[Federal Register Volume 86, Number 57 (Friday, March 26, 2021)]
[Proposed Rules]
[Pages 16137-16140]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-06024]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0191; Project Identifier AD-2020-01492-E]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2019-21-11 and AD 2020-07-02. AD 2019-21-11 applies to all Pratt & 
Whitney (PW) PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, 
PW1525G, PW1525G-3, PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A 
model turbofan engines. AD 2020-07-02 applies to all PW PW1519G, 
PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-
3 model turbofan engines. AD 2019-21-11 requires initial and repetitive 
borescope inspections (BSIs) of the low-pressure compressor (LPC) rotor 
1 (R1) and, depending on the results of the inspections, replacement of 
the LPC. AD 2020-07-02 requires the removal from service of certain 
electronic engine control (EEC) full authority digital electronic 
control (FADEC) software and the installation of a software version 
eligible for installation. Since the FAA issued AD 2019-21-11 and AD 
2020-07-02, the manufacturer developed a new version of EEC FADEC 
software, which terminates the need for repetitive BSIs of the LPC R1. 
This proposed AD would continue to require repetitive BSIs of certain 
LPC R1s until replacement of EEC FADEC software with the updated 
software. This proposed AD would require a BSI after installation of 
the updated EEC FADEC software if certain Onboard Maintenance Message 
fault codes are displayed and meet specified criteria. 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 May 10, 
2021.

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; phone: (800) 565-
0140; email: [email protected]; website: http://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 at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0191; 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: Nicholas Paine, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7116; 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-2021-0191; Project Identifier 
AD-2020-01492-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

[[Page 16138]]

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 NPRM. Submissions containing CBI should be sent to 
Nicholas Paine, 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 2019-21-11, Amendment 39-19777 (84 FR 57813, 
October 29, 2019), (AD 2019-21-11) for certain PW PW1519G, PW1521G, 
PW1521GA, PW1524G, PW1525G, PW1521G-3, PW1524G-3, PW1525G-3, PW1919G, 
PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines. AD 
2019-21-11 was prompted by an in-flight failure and additional findings 
of cracks in the LPC R1. AD 2019-21-11 requires initial and repetitive 
BSI of the LPC R1 and, depending on the results of the BSIs, 
replacement of the LPC. The agency issued AD 2019-21-11 to prevent 
failure of the LPC R1.
    The FAA issued AD 2020-07-02, Amendment 39-21106 (85 FR 17742, 
March 31, 2020), (AD 2020-07-02), for all PW PW1519G, PW1521G, PW1521G-
3, PW1521GA, PW1524G, PW1524G33, PW1525G, and PW1525G33 model turbofan 
engines. AD 2020-07-02 was prompted by reports of four in-flight 
shutdowns due to failure of the LPC R1 and by subsequent findings of 
cracked LPC R1s during inspections. AD 2020-07-02 requires the removal 
from service of certain EEC FADEC software and the installation of a 
software version eligible for installation. The agency issued AD 2020-
07-02 to prevent failure of the LPC R1.

Actions Since AD 2019-21-11 and AD 2020-07-02 Were Issued

    Since the FAA issued AD 2019-21-11 and AD 2020-07-02, the 
manufacturer performed further root cause analysis of the LPC R1 
failures and determined the need to update the EEC FADEC software to 
automate rotor speed management and limit the maximum climb and maximum 
continuous thrust ratings.

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-
72-00-0125-00A-930A-D, Issue No. 002, dated October 24, 2019; Pratt & 
Whitney SB PW1000G-A-72-00-0075-00B-930A-D, Issue No. 003, dated 
October 24, 2019; Pratt & Whitney SB PW1000G-A-73-00-0044-00A-930A-D, 
Issue No. 004, dated February 23, 2021; and Pratt & Whitney SB PW1000G-
A-73-00-0023-00B-930A-D, Issue No. 002, dated February 22, 2021. The 
FAA also reviewed Section PW1000G-A-72-00-00-02A-0B5A-A of Pratt & 
Whitney Engine Maintenance Manual (EMM), Issue No. 016, dated January 
15, 2021; and Section PW1000G-A-72-31-00-00A-312A-D of Pratt & Whitney 
EMM, Issue No. 016, dated January 11, 2021.
    Pratt & Whitney SBs PW1000G-A-72-00-0125-00A-930A-D, Issue No. 002, 
dated October 24, 2019, and PW1000G-A-72-00-0075-00B-930A-D, Issue No. 
003, dated October 24, 2019, specify procedures for performing initial 
and repetitive BSI of certain LPC R1s. Pratt & Whitney SB PW1000G-A-73-
00-0044-00A-930A-D, Issue No. 004, dated February 23, 2021, specifies 
procedures for replacing or modifying the EEC to incorporate EEC FADEC 
software version V2.11.10.4. Pratt & Whitney SB PW1000G-A-73-00-0023-
00B-930A-D, Issue No. 002, dated February 22, 2021, specifies 
procedures for replacing or modifying the EEC to incorporate EEC FADEC 
software version V9.5.6.7.
    Section PW1000G-A-72-00-00-02A-0B5A-A of Pratt & Whitney EMM, Issue 
No. 016, dated January 15, 2021, specifies procedures for inspecting 
the engine for possible engine damage after receiving notification of 
an N1 or N2 overspeed operation. Section PW1000G-A-72-31-00-00A-312A-D 
of Pratt & Whitney EMM, Issue No. 016, dated January 11, 2021, 
specifies procedures for performing a BSI of the LPC.

Proposed AD Requirements in This NPRM

    This proposed AD would retain certain requirements of AD 2019-21-11 
and none of the requirements of AD 2020-07-02. This proposed AD would 
continue to require a BSI of certain LPC R1s for damage and cracks and, 
depending on the results of the BSI, replacement of the LPC R1. This 
proposed AD would continue to require repetitive BSIs of certain LPC 
R1s until replacement of the EEC FADEC software with the updated 
software. This proposed AD would also require a BSI of the LPC R1 after 
installation of the updated EEC FADEC software if certain Onboard 
Maintenance Message fault codes are displayed and meet specified 
criteria.

Interim Action

    The FAA considers that this proposed AD would be an interim action. 
If final corrective action is later identified, the FAA might consider 
additional rulemaking.

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
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace EEC FADEC software............  2 work-hours x $85 per                $0            $170         $15,980
                                         hour = $170.
BSI per inspection cycle..............  2 work-hours x $85 per                 0             170          15,980
                                         hour = $170.
----------------------------------------------------------------------------------------------------------------


[[Page 16139]]


                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace LPC R1................................  40 work-hours x per $85 hour =          $156,000        $159,000
                                                 $3,400.
BSI of the LPC R1 if Onboard Maintenance        2 work-hours x $85 per hour =                  0             170
 Message fault codes are displayed.              $170.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some of the costs of this 
proposed AD may be covered under warranty, thereby reducing the cost 
impact on affected individuals.

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:
0
a. Removing Airworthiness Directive 2019-21-11, Amendment 39-19777 (84 
FR 57813, October 29, 2019); and Airworthiness Directive AD 2020-07-02, 
Amendment 39-21106 (85 FR 17742, March 31, 2020); and
0
b. Adding the following new airworthiness directive:

Pratt & Whitney: Docket No. FAA-2021-0191; Project Identifier AD-
2020-01492-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by May 10, 2021.

(b) Affected ADs

    This AD replaces AD 2019-21-11 Amendment 39-19777 (84 FR 57813, 
October 29, 2019); and AD 2020-07-02, Amendment 39-21106 (85 FR 
17742, March 31, 2020).

(c) Applicability

    This AD applies to Pratt & Whitney (PW) 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 in-flight shutdowns due to 
failure of the low-pressure compressor (LPC) rotor 1 (R1) and by 
subsequent findings of cracked LPC R1s during inspection. The FAA is 
issuing this AD to prevent failure of the LPC R1. The unsafe 
condition, if not addressed, could result in uncontained release of 
the LPC R1, damage to the engine, damage to the airplane, and loss 
of control of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) Except for those model turbofan engines identified in 
paragraph (g)(2) of this AD, perform a borescope inspection (BSI) of 
the LPC R1 for damage and cracks as follows:
    (i) For engines that have accumulated fewer than 300 flight 
cycles since new (CSN), perform a BSI within 50 flight cycles (FCs) 
from October 29, 2019 (the effective date of AD 2019-19-11), or 
before further flight, whichever occurs later.
    (ii) For engines that have accumulated fewer than 300 FCs since 
installation of V2.11.7 or V2.11.8 electronic engine control (EEC) 
full authority digital electronic control (FADEC) software, perform 
a BSI within 50 FCs from October 29, 2019, or before further flight, 
whichever occurs later.
    (iii) Thereafter, at intervals not to exceed 50 FCs until the 
engine accumulates 300 flight CSN or accumulates 300 FCs since the 
installation of V2.11.7 or V2.11.8 EEC FADEC software, whichever 
occurs later, repeat the BSI for damage and cracks.
    (iv) Perform the BSI required by paragraphs (g)(1)(i) through 
(iii) of this AD at the following LPC R1 locations:
    (A) The blade tip;
    (B) The leading edge;
    (C) The leading edge fillet to rotor platform radius; and
    (D) The airfoil convex side root fillet to rotor platform 
radius.
    (2) For any affected PW model turbofan engine installed as a 
``zero time spare,'' except for PW1519G, PW1521GA, PW1919G, and 
PW1922G model turbofan engines, within 15 FCs from the effective 
date of this AD, and thereafter at intervals not to exceed 15 FCs 
until the engine accumulates 300 flight CSN, perform a BSI of the 
LPC R1 for damage and cracks at the locations in paragraph 
(g)(1)(iv) of this AD.
    (3) Based on the results of the BSIs required by paragraphs 
(g)(1) and (2) of this AD, before further flight, remove and replace 
the LPC R1 if:
    (i) There is damage on an LPC R1 that exceeds serviceable 
limits; or
    (ii) Any crack in the LPC R1 exists.

    Note 1 to paragraph (g)(3): Guidance on determining the 
serviceable limits in paragraph (g)(3) of this AD can be found in PW 
Service Bulletin (SB) PW1000G-A-72-00-0125-00A-930A-D, Issue No. 
002, dated October 24, 2019, and PW SB PW1000G-A-72-00-0075-00B-
930A-D, Issue No. 003, dated October 24, 2019.

    (4) For PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G,

[[Page 16140]]

PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines, within 120 
days from the effective date of this AD, remove the EEC FADEC 
software if the version is earlier than EEC FADEC software version 
V2.11.10.4 and install EEC FADEC software that is eligible for 
installation.
    (5) For PW PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A 
model turbofan engines, within 120 days of the effective date of 
this AD, remove the EEC FADEC software if the version is earlier 
than EEC FADEC software version V9.5.6.7 and install EEC FADEC 
software that is eligible for installation.
    (6) For PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, 
PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines with EEC 
FADEC software version V2.11.10.4 or later installed, within 15 FCs 
after receipt of Onboard Maintenance Message fault code 7100F0029 or 
7100F0030, perform a BSI of the LPC R1 for damage and cracks at the 
locations in paragraph (g)(1)(iv) of this AD if the fault code is 
displayed on the ``Active Failure Messages'' and meets the following 
criteria:
    (i) N1 Exceedance is above 95.2%;
    (ii) N1 Exceedance occurred above 29,100 feet; and
    (iii) N1 Exceedance occurs for a duration of 40 seconds (15 
seconds of cockpit display) or more during any flight.

    Note 2 to paragraph (g)(6): Guidance on determining the N1 
Exceedance duration can be found in PW Section PW1000G-A-72-00-00-
02A-0B5A-A of PW Engine Maintenance Manual (EMM), Issue No. 016, 
dated January 15, 2021.


    Note 3 to paragraph (g)(6): Guidance on performing the BSI can 
be found in PW Section PW1000G-A-72-31-00-00A-312A-D of PW EMM, 
Issue No. 016, dated January 11, 2021.

    (7) As the result of the BSI of the LPC R1 required by paragraph 
(g)(6) of this AD, before further flight, remove and replace the LPC 
R1 if:
    (i) There is damage on an LPC R1 that exceeds serviceable 
limits; or
    (ii) Any crack in the LPC R1 exists.

(h) Terminating Actions

    (1) For PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-
3, PW1525G, and PW1525G-3 model turbofan engines, the installation 
of EEC FADEC software required by paragraph (g)(4) of this AD 
terminates the repetitive BSI requirements of paragraphs (g)(1) and 
(2) of this AD.
    (2) For PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A model 
turbofan engines, the installation of EEC FADEC software required by 
paragraph (g)(5) of this AD terminates the repetitive BSI 
requirements of paragraphs (g)(1) and (2) of this AD.

(i) Installation Prohibition

    After the effective date of this AD, do not install EEC FADEC 
software earlier than version V2.11.10.4 or version V9.5.6.7 onto 
any engine identified in paragraph (c) of this AD.

(j) Definitions

    (1) For the purpose of this AD, a ``zero time spare'' is an 
engine that had zero flight hours time-in-service when it was 
installed on an airplane after the airplane had entered service.
    (2) For the purpose of this AD, ``EEC FADEC software that is 
eligible for installation'' is EEC FADEC software version V2.11.10.4 
or later for PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, 
PW1524G-3, PW1525G, PW1525G-3 model turbofan engines and EEC FADEC 
software version V9.5.6.7 or later for PW1919G, PW1921G, PW1922G, 
PW1923G, and PW1923G-A model turbofan engines.

(k) 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 
[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.
    (3) AMOCs approved for AD 2019-21-11 (84 FR 57813, October 29, 
2019) are approved as AMOCs for the corresponding provisions of this 
AD except for paragraphs (g)(1)(i) through (iv) and (g)(3)(i) and 
(ii) of this AD.

(l) Related Information

    (1) For more information about this AD, contact Nicholas Paine, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7116; fax: (781) 238-7719; 
email: [email protected].
    (2) For service information identified in this AD, contact Pratt 
& Whitney, 400 Main Street, East Hartford, CT, 06118; phone: (800) 
565-0140; email: [email protected]; website: http://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 March 18, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-06024 Filed 3-25-21; 8:45 am]
BILLING CODE 4910-13-P