Airworthiness Directives; Pratt & Whitney Turbofan Engines

[Federal Register Volume 86, Number 157 (Wednesday, August 18, 2021)]
[Rules and Regulations]
[Pages 46111-46113]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17654]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0447; Project Identifier AD-2021-00131-E; 
Amendment 39-21692; AD 2021-17-09]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Pratt & Whitney PW1500G and PW1900G series turbofan engines. This AD 
was prompted by reports of cracks in the high-pressure compressor (HPC) 
rotor shaft that resulted in in-flight shutdowns (IFSDs) and 
unscheduled engine removals (UERs). This AD requires removal and 
replacement of the HPC front hub and HPC rotor shaft. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective September 22, 2021.

ADDRESSES: For service information identified in this final rule, 
contact Pratt & Whitney, 400 Main Street, East Hartford, CT 06118; 
phone: (800) 565-0140; email: [email protected]; website: https://fleetcare.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. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2021-0447.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0447; 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 final rule, any 
comments received, and other information. The address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

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:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all PW1519G, PW1521G, 
PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, PW1525G-3, PW1919G, 
PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines. The 
NPRM published in the Federal Register on June 3, 2021 (86 FR 29707). 
The NPRM was prompted by reports of cracks in the HPC rotor shaft that 
resulted in vibration and subsequent IFSDs and

[[Page 46112]]

UERs. The manufacturer determined that the threads on the HPC rotor 
shaft were not optimized for load distribution, which resulted in 
vibration stresses. During one occurrence, oil was released at the 
high-pressure turbine (HPT) disk bore location. The manufacturer 
redesigned the HPC front hub and HPC rotor shaft for increased 
durability and decreased vibration stress. The redesigned HPC front hub 
is made from nickel to help with corrosion resistance. The threads on 
the HPC rotor shaft were also redesigned to help distribute the load on 
the threads and decrease vibration stress. In the NPRM, the FAA 
proposed to require removal and replacement of the HPC front hub and 
HPC rotor shaft. The FAA is issuing this AD to address the unsafe 
condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from one commenter, the Air Line Pilots 
Association, International (ALPA). ALPA supported the NPRM without 
change.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. This AD is adopted as proposed in the 
NPRM.

Related Service Information

    The FAA reviewed Pratt & Whitney Service Bulletin (SB) PW1000G-A-
72-00-0154-00A-930A-D, Issue No. 001, dated May 7, 2021 (PW1000G-A-72-
00-0154-00A-930A-D), and Pratt & Whitney SB PW1000G-A-72-00-0101-00B-
930A-D, Issue No. 001, dated May 7, 2021 (SB PW1000G-A-72-00-0101-00B-
930A-D). These SBs describe procedures for removing and replacing the 
HPC front hub and HPC rotor shaft.

Costs of Compliance

    The FAA estimates that this AD affects 88 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace HPC front hub and HPC rotor     25.75 work-hours x $85          $120,090     $122,278.75     $10,760,530
 shaft.                                  per hour = $2,188.75.
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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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 this AD:
    (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 Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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:

2021-17-09 Pratt & Whitney: Amendment 39-21692; Docket No. FAA-2021-
0447; Project Identifier AD-2021-00131-E.

(a) Effective Date

    This airworthiness directive (AD) is effective September 22, 
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.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the high-pressure 
compressor (HPC) rotor shaft that resulted in in-flight shutdowns 
and unscheduled engine removals. The FAA is issuing this AD to 
prevent cracking of the HPC rotor shaft. The unsafe condition, if 
not addressed, could result in release of a high-pressure turbine 
disk, 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 Action

    At the next engine shop visit after the effective date of this 
AD, remove HPC front hub, part number (P/N) 30G1910 or 30G3210, and 
HPC rotor shaft, P/N 30G1854, 30G3109, 30G4995, 30G4953, or 31G0014, 
from service and replace each part with a part eligible for 
installation.

[[Page 46113]]

(h) 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 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 an HPC front hub: any HPC front hub with a P/N other 
than P/N 30G1910 or 30G3210; and
    (ii) For an HPC rotor shaft: any HPC rotor shaft with a P/N 
other than P/N 30G1854, 30G3109, 30G4995, 30G4953, or 31G0014.

(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

    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].

(k) Material Incorporated by Reference

    None.

    Issued on August 12, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-17654 Filed 8-17-21; 8:45 am]
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