[Federal Register Volume 86, Number 161 (Tuesday, August 24, 2021)]
[Proposed Rules]
[Pages 47264-47266]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-18148]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0699; Project Identifier AD-2020-01685-E]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain General Electric Company (GE) CF34-10E model turbofan 
engines. This proposed 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 proposed AD would require 
initial and repetitive visual inspections of the strainer assembly 
screen. As a terminating action to the initial and repetitive visual 
inspections, this proposed AD would require the replacement of the 
stationary oil seal at the No. 1 forward bearing. The FAA is proposing 
this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by October 8, 
2021.

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 NPRM, contact General 
Electric Company, GE Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 
45215; phone: (513) 552-3272; email: [email protected]; 
website: 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 (781) 238-7759.

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 NPRM, any comments 
received, and other information. The street address for 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; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0699; Project Identifier 
AD-2020-01685-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, 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 proposal 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 NPRM.

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

[[Page 47265]]

(FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your 
comments responsive to this NPRM 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 NPRM, 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 NPRM. 
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.

Background

    The FAA received reports of several 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 
also subject to this unsafe condition. This condition, if not 
addressed, could result in failure of the engine, in-flight shutdown, 
and loss of control of the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

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.

Proposed AD Requirements in This NPRM

    This proposed AD would require initial and repetitive visual 
inspections of the strainer assembly screen. As a terminating action to 
the repetitive visual inspections, this proposed AD would require the 
replacement of the stationary oil seal at the No. 1 forward bearing.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 46 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
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.
----------------------------------------------------------------------------------------------------------------

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

    The FAA 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

General Electric Company: Docket No. FAA-2021-0699; Project 
Identifier AD-2020-01685-E.

[[Page 47266]]

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by October 8, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all 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 has used high thermal stability (HTS) oil 
or high performance capability (HPC) oil for 56 or more flight hours 
(FHs) 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) Within the compliance time specified in paragraph (g)(1)(i) 
or (ii) of this AD, as applicable, perform an initial visual 
inspection of the strainer assembly screen for Teflon material. 
Guidance on performing the visual inspections of the strainer 
assembly screen can be found in the Accomplishment Instructions, 
paragraphs 3.A.(1)(d), of GE CF34-10E Service Bulletin (SB) 72-0365 
R04, dated April 27, 2021.
    (i) For an affected stationary oil seal having fewer than 2,250 
flight hours (FHs) since new on the effective date of this AD, 
perform the initial inspection of the strainer assembly screen at 
the next engine shop visit after accumulating 2,250 FHs since new, 
but no later than 2,350 FHs since new.
    (ii) For an affected stationary oil seal having 2,250 or more 
FHs since new on the effective date of this AD, perform the initial 
inspection of the strainer assembly screen within 100 FHs after the 
effective date of this AD.
    (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 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 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 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 the inspections 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

    Special flight permits, as described in 14 CFR 21.197 and 
21.199, are subject to the requirements of paragraph (j)(1) of this 
AD.
    (1) Operators who are prohibited from further flight due to 
Teflon material found in the strainer assembly screen may perform a 
non-revenue ferry flight, consisting of no more than five cycles, to 
a location where the engine can be removed from service if operators 
perform the actions in Appendix--A, paragraph 4.A., GE CF34-10E 
Service Bulletin (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.
    (2) [Reserved]

(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 Related Information. 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

    (1) For more information about this AD, 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].
    (2) 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: www.ge.com. You may view 
this referenced 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.

    Issued on August 18, 2021.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-18148 Filed 8-23-21; 8:45 am]
BILLING CODE 4910-13-P