Federal Register / Vol. 86, No. 120 / Friday, June 25, 2021 / Proposed Rules 33579 

64106. For information on the availability of 

this material at the FAA, call (816) 329–4148. 

Issued on June 11, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–13463 Filed 6–24–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0511; Project 

Identifier AD–2020–01229–E] 

RIN 2120–AA64 

Airworthiness Directives; Williams 

International Co., L.L.C. 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 

certain Williams International Co., 

L.L.C. (Williams) FJ44–2A, FJ44–2C, 

FJ44–3A, and FJ44–3A–24 model 

turbofan engines. This proposed AD was 

prompted by a report of cracks in highpressure turbine (HPT) disk posts and 

failure of an HPT disk post. This 

proposed AD would require the removal 

and replacement of the affected HPT 

disk before reaching its new life limit. 

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 August 9, 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 Williams 

International Co., L.L.C., Product 

Support, 2000 Centerpoint Pkwy., 

Pontiac, MI 48341; phone: (800) 859– 

3544; website: http://www.williamsint.com/product-support. You may view 

this service information at the Chicago 

ACO Branch, 2300 East Devon Avenue, 

Des Plaines, IL 60018. 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–2021–0511; 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: Kyle 

Bush, Aviation Safety Engineer, Chicago 

ACO Branch, FAA, 2300 East Devon 

Avenue, Des Plaines, IL 60018; phone: 

(847) 294–7870; fax: (847) 294–7834; 

email: kyle.bush@faa.gov. 

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–2021–0511; Project Identifier AD– 

2020–01229–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 Kyle Bush, Aviation 

Safety Engineer, Chicago ACO Branch, 

FAA, 2300 East Devon Avenue, Des 

Plaines, IL 60018. 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 that 

Williams discovered cracks in one HPT 

disk post during a scheduled inspection 

of an FJ44–2A model turbofan engine. 

An operator also discovered that one 

HPT disk post failed, while the engine 

was in service, resulting in the release 

of an HPT blade. 

Williams initiated an investigation to 

understand the root cause of the cracks 

and to determine the necessary 

corrective action. Williams found that, 

between August 2018 and July 2019, 

nine FJ44–2A HPT disks were rejected 

during inspection after discovery of 

cracks in the HPT disk post. As part of 

its investigation, Williams conducted 

several tests and analysis to determine 

the failure mechanism. Engine tests 

confirmed that FJ44–2A and FJ44–2C 

model turbofan engines operate at a 

higher temperature than most recently 

certified engines. Metallurgical 

evaluation showed cracking is intergranular with oxidation attack near and 

around the crack, with no fatigue 

striations. Metallurgical evaluation and 

comparison of HPT disk, part number 

(P/N) 67093, installed on both FJ44–2A 

and FJ44–3A model turbofan engines, 

showed cracking of the HPT disk. 

As a result of this investigation, 

Williams determined the root cause of 

this cracking was due to higher 

temperatures and a difference in 

manufacturing processes (electrical 

discharge machining vs. broaching). 

Williams determined that these cracks 

have only occurred on HPT disks with 

P/N 67093. Williams subsequently 

issued service information to instruct 

operators to remove the HPT disk, P/N 

67093. This condition, if not addressed, 

could result in failure of the engine, inflight shutdown of the engine, and loss 

of control of 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. 


lotter on DSK11XQN23PROD with PROPOSALS1
33580 Federal Register / Vol. 86, No. 120 / Friday, June 25, 2021 / Proposed Rules 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed Williams 

International Service Bulletin (SB) 

WISB–72–1032, dated March 23, 2020. 

This service information specifies 

procedures for removing and replacing 

the HPT rotor assemblies that include 

HPT disk, P/N 67093. The service 

information also provides instructions 

for incorporating the latest HPT 

combustor/fuel slinger module on FJ44– 

2A and FJ44–2C model turbofan 

engines. 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 Williams 

International SB WISB–72–1034, 

Revision 1, dated June 10, 2020. 

Williams International SB WISB–72– 

1034 describes procedures for reidentifying the HPT rotor assembly and 

HPT disk. 

Proposed AD Requirements in This 

NPRM 

This proposed AD would require 

removing the HPT disk, P/N 67093, 

from service before reaching its new life 

limit and replacing it with a part eligible 

for installation. 

Differences Between This Proposed AD 

and the Service Information 

The Accomplishment Instructions, 

paragraph 2.D., of Williams 

International SB WISB–72–1032, dated 

March 23, 2020, instruct operators of 

FJ44–2A and FJ44–2C model turbofan 

engines to replace or rework the HPT 

combustor/fuel slinger module on FJ44– 

2A and FJ44–2C model turbofan 

engines, while this proposed AD does 

not. Replacement or rework of the HPT 

combustor/fuel slinger module is not 

necessary to resolve the unsafe 

condition in this proposed AD and is 

therefore not proposed by this AD. 

The Accomplishment Instructions, 

paragraphs 2.C. and E. and 3.C. and D., 

of Williams International SB WISB–72– 

1032, dated March 23, 2020, specify 

procedures for removing and replacing 

the HP turbine rotor assembly 

containing HPT disk, P/N 67093, 

whereas this proposed AD mandates 

removing and replacing the HPT disk, 

P/N 67093. Although removing the HPT 

rotor assembly is a necessary step in the 

replacement of the HPT disk, this 

proposed AD only requires replacement 

of the HPT disk to resolve the unsafe 

condition addressed by this proposed 

AD. 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 213 

engines installed on airplanes of U.S. 

registry. 

The FAA estimates the following 

costs to comply with this proposed AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Remove and replace the HPT disk ................ 33 work-hours × $85 per hour = $2,805 ........ $16,694 $19,499 $4,153,287 

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 

operators. 

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 

■ 1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

Williams International Co., L.L.C.: Docket 

No. FAA–2021–0511; Project Identifier 

AD–2020–01229–E. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by August 9, 

2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Williams International 

Co., L.L.C. (Williams) FJ44–2A, FJ44–2C, 

FJ44–3A, and FJ44–3A–24 model turbofan 

engines with a serial number identified in 

paragraph 1.A., Effectivity, of Williams 

International Service Bulletin WISB–72– 

1032, dated March 23, 2020 (the SB), with an 

installed high-pressure turbine (HPT) disk, 

part number (P/N) 67093. 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 7250, Turbine Section. 


lotter on DSK11XQN23PROD with PROPOSALS1
Federal Register / Vol. 86, No. 120 / Friday, June 25, 2021 / Proposed Rules 33581 

(e) Unsafe Condition 

This AD was prompted by a report of 

cracks in the HPT disk posts and failure of 

an HPT disk post, resulting in the release of 

an HPT blade. The FAA is issuing this AD 

to prevent cracking and failure of the HPT 

disk posts. The unsafe condition, if not 

addressed, could result in uncontained 

release of the HPT blade, 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) For FJ44–2A and FJ44–2C model 

turbofan engines, within the compliance 

times specified in Table 1 to paragraph (g) of 

this AD, remove the affected HPT disk from 

service and replace it with a part eligible for 

installation using paragraphs 2.C. and E., 

Accomplishment Instructions—FJ44–2A & 

FJ44–2C, of the SB. 

(2) For FJ44–3A and FJ44–3A–24 model 

turbofan engines, within the compliance 

times specified in Table 1 to paragraph (g) of 

this AD, remove the affected HPT disk from 

service and replace it with a part eligible for 

installation using paragraphs 3.C. and D., of 

the SB. 

(h) Definition 

For the purpose of this AD, a part eligible 

for installation is an HPT disk with a P/N 

other than P/N 67093. 

(i) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Chicago ACO, 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. 

(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 Kyle Bush, Aviation Safety Engineer, 

Chicago ACO Branch, FAA, 2300 East Devon 

Avenue, Des Plaines, IL 60018; phone: (847) 

294–7870; fax: (847) 294–7834; email: 

kyle.bush@faa.gov. 

(2) For service information identified in 

this AD, contact Williams International Co., 

L.L.C., Product Support, 2000 Centerpoint 

Pkwy, Pontiac, MI 48341; phone: (800) 859– 

3544; website: http://www.williams-int.com/ 

product-support. 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 21, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–13516 Filed 6–24–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 71 

[Docket No. FAA–2021–0169; Airspace 

Docket No. 21–ASO–3] 

RIN 2120–AA66 

Proposed Amendment of Class D and 

Class E Airspace; South Florida 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This action proposes to 

amend Class D and Class E airspace in 

the south Florida area, by updating the 

geographic coordinates of the following 

airports; Fort Lauderdale-Hollywood 

International Airport, Miami-Opa Locka 

Executive Airport, (formerly Opa Locka 

Airport), North Perry Airport, Pompano 

Beach Airpark, Miami International 

Airport, Homestead ARB, Boca Raton 

Airport, Miami Executive Airport 

(formerly Kendall-Tamiami Executive 

Airport). This action would also update 

the geographic coordinates of the Fort 

Lauderdale Very High Frequency 

Omnidirectional Range Collocated with 

Distance Measuring Equipment (VOR/ 

DME), and the QEEZY Locator Outer 

Marker (LOM). This action would also 

make an editorial change replacing the 

term Airport/Facility Directory with the 

term Chart Supplement in the legal 

descriptions of associated Class D and E 

airspace. Controlled airspace is 

necessary for the safety and 

management of instrument flight rules 

(IFR) operations in the area. 

DATES: Comments must be received on 

or before August 9, 2021. 

ADDRESSES: Send comments on this 

proposal to: The U.S. Department of 

Transportation, Docket Operations, 1200 

New Jersey Avenue SE, West Building 

Ground Floor, Room W12–140, 

Washington, DC 20590–0001; 

Telephone: (800) 647–5527, or (202) 

366–9826. You must identify the Docket 

No. FAA–2021–0169; Airspace Docket 

No. 21–ASO–3, at the beginning of your 

comments. You may also submit 

comments through the internet at 

https://www.regulations.gov. 

FAA Order 7400.11E, Airspace 

Designations and Reporting Points, and 


lotter on DSK11XQN23PROD with PROPOSALS1EP25JN21.009</GPH>

Table 1 to Paragraph (g) - Compliance Time 

HPT disk, PIN 67093, cycles 

since new (CSN) as of the 

effective date of this AD 

Less than 1,000 CSN 

1,000 to 2,000 CSN 

2,001 to 3,000 CSN 

3,001 to 4,000 CSN 

4,001 or higher CSN 

Replace within HPT disk 

cycles 

1,620 CSN 

2,530 CSN 

3,245 CSN 

4,130 CSN 

130 cycles after the effective 

date of this AD