[Federal Register Volume 86, Number 122 (Tuesday, June 29, 2021)]
[Proposed Rules]
[Pages 34166-34168]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-13709]



[[Page 34166]]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0515; Project Identifier AD-2021-00191-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 adopt a new airworthiness directive (AD) 
for all Pratt & Whitney PW1500G and PW1900G series turbofan engines 
with a certain high-pressure turbine (HPT) 1st-stage hub or HPT rotor 
1st-stage blade retaining plate installed. This proposed AD was 
prompted by a report from the manufacturer who determined that the HPT 
1st-stage hub and HPT rotor 1st-stage blade retaining plate fail to 
meet the published life-cycle limits for each part. This proposed AD 
would require removal and replacement of the HPT 1st-stage hub and HPT 
rotor 1st-stage blade retaining plate prior to reaching certain cycle 
limits. 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 June 29, 
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; 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 at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0515; 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: [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-2021-0515; Project Identifier 
AD-2021-00191-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 
https://www.regulations.gov, 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 a report from the manufacturer, who determined 
after recalculating life limits using a thermal match model and other 
life-calculation methodology updates, the HPT 1st-stage hub and HPT 
rotor 1st-stage blade retaining plate failed to meet the published 
life-cycle limits for each part. This condition, if not addressed, 
could result in the release of the HPT 1st-stage hub or HPT rotor 1st-
stage blade retaining plate, damage to the engine, and damage to the 
aircraft.

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-
72-00-0115-00B-930A-D, Issue No. 001, dated April 26, 2021, and Pratt & 
Whitney SB PW1000G-A-72-00-0168-00A-930A-D, Issue No. 001, dated April 
26, 2021. These SBs describe procedures for removing and replacing the 
HPT 1st-stage hub and HPT rotor 1st-stage blade retaining plate.

Proposed AD Requirements in This NPRM

    This proposed AD would require removal and replacement of the HPT 
1st-stage hub and HPT rotor 1st-stage blade retaining plate prior to 
reaching certain cycle limits.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 88 engines installed on airplanes of U.S. registry. The FAA 
estimates that in most cases the affected HPT 1st-stage hub and the 
affected HPT 1st-stage blade retaining plate will both be replaced 
during the same disassembly of the engine. This cost estimate therefore 
reflects the cost of replacing both parts during the same engine 
disassembly.
    The FAA estimates the following costs to comply with this proposed 
AD:

[[Page 34167]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace HPT 1st-stage hub and HPT       300 work-hours x $85 per         $86,252        $111,752      $9,834,176
 rotor 1st-stage blade retaining plate   hour = $25,500.
 (pro-rated part cost).
----------------------------------------------------------------------------------------------------------------

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:

Pratt & Whitney: Docket No. FAA-2021-0515; Project Identifier AD-
2021- 00191-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by August 13, 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 with a high-
pressure turbine (HPT) 1st-stage hub, part number (P/N) 30G5701, or 
an HPT rotor 1st-stage blade retaining plate, P/N 30G1692, 
installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by a report from the manufacturer who 
determined that the HPT 1st-stage hub and HPT rotor 1st-stage blade 
retaining plate fail to meet the published life-cycle limits for 
each part. The FAA is issuing this AD to prevent failure of the HPT 
1st-stage hub or HPT rotor 1st-stage blade retaining plate. The 
unsafe condition, if not addressed, could result in the release of 
the HPT 1st-stage hub or HPT rotor 1st-stage blade retaining plate, 
damage to the engine, and damage to the aircraft.

(f) Compliance

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

(g) Required Actions

    (1) For PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, and 
PW1524G-3 model turbofan engines:
    (i) For an affected HPT 1st-stage hub and an affected HPT rotor 
1st-stage blade retaining plate with 3,000 cycles since new (CSN) or 
fewer on the effective date of this AD, before the affected part 
exceeds 4,700 CSN, remove the affected part, as applicable, and 
replace with a part eligible for installation.
    (ii) For an affected HPT 1st-stage hub and an affected HPT rotor 
1st-stage blade retaining plate with greater than 3,000 CSN but 
fewer than 4,960 CSN on the effective date of the AD, at the next 
engine shop visit after accumulating 4,700 CSN or before the 
affected part exceeds 5,260 CSN, whichever occurs first, remove the 
affected part, as applicable, and replace with a part eligible for 
installation.
    (iii) For an affected HPT 1st-stage hub and an affected HPT 
rotor 1st-stage blade retaining plate with 4,960 CSN or greater on 
the effective date of the AD, at the next engine shop visit or 
within 300 cycles after the effective date of this AD, whichever 
occurs first, remove the affected part, as applicable, and replace 
with a part eligible for installation.
    (2) For PW1919G and PW1921G model turbofan engines:
    (i) For an affected HPT 1st-stage hub and an affected HPT rotor 
1st-stage blade retaining plate with 3,000 CSN or fewer on the 
effective date of this AD, before the affected part exceeds 4,700 
CSN, remove the affected part, as applicable, and replace with a 
part eligible for installation.
    (ii) For an affected HPT 1st-stage hub and an affected HPT rotor 
1st-stage blade retaining plate with greater than 3,000 CSN but 
fewer than 4,700 CSN on the effective date of the AD, at the next 
engine shop visit after the affected part accumulates 4,700 CSN or 
before the affected part exceeds 5,000 CSN, whichever occurs first, 
remove the affected part, as applicable, and replace with a part 
eligible for installation.
    (iii) For an affected HPT 1st-stage hub and an affected HPT 
rotor 1st-stage blade retaining plate with 4,700 CSN or greater on 
the effective date of the AD, at the next engine shop visit or 
within 300 cycles after the effective date of this AD, whichever 
occurs first, remove the affected part, as applicable, and replace 
with a part eligible for installation.
    (3) For PW1525G and PW1525G-3 model turbofan engines:
    (i) Before the affected HPT 1st-stage hub and affected HPT rotor 
1st-stage blade retaining plate exceeds 2,800 CSN, respectively, or 
within 300 cycles after the effective date of this AD, whichever 
occurs later, remove the affected part, as applicable, and replace 
with a part eligible for installation.
    (ii) [Reserved]
    (4) For PW1922G, PW1923G, and PW1923G-A model turbofan engines:
    (i) Before the affected HPT 1st-stage hub and affected HPT rotor 
1st-stage blade retaining plate exceeds 3,000 CSN,

[[Page 34168]]

respectively, or within 300 cycles after the effective date of this 
AD, whichever occurs later, remove the affected part, as applicable, 
and replace with a part eligible for installation.
    (ii) [Reserved]

(h) Definition

    (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 PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-
3, PW1919G, and PW1921G model turbofan engines:
    (A) Any HPT 1st-stage hub with P/N 30G5701 with 4,700 CSN or 
fewer, or with a P/N not listed in this AD.
    (B) Any HPT rotor 1st-stage blade retaining plate with P/N 
30G1692 with 4,700 CSN or fewer, or with a P/N not listed in this 
AD.
    (ii) For PW1525G and PW1525G-3 model turbofan engines:
    (A) Any HPT 1st-stage hub with P/N 30G5701 with 2,800 CSN or 
fewer, or with a P/N not listed in this AD.
    (B) Any HPT rotor 1st-stage blade retaining plate with P/N 
30G1692 with 2,800 CSN or fewer, or with a P/N not listed in this 
AD.
    (iii) For PW1922G, PW1923G, and PW1923G-A model turbofan 
engines:
    (A) Any HPT 1st-stage hub with P/N 30G5701 with 3,000 CSN or 
fewer, or with a P/N not listed in this AD.
    (B) Any HPT rotor 1st-stage blade retaining plate with P/N 
30G1692 with 3,000 CSN or fewer, or with a P/N not listed in this 
AD.

(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: 
[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.

(j) Related Information

    (1) 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: [email protected].
    (2) For service information identified in this AD, contact Pratt 
& Whitney, 400 Main Street, East Hartford, CT 06118; 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 June 23, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-13709 Filed 6-28-21; 8:45 am]
BILLING CODE 4910-13-P