Airworthiness Directives; Pratt & Whitney Turbofan Engines
| Published date | 01 June 2020 |
| Citation | 85 FR 33043 |
| Record Number | 2020-11499 |
| Section | Proposed rules |
| Court | Federal Aviation Administration |
Federal Register, Volume 85 Issue 105 (Monday, June 1, 2020)
[Federal Register Volume 85, Number 105 (Monday, June 1, 2020)]
[Proposed Rules]
[Pages 33043-33045]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-11499]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0442; Project Identifier AD-2020-00260-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) PW2037, PW2037M, PW2040, and F117-PW-100
model turbofan engines. This proposed AD was prompted by a report of an
uncontained engine failure resulting from cracks in the knife edge of
the high-pressure turbine (HPT) 2nd-stage air seal. This proposed AD
would require initial and repetitive borescope inspections (BSIs),
fluorescent penetrant inspections (FPIs), and visual inspections of the
HPT 2nd-stage air seal assembly and, depending on the results of the
inspections, replacement of the HPT 2nd-stage air seal assembly with a
part eligible for installation. This proposed AD would also require
replacement of the affected HPT 2nd-stage air seal assembly, depending
on the engine model, at either the next engine shop visit or the next
piece-part opportunity. 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 16,
2020.
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 Pratt &
Whitney, 400 Main Street, East Hartford, CT 06118, United States;
phone: 800-565-0140; fax: 860-565-5442; email: [email protected];
website: https://fleetcare.pw.utc.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 on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0442; 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. Comments will be
available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7655; 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 the ADDRESSES section. Include ``Docket No. FAA-2020-0442;
Project Identifier AD-2020-00260-E'' at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this NPRM. The FAA will
consider all comments received by the closing date and may amend this
NPRM because of those comments.
Except for Confidential Business Information 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 FAA will also post a report summarizing each substantive
verbal contact received about this NPRM.
Confidential Business Information
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 Carol Nguyen, Aerospace 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.
Discussion
The FAA received a report of an uncontained engine failure during a
revenue flight. The failure resulted from a crack originating in the
knife edge of the HPT 2nd-stage air seal assembly. After further
analysis, it was determined that the knife-edge crack was due to seal
rubbing that elevated the HPT 2nd-stage air seal temperature and
induced fatigue. This condition, if not addressed, could result in
uncontained HPT 2nd-stage air seal assembly release, damage to the
engine, and damage to the airplane.
Related Service Information Under 1 CFR Part 51
The FAA reviewed PW Service Bulletin (SB) PW2000 72-773, dated
March 11, 2020. The SB describes procedures for performing a BSI of the
HPT 2nd-stage air seal assembly. This service information is reasonably
available because the interested parties have access to it through
their normal
[[Page 33044]]
course of business or by the means identified in the ADDRESSES section.
Other Related Service Information
The FAA reviewed PW SB PW2000 72-754, Revision No. 2, dated April
30, 2019, and PW SB PWF117 72-402, Revision No. 2, dated May 3, 2019.
The SBs describe procedures for inspecting and replacing the HPT 2nd-
stage air seal assembly.
FAA's Determination
The FAA is proposing this AD because it evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Proposed AD Requirements
This proposed AD would require initial and repetitive BSIs, FPIs,
and visual inspections of the HPT 2nd-stage air seal assembly and,
depending on the results of the inspections, replacement of the HPT
2nd-stage air seal assembly with a part eligible for installation. This
proposed AD would also require replacement of the affected HPT 2nd-
stage air seal assembly, depending on the engine model, at either the
next engine shop visit or the next piece-part opportunity.
Costs of Compliance
The FAA estimates that this proposed AD affects 445 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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BSI the HPT 2nd-stage air seal 2 work-hours x $85 per $0 $170 $75,650
assembly. hour = $170.
Visual inspection, strip the knife 10 work-hours x $85 per 0 850 378,250
edge coating, and FPI the HPT 2nd- hour = $850.
stage air seal assembly.
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The FAA estimates the following costs to do any necessary
replacements. The FAA has no way of determining how many replacements
of the HPT 2nd-stage air seal assembly will be done with a modified HPT
2nd-stage air seal assembly and how many will be done with a new HPT
2nd-stage air seal assembly. The FAA also has no way of determining the
number of engines that might need replacement of the HPT 2nd-stage air
seal assembly, HPT 1st-stage disk, and HPT 2nd-stage hub.
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Replace the HPT 2nd-stage air seal assembly 10 work-hours x $85 per hour = $5,000 $5,850
with modified HPT 2nd-stage air seal assembly. $850.
Replace the HPT 2nd-stage air seal assembly 0.25 work-hours x $85 per hour = 355,000 355,021.25
with new seal assembly. $21.25.
Replace the HPT 2nd-stage air seal assembly, 0.25 work-hours x $85 per hour = 970,000 970,021.25
HPT 1st-stage disk, and HPT 2nd-stage hub $21.25.
(based on FPI results).
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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) 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 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.
[[Page 33045]]
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
Pratt & Whitney: Docket No. FAA-2020-0442; Project Identifier AD-
2020-00260-E.
(a) Comments Due Date
The FAA must receive comments by July 16, 2020.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all Pratt & Whitney (PW) PW2037, PW2037M,
PW2040, and F117-PW-100 model turbofan engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine
Section.
(e) Unsafe Condition
This AD was prompted by a report of an uncontained engine
failure resulting from cracks originating in the knife edge of the
high-pressure turbine (HPT) 2nd-stage air seal assembly. The FAA is
issuing this AD to prevent failure of the HPT 2nd-stage air seal
assembly. The unsafe condition, if not addressed, could result in
uncontained HPT 2nd-stage air seal assembly release, 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) Borescope Inspection (BSI) of HPT 2nd-Stage Air Seal Assembly
For PW PW2037, PW2037M, and PW2040 model turbofan engines with
an HPT 2nd-stage air seal assembly, part number (P/N) 1A8209 or
1A8209-001, installed, and with any of the following: An engine with
serial number 716301 to 716600, inclusive; 717901 to 717999,
inclusive; 718000; 726501 to 727132, inclusive; or 727135 to 727143,
inclusive; or an engine that has operated with electronic engine
control model number EEC104-1 since the last HPT overhaul:
(i) Within 2,500 flight cycles (FCs) since the last HPT 2nd
stage air seal assembly installation or 500 FCs after the effective
date of this AD, whichever occurs later, perform an initial BSI of
the HPT 2nd-stage air seal assembly using the Accomplishment
Instructions, paragraph 6, of PW Service Bulletin (SB) PW2000 72-
773, dated March 11, 2020.
(ii) Thereafter, perform the BSI required by paragraph (g)(1)(i)
of this AD within every 500 FCs since performance of the last BSI.
(iii) If, during any BSI required by paragraphs (g)(1)(i) or
(ii) of this AD, a cracked seal is found, before further flight,
remove the HPT 2nd-stage air seal assembly from the engine and
perform additional inspections of the HPT 2nd-stage air seal
assembly using paragraph (g)(2) of this AD.
(2) Visual Inspection and Fluorescent Penetrant Inspection (FPI) of HPT
2nd-Stage Air Seal Assembly
For PW PW2037, PW2037M, PW2040, and F117-PW-100 model turbofan
engines, after the effective date of this AD, at every piece part
opportunity of the HPT 1st-stage disk, HPT 2nd-stage disk, or the
HPT 2nd-stage air seal assembly:
(i) Perform a visual inspection of the HPT 2nd-stage air seal
assembly, strip the knife edge coating from the HPT 2nd-stage air
seal assembly, and then perform an FPI of the HPT 2nd-stage air seal
assembly.
(ii) If a crack is found in the HPT 2nd-stage air seal assembly
during the visual inspection or FPI required by paragraph (g)(2)(i)
of this AD, before further flight, remove the HPT 2nd-stage air seal
assembly from service and replace it with a part eligible for
installation.
(iii) If a through-crack is found in the forward edge or aft
edge of the HPT 2nd-stage air seal assembly during the visual
inspection or FPI required by paragraph (g)(2)(i) of this AD, before
further flight, remove the HPT 2nd-stage air seal assembly, mating
HPT 1st-stage disk, and HPT 2nd-stage hub from service, and replace
the parts with parts eligible for installation. In order to return
the mating HPT 1st-stage disk and HPT 2nd-stage hub to service, the
inspections of the HPT 2nd-stage air seal assembly cannot reveal a
through-crack.
(3) Replacement of HPT 2nd-Stage Air Seal Assembly
(i) For PW PW2037, PW2037M, and PW2040 model turbofan engines,
at the next engine shop visit after the effective date of this AD,
remove the HPT 2nd-stage air seal assembly, P/N 1A8209 or 1A8209-
001, and replace it with a part eligible for installation.
(ii) For PW F117-PW-100 model turbofan engines, at the next
piece part opportunity after the effective date of this AD, remove
the HPT 2nd-stage air seal assembly, P/N 1A8209 or 1A8209-001, and
replace it with a part eligible for installation.
(h) Terminating Action
Removal of the HPT 2nd-stage air seal assembly, P/N 1A8209 or
1A8209-001, and its replacement with a part eligible for
installation as required by paragraph (g)(3) of this AD is a
terminating action for the repetitive BSI requirements in paragraph
(g)(1)(ii) of this AD.
(i) 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 flanges, except that the
separation of engine flanges solely for the purposes of
transportation of the engine without subsequent engine maintenance
does not constitute an engine shop visit.
(2) For the purpose of this AD, a ``piece-part opportunity'' is
when the part is completely disassembled.
(3) For the purpose of this AD, a ``part eligible for
installation'' is:
(i) An HPT 2nd-stage air seal assembly that is not P/N 1A8209 or
1A8209-001, or;
(ii) An HPT 2nd-stage air seal assembly that has been modified
using PW SB PW2000 72-754, Revision No. 2, dated April 30, 2019, or
PW SB PWF117 72-402, Revision No. 2, dated May 3, 2019.
(4) For the purpose of this AD, a ``through-crack'' is a crack
that has propagated through the thickness of the part and is present
on both the inner diameter and outer diameter of either the forward
or aft edge of the HPT 2nd-stage air seal assembly.
(5) For the purpose of this AD, an ``HPT overhaul'' is the
disassembly of the HPT and maintenance of the HPT module that
included an inspection of the HPT 2nd-stage air seal assembly.
(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
certification office, send it to the attention of the person
identified in paragraph (k)(1) 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.
(k) Related Information
(1) For more information about this AD, contact Carol Nguyen,
Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: 781-238-7655; fax: 781-238-7199; email:
[email protected].
(2) For service information identified in this AD, contact Pratt
& Whitney, 400 Main Street, East Hartford, CT 06118, United States;
phone: 800-565-0140; fax: 860-565-5442; email: [email protected];
website: https://fleetcare.pw.utc.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 May 22, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2020-11499 Filed 5-29-20; 8:45 am]
BILLING CODE 4910-13-P
