Airworthiness Directives; General Electric Company CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 Turbofan Engines, 42725-42727 [E8-16884]
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Federal Register / Vol. 73, No. 142 / Wednesday, July 23, 2008 / Proposed Rules
would cost about $16,972 per engine.
Based on these figures, we estimate the
total cost of the proposed AD to U.S.
operators to be $1,514,068.
Authority for This Rulemaking
Regulatory Findings
We have determined that this
proposed AD would not have federalism
implications under Executive Order
13132. This proposed AD would 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 the proposed AD:
1. Is not a ‘‘significant regulatory
action’’ under Executive Order 12866;
2. Is not a ‘‘significant rule’’ under the
DOT Regulatory Policies and Procedures
(44 FR 11034, February 26, 1979); and
3. Would 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 regulatory evaluation
of the estimated costs to comply with
this proposed AD. You may get a copy
of this summary at the address listed
under ADDRESSES.
pwalker on PROD1PC71 with PROPOSALS
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation
safety, Safety.
The Proposed Amendment
Under the authority delegated to me
by the Administrator, the Federal
Aviation Administration proposes to
amend 14 CFR part 39 as follows:
17:30 Jul 22, 2008
Jkt 214001
1. The authority citation for part 39
continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
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.
VerDate Aug<31>2005
PART 39—AIRWORTHINESS
DIRECTIVES
§ 39.13
[Amended]
2. The FAA amends § 39.13 by adding
the following new airworthiness
directive:
General Electric Company (GE): Docket No.
FAA–2008–0808; Directorate Identifier
2008–NE–18–AD.
Comments Due Date
(a) The Federal Aviation Administration
(FAA) must receive comments on this
airworthiness directive (AD) action by
September 22, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to GE CT58 series
turboshaft engines with a compressor spool,
part number (P/N) 5920T82G07,
6010T57G07, or 6010T57G08, installed.
These engines are installed on, but not
limited to, Sikorsky S–61A, S–61L, S–61N,
S–61R, S–62, and Columbia 107–II
helicopters.
Unsafe Condition
(d) This AD results from reports of cracks
originating from the inner faces of the locking
screw holes in the compressor spool. We are
issuing this AD to prevent cracks due to
repetitive heavy lift (RHL) missions. Cracks
could result in an uncontained rotor burst
and damage to, or loss of, the helicopter and
serious injuries to any person onboard.
42725
spool exceeds its part life limit as calculated
using an RHL multiplying factor of 6.0.
(i) As of January 1, 2010, don’t use an RHL
multiplying factor of 3.7 to calculate the life
of the compressor spool.
Installation Prohibition
(j) After the effective date of this AD, don’t
install any engine that has a compressor
spool installed that meets or exceeds the life
limits as calculated in paragraph (g)(1)
through (g)(2) or (h) of this AD.
Alternative Methods of Compliance
(k) The Manager, Engine Certification
Office, has the authority to approve
alternative methods of compliance for this
AD if requested using the procedures found
in 14 CFR 39.19.
Related Information
(l) GE Alert Service Bulletin CT58 S/B 72–
A0162, Revision 12, dated April 17, 2008,
pertains to the subject of this AD.
(m) Contact Christopher J. Richards,
Aerospace Engineer, Engine Certification
Office, FAA, Engine & Propeller Directorate,
12 New England Executive Park, Burlington,
MA 01803; e-mail:
christopher.j.richards@faa.gov; telephone
(781) 238–7133; fax (781) 238–7199, for more
information about this AD.
Issued in Burlington, Massachusetts, on
July 17, 2008.
Marc Bouthillier,
Acting Manager, Engine and Propeller
Directorate, Aircraft Certification Service.
[FR Doc. E8–16883 Filed 7–22–08; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
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.
Federal Aviation Administration
Recalculating Compressor Spool Cycles
(f) Within 30 days after the effective date
of this AD, recalculate the life of compressor
spools, P/N 5920T82G07, 6010T57G07, or
6010T57G08, using an RHL mission
multiplying factor of both 3.7 cycles per hour
and 6.0 cycles per hour. GE Alert Service
Bulletin CT58 S/B 72–A0162, Revision 12,
dated April 17, 2008, contains information
on calculating life cycles for the compressor
spools.
RIN 2120–AA64
Removing Compressor Spools Based on the
New Recalculated Cycles
(g) Before January 1, 2010, remove the
compressor spools, P/N 5920T82G07,
6010T57G07, or 6010T57G08, at the earlier of
when:
(1) The compressor spool reaches its part
life limit as calculated using an RHL
multiplying factor of 3.7, or
(2) You can see the spool at shop visit after
it has reached its part life limit using an RHL
multiplying factor of 6.0.
(h) On January 1, 2010 and thereafter,
remove the engine before the compressor
PO 00000
Frm 00002
Fmt 4702
Sfmt 4702
14 CFR Part 39
[Docket No. FAA–2007–0419; Directorate
Identifier 2007–NE–52–AD]
Airworthiness Directives; General
Electric Company CF34–1A, –3A, –3A1,
–3A2, –3B, and –3B1 Turbofan Engines
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
AGENCY:
SUMMARY: The FAA proposes to adopt a
new airworthiness directive (AD) for
General Electric Company (GE) CF34–
1A, –3A, –3A1, –3A2, –3B, and –3B1
turbofan engines with high-pressure
(HP) rotor 4-step air balance piston
stationary seals (4-step seals), part
numbers 4923T54G01, 6019T90G03,
6037T99G01, 6037T99G02, and
6037T99G03, installed. This proposed
AD would require removing the 4-step
seals and incorporating an 8-step seal at
E:\FR\FM\23JYP1.SGM
23JYP1
42726
Federal Register / Vol. 73, No. 142 / Wednesday, July 23, 2008 / Proposed Rules
pwalker on PROD1PC71 with PROPOSALS
the next piece-part exposure. This
proposed AD results from the
investigation of an airplane accident.
Both engines experienced high-altitude
flameouts. Rotation of the HP rotors was
not maintained during descent and the
engines could not be restarted. We are
proposing this AD to prevent the
inability to restart both engines after
flameout due to excessive friction of the
4-step seal, which could result in
subsequent forced landing of the
airplane.
DATES: We must receive any comments
on this proposed AD by September 22,
2008.
ADDRESSES: Use one of the following
addresses to comment on this proposed
AD.
• Federal eRulemaking Portal: Go to
https://www.regulations.gov and follow
the instructions for sending your
comments electronically.
• Mail: Docket Management Facility,
U.S. Department of Transportation, 1200
New Jersey Avenue, SE., West Building
Ground Floor, Room W12–140,
Washington, DC 20590–0001.
• Hand Delivery: Deliver to Mail
address above between 9 a.m. and 5
p.m., Monday through Friday, except
Federal holidays.
• Fax: (202) 493–2251.
You can get the service information
identified in this proposed AD from
General Electric Company via Lockheed
Martin Technology Services, 10525
Chester Road, Suite C, Cincinnati, Ohio
45215, telephone (513) 672–8400, fax
(513) 672–8422.
FOR FURTHER INFORMATION CONTACT:
Kenneth Steeves, Aerospace Engineer,
Engine Certification Office, Engine and
Propeller Directorate, FAA, 12 New
England Executive Park, Burlington, MA
01803; e-mail: kenneth.steeves@faa.gov;
telephone: (781) 238–7765; fax: (781)
238–7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send us any written
relevant data, views, or arguments
regarding this proposal. Send your
comments to an address listed under
ADDRESSES. Include ‘‘Docket No. FAA–
2007–0419; Directorate Identifier 2007–
NE–52–AD’’ in the subject line of your
comments. We specifically invite
comments on the overall regulatory,
economic, environmental, and energy
aspects of the proposed AD. We will
consider all comments received by the
closing date and may amend the
proposed AD in light of those
comments.
We will post all comments we
receive, without change, to https://
VerDate Aug<31>2005
17:30 Jul 22, 2008
Jkt 214001
www.regulations.gov, including any
personal information you provide. We
will also post a report summarizing each
substantive verbal contact with FAA
personnel concerning this proposed AD.
Using the search function of the Web
site, anyone can find and read the
comments in any of our dockets. This
includes, if provided, the name of the
individual who sent the comment (or
signed the comment on behalf of an
association, business, labor union, etc.).
You may review the DOT’s complete
Privacy Act Statement in the Federal
Register published on April 11, 2000
(65 FR 19477–78).
Examining the AD Docket
You may examine the AD docket on
the Internet at http: //
www.regulations.gov; or in person at the
Docket Operations office between 9 a.m.
and 5 p.m., Monday through Friday,
except Federal holidays. The AD docket
contains this proposed AD, the
regulatory evaluation, any comments
received, and other information. The
street address for the Docket Operations
office (telephone (800) 647–5527) is the
same as the Mail address provided in
the ADDRESSES section. Comments will
be available in the AD docket shortly
after receipt.
Discussion
In October 2004, a Bombardier
CL600–2B19 Regional Jet airplane
experienced high-altitude flameouts of
both engines while on a ferry flight.
After flameout, when the airplane was
descending, sufficient airspeed was not
maintained to ensure rotation of the HP
rotors and they stopped rotating. During
repeated unsuccessful engine restart
attempts on both engines, the HP rotors
did not obtain sufficient rotational
speeds for the engines to restart. The
airplane eventually crashed while
attempting to glide to an airport, and the
crew was fatally injured. When these
engines experience a high-altitude
flameout, the engines are immediately
subjected to rapid cooling due to the
extremely cold air flowing around and
through them. The static seal parts cool
more rapidly than the rotors, and shrink
until they contact the rotating seal
surfaces. If the speed of the airplane is
not sufficient to maintain windmill
rotation of the HP rotors, the rotors will
stop rotating and could lock if sufficient
friction develops between the rotating
and static air balance piston seal
surfaces. This condition, if not
corrected, could result in the inability to
restart the engines and the subsequent
forced landing of the airplane.
Investigation by GE determined that
under certain conditions, the existing 4-
PO 00000
Frm 00003
Fmt 4702
Sfmt 4702
step seals used in CF34–1A, –3A, –3A1,
–3A2, –3B, and –3B1 turbofan engines
can come into contact with the rotating
seal surfaces and create friction. In a
worse case, this friction could cause
locking of the HP rotors, called ‘‘rotor
lock’’. GE is introducing 8-step seals for
all CF34–1A, –3A, –3A1, –3A2, –3B,
and –3B1 turbofan engines. The 8-step
seals will reduce potential drag in the
rotor system and enhance the
windmilling capabilities of HP rotors.
This will ultimately reduce the
possibility of the HP rotor locking after
a high-altitude flameout when HP rotor
rotation is not maintained during
descent.
FAA’s Determination and Requirements
of the Proposed AD
We have evaluated all pertinent
information and identified an unsafe
condition that is likely to exist or
develop on other products of this same
type design. We are proposing this AD,
which would require removing the 4step seal at next piece-part exposure and
incorporating an 8-step seal, either by
modifying the existing 4-step seal to an
8-step seal or by replacing it with an 8step seal.
Costs of Compliance
We estimate that this proposed AD
would affect 2,722 CF34–1A, –3A,
–3A1, –3A2, –3B, and –3B1 turbofan
engines installed on airplanes of U.S.
registry. We also estimate that this
proposed AD will not impose any
additional labor or material costs as
most of the seals will require
replacement when they are removed
from the engine during scheduled
engine overhaul. For those few seals
that can be reworked, we estimate that
it would take about 5 work-hours per
engine to perform the proposed seal
modification, and that the average labor
rate is $80 per work-hour. Based on
these figures, we estimate the total cost
of the proposed AD to U.S. operators to
be $108,800.
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
E:\FR\FM\23JYP1.SGM
23JYP1
Federal Register / Vol. 73, No. 142 / Wednesday, July 23, 2008 / Proposed Rules
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
proposed AD would not have federalism
implications under Executive Order
13132. This proposed AD would 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 the proposed AD:
1. Is not a ‘‘significant regulatory
action’’ under Executive Order 12866;
2. Is not a ‘‘significant rule’’ under the
DOT Regulatory Policies and Procedures
(44 FR 11034, February 26, 1979); and
3. Would 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 regulatory evaluation
of the estimated costs to comply with
this proposed AD. 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.
The Proposed Amendment
Under the authority delegated to me
by the Administrator, the Federal
Aviation Administration proposes to
amend 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.
§ 39.13
[Amended]
2. The FAA amends § 39.13 by adding
the following new airworthiness
directive:
pwalker on PROD1PC71 with PROPOSALS
General Electric Company: Docket No. FAA–
2007–0419; Directorate Identifier 2007–
NE–52–AD.
Comments Due Date
(a) The Federal Aviation Administration
(FAA) must receive comments on this
airworthiness directive (AD) action by
September 22, 2008.
Affected ADs
(b) None.
VerDate Aug<31>2005
Applicability
(c) This AD applies to General Electric
Company (GE) CF34–1A, –3A, –3A1, –3A2,
–3B, and –3B1 turbofan engines, with highpressure (HP) rotor 4-step air balance piston
stationary seals (4-step seals), part numbers
(P/Ns) 4923T54G01, 6019T90G03,
6037T99G01, 6037T99G02, and 6037T99G03,
installed. These engines are installed on, but
not limited to, Bombardier, Inc. airplane
models CL–600–2A12, –2B16, and –2B19.
Unsafe Condition
(d) This AD results from the investigation
of an airplane accident. Both engines
experienced high-altitude flameouts.
Rotation of the HP rotors was not maintained
during descent and the engines could not be
restarted. We are issuing this AD to prevent
the inability to restart both engines after
flameout due to excessive friction of the 4step seal, which could result in subsequent
forced landing of the airplane.
Compliance
(e) You are responsible for having the
actions required by this AD performed at the
next piece-part exposure after the effective
date of this AD, unless the actions have
already been done.
(f) Remove the 4-step seals, P/Ns
4923T54G01, 6019T90G03, 6037T99G01,
6037T99G02, and 6037T99G03.
(g) Incorporate an 8-step seal, either by
modifying the existing 4-step seal to an 8step seal, or by replacing it with an 8-step
seal.
(h) Information on modifying the seal and
part number configuration charts, can be
found in GE Service Bulletin (SB) No. CF34–
AL S/B 72–0238, dated July 27, 2007 (CL–
600–2B19), and SB No. CF34–BJ S/B 72–
0217, dated July 27, 2007 (CL–600–2A12 and
CL–600–2B16).
Definition
(i) For the purposes of this AD, piece-part
exposure means when the 4-step seal is
removed from the combustion module in
accordance with the disassembly instructions
in the engine manufacturer’s, or other FAAapproved engine manual.
Alternative Methods of Compliance
(j) The Manager, Engine Certification
Office, has the authority to approve
alternative methods of compliance for this
AD if requested using the procedures found
in 14 CFR 39.19.
Related Information
(k) Contact Kenneth Steeves, Aerospace
Engineer, Engine Certification Office, Engine
and Propeller Directorate, FAA, 12 New
England Executive Park, Burlington, MA
01803; e-mail: keneth.steeves@faa.gov;
telephone: (781) 238–7765, fax: (781) 238–
7199; for more information about this AD.
Issued in Burlington, Massachusetts, on
July 16, 2008.
Marc Bouthillier,
Acting Manager, Engine and Propeller
Directorate, Aircraft Certification Service.
[FR Doc. E8–16884 Filed 7–22–08; 8:45 am]
BILLING CODE 4910–13–P
17:30 Jul 22, 2008
Jkt 214001
PO 00000
Frm 00004
Fmt 4702
Sfmt 4702
42727
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R02–OAR–2008–0479; FRL–8696–2]
Determination of Attainment of the
One-Hour Ozone Standard for the
Southern New Jersey Portion of the
Philadelphia Metropolitan
Nonattainment Area
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
SUMMARY: EPA is proposing to
determine that the one-hour ozone
nonattainment area in Southern New
Jersey, that is, the New Jersey portion of
the Philadelphia-Wilmington-Trenton,
PA-NJ-DE-MD area, attained the onehour ozone standard, is not subject to
the imposition of penalty fees under
section 185 of the Clean Air Act and
does not need to implement
contingency measures. Areas that EPA
classified as severe ozone
nonattainment areas for the one-hour
National Ambient Air Quality Standard
and did not attain the Standard by the
applicable attainment date of November
15, 2005 may be subject to these penalty
fees. However, since the air quality in
the Philadelphia-Wilmington-Trenton
area attained the ozone standard as of
November 15, 2005, EPA is proposing
not to implement these fees. This
proposed determination of attainment is
not a redesignation of attainment for
this area, only a fulfillment of a Clean
Air Act obligation to determine if an
area attains the ozone standard by its
applicable attainment date.
DATES: Comments must be received on
or before August 22, 2008.
ADDRESSES: Submit your comments,
identified by Docket ID No. EPA–R02–
OAR–2008–0479, by one of the
following methods:
• www.regulations.gov: Follow the
online instructions for submitting
comments.
• E-mail: Werner.Raymond@epa.gov.
• Fax: 212–637–3901.
• Mail: Raymond Werner, Chief, Air
Programs Branch, Environmental
Protection Agency, Region 2 Office, 290
Broadway, 25th Floor, New York, New
York 10007–1866.
• Hand Delivery: Raymond Werner,
Chief, Air Programs Branch,
Environmental Protection Agency,
Region 2 Office, 290 Broadway, 25th
Floor, New York, New York 10007–
1866. Such deliveries are only accepted
during the Regional Office’s normal
hours of operation. The Regional
E:\FR\FM\23JYP1.SGM
23JYP1
]]>Agencies
[Federal Register Volume 73, Number 142 (Wednesday, July 23, 2008)]
[Proposed Rules]
[Pages 42725-42727]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-16884]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0419; Directorate Identifier 2007-NE-52-AD]
RIN 2120-AA64
Airworthiness Directives; General Electric Company CF34-1A, -3A,
-3A1, -3A2, -3B, and -3B1 Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for General Electric Company (GE) CF34-1A, -3A, -3A1, -3A2, -3B, and -
3B1 turbofan engines with high-pressure (HP) rotor 4-step air balance
piston stationary seals (4-step seals), part numbers 4923T54G01,
6019T90G03, 6037T99G01, 6037T99G02, and 6037T99G03, installed. This
proposed AD would require removing the 4-step seals and incorporating
an 8-step seal at
[[Page 42726]]
the next piece-part exposure. This proposed AD results from the
investigation of an airplane accident. Both engines experienced high-
altitude flameouts. Rotation of the HP rotors was not maintained during
descent and the engines could not be restarted. We are proposing this
AD to prevent the inability to restart both engines after flameout due
to excessive friction of the 4-step seal, which could result in
subsequent forced landing of the airplane.
DATES: We must receive any comments on this proposed AD by September
22, 2008.
ADDRESSES: Use one of the following addresses to comment on this
proposed AD.
Federal eRulemaking Portal: Go to https://
www.regulations.gov and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility, U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Fax: (202) 493-2251.
You can get the service information identified in this proposed AD
from General Electric Company via Lockheed Martin Technology Services,
10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513)
672-8400, fax (513) 672-8422.
FOR FURTHER INFORMATION CONTACT: Kenneth Steeves, Aerospace Engineer,
Engine Certification Office, Engine and Propeller Directorate, FAA, 12
New England Executive Park, Burlington, MA 01803; e-mail:
kenneth.steeves@faa.gov; telephone: (781) 238-7765; fax: (781) 238-
7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send us any written relevant data, views, or
arguments regarding this proposal. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2007-0419; Directorate
Identifier 2007-NE-52-AD'' in the subject line of your comments. We
specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of the proposed AD. We will consider
all comments received by the closing date and may amend the proposed AD
in light of those comments.
We will post all comments we receive, without change, to https://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact
with FAA personnel concerning this proposed AD. Using the search
function of the Web site, anyone can find and read the comments in any
of our dockets. This includes, if provided, the name of the individual
who sent the comment (or signed the comment on behalf of an
association, business, labor union, etc.). You may review the DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (65 FR 19477-78).
Examining the AD Docket
You may examine the AD docket on the Internet at http: //
www.regulations.gov; or in person at the Docket Operations office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Operations office (telephone (800) 647-5527) is
the same as the Mail address provided in the ADDRESSES section.
Comments will be available in the AD docket shortly after receipt.
Discussion
In October 2004, a Bombardier CL600-2B19 Regional Jet airplane
experienced high-altitude flameouts of both engines while on a ferry
flight. After flameout, when the airplane was descending, sufficient
airspeed was not maintained to ensure rotation of the HP rotors and
they stopped rotating. During repeated unsuccessful engine restart
attempts on both engines, the HP rotors did not obtain sufficient
rotational speeds for the engines to restart. The airplane eventually
crashed while attempting to glide to an airport, and the crew was
fatally injured. When these engines experience a high-altitude
flameout, the engines are immediately subjected to rapid cooling due to
the extremely cold air flowing around and through them. The static seal
parts cool more rapidly than the rotors, and shrink until they contact
the rotating seal surfaces. If the speed of the airplane is not
sufficient to maintain windmill rotation of the HP rotors, the rotors
will stop rotating and could lock if sufficient friction develops
between the rotating and static air balance piston seal surfaces. This
condition, if not corrected, could result in the inability to restart
the engines and the subsequent forced landing of the airplane.
Investigation by GE determined that under certain conditions, the
existing 4-step seals used in CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1
turbofan engines can come into contact with the rotating seal surfaces
and create friction. In a worse case, this friction could cause locking
of the HP rotors, called ``rotor lock''. GE is introducing 8-step seals
for all CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 turbofan engines. The
8-step seals will reduce potential drag in the rotor system and enhance
the windmilling capabilities of HP rotors. This will ultimately reduce
the possibility of the HP rotor locking after a high-altitude flameout
when HP rotor rotation is not maintained during descent.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other products
of this same type design. We are proposing this AD, which would require
removing the 4-step seal at next piece-part exposure and incorporating
an 8-step seal, either by modifying the existing 4-step seal to an 8-
step seal or by replacing it with an 8-step seal.
Costs of Compliance
We estimate that this proposed AD would affect 2,722 CF34-1A, -3A,
-3A1, -3A2, -3B, and -3B1 turbofan engines installed on airplanes of
U.S. registry. We also estimate that this proposed AD will not impose
any additional labor or material costs as most of the seals will
require replacement when they are removed from the engine during
scheduled engine overhaul. For those few seals that can be reworked, we
estimate that it would take about 5 work-hours per engine to perform
the proposed seal modification, and that the average labor rate is $80
per work-hour. Based on these figures, we estimate the total cost of
the proposed AD to U.S. operators to be $108,800.
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
[[Page 42727]]
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 proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the proposed AD:
1. Is not a ``significant regulatory action'' under Executive Order
12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979); and
3. Would 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 regulatory evaluation of the estimated costs to
comply with this proposed AD. 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.
The Proposed Amendment
Under the authority delegated to me by the Administrator, the
Federal Aviation Administration proposes to amend 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. The FAA amends Sec. 39.13 by adding the following new
airworthiness directive:
General Electric Company: Docket No. FAA-2007-0419; Directorate
Identifier 2007-NE-52-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this airworthiness directive (AD) action by September
22, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to General Electric Company (GE) CF34-1A, -
3A, -3A1, -3A2, -3B, and -3B1 turbofan engines, with high-pressure
(HP) rotor 4-step air balance piston stationary seals (4-step
seals), part numbers (P/Ns) 4923T54G01, 6019T90G03, 6037T99G01,
6037T99G02, and 6037T99G03, installed. These engines are installed
on, but not limited to, Bombardier, Inc. airplane models CL-600-
2A12, -2B16, and -2B19.
Unsafe Condition
(d) This AD results from the investigation of an airplane
accident. Both engines experienced high-altitude flameouts. Rotation
of the HP rotors was not maintained during descent and the engines
could not be restarted. We are issuing this AD to prevent the
inability to restart both engines after flameout due to excessive
friction of the 4-step seal, which could result in subsequent forced
landing of the airplane.
Compliance
(e) You are responsible for having the actions required by this
AD performed at the next piece-part exposure after the effective
date of this AD, unless the actions have already been done.
(f) Remove the 4-step seals, P/Ns 4923T54G01, 6019T90G03,
6037T99G01, 6037T99G02, and 6037T99G03.
(g) Incorporate an 8-step seal, either by modifying the existing
4-step seal to an 8-step seal, or by replacing it with an 8-step
seal.
(h) Information on modifying the seal and part number
configuration charts, can be found in GE Service Bulletin (SB) No.
CF34-AL S/B 72-0238, dated July 27, 2007 (CL-600-2B19), and SB No.
CF34-BJ S/B 72-0217, dated July 27, 2007 (CL-600-2A12 and CL-600-
2B16).
Definition
(i) For the purposes of this AD, piece-part exposure means when
the 4-step seal is removed from the combustion module in accordance
with the disassembly instructions in the engine manufacturer's, or
other FAA-approved engine manual.
Alternative Methods of Compliance
(j) The Manager, Engine Certification Office, has the authority
to approve alternative methods of compliance for this AD if
requested using the procedures found in 14 CFR 39.19.
Related Information
(k) Contact Kenneth Steeves, Aerospace Engineer, Engine
Certification Office, Engine and Propeller Directorate, FAA, 12 New
England Executive Park, Burlington, MA 01803; e-mail:
keneth.steeves@faa.gov; telephone: (781) 238-7765, fax: (781) 238-
7199; for more information about this AD.
Issued in Burlington, Massachusetts, on July 16, 2008.
Marc Bouthillier,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. E8-16884 Filed 7-22-08; 8:45 am]
BILLING CODE 4910-13-P
