[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
----------------------------------------------------------------------------------------------------------------
                                                                                     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.
----------------------------------------------------------------------------------------------------------------

    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
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
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).
----------------------------------------------------------------------------------------------------------------

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