Proposed Rule2021-23237
Airworthiness Directives; General Electric Company Turbofan Engines
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
October 28, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) GEnx-1B and GEnx-2B model turbofan engines. This proposed AD was prompted by the manufacturer's report of two findings of sheared compressor discharge pressure (CDP) bolts during engine shop visits. This proposed AD would require initial and repetitive inspections of the CDP bolted joint and, depending on the findings, a piece part inspection of the stages 6-10 compressor rotor spool, CDP seal, and high-pressure turbine (HPT) rotor stage 1 disk. As a terminating action, this proposed AD would require operators to reassemble the CDP bolted joint using a specific torque wrench. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 206 (Thursday, October 28, 2021)</title>
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[Federal Register Volume 86, Number 206 (Thursday, October 28, 2021)]
[Proposed Rules]
[Pages 59667-59670]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-23237]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0831; Project Identifier AD-2021-00712-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 adopt a new airworthiness directive (AD)
for certain General Electric Company (GE) GEnx-1B and GEnx-2B model
turbofan engines. This proposed AD was prompted by the manufacturer's
report of two findings of sheared compressor discharge pressure (CDP)
bolts during engine shop visits. This proposed AD would require initial
and repetitive inspections of the CDP bolted joint and, depending on
the findings, a piece part inspection of the stages 6-10 compressor
rotor spool, CDP seal, and high-pressure turbine (HPT) rotor stage 1
disk. As a terminating action, this proposed AD would require operators
to reassemble the CDP bolted joint using a specific torque wrench. The
FAA is proposing this AD to address the unsafe condition on these
products.
[[Page 59668]]
DATES: The FAA must receive comments on this proposed AD by December
13, 2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> 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.
<bullet> 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: <a href="/cdn-cgi/l/email-protection#214057484055484e4f0f474d444455525451514e53556140440f46440f424e4c"><span class="__cf_email__" data-cfemail="7f1e09161e0b1610115119131a1a0b0c0a0f0f100d0b3f1e1a51181a511c1012">[email protected]</span></a>; website: <a href="http://www.ge.com">www.ge.com</a>.
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 <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-0831; 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: Alexei Marqueen, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7178; fax: (781) 238-7199; email:
<a href="/cdn-cgi/l/email-protection#47062b223f222e6913690a263536322222290721262669202831"><span class="__cf_email__" data-cfemail="62230e071a070b4c364c2f0310131707070c220403034c050d14">[email protected]</span></a>.
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-2021-0831; Project Identifier
AD-2021-00712-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
<a href="https://www.regulations.gov">https://www.regulations.gov</a>, 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 (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
Alexei Marqueen, 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 was notified by the manufacturer of two findings of sheared
CDP bolts at engine shop visits during disassembly of the CDP bolted
joint on GEnx-1B70/75/P2 and GEnx-2B67/P model turbofan engines.
Subsequent investigation by the manufacturer determined that the
fracture and liberation of the CDP bolts was caused by the inadvertent
over-torque condition of the bolts during assembly and reassembly with
a 11C4525P01 torque fixture or during assembly with a 11C4629P01 torque
wrench. In one finding, the fractured CDP bolt caused damage to the
stages 6-10 compressor rotor spool, CDP seal, and HPT rotor stage 1
disk. This condition, if not addressed, could result in damage to the
engine and damage to 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 GEnx-1B Service Bulletin (SB) 72-0495 R00,
dated May 11, 2021, (GEnx-1B SB 72-0495) and GE GEnx-2B SB 72-0433 R00,
dated May 11, 2021 (GEnx-2B S/B 72-0433). GEnx-1B SB 72-0495 describes
procedures for the inspection of the CDP bolted joint components on
GEnx-1B model turbofan engines. GEnx-2B SB 72-0433 describes procedures
for the inspection of the CDP bolted joint components on GEnx-2B model
turbofan engines. 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 inspections
of the CDP bolted joint and, depending on the findings, a piece part
inspection of the stages 6-10 compressor rotor spool, CDP seal, and HPT
rotor stage 1 disk. As a terminating action, this proposed AD would
require operators to reassemble the CDP bolted joint using a 11C4888P01
torque wrench.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 320 engines installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspection of CDP bolted joint........ 1 work-hour x $85 per $0 $85 $27,200
hour = $85.
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[[Page 59669]]
The FAA estimates the following costs to do any necessary
additional inspections 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 these inspections.
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Piece part inspection of stages 6-10 56 work-hours x $85 per hour = $0 $4,760
compressor rotor spool. $4,760.
Piece part inspection of CDP seal............. 22 work-hours x $85 per hour = 0 1,870
$1,870.
Piece part inspection of HPT rotor stage 1 59 work-hours x $85 per hour = 0 5,015
disk. $5,015.
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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-2021-0831; Project
Identifier AD-2021-00712-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by December 13, 2021.
(b) Affected ADs
None.
(c) Applicability
This AD applies to General Electric Company (GE) GEnx-1B64,
GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2,
GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-
1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/
75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, GEnx-2B67, GEnx-2B67B, and GEnx-
2B67/P model turbofan engines with a compressor discharge pressure
(CDP) bolted joint assembled or reassembled with the 11C4525P01
torque fixture or assembled with the 11C4629P01 torque wrench.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine
Section.
(e) Unsafe Condition
This AD was prompted by a report from the manufacturer of two
findings of sheared CDP bolts during engine shop visits. The FAA is
issuing this AD to prevent fracture of the CDP bolt. The unsafe
condition, if not addressed, could result in damage to the engine
and damage to the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) At the next engine shop visit after the effective date of
this AD, perform an inspection of the CDP bolted joint for fractured
or missing material using the Accomplishment Instructions, paragraph
3.A.(2) of GE GEnx-1B Service Bulletin (SB) 72-0495 R00, dated May
11, 2021 (GEnx-1B SB 72-0495) (for GEnx-1B models) or Accomplishment
Instructions, paragraph 3.A.(2) of GE GEnx-2B SB 72-0433 R00, dated
May 11, 2021, (GEnx-2B SB 72-0433) (for GEnx-2B models).
(2) Repeat the inspection required by paragraph (g)(1) of this
AD at every engine shop visit.
(3) If a fractured or missing bolt or nut is found during any
inspection required by paragraph (g)(1) or (2) of this AD, before
further flight, perform piece part inspections in accordance with
the Instructions for Continued Airworthiness of the stages 6-10
compressor rotor spool, CDP seal, and high-pressure turbine rotor
stage 1 disk.
(h) Terminating Action
As terminating action to the repetitive inspections required by
paragraph (g)(2) of this AD, reassemble the CDP bolted joint using
the 11C4888P01 torque wrench, in accordance with the Accomplishment
Instructions, paragraph 3.B.(1) of GEnx-1B SB 72-0495 (for GEnx-1B
models) or the Accomplishment Instructions, paragraph 3.B.(1) of
GEnx-2B SB 72-0433 (for GEnx-2B models).
(i) Definition
For the purpose of this AD, an ``engine shop visit'' is the
induction of an engine into the shop for maintenance involving a
module exposure in which the mid fan shaft removal exposes the CDP
bolted joint.
(j) 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
[[Page 59670]]
paragraph (k)(1) of this AD. You may email your request to: <a href="/cdn-cgi/l/email-protection#0a4b444f274b4e274b4745494a6c6b6b246d657c"><span class="__cf_email__" data-cfemail="25646b600864610864686a66654344440b424a53">[email protected]</span></a>.
(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.
(k) Related Information
(1) For more information about this AD, contact Alexei Marqueen,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7178; fax: (781) 238-7199;
email: <a href="/cdn-cgi/l/email-protection#450429203d202c6b116b082437343020202b052324246b222a33"><span class="__cf_email__" data-cfemail="71301d140914185f255f3c1003000414141f311710105f161e07">[email protected]</span></a>.
(2) For service information identified in this AD, contact
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215;
phone: (513) 552-3272; email: <a href="/cdn-cgi/l/email-protection#6504130c04110c0a0b4b0309000011161015150a17112504004b02004b060a08"><span class="__cf_email__" data-cfemail="2342554a42574a4c4d0d454f464657505653534c51576342460d44460d404c4e">[email protected]</span></a>;
website: <a href="http://www.ge.com">www.ge.com</a>. 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 September 21, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2021-23237 Filed 10-27-21; 8:45 am]
BILLING CODE 4910-13-P
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