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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0679; Project Identifier AD-2020-01060-E;
Amendment 39-21197; AD 2020-16-13]
RIN 2120-AA64
Airworthiness Directives; Rolls-Royce Corporation (Type
Certificate Previously Held by Allison Engine Company) Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD)
for
certain Rolls-Royce Corporation (RRC) AE 3007A, AE 3007A1, AE 3007A1/1,
AE
3007A1/2, AE 3007A1/3, AE 3007A1E, AE 3007A1P, and AE 3007A3 model
turbofan engines. This AD was prompted by an in-flight shutdown (IFSD)
of an engine and subsequent investigation by the manufacturer that
revealed a crack in the 3rd-stage compressor wheel. This AD requires
replacement of affected 3rd-stage compressor wheels. The FAA is issuing
this AD to address the unsafe condition on these products.
DATES: This AD is effective August 14, 2020.
The FAA must receive comments on this AD by September 14, 2020.
ADDRESSES: You may send comments, using the procedures found in
14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
the
instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this final rule, contact
Rolls-Royce Corporation, 450 South Meridian Street, Mail Code NB-01-06,
Indianapolis, IN 46225; phone: (317) 230-1667; email: CMSEindyOSD@
rolls-royce.com; internet: www.rolls-royce.com. You may
view this service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 1200 District Avenue, Burlington,
MA 01803. For information on the availability of this material at the
FAA, call 781-238-7759.
Examining the AD Docket
You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-
0679; or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this final rule, any comments received, and other information. The
street address for the Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Kyri Zaroyiannis, Aerospace Engineer,
Chicago ACO, FAA, 2300 E Devon Ave., Des Plaines, IL 60018; phone:
(847) 294-7836; fax: (847) 294-7834; email: kyri.zaroyiannis@faa.gov.
SUPPLEMENTARY INFORMATION:
Background
The FAA learned of an uncommanded IFSD of a RRC AE 3007A1 model
turbofan engine installed on an Embraer S.A. ERJ-145 airplane
conducting a revenue flight. The manufacturer's investigation of this
incident revealed that the IFSD resulted from a low-cycle fatigue crack
in the dovetail slot for the blade attachment in the 3rd-stage
compressor wheel, causing one 3rd-stage compressor blade to release.
The crack initiated in the dovetail slot due to a sharp corner in the
wheel slot geometry. The broaching process was identified as the cause
and parts from this manufacturing lot require removal from service.
This condition, if not addressed, could result in uncontained release
of the 3rd-stage compressor wheel, damage to the engine, and damage to
the airplane. The FAA is issuing this AD to address the unsafe
condition on these products.
FAA's Determination
The FAA is issuing this AD because the agency evaluated all the
relevant information and determined the unsafe condition described
previously is likely to exist or develop in other products of the same
type design.
Related Service Information
The FAA reviewed Rolls-Royce Alert Service Bulletin (ASB) AE 3007A-
A-72-446, Revision 2, dated July 28, 2020. The ASB describes procedures
for replacing certain 3rd-stage compressor wheels.
AD Requirements
This AD requires replacement of certain 3rd-stage compressor wheels
before they accumulate a specified number of cycles.
FAA's Justification for Immediate Adoption and Determination of the
Effective Date
Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C.) authorizes agencies to dispense with notice and comment
procedures for rules when the agency, for ``good cause,'' finds that
those procedures are ``impracticable, unnecessary, or contrary to the
public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than 30 days, upon
a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies waiving notice and comment prior to adoption of this rule.
RRC inspected a RRC AE3007A1 model turbofan engine after it experiences
an uncommanded IFSD during a revenue flight on an Embraer ERJ-145
airplane.
The manufacturer's inspection discovered a low-cycle fatigue crack
in a 3rd-stage compressor wheel that allowed a 3rd-stage compressor
blade to release during the flight. The manufacturer traced the cause
of the cracked 3rd-stage compressor wheel to a specific machining
process that occurred during manufacture of the 3rd-stage compressor
wheels. The manufacturer's subsequent investigation discovered multiple
3rd-stage compressor wheels in the affected serial numbered population
with similar low-cycle fatigue cracks. The 3rd-stage compressor wheels
identified in this AD are unable to remain in service beyond the cycles
since new limits listed in paragragh (g) of this AD. As a result of the
shortened compliance times established based on the FAA's risk
assessment, the FAA has determined that there is insufficient time
available to allow for notice and opportunity for prior public comment.
The FAA considers the removal of these 3rd-stage compressor wheels
from service to be an urgent safety issue. Exceeding the reduced cycle
limits on the 3rd-stage compressor wheels required by this AD could
lead to failure of the 3rd-stage compressor wheel and high-energy
release of the 3rd-stage compressor wheel, resulting in damage to the
engine and damage to the airplane. Accordingly, notice and opportunity
for prior public comment are impracticable and contrary to public
interest pursuant to 5 U.S.C. 553(b)(3)(B).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forgo notice and
comment.
Comments Invited
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
the ADDRESSES section. Include the docket number FAA-2020-0679 and
Project Identifier AD-2020-01060-E at the beginning of your comments.
The most helpful comments reference a specific portion of the final
rule, explain the reason for any recommended change, and include
supporting data. The FAA will consider all comments received by the
closing date and may amend this final rule because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The FAA will also post a report summarizing each substantive
verbal contact received about this final rule.
Confidential Business Information
Confidential Business Information (CBI) is commercial or financial
information that is both customarily and actually treated as private by
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552),
CBI is exempt from public disclosure. If your comments responsive to
this final rule contain commercial or financial information that is
customarily treated as private, that you actually treat as private, and
that is relevant or responsive to this final rule, it is important that
you clearly designate the submitted comments as CBI. Please mark each
page of your submission containing CBI as ``PROPIN.'' The FAA will
treat such marked submissions as confidential under the FOIA, and they
will not be placed in the public docket of this final rule. Submissions
containing CBI should be sent to Kyri Zaroyiannis, Aerospace Engineer,
Chicago ACO, FAA, 2300 E. Devon Ave., Des Plaines, IL 60018. Any
commentary that the FAA receives which is not specifically designated
as CBI will be placed in the public docket for this rulemaking.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.
Costs of Compliance
The FAA estimate that this AD affects 4 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
|
Action
|
Labor cost
|
Parts cost
|
Cost per
product
|
Cost on
U.S. operators
|
| Remove 3rd-stage compressor wheel |
40 work-hours x $85 per hour
= $3,400 |
$0
|
$3,400
|
$13,600
|
| Replace 3rd-stage compressor
wheel |
85 work-hours x $85 per hour
= $7,225 |
32,844
|
40,069
|
160,276
|
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.
The FAA is 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
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) Will not affect intrastate aviation in Alaska, and
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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 (AD):
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