[Federal Register Volume 86, Number 246 (Tuesday, December 28, 2021)]
[Proposed Rules]
[Pages 73688-73690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-27839]
[[Page 73688]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0963; Project Identifier AD-2021-01026-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain The Boeing Company Model 777-200 and -300 series airplanes.
This proposed AD was prompted by reports of three incidents involving
in-flight fan blade failures on certain Pratt & Whitney engines (``fan
blades'' are also known as ``1st-stage low-pressure compressor (LPC)
blades''--these terms are used interchangeably in this proposed AD).
This proposed AD would require modifying the engine inlet to withstand
fan blade failure event loads. 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 Boeing service information identified in this NPRM, contact
Boeing Commercial Airplanes, Attention: Contractual & Data Services
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600;
telephone 562-797-1717; internet https://www.myboeingfleet.com. For
Pratt & Whitney 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, 2200
South 216th St., Des Moines, WA. For information on the availability of
this material at the FAA, call 206-231-3195.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0963; 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: Luis Cortez-Muniz, Aerospace Engineer,
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des
Moines, WA 98198; phone and fax: (206) 231-3958; 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-2021-0963; Project Identifier
AD-2021-01026-T'' 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 Luis
Cortez-Muniz, Aerospace Engineer, Airframe Section, FAA, Seattle ACO
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax:
(206) 231-3958; email: [email protected]. 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 has received reports of three incidents involving in-flight
fan blade failures and shutdowns on certain The Boeing Company Model
777-200 and 777-300 series airplanes equipped with Pratt & Whitney
(P&W) Model PW4000 series turbofan engines. The two most recent events
occurred in December 2020 and February 2021. In the latter incident,
the engine fan blade failure occurred during climb at approximately
13,000 feet. While the engine fan blade failure was contained by the
fan case, the event loads caused structural failures that resulted in
the inlet (inlet lip, inner and outer barrel, and aft bulkhead) and fan
cowl doors separating from the engine and airplane. The resultant
separated engine and nacelle parts caused damage to the wing and
fuselage. Several flammable fluid lines, the engine accessory gearbox,
and thrust reverser (T/R) structure were fractured. The hydraulic pump
shutoff valve failed to close when the fire handle was pulled,
contributing additional flammable fluid to the engine nacelle and T/R
resulting in an uncontained engine fire.
In the December 2020 incident, the engine fan blade failure
occurred during climb at approximately 15,000 feet. While the engine
fan blade failure was contained by the fan case, the event loads caused
structural failures that resulted in the fan cowl doors separating from
the engine and airplane. The resultant separated engine and nacelle
parts caused damage to the left side horizontal stabilizer and
fuselage. The engine accessory gearbox and T/R attachment to the engine
were also fractured.
In the earliest incident, which occurred in 2018, the engine fan
blade failure occurred just after beginning the descent. While the
engine fan blade failure was contained by the fan case, the event loads
caused structural failures that resulted in the inlet (inlet
[[Page 73689]]
lip, inner and outer barrel, and aft bulkhead) and fan cowl doors
separating from the engine and airplane. The resultant separated engine
and nacelle parts caused damage to the right side horizontal
stabilizer, wing and fuselage.
Upon the occurrence of the February 2021 in-flight engine fan blade
failure, the FAA issued an Emergency AD 2021-05-51, Amendment 39-21470
(86 FR 13445, March 9, 2021), requiring inspection of the engine fan
blades for cracking and removal from service if any cracking is found.
Since the two most recent incidents and issuance of that Emergency AD,
the FAA, Boeing, and P&W have continued to examine the airplane and
engine design, along with the information provided through the incident
investigations, to determine if further action is necessary. The FAA
has determined that further action is necessary to address the
airplane-level implications and unsafe condition resulting from in-
flight engine fan blade failures. Fan blade failures can cause fan
rotor imbalance and result in fan blade fragments penetrating the inner
and outer barrel of the inlet. This condition, if not addressed, could
result in the separation of inlet and fan cowl doors and the T/R cowl.
This could lead to engine in-flight shutdown, impact damage to the
empennage, fuselage, or window, with significantly increased
aerodynamic drag causing fuel exhaustion or the inability to maintain
altitude during operations under extended-range twin-engine operational
performance standards (ETOPS) missions, which could result in loss of
control of the airplane, a forced off-airport landing, and injury to
passengers.
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 Under 1 CFR Part 51
The FAA reviewed Pratt & Whitney Alert Service Bulletin PW4G-112-
A72-361, dated October 15, 2021. This service information specifies
procedures for performing thermal acoustic image and ultrasonic testing
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.
Related Service Information
The FAA reviewed 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 a functional check of the engine-driven pump shutoff
valve.
Proposed AD Requirements in This NPRM
This proposed AD would require modifying the engine inlet to
withstand fan blade failure event loads in accordance with a method
approved by the Manager, Seattle ACO Branch, FAA. The modification
includes an inspection of the inlet outer barrel for moisture
ingression and repair if necessary, adding ballistic shielding and
support structure to the inlet outer barrel, revising the outer cowl
aft row fasteners, adding support structures to the aft bulkhead, and
revising the inlet attach-ring to A-flange engine bolts and associated
barrel nuts.
Explanation of Special Flight Permit Paragraph
This proposed AD is related to NPRM Docket Number FAA-2021-0959,
which proposes to require initial and repetitive ultrasonic testing
(UT) inspections and thermal acoustic image inspections for cracks in
certain 1st-stage LPC blades and removal of those blades that fail
inspection. This proposed AD is also related to NPRM Docket Number FAA-
2021-0962, which proposes to require, among other actions, repetitive
functional checks of the hydraulic pump shutoff valves to ensure they
close in response to the fire handle input, and corrective actions if
necessary. The special flight permit paragraphs in those proposed ADs
are similar to the one in this proposed AD. The special flight permit
paragraph includes a limitation requiring that the following actions
have been done before the special flight is permitted: A flow path UT
inspection of the 1st-stage LPC blades for cracking and the 1st-stage
LPC blades have been found serviceable, and a functional check of the
left and right hydraulic pump shutoff valves to ensure they close in
response to the fire handle input within 10 days prior to flight.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 54 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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Modification.......................... 660 work-hours x $85 per $362,560 $418,660 $22,607,640
hour = $56,100.
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The FAA has received no definitive data on which to base the cost
estimates for the on-condition repairs that are part of the
modification specified in this proposed AD.
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,
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(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:
The Boeing Company: Docket No. FAA-2021-0963; Project Identifier AD-
2021-01026-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by January 27, 2022.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company airplanes, certificated in
any category, as specified in paragraphs (c)(1) and (2) of this AD.
(1) Model 777-200 series airplanes equipped with Pratt & Whitney
PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3
model turbofan engines.
(2) Model 777-300 series airplanes equipped with Pratt & Whitney
PW4090 and PW4098 model turbofan engines.
(d) Subject
Air Transport Association (ATA) of America Code 54, Nacelles/
pylons.
(e) Unsafe Condition
This AD was prompted by reports of three incidents involving in-
flight fan blade failures on certain Pratt & Whitney engines. The
FAA is issuing this AD to address engine fan blade failure, which
could result in the separation of inlet and fan cowl doors and the
thrust reverser (T/R) cowl. This could lead to engine in-flight
shutdown, impact damage to the empennage, fuselage, or window, with
significantly increased aerodynamic drag causing fuel exhaustion or
the inability to maintain altitude during operations under extended-
range twin-engine operational performance standards (ETOPS)
missions, which could result in loss of control of the airplane, a
forced off-airport landing, and injury to passengers.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Modification
Before further flight after the effective date of this AD,
modify the engine inlet to withstand fan blade failure event loads,
in accordance with a method approved by the Manager, Seattle ACO
Branch, FAA.
(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 ultrasonic testing (UT) inspection of the 1st-
stage low-pressure compressor (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 Pratt & Whitney Alert Service Bulletin
PW4G-112-A72-361, dated October 15, 2021, 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 (1) 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
paragraph (h)(1) of this AD, if those actions were performed before
the effective date of this AD using the service information
specified in paragraph (i)(1), (2), or (3) of this AD.
(1) Paragraph 2. of the Accomplishment Instructions of Pratt &
Whitney Special Instruction No. 85F-21, dated May 12, 2021, for a
flow path UT inspection.
(2) Paragraph 1.a) of the Accomplishment Instructions of Pratt &
Whitney Special Instruction No. 130F-21, dated July 1, 2021, for a
flow path UT inspection.
(3) Paragraph 2.a) of the Accomplishment Instructions of Pratt &
Whitney Special Instruction No. 130F-21, Revision A, dated July 28,
2021, for a flow path UT inspection.
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Seattle ACO 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 responsible Flight Standards 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. Information may be
emailed to: [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.
(k) Related Information
(1) For more information about this AD, contact Luis Cortez-
Muniz, Aerospace Engineer, Airframe Section, FAA, Seattle ACO
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax:
(206) 231-3958; email: [email protected].
(2) For Boeing service information identified in this AD,
contact Boeing Commercial Airplanes, Attention: Contractual & Data
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA
90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. For Pratt & Whitney 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, 2200
South 216th St., Des Moines, WA. For information on the availability
of this material at the FAA, call 206-231-3195.
Issued on December 14, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-27839 Filed 12-22-21; 11:15 am]
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