Proposed Rule2021-11565
Airworthiness Directives; Pratt & Whitney Turbofan Engines
Primary source
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Published
June 3, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for all Pratt & Whitney (PW) PW1500G and PW1900G series turbofan engines. This proposed AD was prompted by reports of cracks in the high-pressure compressor (HPC) rotor shaft that resulted in in-flight shutdowns (IFSDs) and unscheduled engine removals (UERs). This proposed AD would require removal and replacement of the HPC front hub and HPC rotor shaft. 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 105 (Thursday, June 3, 2021)</title>
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[Federal Register Volume 86, Number 105 (Thursday, June 3, 2021)]
[Proposed Rules]
[Pages 29707-29709]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-11565]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0447; Project Identifier AD-2021-00131-E]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney 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 all Pratt & Whitney (PW) PW1500G and PW1900G series turbofan
engines. This proposed AD was prompted by reports of cracks in the
high-pressure compressor (HPC) rotor shaft that resulted in in-flight
shutdowns (IFSDs) and unscheduled engine removals (UERs). This proposed
AD would require removal and replacement of the HPC front hub and HPC
rotor shaft. 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 July 19,
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 Pratt &
Whitney, 400 Main Street, East Hartford, CT 06118; phone: (800) 565-
0140; fax: (860) 565-5442; email: <a href="/cdn-cgi/l/email-protection#e58d808995d7d1a59592cb909186cb868a88"><span class="__cf_email__" data-cfemail="68000d04185a5c28181f461d1c0b460b0705">[email protected]</span></a>; website: <a href="https://fleetcare.pw.utc.com">https://fleetcare.pw.utc.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.
[[Page 29708]]
FAA-2021-0447; 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: Mark Taylor, Aviation Safety Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7229; fax: (781) 238-7199; email: <a href="/cdn-cgi/l/email-protection#652804170e4b31041c090a17250304044b020a13"><span class="__cf_email__" data-cfemail="0944687b62275d687065667b496f6868276e667f">[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-2021-0447; Project Identifier
AD-2021-00131-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 Mark
Taylor, 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 cracks in the HPC rotor shaft that
resulted in vibration and subsequent IFSDs and UERs. The manufacturer
determined that the threads on the HPC rotor shaft were not optimized
for load distribution, which resulted in vibration stresses. During one
occurrence, oil was released at the high-pressure turbine (HPT) disk
bore location. The manufacturer redesigned the HPC front hub and HPC
rotor shaft for increased durability and decreased vibration stress.
The redesigned HPC front hub is made from nickel to help with corrosion
resistance. The threads on the HPC rotor shaft were also redesigned to
help distribute the load on the threads and decrease vibration stress.
This condition, if not addressed, could result in release of an HPT
disk, 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
The FAA reviewed Pratt & Whitney Service Bulletin (SB) PW1000G-A-
72-00-0154-00A-930A-D, Issue No. 001, dated May 7, 2021 (PW1000G-A-72-
00-0154-00A-930A-D), and Pratt & Whitney SB PW1000G-A-72-00-0101-00B-
930A-D, Issue No. 001, dated May 7, 2021 (SB PW1000G-A-72-00-0101-00B-
930A-D). These SBs describe procedures for removing and replacing the
HPC front hub and HPC rotor shaft.
Proposed AD Requirements in This NPRM
This proposed AD would require removal and replacement of the HPC
front hub and HPC rotor shaft.
Differences Between This Proposed AD and the Service Information
Pratt & Whitney SB PW1000G-A-72-00-0154-00A-930A-D and Pratt &
Whitney SB PW1000G-A-72-00-0101-00B-930A-D provide instructions to
concurrently perform the actions in Pratt & Whitney SB PW1000G-A-72-00-
0157-00A-930A-D and SB PW1000G-A-72-00-0105-00B-930A-D, respectively.
This AD does not require performance of the actions described in Pratt
& Whitney SB PW1000G-A-72-00-0157-00A-930A-D or SB PW1000G-A-72-00-
0105-00B-930A-D since these SBs describe ring seal replacement, which
is not related to the unsafe condition addressed by this AD.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 94 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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Replace HPC front hub and HPC rotor 25.75 work-hours x $85 $120,090 $122,278.75 $11,494,202.50
shaft. per hour = $2,188.75.
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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.
[[Page 29709]]
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:
Pratt & Whitney: Docket No. FAA-2021-0447; Project Identifier AD-
2021-00131-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by July 19, 2021.
(b) Affected ADs
None.
(c) Applicability
This AD applies to Pratt & Whitney PW1519G, PW1521G, PW1521G-3,
PW1521GA, PW1524G, PW1524G-3, PW1525G, PW1525G-3, PW1919G, PW1921G,
PW1922G, PW1923G, and PW1923G-A model turbofan engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7230, Turbine Engine
Compressor Section.
(e) Unsafe Condition
This AD was prompted by reports of cracks in the high-pressure
compressor (HPC) rotor shaft that resulted in in-flight shutdowns
and unscheduled engine removals. The FAA is issuing this AD to
prevent cracking of the HPC rotor shaft. The unsafe condition, if
not addressed, could result in release of a high-pressure turbine
disk, 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 Action
At next engine shop visit after the effective date of this AD,
remove HPC front hub, part number (P/N) 30G1910 or 30G3210, and HPC
rotor shaft, P/N 30G1854, 30G3109, 30G4995, 30G4953, or 31G0014,
from service and replace each part with a part eligible for
installation.
(h) Definitions
(1) For the purpose of this AD, an ``engine shop visit'' is the
induction of an engine into the shop for maintenance involving the
separation of pairs of major mating engine case flanges, except for
the following, which do not constitute an engine shop visit:
(i) Separation of engine flanges solely for the purposes of
transportation without subsequent maintenance does not constitute an
engine shop visit.
(ii) Separation of engine flanges solely for the purpose of
replacing the fan without subsequent maintenance does not constitute
an engine shop visit.
(2) For the purpose of this AD, a ``part eligible for
installation'' is:
(i) For a HPC front hub: Any HPC front hub with a P/N other than
P/N 30G1910 or 30G3210; and
(ii) For a HPC rotor shaft: Any HPC rotor shaft with a P/N other
than P/N 30G1854, 30G3109, 30G4995, 30G4953, or 31G0014.
(i) 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:
<a href="/cdn-cgi/l/email-protection#7c3d3239513d38513d31333f3c1a1d1d521b130a"><span class="__cf_email__" data-cfemail="b0f1fef59df1f49df1fdfff3f0d6d1d19ed7dfc6">[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.
(j) Related Information
For more information about this AD, contact Mark Taylor,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7229; fax: (781) 238-7199;
email: <a href="/cdn-cgi/l/email-protection#d598b4a7befb81b4acb9baa795b3b4b4fbb2baa3"><span class="__cf_email__" data-cfemail="115c70637a3f4570687d7e63517770703f767e67">[email protected]</span></a>.
Issued on May 27, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2021-11565 Filed 6-2-21; 8:45 am]
BILLING CODE 4910-13-P
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