Nachrichten für Luftfahrer 2022 Teil 2 (weicht ggf. von Druckversion ab)
LUFTTÜCHTIGKEITSANWEISUNGEN
2022-2-672
Lufttüchtigkeitsanweisung Luftfahrt-Bundesamt
- Sachgebiet T12 -
D-2022-089R1 38144 Braunschweig
EASA AD 2022-0054 vom 23.03.2022 Fax: +49-531-2355-5199
email: AD@LBA.de
AIRBUS 28.03.2022
Betroffenes Luftfahrtgerät:
Art des Luftfahrtgerätes: Flugzeug
Inhaber der Musterzulassung: AIRBUS S.A.S.
Hersteller: Airbus
Muster: A350
Baureihen: A350-941 und A350-1041
Werknummern: Alle
Gerätenummer: EASA.A.151
Revisionsstand:
Diese LTA ersetzt D-2022-089 vom 23.03.2022
Airworthiness Directive der ausländischen Behörde:
EASA AD 2022-0054 vom 23.03.2022
Genannte Airworthiness Directives unter dieser Rubrik, die nicht durch die EASA herausgegeben worden sind,
wurden durch die EASA über die Entscheidung Nr. 2019/018/ED übernommen und sind somit ebenfalls Airworthin-
ess Directives der EASA.
Die genannte Airworthiness Directive wird im Luftfahrt-Bundesamt unter der Nummer 2022-089R1 geführt.
Betrifft:
(AFM) Aircraft Flight Manual - Performance Database - Amendment
Anmerkungen:
Gemäß der EU Verordnung Nr. 1321/2014, Anhang I, Teil M, Unterabschnitt C, M.A.301(f)(1), ML.A.301(d)(1),
M.A.303 und ML.A.303 dürfen Luftfahrzeuge nach dem in der Lufttüchtigkeitsanweisung angegebenen
Termin nur in Betrieb genommen werden, wenn die angeordneten Maßnahmen ordnungsgemäß durchge-
führt worden sind.
Die Europäische Agentur für Flugsicherheit (EASA) hat die oben referenzierte Lufttüchtigkeitsanweisung
EASA AD 2022-0054 vom 23.03.2022 herausgegeben oder per Entscheidung Nr. 2019/018/ED übernommen.
Gemäß § 14 Abs. 2 der Betriebsordnung für Luftfahrtgerät (LuftBO) sind diese Lufttüchtigkeitsanweisun-
gen direkt in der Bundesrepublik Deutschland gültig und bedürfen keiner Umsetzung durch das Luftfahrt-
Bundesamt.
Mit Hilfe dieser Übersichtsseite veröffentlicht das Luftfahrt-Bundesamt ebenfalls die über § 14 Abs. 2 direkt
gültigen Lufttüchtigkeitsanweisungen der EASA in den Nachrichten für Luftfahrer und im Internet unter
www2.LBA.de/LTAs/. Dieser Service dient reinen Informationszwecken und liegt keinem Verwaltungsver-
fahren zu Grunde. Rechtsmittel sind damit ausgeschlossen.
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EASA AD No.: 2022-0054
Airworthiness Directive
AD No.: 2022-0054
Issued: 23 March 2022
Note: Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation (EU)
2018/1139 on behalf of the European Union, its Member States and of the European third
countries that participate in the activities of EASA under Article 129 of that Regulation.
This AD is issued in accordance with Regulation (EU) 748/2012, Part 21.A.3B. In accordance with Regulation (EU) 1321/2014 Annex I, Part M.A.301 or
Annex Vb Part ML.A.301, as applicable, the continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently,
no person may operate an aircraft to which an AD applies, except in accordance with the requirements of that AD, unless otherwise specified by the
Agency [Regulation (EU) 1321/2014 Annex I, Part M.A.303 or Annex Vb Part ML.A.303, as applicable] or agreed with the Authority of the State of Registry
[Regulation (EU) 2018/1139, Article 71 exemption].
Design Approval Holder’s Name: Type/Model designation(s):
AIRBUS A350 aeroplanes
Effective Date: 06 April 2022
TCDS Number(s): EASA.A.151
Foreign AD: Not applicable
Supersedure: This AD supersedes EASA AD 2022-0045 dated 16 March 2022.
ATA – Aircraft Flight Manual – Performance Database – Amendment
Manufacturer(s):
Airbus
Applicability:
Airbus A350-941 and A350-1041 aeroplanes, all manufacturer serial numbers.
Definitions:
For the purpose of this AD, the following definitions apply:
The AFM revision: Any Airbus A350 Airplane Flight Manual (AFM) revision dated 29 November 2021
or later.
Reason:
It has been determined that, in the event of rapid decompression at a specific location of the
aeroplane, possible deflections of the passenger floor crossbeams may result in wiring damages,
leading to potential system losses.
This condition, if not corrected, could lead to an increase of the landing distance, exceeding the
value provided in the current in-flight failure data file for landing, and potentially resulting in a
runway excursion.
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TE.CAP.00110-010 © European Union Aviation Safety Agency. All rights reserved. ISO9001 Certified. Page 1 of 2
Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.
An agency of the European Union
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EASA AD No.: 2022-0054
To address this potential unsafe condition, Airbus revised the AFM updating the landing
performance database, and EASA issued AD 2022-0045 to require amendment of the applicable
AFM.
Since that AD was issued, it has been determined that the revision of the AFM referenced in AD
2022-0045 does not include the required amendments.
For the reasons described above, this AD supersedes AD 2022-0045, requires amending the
applicable AFM to a later revision, and to operate the aeroplane accordingly.
Required Action(s) and Compliance Time(s):
Required as indicated, unless accomplished previously:
AFM Amendment:
Within 3 months after 30 March 2022 [the effective date of EASA AD 2022-0045], implement the
AFM revision, as defined in this AD, inform all flight crews, and thereafter, operate the aeroplane
accordingly.
Ref. Publications:
Airbus A350 AFM revision dated 29 November 2021 or later.
Remarks:
1. If requested and appropriately substantiated, EASA can approve Alternative Methods of
Compliance for this AD.
2. Based on the required actions and the compliance time, EASA have decided to issue a Final AD
with Request for Comments, postponing the public consultation process until after publication.
3. Enquiries regarding this AD should be referred to the EASA Safety Information Section,
Certification Directorate. E-mail: ADs@easa.europa.eu.
4. Information about any failures, malfunctions, defects or other occurrences, which may be
similar to the unsafe condition addressed by this AD, and which may occur, or have occurred on
a product, part or appliance not affected by this AD, can be reported to the EU aviation safety
reporting system. This may include reporting on the same or similar components, other than
those covered by the design to which this AD applies, if the same unsafe condition can exist or
may develop on an aircraft with those components installed. Such components may be
installed under an FAA Parts Manufacturer Approval (PMA), Supplemental Type Certificate
(STC) or other modification.
5. For any question concerning the technical content of the requirements in this AD, please
contact: AIRBUS A350 XWB, E-mail: continued-airworthiness.a350@airbus.com.
11.04.2022
TE.CAP.00110-010 © European Union Aviation Safety Agency. All rights reserved. ISO9001 Certified. Page 2 of 2
Proprietary document. Copies are not controlled. Confirm revision status through the EASA-Internet/Intranet.
An agency of the European Union
LUFTTÜCHTIGKEITSANWEISUNGEN
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Lufttüchtigkeitsanweisung Luftfahrt-Bundesamt
- Sachgebiet T12 -
D-2022-093 38144 Braunschweig
FAA AD 2022-06-10 - Amdt. 39-21976 Fax: +49-531-2355-5199
email: AD@LBA.de
BOEING 28.03.2022
Betroffenes Luftfahrtgerät:
Art des Luftfahrtgerätes: Flugzeug
Inhaber der Musterzulassung: The Boeing Company
Hersteller: The Boeing Company
Muster: BOEING 777
Baureihen: 777-200 und 777-300
Werknummern: Betroffen sind folgende Flugzeuge:
(1) Alle 777-200 Flugzeuge, die mit Pratt & Whitney PW4074, PW4074D,
PW4077, PW4077D, PW4084D, PW4090 und PW4090-3 Triebwerken
ausgerüstet sind, und
(2) Alle 777-300 Flugzeuge, die mit Pratt & Whitney PW4090 und PW4098
Triebwerken ausgerüstet sind.
Gerätenummer: 2863, EASA.IM.A.003, FAA TCDS T00001SE
Revisionsstand:
Originalausgabe
Airworthiness Directive der ausländischen Behörde:
FAA AD 2022-06-10 - Amdt. 39-21976
Genannte Airworthiness Directives unter dieser Rubrik, die nicht durch die EASA herausgegeben worden sind,
wurden durch die EASA über die Entscheidung Nr. 2019/018/ED übernommen und sind somit ebenfalls Airworthin-
ess Directives der EASA.
Die genannte Airworthiness Directive wird im Luftfahrt-Bundesamt unter der Nummer 2022-093 geführt.
Betrifft:
(ATA 71, 78) Exhaust - Thrust Reverser Inner Wall Debris Shields - Installation // Powerplant - Fan Cowl Doors /
Hydraulic Pump Shutoff Valves - Inspection / Functional Check
Anmerkungen:
Gemäß der EU Verordnung Nr. 1321/2014, Anhang I, Teil M, Unterabschnitt C, M.A.301(f)(1), ML.A.301(d)(1),
M.A.303 und ML.A.303 dürfen Luftfahrzeuge nach dem in der Lufttüchtigkeitsanweisung angegebenen
Termin nur in Betrieb genommen werden, wenn die angeordneten Maßnahmen ordnungsgemäß durchge-
führt worden sind.
Die Europäische Agentur für Flugsicherheit (EASA) hat die oben referenzierte Lufttüchtigkeitsanweisung
FAA AD 2022-06-10 - Amdt. 39-21976 herausgegeben oder per Entscheidung Nr. 2019/018/ED übernommen.
Gemäß § 14 Abs. 2 der Betriebsordnung für Luftfahrtgerät (LuftBO) sind diese Lufttüchtigkeitsanweisun-
gen direkt in der Bundesrepublik Deutschland gültig und bedürfen keiner Umsetzung durch das Luftfahrt-
Bundesamt.
Mit Hilfe dieser Übersichtsseite veröffentlicht das Luftfahrt-Bundesamt ebenfalls die über § 14 Abs. 2 direkt
gültigen Lufttüchtigkeitsanweisungen der EASA in den Nachrichten für Luftfahrer und im Internet unter
www2.LBA.de/LTAs/. Dieser Service dient reinen Informationszwecken und liegt keinem Verwaltungsver-
fahren zu Grunde. Rechtsmittel sind damit ausgeschlossen.
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LUFTTÜCHTIGKEITSANWEISUNGEN
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[Federal Register Volume 87, Number 48 (Friday, March 11, 2022)]
[Rules and Regulations]
[Pages 13930-13935]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-05309]
––––––––––––––––––––––––––––––––––
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0962; Project Identifier AD-2021-00997-T; Amendment 39-21976; AD
2022-06-10]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
––––––––––––––––––––––––––––––––––
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain The Boeing
Company Model 777-200 and -300 series airplanes. This 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 AD). This AD requires installation of debris shields on
the thrust reverser (T/R) inner wall at the left and right sides of the lower bifurcation, inspection of
the fan cowl doors for moisture ingression, 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 FAA is issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective April 15, 2022.
The Director of the Federal Register approved the incorporation by reference of certain
publications listed in this AD as of April 15, 2022.
ADDRESSES: 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: help24@prattwhitney.com;
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. It is also available
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at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0962.
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Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by searching for and locating
Docket No. FAA-2021-0962; 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: James Laubaugh, Aerospace Engineer,
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198;
phone and fax: 206-231-3622; email: james.laubaugh@faa.gov.
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 certain The Boeing Company Model 777-200 and -300 series airplanes.
The NPRM published in the Federal Register on December 28, 2021 (86 FR 73712). The NPRM was
prompted by reports of three incidents involving in-flight fan blade failures on certain Pratt &
Whitney engines. In the NPRM, the FAA proposed to require installation of debris shields on the T/R
inner wall at the left and right sides of the lower bifurcation, inspection of the fan cowl doors for
moisture ingression, 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 FAA is issuing this
AD to address the airplane-level implications of the unsafe condition of engine fan blade failure. 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 engine in-flight
shutdown, and could result in separation of the inlet, the fan cowl doors, or the T/R cowl, or result in
uncontrolled engine fire. Separation of the inlet, the fan cowl doors, or the T/R cowl could result in
impact damage to the empennage and loss of control of the airplane, or to the fuselage or windows
with potential injury to passengers; or it could result in significantly increased aerodynamic drag
causing fuel exhaustion or the inability to maintain altitude above terrain during extended operations
(ETOPS) flights, either of which could result in a forced off-airport landing and injury to passengers.
Uncontrolled engine fire could result in loss of control of the airplane.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from The Air Line Pilots Association, International (ALPA) who
supported the NPRM without change.
The FAA received additional comments from five commenters, including All Nippon Airways
(ANA), Boeing, Japan Airlines (JAL), United Airlines (UAL), and an individual. The following
presents the comments received on the NPRM and the FAA's response to each comment.
Request To Clarify Certain Sentences in the “Background” Paragraph
Boeing requested that the “Background” paragraph in the NPRM be revised to clarify that the
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failed hydraulic pump shutoff valve was not the direct cause of the uncontained engine fire. Boeing
stated that flight data indicates that while the hydraulic pump shutoff valve failed to close, no
hydraulic fluid was leaked from the system until well after the engine fire initiated.
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Boeing proposed that two sentences in the “Background” paragraph of the NPRM be revised to,
“Several flammable fluid lines, the engine accessory gearbox, and T/R structure were fractured and
an uncontained engine fire occurred. The hydraulic pump shutoff valve failed to close when the fire
handle was pulled, contributing additional flammable fluid to the T/R area.” Boeing commented that
the proposed wording recognizes that the failure may have contributed additional flammable fluid to
the T/R area, but that it did not directly cause the uncontained fire.
The FAA agrees with the commenter's clarification and did not intend to imply that the failed
hydraulic pump shutoff valve was the direct cause of the uncontained engine fire. However, the
detailed background information, which includes the sentences that the commenter proposed for the
“Background” paragraph, are not carried over into the final rule. The FAA has not changed this final
rule in this regard.
Request To Use Certain Service Information as a Method of Compliance
ANA requested clarification on whether Boeing Alert Service Bulletin 777-71A0092, dated
January 13, 2022, and Boeing Alert Service Bulletin 777-78A0103 will be allowed as an alternative
method of compliance for the requirements in the proposed AD.
In addition, for the actions in paragraph (g) of the proposed AD, Boeing and UAL requested the
use of Boeing Alert Service Bulletin 777-78A0103 for installing debris shields on the T/R inner wall
at the left and right sides of the lower bifurcation. Boeing and UAL also proposed the use of Boeing
Alert Service Bulletin 777-71A0092, dated January 13, 2022, for inspecting the fan cowl doors for
moisture ingression. Boeing stated that the description of the modification in the proposed AD is
vague.
The FAA agrees to allow the use of Boeing Alert Requirements Bulletin 777-71A0092 RB,
dated January 13, 2022, for the inspection of the fan cowl doors for moisture ingression. The FAA
has revised the “Related Service Information under 1 CFR part 51” paragraph and paragraph (g)(2) of
this AD accordingly. The FAA disagrees with allowing the use of Boeing Alert Service Bulletin 777-
78A0103 for the actions specified in paragraph (g)(1) of this AD because the service bulletin is not
yet an FAA-approved service bulletin.
Request To Add Certain Exceptions for Ferry Flights
JAL requested that the FAA revise the AD to include certain exceptions for ferry flights. JAL
stated it is planning to ferry affected airplanes to a storage point in the United States. JAL commented
that although the local authority in Japan provides regulatory requirements for special flight
permissions which are similar to 14 CFR 21.197, Special flight permits, the Japanese regulatory
requirements do not include “to a point of storage” language for the purpose of the flights. JAL
proposes to add the following wording to paragraphs (c) and (g) of the proposed AD, “except for
ferry flights, without passenger and cargo, of the airplanes on which the actions specified in
paragraphs (h)(1) and (2) of this AD have been done.”
The FAA disagrees with revising paragraph (c) Applicability or paragraph (g) Required Actions
of this AD in response to JAL's comment. Paragraph (i), Special Flight Permit, provides that special
flight permits, as described in 14 CFR 21.197 and 21.199, are permitted provided that the actions in
paragraphs (h)(1) and (2) of this AD have first been accomplished. 14 CFR 21.197(a)(1) provides, in
relevant part, that a special flight permit may be issued for flying the aircraft to a base where repairs,
alterations, or maintenance are to be performed, or to a point of storage. The requested change is
already permitted by this AD. The FAA did not change this AD as a result of this comment.
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Request To Change the Initial Compliance Time to Before Revenue Flight
ANA requested that in paragraph (g) of the proposed AD, the FAA update the initial compliance
time of “before further flight after the effective of this AD” to “before the next revenue flight” to
clarify the ferry flight requirement.
Similarly, JAL requested that in paragraph (g) of the proposed AD, the FAA update the initial
compliance time of “before further flight after the effective of this AD” to “before the next revenue
flight” or “before further flight except the ferry flight without passenger and cargos.”
The FAA disagrees with revising the initial compliance in paragraph (g) of this AD as requested
by ANA and JAL. The FAA has determined it is necessary to require certain actions prior to any
flight, except as permitted in paragraph (h), Special Flight Permit, of this AD.
Request To Add a Note for Airplanes Under Storage or Heavy Check
JAL requested that the FAA add a note to paragraph (g)(3) of the proposed AD to clarify that the
repetitive functional checks are not applicable to airplanes under storage or heavy check.
The FAA partially agrees with the commenter. The FAA did not intend for the repetitive
functional checks of the left and right hydraulic pump shutoff valves to be performed every 10 days
when the airplane is not flown. The FAA has revised the compliance time in paragraph (g)(3) of this
AD to specify that the repetitive functional check is only required within 10 days prior to each flight.
The FAA disagrees that a note is necessary to specify that the functional check is not applicable to
airplanes under storage or heavy check because of the previously discussed revisions to paragraph
(g)(3) of this AD.
Request To Clarify the Use of Revised Non-Destructive Inspection Procedure (NDIP)
Documents
JAL requested clarification for the use of revised NDIP documents for the flow path ultrasonic
(UT) inspection of the 1st-stage LPC blades specified in paragraph (h)(1) of the proposed AD. JAL
commented that Pratt & Whitney Alert Service Bulletin PW4G-112-A72-361, dated October 15,
2021, references the UT inspection procedures in NDIP-1238, NDIP-1240, and NDIP-1241, which
are currently at the original version. JAL asked if the submission of an alternative method of
compliance (AMOC) request is necessary if the NDIPs are later revised to meet the requirements in
paragraph (h)(1) of the proposed AD.
The FAA acknowledges that Pratt & Whitney Alert Service Bulletin PW4G-112-A72-361, dated
October 15, 2021, requires the latest FAA-approved revision of NDIP-1238, NDIP-1240, and NDIP-
1241 at the time the inspection is accomplished. Furthermore, the FAA has provided credit for
accomplishment of the flow path UT inspection identified in paragraph (h)(1) of this AD using the
service information specified in paragraph (i) of this AD.
Request To Provide a Threshold for the Special Flight Permit
JAL and UAL requested that the FAA provide a threshold in paragraph (h)(1) of the proposed
AD for the last flow path UT inspection. JAL suggested a threshold of 275 flight cycles since the last
flow path UT inspection for 1st-stage LPC blades that have zero cycles since new and also for 1st-
stage LPC that have accumulated any number of cycles since new greater than zero.
UAL stated that omitting a compliance time in paragraph (h) of the proposed AD for the special
flight permits creates ambiguity regarding when and how often the flow path UT inspection is
required for special flight permits. UAL suggested a threshold of 275 flight cycles since the last flow
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path UT inspection.
The FAA agrees to add a threshold of 275 cycles to paragraph (h)(1) of this AD, which is
specified in Pratt & Whitney Alert Service Bulletin PW4G-112-A72-361, dated October 15, 2021.
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This allows airplanes with 1st-stage LPC blades that have accumulated 275 cycles since new or fewer
to be eligible for a special flight permit.
Request To Add Aircraft Maintenance Manual Task to Special Flight Permit
ANA, JAL, and UAL requested that paragraph (h)(2) of the proposed AD include Task 29-11-
00-710-806 of the Boeing 777-200/300 Aircraft Maintenance Manual as an acceptable method for
accomplishing the functional check of the left and right hydraulic pump shutoff valves.
The FAA agrees with the commenter's request and has added Task 29-11-00-710-806 of Boeing
777-200/300 Aircraft Maintenance Manual to the “Other Related Service Information” paragraph and
to Note (1) to paragraph (g)(3) of this AD as guidance for accomplishing the actions required by
paragraphs (g)(3) and (h)(2) of this AD.
Request To Clarify Requirements in the NPRM
ANA requested that the FAA provide clarification of why affected operators will have to conduct
required periodic testing [repetitive functional checks of the left and right hydraulic pump shutoff
valves] even though Boeing recommends similar testing to be performed as a one-time check before
return-to-service per Boeing MOM-MOM-21-0398-01B. ANA also requested clarification whether
the repetitive 10 day interval continues until a terminating action has been found.
The FAA infers that ANA considers the low average failure rate per flight hour of the hydraulic
pump shutoff valve in service to justify the performance of the one-time check of the hydraulic pump
shutoff valve described in the Boeing MOM-MOM-21-0398-01B, combined with the existing
maintenance program recommendation to check the function of the hydraulic pump shutoff valve at
18,000 flight hour intervals, as providing an acceptable level of safety. The FAA does not agree.
Investigation of the February 2021 incident, as specified in the proposed AD, revealed that the
hydraulic pump shutoff valve, which is remotely controlled by electrical switches, does not have an
indication to the flightcrew to indicate when the hydraulic pump shutoff valve has failed to move to
the commanded position. The hydraulic pump shutoff valve failed to close when commanded via the
engine fire handle in that incident. Failure of this hydraulic pump shutoff valve to close in response to
commands in the event of an engine fire could lead to flammable fluid continuing to be supplied to an
engine fire for a prolonged period, potentially resulting in an uncontained fire that jeopardizes flight
safety. The FAA has determined that this issue is an unsafe condition requiring corrective action.
For transport airplanes, the determination that an unsafe condition exists is based on several
criteria, and the failure to meet one or more of the criteria could lead the FAA to determine that
corrective action is warranted.
For each identified potential safety issue on a transport airplane, the FAA examines the risk on
the worst reasonably anticipated flights (flights actually predicted to occur) to ensure that each flight
provides an acceptable level of safety (identified as “individual flight risk” in FAA risk analysis
policy). That acceptable level of safety consists of three basic expectations:
That each flight begins in a fail-safe state (including consideration of latent failure conditions
and allowed dispatch states under the minimum equipment list (MEL)), meaning that a
foreseeable single failure on any anticipated flight should not have a significant likelihood of
causing a catastrophic event.
That each flight does not have a numerical risk of a catastrophic event due to the issue being
examined that is excessively (an order of magnitude or more) greater than the risk of a
catastrophic event on an average transport airplane.
That safety features that were prescriptively required due to lessons learned from past
incidents and accidents are not excessively reduced in their effectiveness or availability.
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Failure to meet any of these three criteria can lead to a determination that an unsafe condition
exists and AD action is necessary, because the level of safety on the affected flights does not meet the
FAA's thresholds for an acceptable level of safety on individual flights.
For each identified potential safety issue, the FAA also assesses the total cumulative risk of an
event occurring at any time in the remaining life of the fleet of affected airplanes (identified as “total
fleet risk” in FAA risk analysis policy). The FAA may determine that corrective action is needed to
limit total fleet risk even when the assessed individual flight risk does not violate any of the three
individual flight risk criteria discussed above. Total fleet risk is typically assessed by multiplying the
average probabilities of each of the failures or other factors that contribute to the occurrence of an
event, the total number of airplanes affected, the average utilization of those airplanes, and the
average remaining life for those airplanes. The FAA also considers the number of occupants of an
aircraft in assessing fleet risk, and applies total fleet risk guideline thresholds expressed in terms of
both aircraft accidents and number of fatalities.
Either excessive individual flight risk or excessive total fleet risk, or both, can lead the FAA to
determine that an unsafe condition exists that requires corrective action. The FAA does not use or
accept calculations of acceptable total fleet risk, or acceptable average per-flight-hour risk, as a
justification for taking no action on issues where an excessive individual flight risk is determined to
exist on flights that are anticipated to occur.
In this case, the FAA determined that corrective action is necessary under the individual flight
risk guideline above to minimize the occurrence of flights that are not fail safe for an engine fire due
to latent failure of the hydraulic pump shutoff valve. The repetitive functional check will minimize
the number of flights that occur with a latent failure of the hydraulic pump shutoff valve. The FAA
determined that the 10-day interval for the inspections required by paragraph (g) of this AD is
practical and provides an acceptable level of safety.
Additionally, regarding the commenter's request as to whether the repetitive 10-day interval
continues until a terminating action has been found, the FAA has determined that the repetitive
functional check of the left and right hydraulic pump shutoff valves is required until an alternative
corrective action is approved.
Request for Credit for Previous Actions
UAL requested that Boeing Alert Service Bulletin 777-71A0092, dated January 13, 2022, and
Boeing Alert Service Bulletin 777-78A0103 be added to paragraph (i) of the proposed AD as credit
for actions that were previously accomplished in paragraph (g)(1) and (2) of the proposed AD. UAL
also requested that credit be given in paragraphs (i)(2) and (3) of the proposed AD for doing a mid
span UT inspection, in addition to providing credit for doing a flow path UT inspection.
The FAA partially agrees with the commenter's requests. The FAA has not yet approved a
method of compliance for paragraph (g)(1) of this AD using a specific service bulletin, and therefore,
credit cannot be provided. As previously mentioned the FAA has revised paragraph (g)(2) of this AD
allowing for accomplishment of the inspection using Boeing Alert Requirements Bulletin 777-
71A0092 RB, dated January 13, 2022 (original revision), and therefore, credit is not necessary.
Although Pratt & Whitney Special Instruction No. 130F-21, dated July 1, 2021, and Pratt & Whitney
Special Instruction No. 130F-21, Revision A, dated July 28, 2021, include instructions for a mid span
UT inspection, the special flight permit paragraph in this AD does not include a requirement for the
mid span UT inspection, and therefore, credit is not necessary. However, the FAA has retained the
credit specified in paragraph (i) of this AD for doing the flow path UT inspection.
Request To Delegate AMOCs
11.04.2022
UAL requested that if Boeing Alert Service Bulletin 777-71A0092, dated January 13, 2022, and
Boeing Alert Service Bulletin 777-78A0103 become a FAA-approved method of compliance, the
FAA should delegate The Boeing Company Organization Designation Authorization (ODA)
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