[Federal Register Volume 86, Number 246 (Tuesday, December 28, 2021)]
[Proposed Rules]
[Pages 73699-73702]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-27840]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0959; Project Identifier AD-2021-00830-E]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Division Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

[[Page 73700]]


ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2019-03-01 and AD 2021-05-51, which apply to certain Pratt & Whitney 
Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and 
PW4090-3 model turbofan engines. AD 2019-03-01 requires performing 
initial and repetitive thermal acoustic image (TAI) inspections for 
cracks in certain 1st-stage low-pressure compressor (LPC) blades and 
removal of those blades that fail inspection. AD 2021-05-51 requires 
performing a one-time TAI inspection for cracks in certain 1st-stage 
LPC blades and removal of those blades that fail inspection. Since the 
FAA issued AD 2019-03-01 and AD 2021-05-51, the manufacturer determined 
the need to add initial and repetitive ultrasonic testing (UT) 
inspections of the 1st-stage LPC blades. This proposed AD would require 
initial and repetitive UT inspections and TAI inspections for cracks in 
certain 1st-stage LPC blades and removal of those blades that fail 
inspection. 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 January 27, 
2022.

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 Division, 400 Main Street, East Hartford, CT 06118; phone: 
(860) 565-0140; email: [email protected]; website: https://connect.prattwhitney.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-2021-0959; 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: Carol Nguyen, Aviation Safety 
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 ADDRESSES. Include ``Docket No. FAA-2021-0959; Project Identifier 
AD-2021-00830-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.
    The FAA has been informed that PW has done some outreach with 
affected operators regarding the proposed corrective actions for this 
unsafe condition. As a result, affected operators are already aware of 
the proposed corrective actions and, in some cases, have already begun 
implementation of the updated inspections on the 1st-stage LPC blades 
proposed by this AD. Therefore, the FAA has determined that a 30-day 
comment period is appropriate.
    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 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 Carol 
Nguyen, 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 2019-03-01, Amendment 39-19553 (84 FR 4320, 
February 15, 2019) (AD 2019-03-01), and AD 2021-05-51, Amendment 39-
21470 (86 FR 13445, March 9, 2021) (AD 2021-05-51) for certain PW 
PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 model 
turbofan engines. AD 2019-03-01 and AD 2021-05-51 were prompted by 
three in-flight failures of a 1st-stage LPC blade, with one failure 
resulting in an engine fire during flight. AD 2019-03-01 and AD 2021-
05-51 require performing a TAI inspection for cracks in certain 1st-
stage LPC blades and removal of those blades that fail inspection. The 
agency issued AD 2019-03-01 and AD 2021-05-51 to prevent failure of the 
1st-stage LPC blades.

Actions Since AD 2019-03-01 and AD 2021-05-51 Was Issued

    Since the FAA issued AD 2019-03-01 and AD 2021-05-51, the 
manufacturer developed an improved UT inspection for the three critical 
locations on the 1st-stage LPC blade, two at the mid span region of the 
blade and one at the flow path region of the blade. The manufacturer 
published Pratt & Whitney Alert Service Bulletin (ASB) PW4G-112-A72-
361, dated October 15, 2021, which provides instructions for performing 
both the improved UT inspection and the TAI inspection. The 
manufacturer also determined that it was necessary to adjust the 
initial TAI inspection threshold and lower the repetitive TAI 
inspection interval on the 1st-stage LPC blades to address the unsafe 
condition.

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.

[[Page 73701]]

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Pratt & Whitney ASB PW4G-112-A72-361, dated 
October 15, 2021. This ASB specifies procedures for performing the TAI 
and UT inspections of 1st-stage LPC blades. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
ADDRESSES.

Other Related Service Information

    The FAA reviewed ``Engine-Driven Pump (EDP) Shutoff Valve Check'' 
(Subtasks 26-21-00-200-018, 26-21-00-200-019, and 26-21-00-840-022) of 
Boeing 777-200/300 Aircraft Maintenance Manual, dated September 5, 
2021. The service information specifies procedures for performing the 
engine-driven pump shutoff valve functional check.

Proposed AD Requirements in This NPRM

    This proposed AD would retain none of the requirements of AD 2019-
03-01 and AD 2021-05-51. This proposed AD would require initial and 
repetitive UT inspections and TAI inspections for cracks in certain 
1st-stage LPC blades and removal of those blades that fail inspection.

Interim Action

    The FAA considers this AD to be an interim action. The FAA 
anticipates that further AD action will follow.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 108 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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Perform UT flow path inspection of 1st- 15 work-hours x $85 per               $0          $1,275        $137,700
 stage LPC blades.                       hour = $1,275.
Perform UT mid span inspection of 1st-  30 work-hours x $85 per                0           2,550         275,400
 stage LPC blades.                       hour = $2,550.
Perform TAI inspection of 1st-stage     22 work-hours x $85 per                0           1,870         201,960
 LPC blades.                             hour = $1,870.
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    The FAA estimates the following costs to do any necessary 
replacement that would be required based on the results of the proposed 
inspection. The agency has no way of determining the number of aircraft 
that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace 1st-stage LPC blade...................  0 work-hours x $85 per hour = $0        $125,000        $125,000
----------------------------------------------------------------------------------------------------------------

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 (AD) 2019-03-01, Amendment 39-19553 
(84 FR 4320, February 15, 2019), and AD 2021-05-51, Amendment 39-21470 
(86 FR 13445, March 9, 2021); and
0
b. Adding the following new airworthiness directive:

Pratt & Whitney Division: Docket No. FAA-2021-0959; Project 
Identifier AD-2021-00830-E.

[[Page 73702]]

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by January 27, 2022.

(b) Affected ADs

    This AD replaces AD 2019-03-01, Amendment 39-19553 (84 FR 4320, 
February 15, 2019), and AD 2021-05-51, Amendment 39-21470 (86 FR 
13445, March 9, 2021).

(c) Applicability

    This AD applies to Pratt & Whitney Division (PW) PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 model 
turbofan engines, with a 1st-stage low-pressure compressor (LPC) 
blade, with part number 52A241, 55A801, 55A801-001, 55A901, 55A901-
001, 56A201, 56A201-001, or 56A221, installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by three in-flight failures of a 1st-stage 
LPC blade, with one failure resulting in an engine fire during 
flight, and subsequent manufacturer publication of service 
information specifying improved inspections for three critical 
locations on the 1st-stage LPC blade. The FAA is issuing this AD to 
prevent failure of the 1st-stage LPC blades. The unsafe condition, 
if not addressed, could result in 1st-stage LPC blade 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) Initial 1st-Stage LPC Blade Inspections

    (i) For 1st-stage LPC blades that have accumulated any number of 
cycles since new (CSN) greater than zero, before further flight 
after the effective date of this AD, perform a flow path and a mid 
span ultrasonic testing (UT) inspection of the 1st-stage LPC blades 
in accordance with the Accomplishment Instructions, Part A--Initial 
Inspection of All LPC Fan Blades Prior to Their Return to Service, 
paragraph 1.A. through C., of Pratt & Whitney Alert Service Bulletin 
(ASB) PW4G-112-A72-361, dated October 15, 2021 (PW4G-112-A72-361).
    Note 1 to paragraph (g)(1)(i): New fan blades that have zero CSN 
do not need to undergo the initial 1st-stage LPC blade flow path and 
mid span UT inspection required by paragraph (g)(1)(i) of this AD, 
but must undergo the repetitive inspections of paragraph (g)(2) of 
this AD.
    (ii) Within the following compliance times after the effective 
date of this AD, perform a thermal acoustic image (TAI) inspection 
of the 1st-stage LPC blades for cracks using a method approved by 
the FAA:
    (A) For 1st-stage LPC blades with 1,000 CSN or more, with no 
prior TAI inspection, inspect before further flight.
    (B) For 1st-stage LPC blades with 1,000 flight cycles (FCs) or 
more since the last TAI inspection, inspect before further flight.
    (C) For 1st-stage LPC blades with fewer than 1,000 CSN, with no 
prior TAI inspection, inspect before accumulating 1,000 CSN.
    (D) For 1st-stage LPC blades with fewer than 1,000 FCs since the 
last TAI inspection, inspect before accumulating 1,000 FCs since the 
last TAI inspection.
    Note 2 to paragraph (g)(1)(ii): Vendors that can perform an FAA-
approved TAI inspection are listed in the Vendor Services section of 
PW4G-112-A72-361.

(2) Repetitive 1st-Stage LPC Blade Inspections

    (i) Before exceeding 275 FCs since the last flow path UT 
inspection, and thereafter at intervals not exceeding 275 FCs since 
the last flow path UT inspection, perform a flow path UT inspection 
of the 1st-stage LPC blades in accordance with the Accomplishment 
Instructions, Part B--Repetitive Inspection of All LPC Fan Blades 
After Their Return to Service, paragraph 1.A., of PW4G-112-A72-361.
    (ii) Before exceeding 550 FCs since the last mid span UT 
inspection, and thereafter at intervals not exceeding 550 FCs since 
the last mid span UT inspection, perform a mid span UT inspection of 
the 1st-stage LPC blades in accordance with the Accomplishment 
Instructions, Part B--Repetitive Inspection of All LPC Fan Blades 
After Their Return to Service, paragraphs 1.B. and C., of PW4G-112-
A72-361.
    (iii) Before exceeding 1,000 FCs since the last TAI inspection, 
and thereafter at intervals not exceeding 1,000 FCs since the last 
TAI inspection, perform repetitive TAI inspections of the 1st-stage 
LPC blades using a method approved by the FAA.

(3) Removal of the 1st-Stage LPC Blade

    (i) If any 1st-stage LPC blade fails any inspection required by 
paragraphs (g)(1) or (2) of this AD, before further flight, remove 
the 1st-stage LPC blade from service and replace with a part 
eligible for installation.
    (ii) [Reserved]

(h) Special Flight Permit

    Special flight permits, as described in 14 CFR 21.197 and 
21.199, are not permitted except for airplanes on which the actions 
specified in paragraphs (h)(1) and (2) of this AD have been done.
    (1) A flow path UT inspection of the 1st-stage LPC blades for 
cracking has been done as specified in the Accomplishment 
Instructions, Part A--Initial Inspection of All LPC Fan Blades Prior 
to their Return to Service, paragraph 1.A., of PW4G-112-A72-361, and 
the 1st-stage LPC blades have been found serviceable.
    (2) A functional check of the left and right hydraulic pump 
shutoff valves to ensure they close in response to the fire handle 
input and all applicable corrective actions (i.e., repair) within 10 
days prior to flight.
    Note 3 to paragraph (h)(2): Guidance for accomplishing the 
actions required by paragraph (h)(2) of this AD can be found in the 
``Engine-Driven Pump (EDP) Shutoff Valve Check'' (Subtasks 26-21-00-
200-018, 26-21-00-200-019, and 26-21-00-840-022) of Boeing 777-200/
300 Aircraft Maintenance Manual.

(i) Credit for Previous Actions

    This paragraph provides credit for the actions specified in 
paragraphs (g)(1) and (h)(1) of this AD, if those actions were 
performed before the effective date of this AD using the service 
information specified in paragraphs (i)(1), (2), or (3) of this AD.
    (1) Paragraph 2. of the Accomplishment Instructions of Pratt & 
Whitney Special Instruction No. 85F21, dated May 12, 2021, for a 
flow path UT inspection.
    (2) Paragraph 1.a) through c) of the Accomplishment Instructions 
of Pratt & Whitney Special Instruction No. 130F-21, dated July 1, 
2021, for a flow path and a mid span UT inspection.
    (3) Paragraph 2.a) through c) of the Accomplishment Instructions 
of Pratt & Whitney Special Instruction No. 130F-21, Revision A, 
dated July 28, 2021, for a flow path and a mid span UT inspection.

(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, 
Aviation Safety 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 Division, 400 Main Street, East Hartford, CT 06118; phone: 
(860) 565-0140; email: [email protected]; website: https://connect.prattwhitney.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 December 14, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-27840 Filed 12-22-21; 11:15 am]
BILLING CODE 4910-13-P


