Document ID: FAA-2021-1167-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2021-12-29T05:00Z

[Federal Register Volume 86, Number 247 (Wednesday, December 29, 2021)]
[Proposed Rules]
[Pages 73997-74000]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-28134]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1167; Project Identifier AD-2021-00823-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2019-22-05, which applies to all General Electric Company (GE) CF34-8C 
model turbofan engines. AD 2019-22-05 requires initial and repetitive 
inspections of the operability bleed valve (OBV) fuel tubes, OBV bleed 
air manifold link rod assemblies, and the OBV fuel fittings. AD 2019-
22-05 also requires replacement of OBVs or related OBV hardware that 
fail inspection. Since the FAA issued AD 2019-22-05, the manufacturer 
has redesigned the OBV, which terminates the need for the repetitive 
inspections. This proposed AD would require initial and repetitive 
inspections of the OBV fuel tubes, OBV bleed air manifold link rod 
assemblies, and the OBV fuel fittings. This proposed AD would also 
require replacement of OBVs or related OBV hardware that fail 
inspection. As a terminating action to the repetitive inspections, this 
proposed AD would require replacement of certain OBVs installed on GE 
CF34-8C and CF34-8E model turbofan engines. 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 February 
14, 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 NPRM, contact General 
Electric Company, 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 Airworthiness 
Products Section, Operational Safety Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
material at the FAA, call (817) 222-5110.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1167; 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-2021-1167; Project Identifier 
AD-2021-00823-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 
the 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 we receive about this proposed AD.

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 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

[[Page 73998]]

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 issued AD 2019-22-05, Amendment 39-19784 (84 FR 63569, 
November 18, 2019), (AD 2019-22-05), for all GE CF34-8C1, CF34-8C5, 
CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, and CF34-8C5A3 model turbofan 
engines. AD 2019-22-05 was prompted by multiple reports of fuel leaks, 
some leading to engine fires, that have occurred as a result of 
malfunctions related to the OBV. AD 2019-22-05 requires initial and 
repetitive inspections of the OBV fuel tubes, OBV bleed air manifold 
link rod assemblies, and the OBV fuel fittings. AD 2019-22-05 also 
requires replacement of OBVs or related OBV hardware that fail 
inspection. The agency issued AD 2019-22-05 to prevent failure of the 
OBV.

Actions Since AD 2019-22-05 Was Issued

    Since the FAA issued AD 2019-22-05, the manufacturer redesigned the 
OBV to eliminate the need for the repetitive inspections of the OBV 
fuel tubes, OBV bleed air manifold link rod assemblies, and the OBV 
fuel fittings. The manufacturer has issued service information 
specifying procedures to replace certain OBVs installed on CF34-8C1, 
CF34-8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3 (CF34-8C), and 
GE CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, 
and CF34-8E6A1 (CF34-8E) model turbofan engines. Additionally, the FAA 
determined that the CF34-8E model turbofan engines are susceptible to 
the same unsafe condition as the CF34-8C model turbofan engines, and 
therefore, added the CF34-8E model turbofan engines to the 
applicability of this proposed AD. The FAA is proposing to require 
installation of the newly-designed OBV as a terminating action to the 
repetitive inspections required for CF34-8C model turbofan engines. The 
FAA is also proposing to require replacement of certain OBVs installed 
on CF34-8E model turbofan engines.

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 CF34-8C Service Bulletin (SB) 75-0020 R04, 
dated May 10, 2019 (GE SB 75-0020). The SB specifies procedures for 
inspecting the bleed air manifold link rod assemblies; the supply, 
return, and drain fuel fittings; and the fuel tubes on the OBV. The SB 
also specifies procedures for performing corrective actions and 
replacing any OBVs or related OBV hardware that fail the inspection 
criteria. The Director of the Federal Register approved the 
incorporation by reference of GE SB 75-0020 as of December 23, 2019 (84 
FR 63569, November 18, 2019).
    The FAA reviewed GE CF34-8C SB 75-0025 R01, dated August 1, 2019. 
This SB describes procedures for replacing and upgrading the suspect 
population of OBVs VIN 5000728-104 (part number (P/N) 4123T71P02), VIN 
5000728-106 (P/N 4123T71P03), and VIN 5080046-101 (P/N 4123T71P04).
    The FAA reviewed GE CF34-8E SB 75-0019 R01, dated August 1, 2019. 
This SB describes procedures for replacing and upgrading the suspect 
population of OBVs VIN 5000728-104 (P/N 4123T71P02), VIN 5000728-106 
(P/N 4123T71P03), and VIN 5080046-101 (P/N 4123T71P04).
    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.

Other Related Service Information

    The FAA reviewed GE CF34-8C SB 75-0026 R00, dated February 21, 
2020. This SB introduces OBV VIN 5080046-103 (P/N 4123T71P06).
    The FAA also reviewed GE CF34-8E SB 75-0021 R00, dated February 21, 
2020. This SB introduces OBV VIN 5080046-103 (P/N 4123T71P06).

Proposed AD Requirements in This NPRM

    This proposed AD would retain certain requirements of AD 2019-22-
05. This proposed AD would require initial and repetitive inspections 
of the OBV fuel tubes, OBV bleed air manifold link rod assemblies, and 
the OBV fuel fittings and replacement of OBVs or related OBV hardware 
that fail inspection. As a terminating action to the repetitive 
inspections of the OBV fuel tubes, OBV bleed air manifold link rod 
assemblies, and the OBV fuel fittings, this proposed AD would require 
replacement of certain OBVs installed on GE CF34-8C model turbofan 
engines. This proposed AD would also require replacement of certain 
OBVs installed on CF34-8E model turbofan engines.

Differences Between This Proposed AD and the Service Information

    GE SB 75-0020 specifies that the results of the inspections must be 
documented in an inspection chart form and sent to GE Product Support 
Engineering. This proposed AD would not mandate sending information to 
GE Product Support Engineering.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,172 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
----------------------------------------------------------------------------------------------------------------
Replace OBV.........................  2 work-hours x $85 per          $17,230         $17,400        $20,392,800
                                       hour = $170.
Inspect OBV fuel tubes, assemblies,   1 work-hour x 85 per                  0              85             99,620
 and fittings.                         hour = 85.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
proposed inspection. The agency has no way of determining the number of 
aircraft that might need this replacement.

[[Page 73999]]

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace OBV tubes, clamps, support hardware...  2.25 work-hours x $85 per hour =       $3,786.25       $3,977.50
                                                 $191.25.
----------------------------------------------------------------------------------------------------------------

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 that the 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:
    a. Removing Airworthiness Directive 2019-22-05, Amendment 39-19784 
(84 FR 63569, November 18, 2019); and
    b. Adding the following new airworthiness directive:

General Electric Company: Docket No. FAA-2021-1167; Project 
Identifier AD-2021-00823-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by February 14, 2022.

(b) Affected ADs

    This AD replaces AD 2019-22-05, Amendment 39-19784 (84 FR 63569, 
November 18, 2019).

(c) Applicability

    This AD applies to General Electric Company (GE) CF34-8C1, CF34-
8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-
8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 
model turbofan engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7532, Compressor 
Bleed Valve.

(e) Unsafe Condition

    This AD was prompted by multiple reports of fuel leaks, some 
leading to engine fires, that have occurred as a result of 
malfunctions related to the operability bleed valve (OBV). The FAA 
is issuing this AD to prevent failure of the OBV. The unsafe 
condition, if not addressed, could result in an engine fire and 
damage to the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For CF34-8C1, CF34-8C5, CF34-8C5A1, and CF34-8C5B1 model 
turbofan engines with serial numbers (S/Ns): 965101 through 965670 
inclusive; 194101 through 194999 inclusive; and 195101 through 
195653 inclusive:
    (i) Within 880 flight hours (FHs) since the previous inspection, 
500 FHs after December 23, 2019 (the effective date of AD 2019-22-
05), or 6,880 FHs since new, whichever occurs later, inspect the OBV 
bleed air manifold link rod assemblies, the OBV fuel fittings, and 
the OBV fuel tubes.
    (ii) Thereafter, within every 880 FHs since the previous 
inspection, perform additional repeat inspections of the OBV bleed 
air manifold link rod assemblies, the OBV fuel fittings, and the OBV 
fuel tubes.
    (iii) Use the Accomplishment Instructions, paragraph 3.B., of GE 
CF34-8C Service Bulletin (SB) 75-0020 R04, dated May 10, 2019 (GE SB 
75-0020), to perform inspections required by paragraphs (g)(1)(i) 
and (ii) of this AD and, per the inspection criteria in paragraph 
3.B., of GE SB 75-0020 (the inspection criteria), do the following:
    (A) Before further flight, if fuel leakage is observed at the 
OBV fittings or the OBV fittings are loose, replace the OBV with a 
part eligible for installation.
    (B) Before further flight, if any OBV fuel tube clamp is found 
to be outside the inspection criteria, re-torque the OBV fuel tube 
clamp or replace the OBV fuel tube clamp.
    (C) Within 50 flight cycles (FCs) after the inspections required 
by paragraphs (g)(1)(i) and (ii) of this AD, replace any link rod 
hardware found to be outside the inspection criteria. Until the worn 
link rod hardware is replaced, the OBV fittings must be inspected 
before the first flight of each day for leakage and looseness in 
accordance with the inspection criteria. If the OBV fittings fail to 
meet the inspection criteria, before further flight, replace the OBV 
and worn link rod hardware.
    (2) For CF34-8C5B1 model turbofan engines with S/Ns not listed 
in paragraph (g)(1) of this AD and for all CF34-8C5A2 and CF34-8C5A3 
model turbofan engines, perform the following:
    (i) Within 880 FHs after the effective date of this AD or prior 
to accumulating 6,880 FHs since new, whichever occurs later, perform 
an initial inspection of the OBV bleed air manifold link rod 
assemblies, OBV fuel fittings, and OBV fuel tubes.
    (ii) Thereafter, within every 880 FHs since the last inspection, 
repeat the inspection of the OBV bleed air manifold link rod 
assemblies, OBV fuel fittings, and OBV fuel tubes.
    (iii) Use the Accomplishment Instructions, paragraph 3.B., of GE 
SB 75-0020, to perform the inspections in paragraph (g)(2)(i) or 
(ii) of this AD and, per the inspection criteria in paragraph 3.B., 
of GE SB 75-0020, do the following:
    (A) Before further flight, if fuel leakage is observed at the 
OBV fittings or the OBV fittings are loose, replace the OBV with a 
part eligible for installation.
    (B) Before further flight, if any OBV fuel tube clamp is found 
to be outside the inspection criteria, re-torque the OBV fuel tube 
clamp or replace the OBV fuel tube clamp.

[[Page 74000]]

    (C) Within 50 FCs after the inspections required by paragraphs 
(g)(2)(i) and (ii) of this AD, replace any link rod hardware found 
to be outside the inspection criteria. Until the worn link rod 
hardware is replaced, the OBV fittings must be inspected before the 
first flight of each day for leakage and looseness in accordance 
with the inspection criteria. If the OBV fittings fail to meet the 
inspection criteria, before further flight, replace the OBV and worn 
link rod hardware.
    (3) For all affected engines with an installed OBV, VIN 5000728-
104 part number (P/N) (P/N 4123T71P02), VIN 5000728-106 (P/N 
4123T71P03), or VIN 5080046-101 (P/N 4123T71P04), having an OBV S/N 
listed in Appendix A, paragraph 4., of GE CF34-8C SB 75-0025 R01, 
dated August 1, 2019 (GE SB 75-0025), or Appendix A, paragraph 4., 
of GE CF34-8E SB 75-0019 R01, dated August 1, 2019 (GE SB 75-0019), 
respectively, within 180 days after the effective date of this AD, 
remove the OBV and replace with a part eligible for installation.
    (4) For all affected engines with an installed OBV, VIN 5000728-
104 (P/N 4123T71P02), VIN 5000728-106 (P/N 4123T71P03), or VIN 
5080046-101 (P/N 4123T71P04), having an OBV S/N not listed in 
Appendix A, paragraph 4., of GE SB 75-0025 or Appendix A, paragraph 
4., of GE SB 75-0019, respectively, remove the OBV and replace with 
a part eligible for installation within the following compliance 
times:
    (i) Within 16 months after the effective date of this AD for an 
OBV that has accumulated more than 25,000 FHs since new.
    (ii) Within 32 months after the effective date of this AD for an 
OBV that has accumulated between 12,500 to 25,000 FHs since new, 
inclusive.
    (iii) Within 48 months after the effective date of this AD for 
an OBV with fewer than 12,500 FHs since new.
    (5) For all affected engines with an installed OBV, VIN 5080046-
102 (P/N 4123T71P05), before the OBV accumulates 25,000 FHs since 
new or within 10 years after the effective date of this AD, 
whichever occurs first, remove the OBV and replace with a part 
eligible for installation.

(h) Terminating Action

    Installation of an OBV that meets the definition of a part 
eligible for installation in paragraph (i) of this AD constitutes 
terminating action for the 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 an OBV VIN 5080046-103 (P/N 4123T71P06) or an OBV reworked to VIN 
5080046-103 (P/N 4123T71P06).

(j) No Reporting Requirement

    The reporting instructions specified in GE SB 75-0020 are not 
required by this AD.

(k) Credit for Previous Actions

    You may take credit for the initial inspection required by 
paragraph (g)(1)(i) or (2)(i), of this AD if you performed this 
initial inspection before the effective of this AD using GE CF34-8C 
SB 75-0019 R01, dated October 24, 2017, or R00, dated August 4, 
2017; or GE CF34-8C-AL S/B 75-0020, Revision 03, dated December 14, 
2018, as applicable.

(l) 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 
ECO Branch, send it to the attention of the person identified in 
paragraph (m)(1) of this AD. Information may be emailed 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.

(m) 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, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: [email protected]; website: 
https://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 (817) 222-
5110.

    Issued on December 21, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-28134 Filed 12-28-21; 8:45 am]
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