Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 87, Number 44 (Monday, March 7, 2022)]
[Rules and Regulations]
[Pages 12571-12574]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-04694]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0699; Project Identifier AD-2020-01685-E; 
Amendment 39-21959; AD 2022-05-08]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) CF34-10E model turbofan engines. 
This AD was prompted by a manufacturer investigation that revealed 
Teflon material in the A-sump oil strainer (strainer assembly) screen 
after several reports of in-flight shutdowns (IFSDs) and unscheduled 
engine removals (UERs). This AD requires initial and repetitive visual 
inspections of the strainer assembly screen. As a terminating action to 
the initial and repetitive visual inspections, this AD requires the 
replacement of the stationary oil seal at the No. 1 forward bearing. 
The FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective April 11, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of April 11, 
2022.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: (513) 552-3272; email: 
[email protected]; 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-2021-0699.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0699; 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 address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Scott Stevenson, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7132; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain GE CF34-10E2A1, 
CF34-10E5, CF34-10E5A1, CF34-10E6, CF34-10E6A1, CF34-10E7, and CF34-
10E7-B (CF34-10E) model turbofan engines. The NPRM published in the 
Federal Register on August 24, 2021 (86 FR 47264). The NPRM was 
prompted by a manufacturer investigation that revealed Teflon material 
in the strainer assembly screen after several reports of IFSDs and UERs 
on airplanes operating with GE CF34-10E5, CF34-10E5A1, CF34-10E6, and 
CF34-10E7 model turbofan engines. After investigation, the manufacturer 
determined that the failures were the result of Teflon oil seals 
disbonding from the aluminum housing when used with either high thermal 
stability (HTS) or high performance capability (HPC) oils. The 
stationary oil seal deterioration resulted from the failure of the 
bonding adhesive, known as EA9658, which does not have the high 
temperature capabilities as designed and is negatively impacted by the 
use of HTS or HPC oils. This deterioration results in Teflon particles 
collecting in the strainer assembly. The manufacturer determined that 
CF34-10E2A1, CF34-10E6A1, and CF34-10E7-B model turbofan engines are 
subject to the same unsafe condition. In the NPRM, the FAA proposed to 
require initial and repetitive visual inspections of the strainer 
assembly screen. As a terminating action to the initial and repetitive 
visual inspections, the FAA proposed to require the replacement of the 
stationary oil seal, part number (P/N) B1316-00453 or P/N B1316-01274, 
installed at the No. 1 forward bearing. The FAA is issuing this AD to 
address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from four commenters. The commenters were 
the Air Line Pilots Association, International (ALPA), GE, Helvetic 
Airways AG (Helvetic Airways), and JetBlue Airways (JetBlue). The 
following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Change the Applicability

    GE, Helvetic Airways, and JetBlue requested that the FAA change 
paragraph (c), Applicability, of this AD to align with GE CF34-10E 
Service Bulletin (SB) 72-0365 R04, dated April 27, 2021 (GE CF34-10E SB 
72-0365 R04). GE specifically requested that the FAA include language 
that specifies the timeframe (after September 2014) to

[[Page 12572]]

identify which stationary oil seals have adhesive EA9658 and are 
subject to the disbonding failure mode. GE and JetBlue noted that 
paragraph (c), Applicability, of the NPRM differs from GE CF34-10E SB 
72-0365 R04, as it does not identify stationary oil seal, P/N B1316-
00453 or P/N B1316-01274, replaced or repaired after September 2014, 
which is when the EA9658 adhesive was introduced to the field. GE and 
JetBlue commented that the NPRM, as written, would apply to all 
stationary oil seals, regardless of when they were manufactured or 
repaired. Helvetic Airways noted that paragraph (c), Applicability, of 
the NPRM does not account for the population of affected stationary oil 
seals, as identified in paragraph A., Effectivity, of GE CF34-10E SB 
72-0365 R04.
    In response to these comments, the FAA updated paragraph (c), 
Applicability, of this AD to specify this AD applies to GE CF34-10E 
model turbofan engines with a stationary oil seal, P/N B1316-00453 or 
P/N B1316-01274, installed at the No. 1 forward bearing, that has been 
repaired, overhauled, or entered into service after August 2014, and 
used HTS oil or HPC oil for 56 flight hours or more during the life of 
the stationary oil seal.

Request To Clarify the Applicability by Engine Serial Number

    GE suggested that the FAA revise paragraph (c), Applicability, of 
this AD to include the list of engine serial numbers (ESNs), 424714 
through 424892, as an additional but alternate approach to identify 
affected CF34-10E engines.
    The FAA notes that the list of ESNs includes those engines that 
were produced with the affected stationary oil seal. Those new-make 
engines are included in paragraph (c), Applicability, of this AD by 
referencing the stationary oil seal, P/N B1316-00453 or P/N B1316-
01274, which entered service after August 2014. The FAA did not change 
this AD as a result of this comment.

Request To Update Compliance Time

    GE requested that the FAA update paragraph (g)(1)(i) of the NPRM to 
remove ``at the next engine shop visit.'' GE reasoned that the intent 
of GE CF34-10E SB 72-0365 R04 is to perform the inspection on-wing 
without removing the engine.
    In response to GE's comment, the FAA has removed ``at the next 
engine shop visit'' and combined paragraphs (g)(1)(i) and (ii) of the 
NPRM into one paragraph, (g)(1) of this AD, to eliminate reference to 
an engine shop visit.

Request To Update Definition

    GE requested that the FAA update paragraph (i), Definition, of this 
AD to indicate that a part eligible for installation is a stationary 
oil seal with a P/N other than P/N B1316-00453 or P/N B1316-001274 and 
with FM57 adhesive. GE reasoned that there could be room for 
interpretation as to what P/N other than B1316-00453 and P/N B1316-
01274 could be in the future, especially if the manufacturer redesigns 
the stationary oil seal with a new adhesive and a new failure mode is 
introduced.
    The FAA disagrees with updating the definition of a part eligible 
for installation in paragraph (i) of this AD to include a reference to 
FM57 adhesive. The FAA cannot define a part eligible for installation 
based on future redesigns by the manufacturer. The FAA may consider 
future rulemaking if a new failure mode is discovered. The FAA did not 
change this AD as a result of this comment.

Request To Update Service Information or Allow for Credit

    GE requested that the FAA revise paragraph (g)(1) of this AD to 
reference GE CF34-10E SB 72-0365 R04, R03, and R02. GE commented that 
paragraph (g)(1) of the NPRM references GE CF34-10E SB 72-0365 R04 to 
comply with the AD; however, some operators may have complied with 
earlier revisions of the service bulletin. GE reasoned that paragraph 
3.A.(1)(d) of GE CF34-10E SB 72-0365 R04, R03, R02 are identical.
    JetBlue requested that the FAA update this AD to allow credit for 
inspections performed using previous revisions of GE CF34-10E SB 72-
0365. JetBlue commented that the NPRM specifically references GE CF34-
10E SB 72-0365 R04. JetBlue reasoned that, in addition to R04 of GE 
CF34-10E SB 72-0365, they performed repetitive inspections in 
accordance with R03 and R02.
    This AD does not mandate that operators use GE CF34-10E SB 72-0365 
R04 to perform the visual inspections. GE CF34-10E SB 72-0365 R04 is 
referenced in paragraph (g), Required Actions, of this AD as guidance 
to perform the visual inspections of the strainer assembly screen. 
Therefore, if operators used earlier versions of the service 
information to perform the visual inspections, they would be in 
compliance with the requirements in paragraph (g) of this AD. Regarding 
the comment requesting that this AD include credit for pervious actions 
using earlier versions of the service information, the FAA notes that 
this change is unnecessary. Paragraph (f) of this AD mandates 
compliance with the required actions, unless already done. The FAA did 
not change this AD as a result of this comment.

Support for the AD

    ALPA expressed support for the AD as written.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE CF34-10E Service Bulletin 72-0365 R04, dated 
April 27, 2021. This service information specifies procedures for 
performing a visual inspection and a borescope inspection of the 
strainer assembly for Teflon particles. 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.

Costs of Compliance

    The FAA estimates that this AD affects 46 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspect the strainer assembly        1 work-hour x $85 per hour               $0             $85          $3,910
 screen.                              = $85.
Replace the stationary oil seal....  2 work-hours x $85 per hour           8,628           8,798         404,708
                                      = $170.
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[[Page 12573]]

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
    (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.

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

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:

2022-05-08 General Electric Company: Amendment 39-21959; Docket No. 
FAA-2021-0699; Project Identifier AD-2020-01685-E.

(a) Effective Date

    This airworthiness directive (AD) is effective April 11, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) CF34-10E2A1, 
CF34-10E5, CF34-10E5A1, CF34-10E6, CF34-10E6A1, CF34-10E7, and CF34-
10E7-B model turbofan engines with a stationary oil seal, part 
number (P/N) B1316-00453 or P/N B1316-01274, installed at the No. 1 
forward bearing, that:
    (1) Has been repaired, overhauled, or entered into service after 
August 2014; and
    (2) Has used high thermal stability oil or high performance 
capability oil for 56 flight hours (FHs) or more during the life of 
the stationary oil seal.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7261, Turbine Engine 
Oil System.

(e) Unsafe Condition

    This AD was prompted by investigation by the manufacturer that 
revealed Teflon material in the A-sump oil strainer (strainer 
assembly) screen after several reports of in-flight shutdowns and 
unscheduled engine removals. The FAA is issuing this AD to prevent 
failure of the stationary oil seal at the No. 1 forward bearing. The 
unsafe condition, if not addressed, could result in failure of the 
engine, in-flight shutdown, and loss of control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) Before the stationary oil seal accumulates 100 FHs after the 
effective date of this AD, or within 100 FHs of the stationary oil 
seal accumulating 2,250 FHs since new, whichever occurs later, 
perform an initial visual inspection of the strainer assembly screen 
for Teflon material. Guidance on performing the visual inspection of 
the strainer assembly screen can be found in the Accomplishment 
Instructions, paragraph 3.A.(1)(d), of GE CF34-10E Service Bulletin 
(SB) 72-0365 R04, dated April 27, 2021.
    (2) Thereafter, within the following compliance times, repeat 
the visual inspection of the strainer assembly screen required by 
paragraph (g)(1) of this AD:
    (i) For an affected stationary oil seal having accumulated 2,250 
to 7,000 FHs since new at the time of the last inspection, repeat 
the visual inspection every 750 FHs.
    (ii) For an affected stationary oil seal having accumulated 
7,001 to 10,000 FHs since new at the time of the last inspection, 
repeat the visual inspection every 375 FHs.
    (iii) For an affected stationary oil seal having accumulated 
more than 10,000 FHs since new at the time of the last inspection, 
repeat the visual inspection every 100 FHs.
    (3) If, based on any inspection required by paragraph (g)(1) or 
(2) of this AD, Teflon material is found in the strainer assembly 
screen, before further flight, remove the stationary oil seal at the 
No. 1 forward bearing from service and replace it with a part 
eligible for installation.
    (4) Before an affected stationary oil seal accumulates 10,000 
FHs since new or within 500 FHs after the effective date of this AD, 
whichever occurs later, remove the stationary oil seal at the No. 1 
forward bearing from service and replace it with a part eligible for 
installation.

(h) Terminating Action

    Removal of the stationary oil seal, P/N B1316-00453 or P/N 
B1316-01274, installed at the No. 1 forward bearing, and replacement 
with a part eligible for installation, constitutes terminating 
action for the initial and repetitive inspections required by 
paragraphs (g)(1) and (2) of this AD.

(i) Definition

    For the purpose of this AD, a ``part eligible for installation'' 
is a stationary oil seal that has a P/N other than P/N B1316-00453 
or P/N B1316-01274.

(j) Special Flight Permit

    A special flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to permit a non-revenue ferry flight, consisting 
of no more than five cycles, to a location where the engine can be 
removed from service for operators who are prohibited from further 
flight due to Teflon material found in the strainer assembly screen 
if operators perform the actions in Appendix--A, paragraph 4.A., of 
GE CF34-10E SB 72-0365 R04, dated April 27, 2021, and the engine 
still meets the criteria in paragraph 4.A. for flying an additional 
five cycles. This ferry flight must be performed with only essential 
flight crew, without passengers, and involve non-ETOPS operations.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO Branch, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. In accordance with 14 CFR 39.19, send your request to your 
principal inspector or local Flight Standards District Office, as 
appropriate. If sending information directly to the manager of the 
certification office, send it to the attention of the person 
identified in paragraph (l) of this AD. You may email your request 
to [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(l) Related Information

    For more information about this AD, contact Scott Stevenson, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781)

[[Page 12574]]

238-7132; fax: (781) 238-7199; email: [email protected].

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) GE CF34-10E Service Bulletin 72-0365 R04, dated April 27, 
2021.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: (513) 552-3272; email: 
[email protected]; website: https://www.ge.com.
    (4) You may view this service information at 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on February 18, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-04694 Filed 3-4-22; 8:45 am]
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