
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