DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0400; Project Identifier AD-2022-00179-E;
Amendment 39-22009; AD 2022-08-06]
RIN 2120-AA64

Airworthiness Directives; General Electric 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 General Electric Company (GE) CF34-8C and CF34-8E model
turbofan engines. This AD was prompted by an ``Engine Degraded''
message received in-flight from the Engine Indicating and Crew Alerting
System (EICAS), and a subsequent investigation by the manufacturer that
revealed corrosion of the variable geometry (VG) system actuator, which
can cause the full authority digital engine control (FADEC) software to
command and lock the engine at idle until it is restarted. This AD
requires performing a rotational torque check on the actuating linkage
assembly and, depending on the results of the rotational torque check,
replacement of the compressor inlet guide vane (IGV) outer shroud
bushing and vane spindle bushing with parts eligible for installation.
This AD also requires reporting the results of the rotational torque
check to GE. The FAA is issuing this AD to address the unsafe condition
on these products.

DATES: AD is effective April 29, 2022.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of April 29,
2022.
The FAA must receive comments on this AD by May 31, 2022.

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: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this final rule, contact
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone:
(513) 552-3272; email: aviation.fleetsupport@ge.com; website: https://www.ge.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 (817) 222-5110. It is
also available at https://www.regulations.gov by searching for and
locating Docket No. FAA-2022-0400.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0400; 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: Scott Stevenson, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7132; email: Scott.M.Stevenson@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

On August 11, 2021, a Bombardier CRJ1000 airplane, powered by GE
CF34-8C5 model turbofan engines, experienced an in-flight engine
shutdown that resulted in a diversion. The manufacturer's investigation
found that this airplane was parked outdoors for extended lengths of
time within 10 miles (16 km) from a saltwater coastline, causing
corrosion to develop on the CF34-8C5 engines' compressor VG actuator
rod, seizure of the rod end bearing, and fracture of the rod end. Based
on the manufacturer's investigation, on November 4, 2021, the FAA
issued Emergency AD 2021-23-51 (followed by publication in the Federal
Register on December 14, 2021, as a Final Rule, Request for Comments
(86 FR 70969)), which requires performing an inspection of the master
compressor VG actuator and slave compressor VG actuator on certain GE
CF34-8C and CF34-8E model turbofan engines and, depending on the
results of the inspection, replacement of the part with a part eligible
for installation.
Since the FAA issued AD 2021-23-51, the manufacturer determined
that two additional in-flight events occurred that were related to this
unsafe condition. On September 7, 2021 and October 26, 2021, two
Bombardier CRJ-900 airplanes powered by GE CF34-8C5 model turbofan
engines received ``Engine Degraded'' messages from the EICAS during
flight. A subsequent investigation by the manufacturer found that these
engines were operated infrequently over the past 2 years, with one
engine showing corrosion findings after being stored approximately 45
miles (72 km) from a saltwater coastline, and another engine showing
corrosion findings after being installed on an airplane parked for over
250 days. The manufacturer's investigation concluded that engines
stored outdoors for 250 or more days are at risk of the excessive
corrosion build up, with the risk increasing if the engines were stored
outdoors in close proximity to a saltwater coastline. These conditions
caused corrosion to develop between the high-pressure compressor case
and vane bushings, increasing the VG actuation loads and slowing the VG
response. As a result, the VG command and actual positions exceeded
acceptable disagreement parameters, triggering an EICAS ``Engine
Degraded'' message. In response to the ``Engine Degraded'' message, all
versions of the full authority digital engine control (FADEC) software
on GE CF34-8E engines, and FADEC software earlier than Version 6.60 on
GE CF34-8C engines automatically reduces the engine to idle and locks
the throttle until the engine is shut down and restarted. This
condition, if not addressed, could result in failure of one or more
engines, loss of engine thrust control, and reduced control of 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 has determined the
unsafe condition described previously is likely to exist or develop in
other products of the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed GE CF34-8C Service Bulletin (SB) 72-0356 R00 and
GE CF34-8E SB 72-0244 R00, both dated February 15, 2022. These SBs
specify procedures for performing a one-time rotational torque check of
the actuating linkage assembly, differentiated by engine model, to
identify possible interface corrosion or seizure on the compressor
case, compressor IGV outer shroud bushing, vane spindle bushing,
compressor stator IGV variable vane, compressor stator stage 1 variable
vane, compressor stator stage 2 variable vane, compressor stator stage
3 variable vane, and compressor stator stage 4 variable vane. These SBs
also specify instructions for operators to report the rotational torque
check results to GE. This service information is reasonably available
because the interested parties have access to it through their normal
course of business or by the means identified in ADDRESSES.

AD Requirements

This AD requires performing a rotational torque check on the
actuating linkage assembly and, depending on the results of the
rotational torque check, replacement of the compressor IGV outer shroud
bushing and vane spindle bushing with parts eligible for installation.
This AD also requires reporting the results of the rotational torque
check to GE.

Interim Action

The FAA considers this AD to be an interim action. The inspection
reports that are required by this AD will enable the manufacturer to
obtain better insight into the nature, cause, and extent of the
corrosion, and eventually to develop final action to address the unsafe
condition. Once final action has been identified, the FAA might
consider further rulemaking.

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. 551 et seq.) 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 thirty 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 foregoing notice and comment prior to adoption of this rule.
The FAA considers corrosion of the VG system actuator to be an urgent
safety issue. Performance of a rotational torque check of the actuating
linkage assembly will detect excessive corrosion build up on the VG
system actuator. This rotational torque check is necessary to prevent
failure of one or more engines, loss of engine thrust control, and
reduced control of the airplane. Engines installed on airplanes parked
outdoors for 250 or more days are at risk of excessive corrosion build
up. The risk of the excessive corrosion build up increases if the
engines are stored outdoors in close proximity to a saltwater
coastline. For affected engines installed on airplanes that were parked
outdoors within 10 miles of a saltwater coastline, a rotational torque
check on the actuating linkage assembly must be accomplished within 30
flight hours or 5 calendar days after the effective date of this AD.
For affected engines installed on airplanes that were parked outdoors
within 50 miles of a saltwater coastline, a rotational torque check of
the actuating linkage assembly must be accomplished within 200 FHs or
35 calendar days after the effective date of this AD. Additionally, for
all other affected engines installed on airplanes that were parked
outdoors, the rotational torque check on the actuating linkage assembly
must be accomplished before exceeding 880 FHs. According to fleet data,
880 FHs is approximately 100 calendar days. For affected engines with
an actuating linkage assembly that does not pass the rotational torque
check, this AD requires replacement of the compressor IGV outer shroud
bushing and vane spindle bushing before further flight. Accordingly,
notice and opportunity for prior public comment are impracticable and
contrary to the 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 forego 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
ADDRESSES. Include ``Docket No. FAA-2022-0400 and Project Identifier
AD-2022-00179-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 agency will also post a report summarizing each
substantive verbal contact received about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Scott
Stevenson, Aviation Safety Engineer, ECO Branch, FAA, 1200 District
Avenue, Burlington, MA 01803. 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 FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 617 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

The FAA estimates the following costs to do any necessary
replacement that would be required based on the results of the
rotational torque check. The agency has no way of determining the
number of aircraft that might need these replacements:

On-Condition Costs

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to be
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information. All responses to this collection of
information are mandatory. Send comments regarding this burden estimate
or any other aspect of this collection of information, including
suggestions for reducing this burden to: Information Collection
Clearance Officer, Federal Aviation Administration, 10101 Hillwood
Parkway, Fort Worth, TX 76177-1524.

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, and
(2) Will not affect intrastate aviation in Alaska.

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: